Chemical Constituents of Neem

 

1. Therapeutic and chemical properties of neem oil and neem extract / margosa oil and margosa extract are described. Oil contains bitter substances namely nimbin mp. 1920, nimbidin, mp. 900 and nimbidol (Seifen - Oele-Fette-Wachse 1963,59,894); a paraffin alcohol, sugiol and a new oxophenol, nimbiol, mp. 2500 in addition to known nimbosterol, mp. 820, isolated from trunk bark (Tetrahedron 1960,10,45); structure of nimbin, mp. 2040, was elucidated; nimbidic acid, mp. 2590, was isolated (Tetrahedron 1960, 11, 67; Chem Ind. 1964, 322); synthesis of degradation products of nimbiol were reported (J. Sci. Ind. Res. 1962, 21, 50; J. Org. Chem. 1975,40,3686); tetranortriterpenoids, epoxyazadiradione, mp. 1990, azadiradione and azadirone were isolated from from seed oil (Chem. Commun. 1967,278); a new meliacin, nimbolide, mp. 2450 was isolated from leaves (Chem. Commmun. 1967, 808); The seed oil yielded meliantriol, m.p. 1760,(Chem. Commun. 1967,910); deacetylnimbin mp. 208 was reported from seed and bark (Indian J. Chem. 1967,5,460); quercetin and b-sitosterol from leaves (J. lndian Chem. Soc. 1968,45,466), cyclolucalenol, mp. 1350 , 24 methylenecycloartanol, mp. 1150 and b-sitosterol from wood oil of West African tree (Chem. lnd. 1968, 1808), a new tetranortriterpenoid, meldenin, mp. 2400 from seed oil (Tetrahedron Lett. 19689 437), nimbolin A, mp. 1800, nimbolin B, mp. 2430 from trunk wood (Chem. Commun. 1969, 1166) and vepinin from oil were isolated (Indian J. Chem. 1969, b, 187).

 

2. A new tetranortriterpene, nimbidinin was isolated from amorphous bitter principle (nimbin) of seeds and characterised; nimbidic acid was found to be identical to salannic acid (Tetrahedron Left. 1970, 2761; Phytochemistry 1971, 10, 857); limonoids, azadirone, azadiradione and epoxyazadiradione, mp.2020, [a]D + 4, - were isolated and structures elucidated (Tetrahedron 1971, 27, 3927; Z Naturforsch. 1975, 30B, 961); b-sitosterol- b-D-glucoside, n-hexacosanol, b-carotene from leaves were isolated (Phytochemistry 1971,10, 2842); a new myricetin glycoside, melicitrin along with quercetin-3-galactoside and kaempferol-3- glucoside were isolated from flowers and characterised as myricetin- 3'-L-arabinoside (Indian J. Chem. 1972,10,452); a triterpenold, azadirachtin was isolated from fruits (Phytochemistry 1973, 12, 391); kulinone, kulactone, kulolactone and methyl kulonate were isolated from bark (Tetrahedron 1973, 29, 1911); 6b-hydroxy- 4- stigmasten-3-one (I) and 6b-hydroxy-4-campesten-3-one (II) were isolated from bark and their structures confirmed by partial synthesis (Phytochemistry 1973, 12,903); a new hexacyclic tetranortriterpenoid, vilasinin was isolated and its structure established (Chem. Lett. 1974, 357);,b-sitosterol and 24-methylenecycloartanol were isolated from the heartwood (Indian J. Appl. Chem. 1970, 33, 384) along with two new meliacians, melianin A and melianin B whose structures were determined; cycloeucalenone, fraxinellone, azedaric acid, nimbolin A, gedunin, 7-deacetyl-7-oxogedunin were also isolated (J. Chem. Soc. Perkin 1 1975, 1352).

 

3. Stereostructure of melianone, having 23R,24S configuration was established (Chem. Commun. 1975, 517); isolation and characterisation of an isomer of epoxyazadiradione was reported, [a]D - 720, from fruit pulp (Chem. Ztg. 1975, 99,504); quercetin-3-0-L-rhamnoside and quercetin-3-0-rutinoside from leaves were reported (Indian J. Chem. 1975, 13, 527); azadirachtin and salanin from berries were isolated; structure of azadirachtin was established (Recent Adv. Phytochemistry. 1975, 9,283); b-sitosterol-O-D-glucoside, 4,14a-dimethyl-5a-ergosta-8,24(28)-dien-3b-ol and 4a-methyl-a-ergosta-8,24(28)-dien-3b-ol were isolated from heartwood (Fitoterapia 1977, 48, 166); structure of a new compound, 17b-hydroxyazadiradione isolated from fruit pulp was established (Tetrahedron Lett. 1978, 611); 24-methylenecycloartanone,cycloeucalenone, 24-methylenecycloartanol, cycloeucalenol, 4-stigmasten-3-one, 4-campesten-3-one, triacontanol, vanillic aldehyde, trans-cinnamic acid and vanillic acid were reported from roots. 21,23:24,25-Diepoxytirucall-7-en-21-ol was isolated from fruits(Planta Med. 1979, 35, 76); structures of two new constituents, 17-epi- azadiradione and 17b-hydroxyazadiradione were established (Tetrahedron Lett. 1978, 2395); isolation of a glycopeptide by pronase digestion of neem gum was reported and it contained arabinose, galactose and glucosamine in ratio of 2.69:2.0:4.9 and asparagine, serine, threonine, arginine, proline, valine, phenylalanine and tyrosine (Indian J. Biochem. Biophys. 1978, 15 '449); scopoletin, 6-hydroxy-7-methoxycoumarin, aesculetin, cinnamic acid, b-sitosterol, campesterol, two unidentified sterols and tiglic acid were isolated from oil(Pharmazie 1979,34,106; Indian J. Chem. 1979, 17B, 169).

 

4. New meliacin, salannolide was isolated and its structure elucidated (Phytochemistry 1984, 23, 2383); isolation of nimocinol from leaves and its characterisation as 6a-hydroxyazadirone have been reported (Phytochemistry 1984,23, 2899); and negative ion MS of epoxyazadiradione, gedunin, nimbolide, deacetyinimbin and nimbin were reported (Indian J. Chem. 1984, 23B, 1082); a new limonoid, deacetyl- azadirachtinol was isolated and its structure established (Tetrahedron Lett. 1984, 25, 4729; Tetrahedron 1986, 42, 489); structure of azadirachtin was revised based on its NMR studies(FE.C.S. Int. Conf. Chem. Biotechnol. Biol. Act. Nat. Prod. 3rd, 1985, 446; Chem. Commun. 1985,968); (Tetrahedron Lett. 1985,26,6435; Chem. Commun. 1986, 46; Tetrahedron 1987, 43, 2789); a new meliacin, 4-epinimbin was isolated from seeds (Indian J. Chem. 1985,24B, 1105); and azadirachtol was reported from fruits (Planta Med. 1985, 51, 478); 2',3'-dehydrosalannol from leaves (Phytochemistry 1985, 24, 866), and a new limonoid, azadirachtanin from leaves (Heterocycles 1985, 23, 2321) were isolated and characterised.

 

5. Azadirachtin,salannin,6-0-acetylnimbandiol and 3-desacetylsalannin were isolated from fruit (Tetrahedron 1986, 42, 489); a new g-hydroxybutenolide,a tetranortriterpenoid, isonimbocinolide was isolated from acidic fraction of fresh leaves and its structure determined (Heterocycles 1986,24,1319); isolation and structure elucidation of margosinolide and isomargosinolide (Tetrahedron 1986, 42, 4849), new meliacins, nimocinolide, isonimocinolide from flesh leaves and nimocin from fruits were reported; azadirone, gedunin, azadiradione, epoxyazadiradione, 7-deacetyl-7-benzoylazadiradione, 17- hydroxyazadiradione, b-sitosterol and cholesterol were also isolated (J. Chem. Soc. Perkin 1 1986, 1021; Z. Naturforsch. 1986, 41B, 922); a new limonoid, nimbocinol was isolated from ripe fruits (Z. Naturforsch. 1986,41B, 922) desacetylnimbinolide and desacetylisonimbinolide were isolated and structure established along with isolation of desacetyinimbin (J. Nat. Prod. 1986, 49, 1068); a new tetranortriterpenoid, isoazadirolide from fresh leaves along with known scopoletin, (Heterocycles 1986, 24, 3163) and a new triterpenoid nimolinone from fresh, uncrushed, ripe fruits (J. Chem. Soc.,Pak. 1986,8,341 were reported, nimbocinone was isolated from fresh winter leaves; known compounds sitosterol and stigmasterol were reported (Phytochemistry 1986,25,2183); isonimolide and isonimbolide from twigs (Heterocycles 1987, 26, 1827), isonimolicinolide and nimolicinoic acid from fruits (J. Chem. Soc. Perkin 1 1987, 1429), salannolactam(21) and salannolactam-(23) from seed kernels (Ana. Chem. 1987, 337) and 7-deacetyl-17a-hydroxy- azadiradione from seeds were isolated and structures determined (Phytochemistry 1988,27, 2773); 24-methylenecycloartanol, nimbin, azadirone, gedunin, protein bound amino acids, glucose, fructose, mannose, xylose and b-sitosterol were isolated from stem exudate (Curr Sci. 1988,57, 550); a new secotetranortriterpenoid, isonimbinolide from bark (Phytochemistry 1988, 27, 1801), nimbocinolide from leaves (Heterocycles 1989, 29, 87), nimbanal and salannol-3-acetate from seeds (Phytochemistry 1989, 28, 203) were isolated and characterised. Isolation and structure determination of nimbolicin from root bark and nimbolin B were reported (Heterocycles 1989,29, 729); 1,3-diacetyl-11,19-deoxa-11-oxomeliacarpin (I) from seeds (Tetrahedron Lett. 1989, 30, 1797) was isolated and its structure established.

 

6. Nimbidiol was isolated from root bark and its structure determined (Phytochemistry 1987,26, 3021) and its synthesis was reported (Indian J. Chem. 1988,27B, 103); new diterpenoids, nimbionone and nimbionol were isolated from bark (Phytochemistry 1988,27, 3903);similarly nimbione and nimbinone were isolated from bark and (Phytochemistry 1988,27,1801); nimosone, nimbosone and methyl nimbionone were isolated from stem bark and structures established (J. Nat. Prod. 1988, 51, 10-54); isolation and structure determination of new-diterpenoids, margolone, margolonone and isomargolonone were reported from stem bark (J. Chem. Soc. Perkin 1 1989, 343); nimbonone and nimbonolone were isolated from stem bark together with methyl grevillate (Phytochemistry 1989,28,1177).

 

7. An isoprenylated flavanone nimbaflavone was isolated from leaves and characterised (Phytochemistry 1984, 23, 2115); two new water-soluble polysaccharides , GIII DO'2 la and Glll DO'2 lla were isolated from bark; GIII DO'2 la was partially characterised as branched fucogalactoglucoarabinan (Shoya-kuga-Ku Zasshi 1984,38,334); antitumor polysaccharide N9GI, was isolated from bark and was shown to be a mixture of N9G1a and N9G1b; former contained glucan and arabinose (5: 1) while the latter contained glucan, fucose and arabinose (5:2-.1) (Jpn. 6,042,329 (1985) Mar. 06; Chem. Abstr 1985, 103, 200865 t); nimbochalcin and nimbocectin were isolated from fruits along with 5-hydroxymethylfurfural and their structures determined; quercetin, its glycoside and isorhamnetin were isolated from leaves (Pakistan J. Sci. Ind. Res. 1985,28, 1); 24-methylenclophenol was isolated from heartwood (Phytochemistry 1987, 26, 2644); viscous steam distillate of fresh leaves was found to contain mixture of cyclic tri- and tetrasulphides of C3, C5, C6 and C9 units by GC-MS (Fitoterapia 1986,57,302); a water- soluble polysaccharide, CSP-1 was isolated from bark, and it composed of galactose, arabinose and glucose in ratio of 4:2:1 and having (13) Iinked galactopyranosyl backbone (Chem. Pharm. Bull. 1936,26,54); detection of di-n-propyl and n-propyl-l-propenyl di-, tri- and tetrasulphides in seeds by GC-MS and di-n-propyl disulphide present as major constituent (75.74%) was carried out (J. Affic. Food Chem. 1988,36,1048); quercetin-3-0-b-D-glucoside, -3-0-rutinoside and -3-0-b-L-rhamnoside, kaempferol-3-0-rutinoside and -3-0-b-D-glucoside and myricetin-3-0-rutinoside from leaves were isolated (Phyother Res. 1989,3, 30).

 

8. Stereoselective synthesis of azadiradione (Tetrahedron Lett. 1989, 30, 3023) was reported. Polysaccharides - CSP-I, CSP-II and C -III- were isolated from bark (Jpn. 1,275,602; Chem. Abstr. 1990, 112, 204642 h; Shoyakugaku Zasshi 1990, 44, 29; Chem. Abstr. 1990,113, 178105 c); and were partially characterised (Shoyakugaku Zasshi 1990, 44, 29; Chem. Abstr. 1990, 113, 178105 c); new diterpenes, nimbicidin and nimbocidin were isolated from root bark (Z Naturforseh. 1989, 44B, 1279;Chem. Abstr. 1990, 112, 52298 d); tetranortriterpenoids, Limbocinin and limbocidin along with two new glycosides of stigmasterol were isolated from seeds and structure elucidated (Pakistan J. Sci. Ind. Res. 1989, 32, 43 5). Isolation of two new polyacetate derivatives, margosinone and margosinolone from stem bark along with their characterisation were reported (Fitoterapia 1989, 60, 519); chemical modification and structure-activity relationships of azadirachtin, azadirachtol and salannin (Tetrahedron 1989, 45, 5175) were reported; isolation of an antimalarial compound gedunin (J. Nat. Prod. 1989, 52, 922)was reported; root bark afforded two new terpenoids, nimibilin and nimolinin and their structures were determined (J. Nat Prod. 1989,52,1209); a new limonoid ,along with nimbolide was isolated from Tanzanian plant and its structure established (J. Nat. Prod. 1989, 52, 1246); new tricyclic diterpenoids, nimbosodione, nimbisonol and demethylnimibionol (J. Nat. Prod. 1990,53,816) margosone and margosolone were isolated from stem bark and their structures determined (Planta Med. 1990, 56, 84); root bark afforded three new tricyclic diterpenoids, margocin, margocinin and margocilin whose structures were established (Phytochemistry 1990, 29, 911); cis- and trans 3,5-diethyl- 1.2,4- trithiolanes were identified in seed volatiles; previously (J. Agric. Food Chem. 1988, 36, 1048) these were wrongly assigned as cis- and trans-n-propyl-l-propenyltrisulphides (Phytochemistry 1990, 29, 3351); 17-epinimbocinol along with nimbocinol was isolated from nimbidin fraction of oil and its structure determined (Phytochemistry 29, 3963); nimbonin along with epoxyazadiradione and azadirachtone was isolated from kernel and characterised (Proc. Pak. Acad. Sci. 1990, 27, 3); 6-deacetyinimbinal, 28-deoxonimbolide from leaves and nimbinol from seeds were isolated and characterised; partial NMR re-assignments to nimbanal, 6-deacetylnimbin, nimbin and nimbolide (Tetrahedron 1990, 46, 775) were reported; total synthesis of azadirachtin was achieved (Tetrahedron 1991, 47, 6813); isolation of azadirachtin as principal insecticidal and antifeedant component from seeds, dipropylsulphide as major volatile component and 1- cinnamoyl melianolone from fruits was reported; fruits also afforded a new insecticidal component characterised as 1-cinnamoyl 3,11-dihydroxymeliacarpin (ACS. Symp Ser. 1991, 293); isolation of a new tetracyclictriterpenoid, azadirol from seed-coat and its structure elucidation were reported; isolation of kulactone was also reported (J. Nat. Prod. 1991, 54, 408); a new limonoid mahmoodin was isolated from oil and its absolute configuration was established; in addition, azadirone, epoxyazadirone, nimbin . gedunin, azadiradione, deacetylnimbin and 17- hydroxyazadiradione were isolated; a new protolimionoid, naheedin was isolated from fruits along with azadirachtol and was characterised; fruit coat contained eicosane, docosene ,2-methyltricosene and docosene as identified by GC-MS (J. Nat. Prod. 1992, 55, 303); two new azadirachtol H and l-were isolated from the kernels and their structures were determined. (J Nat Prod 1992, 55, 596); Azadirachtin K was isolated from seed kernels and characterised; in addition, nimbolonoid, ohchinolide b. deacetylnimbil, azadiradione, nimbin and salannin were isolated (Indian J. Chem. 1992, 31B, 295); isolation of a new triterpene azadirinin from roots and its structure determination were reported (Fitoterapia 1992, 63, 118); a new compound was isolated from seeds and characterised as.1-tigloyl-3-acetyl - 11 - hydroxy - 4b-methylmeliacarpin (Phytochemistry 1992, 32, 213); three new degraded triterpenoids were isolated from fresh uncrushed fruit coat and characterised as desfurano-azadiradione; (7a-acctoxy-4,4,8-trimethyl-5a-(13a-Me)androsta-1,14- dien-3,16-dione , 7a-acetoxy-4,4,8-trimethyl-5a-(13a-Me)-17-oxo-androsta-1,14-dien-3,16- dione and 7a-acetoxy-4,4,8-trimlelyl-5a-17-oxo-androsta-1,14-dien-3,16-dione were reported. (Phytochemistry 1992, 31, 42-75) Structure of nimbonin was confirmed by synthesis (Synth. Commun. 1992, 22, 2571) ; absolute configuration of azadirachtin was determined by X-ray analysis (Chem. Commun. 1992, 1304); isolation of a new isoprenylated flavanone from young leaves and exudates of resin glands present in shoot apices and its characterisation as 8- prenyl-5,7-dihydroxy 3'-(3-hydroxy-3,3-dimethylbutyl)-4'-methoxyflavanone was reported (Phytochemistry 1993, 34,1194).

 

9. Several neem-seed extracts, some used for preparing common azadirachtin-containing insecticides, are cytotoxic to N1E-115 murine neuroblastoma cells with IC50 values of 20-200 mg ext. mL-1 culture medium. Bioassay-directed fractionation by reversed-phase HPLC shows that the toxicity to N1E-115 cells is assocd. primarily with a single minor component identified by isolation and NMR and MS as a nimbolide with an IC50 of 15 mg mL-1 (32 mM). The difference in quantity of nimbolide in seven neem ext. sources generally correlates with their overall cytotoxicity. Three other limonoids (epoxyazadiradione, salannin and possibly deacetylsalannin) but not azadirachtin, nimbin and deacetylnimbin contribute in small part to the cytotoxicity. Reconstituted neem extract with only nimbolide removed is less cytotoxic than the original extract. Thus, nimbolide is the principal cytotoxic component of the neem extracts examined and such minor constituents may warrant consideration in safety evaluations. (Pestic. Sci., 48(2), 135, 1996).

 

10. Isolation of various azadiracthins, ie., Azadirachtin A,B,D,H and I in pure form from neem oil by preparative high performance liq. chromatography procedure is described. (J.Liq. Chromatogr. Relat. Technol., 19(11), 1729, 1996. Chem Abstr 125:80894) A new tetranortriterpenoid, 11-epi-azadirachtin H has been isolated from the methanolic extracts of Azadirachta indica seeds. Its structure is proposed on the basis of various spectral analysis. (Phytochemistry, 42(2), 561, 1996)

 

11. Four new compounds, 11-b- hydroxyazadirachtin, 1-tigloyl-3-acetylazadirachtinin, 1,2-diacetyl-7-tigloyl-12-hydroxyvilasinin and 23-desmethyl limocin-B from neem seeds have been isolated and characterized using spectral studies. (Phytochemistry, 43(2), 451, 1996).

 

12. An investigation has been carried out of the synthesis of structural models for the left hand portion of the natural product azadirachtin (I). This work has culminated in a concise and high-yielding route to decalin derivative II (R = H). The significant antifeedant activity shown by this mimic II (R = H) (AI50 at 9.4 ppm) is greater than that of the other analogs synthesized during this study and has led to the synthesis of further mimics II [R = Me, (CH2)4OH]. (J. Chem. Soc., Perkin Trans. 1, (13), 1523, 1996).

 

13. Forty-two neem ecotypes of India have shown wide variations in the content of oil, and their physicochemical characteristics (color, sp. gr., refractive index, iodine value, acid value, and saponification value), total fatty acid, fatty acid composition (oleic, stearic, palmitic, linoleic, myristic, arachidic, and behenic acids), and the key meliacins (azadirachtin, nimbin, and salannin). The azadirachtin content did not correlate with any of the physicochemical and chemical parameters, but nimbin and salannin contents correlated significantly with each other. The refractive index and iodine value showed weak but significant correlation with the contents of nimbin and salannin. Insect growth inhibition of S. litura revealed a wide variation in the EC50 of the oils. The salannin and azadirachtin contents of the oils correlated the most with bioactivity. The iodine and acid values correlated weakly but significantly with bioactivity. (J.Agric. Food Chem., 44(8), 2137, 1996).

 

14. Chromatographic conditions for the isolation and separation of 12 triterpenoids from Neem seeds, including azadirachtin and 6 closely related compounds are described. The elution orders of the compouds using supercritical fluid chromatography and reversed-phase HPLC are described. (J. Chromatogr., A, 761(1& 2), 53, 1997)

 

15. A new tetranortriterpenoid, 13,14-desepoxyazadirachtin A (I), was isolated from neem kernel extract by preparative HPLC and its structure established by spectroscopic methods. (Phytochemistry, 45(2), 397, 1997)

 

16. Systematic fractionation and repeated column chromatography of an alcoholic extract of leaves of A. indica resulted in the isolation of three flavonoids and one flavone glycoside. Identification of all these compounds was done on the basis of their spectral data. (Natl. Acad. Sci.Lett. (India), 19(11&12), 210, 1996)

 

17. The selective extraction of nimbin, salannin, azadirachtin and oil from Neem seeds, using supercritical carbon dioxide and supercritical Carbon dioxide: methanol, has been investigated using various conditions. Extraction for 30 minutes with 100% carbon dioxide using a capillary restrictor to maintain the critical pressure removed only small amounts of oil and triterpenoids. Slightly higher levels of oil and triterpenoids were removed when a back-pressure regulator was used. Over a 150 min period, in 30 minute intervals, 100% carbon dioxide extracted all the nimbin and salannin from the seeds, while leaving some azadirachtin behind. Using carbon dioxide:methanol, no conditions were found which would allow the selective extraction of azadirachtin. However, the highest pressures (34.4 MPa) and percentages of methanol (20%) removed the most azadirachtin. An optimum was observed for extracting nimbin and salannin at 20.6 MPa and 6% methanol. (Phytochem. Anal., 8(5), 228,1997)

 

18. The fatty acids and glyceride compositions of Nim (Melia azadirachta indica) seed oil were studied. It was observed that Nim seed grown under the soil and climatic condition of Bangladesh, contains 40% acrid bitter greenish yellow to brown oil with a strong disagreeable garlic-like odor. The oil was fractionated into mono-, di- and triglycerides by silicic acid column chromatography. The triglycerides varied from 89.0-89.9%, diglycerides from 2.7-3.2% and monoglycerides from 2.6-3.0% depending on the soil texture of the areas on which the plants grow. The fatty acid composition of oil was analyzed by gas liquid chromatography. (GLC). The percentage composition of fatty acids was found to be oleic 55.8%, palmitic 16.5%, stearic 2.5%, linoleic 20.5%, arachidic 2.4% and behenic 2.2%. (J. Sci. Ind.Res., 31(2), 99, 1996)

 

19. Isolation of azadirachtin-B in pure form suitable for crystallisation from neem seed kernel extract by preparative HPLC followed by another subsequent preparative HPLC using the recycling mode is described. (J. Liq. Chromatogr. Relat. Technol., 20(10), 1633,1997)

 

20. Azadirachta indica afforded two novel tetranortriterpenoids azadirachtolide (I) and deoxyazadirachtolide (II) by gravity column chromatog. Their structures were elucidated by extensive 1D and 2D NMR techniques. (Phytochemistry,46(3), 555, 1997)

 

21. A new tetranortriterpene, 11-epi-azadirachtin D [1-tigloyl-3-acetyl-11a-hydroxy-4b-methylmeliacarpin (I)] has been isolated from the methanolic extracts of Azadirachta indica seeds. Its structure is proposed on the basis of various spectral analysis. (Phytochemistry, 49(1), 265,1998 )

 

22. A new tetranortriterpenoid, nimbinolide and the known biologically active compound isonimbinolide have been obtained from photooxidation of nimbin. The structures of the new compounds were established by spectral methods and by comparison with isonimbinolide.(Nat. Prod. Lett., 11(3),181, 1998)

 

23. a-Linolenic acid has been isolated from fresh A. indica leaves, and an optimized procedure for the isolation of the limonoids nimbolide and 28-deoxonimbolide is described. Extraction of shade-dried leaves for 48 h at 30 with hexane was most suitable in terms of ease of sepn. and yields. (Phytochemistry, 46(7),1177, 1997)

 

24. A marine sterol namely (24x)-isopropenyl cholesterol and its biosynthetic precursor fucosterol have been isolated for the first time from the species Azadirachta indica. (Indian J. Chem., Sect. B: Org.Chem. Incl. Med. Chem., 36B(11), 1082, 1997)

 

25. From the ethanolic extract of the fresh fruit coats of Azadirachta indica (neem), four new tetracyclic triterpenoids salimuzzalin [24,25,26,27-tetranorapotirucalla(apoeupha)-7a-hydroxy-21x,23x-diacetoxy-21,23-epoxy-1,14,20(22)-trien-3-one], azadirolic acid [26,27-dinorapotirucalla(apoeupha)-6 b-acetoxy-7a-hydroxy-1,14,20(22)-trien-3-one-25-oic acid], azadiradionol [26,27-dinorapotirucalla(apoeupha)-7a-acetoxy-24x-hydroxy-1,14-dien- 3,16-dione] and azadironol [4,4,8-trimethyl-5a-(13aMe)-androst-17a-hydroxy-1-en-7a-(p-methoxy- m-hydroxy-trans-cinnamoyloxy)-3-one], were isolated. Structures were elucidated through spectroscopic techniques. (Phytochemistry, 47(8), 1631;1998)

 

26. Salannin and deacetylsalannin were quantitatively converted into 1-detigloyloxy-3-deacetylsalannin-1-en-3-one (I) via Nocardia species. catalyzed deacylation. The pathway for the transformation was discussed, and preliminary studies of antimalarial activity of I were mentioned. (J. Chem. Soc., Perkin Trans. 1, (7),1183,1998)

 

27. Method was optimized for quantitative determination of azadirachtin content in Neem Seed Kernel (NSK) using HPLC. Neem fruits were collected from nine agro-climatic zones of Rajasthan State and the samples were analyzed for the azadirachtin content using this optimized method. The azadirachtin content varied from 0.194% to 0.670% by weight of NSK. (Indian For., 123(11),1067, 1997)

 

28. Azadirachtin A was separated from marrangin in neem seed extract concentrations by double coil cross axis MLCCC, using hexane-tert-Bu Me ether-MeOH-H2O (1:3:1:2) and hexane-ethyl acetate-MeOH-H2O (4:5:4:5) for rechromatography. The azadirachtin A crystals were characterized by TLC and bioassayed using Epilachna varivestis and Spodoptera littoralis. (Meded. - Fac. Landbouwkd. Toegepaste Biol. Wet. (Univ.Gent), 62(2a), 213, 1997)

 

29. A review with many references on chemical mode and spectrum of action, nontarget toxicity and environmental fate of neem insecticides has been published (Pestic. Outlook, 8(5), 32, 1997)

 

30. The extension of our recently developed strategy using the key intermediate I, obtainable in two steps (52% overall yield) from manool (II), to the synthesis of naturally occurring ring C aromatic diterpene derivatives provides in three steps. (+)-12-methyl-7-oxopodocarpa-8,11,13-triene-13- carboxylic acid III (R2 = Me, R3 = CO3Me) and its isomer III (R2 = CO2Me, R3 = Me), and in seven steps (+)-nimbiol (IV), in good overall yields. This synthesis discloses that the structure III assigned to margolone isolated from Azadirachta indica A. Juss may be incorrect and needs to be reinvestigated. (J. Chem. Soc., Perkin Trans. 1(8), 1423,1998)

 

31. Nimbin and salannin, major triterpenoids accompanying azadirachtin in extracts of neem (Azadirachta indica) seeds, were photooxidized by UV light in the presence of oxygen to more polar, unstable intermediates that rearranged on silica gel to two final products in which the furan ring had been oxidized to isomeric hydroxybutenolides. The isomeric hydroxybutenolides were also readily formed when a crude extract of triterpenoids from neem seeds was irradiated, and both isomers of salannin have been isolated from seeds. Photooxidation of nimbin and salannin proceeded much faster than that of azadirachtin. All photoproducts showed some biological activity against Spodoptera littoralis, Locusta migratoria and Schistocerca gregaria. Isonimbinolide was as potent as azadirachtin at feeding inhibition in all three species, and it also inhibited the growth of S. littoralis. Isosalanninolide showed potent antifeedant and growth inhibitory activity against S. littoralis. (J. Chem. Ecol., 23(12), 2841, 1997)

 

32. Neem oil is removed from seeds with hexane and azadirachtin is extracted from the neem seeds with methanol. The extracts are first purified by liq./liq. partition, followed by a chromatographic separation on a Florisil column. HPLC analysis requires a C18 ODS phase. The efficacy of the method is about 97%. Extracts from neem seeds (Azadirachta indica) have been formulated as a emulsifiable concentrate. (EC). This formulation contains 0.3-1% azadirachtin, 18% neem oil, and is used as an insecticide on cotton at 1 L EC/ha mixed with 9 L water (very low volume Spraying technique). The nature of the solvent appeared to be crucial for the stability of azadirachtin (according to CIPAC MT 46) and neem oil can improve the stability of the compound. Surfactants have been selected (emulsification tests according to CIPAc MT 36) to give a good emulsion in soft (CIPAC A) and hard (CIPAC D) waters, after 24 h without agitation. Field results confirm that azadirachtin, used alone at 11 g/ha (EC) cannot control effectively both Heliothis armigera and Aphis gossypii, but demonstrate that these can be controlled by mixtures of 5 g azadirachtin + 25 g cypermethrin per ha or 5 g azadirachtin + 300 g chlorpyriphos-Et per ha (5 sprays each 14 days). The mixture of neem oil and chlorpyriphos-Et has shown a knock-down effect. (Chimie analytique et Phytopharmacie, Passage des Deportes 2, Faculte Universitaire des Sciences Agronomiques, Dakar BP 3148, Senegal). Meded. - Fac. Landbouwkd. Toegepaste Biol. Wet. (Univ. Gent), 62(2a), 225,1997)

 

33. Acid-hydrolysis of the gum exudates of the neem trees, Azadirachta indica Juss (family Meliaceae), followed by acetylation and chromatographic separation afforded the following components in the form of the corresponding acetates: diethylaspartate, 1-methyl-b-D-xylopyranoside, 3,6-di-O-ethyl-1-methyl-a-D-mannopyranoside, as well as its 4,6-di-O-ethyl isomer, which is the predominant component (comprises 88.7% of the gum hydrolyzates), and a -D-glucopyranose. (J. Saudi Chem. Soc.,2(2), 133,1998 ; Bitechnol. Agric. For., 43(Medicinal and Aromatic Plants XI), 11, 1999)

 

34. A microorganism identified as Nocardia sp., capable of converting azadirachtin into three metabolites, viz. 3-deacetylazadirachtin, 1-detigloyl-3-deacetyl-azadirachtin-1-ene-3-one, and 1-detigloyl-3-deacetyl-11,19-deoxa-12,19-oxa-11-oxo-azadirachtin-1-e ne-3-one, has been isolated. This is the first report on the functionalization of azadirachtin using biocatalysts wherein two novel, hitherto unknown metabolites have been isolated and characterized. (Tetrahedron Lett., 40(28), 5243, 1999)

 

35. Two novel compounds, the first 29-oxymethylene azadirachtin analog, 29-oxymethylene-11-demethoxycarbonyl-11a-hydroxyazadirachtin (azadirachtin M) (I) and 22,23-dihydro-23a-hydroxy-3-tigloyl-11-deoxyazadirachtinin (azadirachtin N) (II), together with known compound 11-epi-azadirachtin H were isolated from a methanolic extract of the seed kernels of Azadirachta indica. The structures of I and II were elucidated on the basis of spectral methods. (J. Nat. Prod., 62(7), 1022,1999)

 

36. Three new triterpenoids, azadironolide [24,25,26,27-tetranorapoeupha-7a-acetoxy-23x-hydroxy-21,23-epoxy- 1,14,20(22)-trien-3,21-dione] (I), isoazadironolide [24,25,26,27-tetranorapoeupha-7a-acetoxy-21x-hydroxy-21,23-epoxy- 1,14,20(22)-trien-3,23-dione] (II), and azadiradionolide [24,25,26,27-tetranorapoeupha-7a-acetoxy-21,23-epoxy-1,14,20(22)-trien-3,16,21-trione] (III), were isolated from the fresh fruit coats of Azadirachta indica. Their structures have been elucidated through spectral anal. (J. Nat. Prod., 62(7), 1006-, 1999 )

 

37. A simple and rapid method involving solid phase extraction and liquid chromatography for the determination of azadirachtin A and B, nimbin and salannin at nanogram levels in neem oil samples is presented. The neem oil samples are defatted and the compounds of interest extracted by mixing the sample with hexane and passing the hexane solution through a graphitized carbon black column. After washing the column with 2 mL of hexane, azadirachtin-A and -B, nimbin and salannin are eluted with 5 mL of acetonitrile and quantified using HPLC with UV detection. The recoveries of azadirachtin-A and -B, nimbin and salannin in fortified oil samples were 97.4-104.7%. The upper limit of quantification is up to 100 mg ml-1 without any additional clean-up and with little interference from lipids during the analysis by HPLC. The method was successfully applied to various neem oil samples collected from different locations in India. (Analyst (Cambridge, U. K.), 124(1), 19, 1999)

 

38. A dichloromethane extract of the triterpenoids from seeds of the neem tree (Azadirachta indica) can be fractionated rapidly and with economic use of solvents using the Biotage flash chromatography system. The fractions can be analyzed by TLC, or quant., by supercritical Fluid chromatog. or HPLC, for the determination of 11 tetranortriterpenoids, including the natural insecticide azadirachtin. After a second pass through the Biotage flash column, pure compds., including azadirachtin and salannin can be obtained directly, although these compounds comprise <0.3% of the total mass of the seeds extracted and are present in a complex mixture of similar substances. (Phytochem. Anal., 10(1), 39, 1999 )

 

39. A first expeditious total synthesis of ()-Nimbonone (I), a novel naturally occurring diterpenoid isolated from the Neem tree, is described. In order to induce the Et substituent, Friedel-Crafts acetylation and then decarbonylation have been employed as the key steps. (Indian J. Chem., Sect. B: Org.Chem. Incl. Med. Chem., 37B(9), 929, 1998 )

 

40. Two novel nonterpenoidal constituents, nimbothalin (I) and n-tridecyl benzene, have been isolated from leaves of Azadirachta indica and characterized spectroscopically. The structure of nimbothalin was established as 2-[(2,4-dicarboxy-3-methyl)benzyl]-8,10-dimethyl-1,3,5,7,9-undecapentaene. (Phytochemistry, 49(7), 2121, 1998)

 

41. A review with 12 references has been published. With the continued robust growth of the global biopesticide market, azadirachtin is uniquely positioned to become a key insecticide to expand in this market segment. In the USA the actual or impending cancelation of some organophosphate and carbamate insecticides that have either lost patent protection or are not being re-registered in many markets because of the Food Quality Protection Act of 1996, has opened new opportunities for biopesticides and reduced-risk pesticides in general. The broad-spectrum activity of azadirachtin at low use rates (125 to 40 g Al ha-1) coupled with the insect growth regulator activity (in all larval/nymphal instars including the pupal stage) and unique mode of action (ecdysone disruptor), make azadirachtin an ideal candidate for insecticide resistance, integrated pest control and org. pest control programs. Azadirachtin has been exempted from residue tolerance requirements by the US Environmental Protection Agency for food crop applications. Azadirachtin exhibits good efficacy against key pests such as whiteflies, leafminers, fungus, gnats, thrips, aphids and many leaf-eating caterpillars. Azadirachtin has minimal to no impact on non-target organisms, is compatible with other biol. control agents and has a good fit into classical Integrated Pest Management programs. The world's largest azadirachtin extn. facility has been fully commissioned in India to process over 10,000 tonnes neem seeds per annum. This will ensure the wide availability of azadirachtin tech. grade material in the future. (Pestic. Sci., 54(3), 285, 1998)

 

42. A review with many references on effects on target and nontarget impact of novel insecticides, such as insect development and reproduction disrupters, insecticides interfering with hormonal regulation, neem-derived botanicals, etc. has been published (Insectic. Novel ModesAction, 188-259. Edited by: Ishaaya, Isaac; Degheele, Danny. Springer: Berlin, Germany, 1998)

 

43. Entrapment and dissolution was studied of solid neem seed oil (NSO; 500-2 mm) encapsulated in controlled release (CR) polymeric devices in vitro. CR was studied in cellulose acetate microspheres, starch/urea/formaldehyde granules (St/UF), urea/formaldehyde microcapsules, and Na alginate microparticles. Max. entrapment efficiency and % release was found with St/UF matrix. NSO release depended on matrix, prepn. method, % loading, and soil condition. The authors suggest UF nanoparticles to be advantageous since they can be used for soil and spray applications. (Polym. News, 24(6), 211, 1999)

 

44. Neem seed oil obtained by extraction with analysis grade acetone using a Soxhlet app., NSO(S) and that obtained by the traditional kneading method, NSO(K) were compared with the powder equivalent weights (PEW, the neem seed powder capable of yielding the equiv. amts. of the oil used for the treatments) for their relative efficacy in reducing the reproductive potential of the cowpea seed bruchid, Callosobruchus maculatus in stored cowpea. Also, neem seed oil obtained by cold extraction with analysis grade acetone, NSO(C) was compared with NSO(S) and NSO(K) for their relative effectiveness in suppressing populations of C. maculatus in cowpeas treated before or after eggs had been laid on them. The two NSO formulations, NSO(S) and NSO(K) were significantly more effective in reducing oviposition and adult emergence than the neem seed powder formulation. At 50 mg/5 g seed, the 3 exts. of NSO significantly reduced egg-laying and adult emergence in pre- and post-oviposition treated cowpeas. (J.Stored Prod. Res., 35(2), 135, 1999)

 

45. The alcoholic extract of the fresh stembark yielded the bitter principles: nimbin, 0.04; nimbinin, 0.002; and nimbidin, 0.4%. The alcoholic extract of the air-dried rootbark yielded nimbin and nimbidin. Another terpenic constituent, identical with sugiol, is reported to be present in the stembark. Petrol-ether soluble fraction of the alcoholic extract of the stembark yielded an essential oil (0.02%), having characteristics similar to the oil isolated from the blossoms. All parts of the plant yield -sitosterol (Indian Pat. NO.13343, 1927; Bhattacharji et al, J Sci Industr Res, 1953, 12B, 154; Mitra et al, ibid, 12B, 152; Sengupta et al, Chem & Ind, 1958, 861; Narasimhan, ibid, 1957, 661).

 

46. The stembark contains tannin, 12-16; and non-tannin, 8-11%. The trials on goat-skins were found to compare favourably with avaram-tanned goat-skins in lightness of colour, feel and tanning strength. The bark also yields a red dye (Thampuran & Mathew, Bull cent Leath Res. Inst, Madras, 1960-61, 7, 276; Kedlaya et al, Leath Sci, 1963, 10, 305; Krishnamurthi et al, ibid, 1977, 24, 95; Rama Rao, 72).

 

47. The twigs and leaves can be fed to cattle in conjunction with other feeds; camels also eat the leaves. In Andhra Pradesh, they are regularly fed to cattle and goats to increase the secretion of milk, immediately after parturition. They are carminative and aid digestion. They are used as mulch and manure. The leaves contain nimbin, nimbinene, 6-desacetylnimbinene, nimbandiol, nimbolide and quercetin. The presence of -sitosterol, n-hexacosanol and nonacosane is also reported. Analysis of the mature leaves gave: moisture, 59.4; protein, 7.1; fat, 1.0; fibres, 6.2; carbohydrates, 22.9; and minerals, 3.4g/100 g; calcium, 510.0; phosphorus, 80.0; iron, 17.1; thiamine, 0.04; niacin, 1.4; and vitamin C, 218.0 mg/100 g; carotene, 1998 g/100 g; and cal val, 129 Kcal/100 g. The amino acids present are: glutamic acid, 73.3; tyrosine, 31.5; aspartic acid, 15.5; alanine, 6.4; proline, 4.0; and glutamine, 1.0 mg/100 g. Tender twigs are used to clean teeth, particularly in pyorrhoea [Ketkar, 1976, 208; Troup, I, 180; Dastur, Useful Plants, 39; Mitra, C R , 6, 9, 64; Murthy, Indian Fmg, N S, 1957, 7(9), 9; Macmillan, 29; Basu & Chakraborty, J Indian Chem Soc, 1968, 45, 466; Awasthi & Mitra, Phytochemistry, 1971, 10, 2842; Nutritive Value of Indian Foods, 69; Dakshinamurti, Curr Sci, 1954, 23, 125].

 

48. The fruits contain gedunin, 7-deacetoxy-7a-hydroxy gedunin, azadiradione, azadirone, 17-hydroxy-azadiradione (C28H34O6, m p 177), 17-epiazadiradione (C28H34O5, m p 205) and nimbiol. The seed after cleaning from the pulp is cream-white. When dry, the seed coat is hard and brittle and it can be decorticated with ease. The fruits are collected during April-Aug, the best period for collection being before the monsoon. They are preferably hand-picked to avoid dirt, and sun-dried and stored till Oct-Dec or even later. The fully dried fruits both whole and decorticated, store well without deterioration even up to one year. In South India, the fruits are usually decorticated and the seeds stored whereas in North India, the whole fruits are dried and stored. The seeds with remnants of pulp should not be heaped for long as they become black due to auto-oxidation. Storing of the seeds for three months is necessary for optimum yield of oil. The seed on the average comprises 44.7 per cent kernel and 55.3 per cent shell. The seed is decorticated in stone-grinders or decorticators and the shells are separated by winnowing. The greenish brown kernels constitute 35 per cent of the fresh fruit.

 

49. The seeds contain six new tetranortriterpenoids, viz. 1a-methoxy-1, 2-dihydroepoxyazadirone, 1,2-diepoxyazadiradione, 7-acetylneotrichil-enone, 7-desacetyl-7-benzoylazadiradione, 7-desacetyl-7-benzoylepoxy-azadiradione and 7-desacetyl-7-benzoylgedunin. They also contain azadirachtin which inhibits the feeding of locust (Schistocerca gregaria) at the dose of 40 g/litre. Azadirachtin at the dose of 0.75 mg/kg body wt also delayed moulting from 23rd to 38th day of last instar nymphs of Periplanata americana Linn. with partial moult leading to death among both male and female nymphs [Kraus et al, Phytochemistry, 1981, 20, 117; Mitra, C.R., 14, 112-27; Ketkar, 1976, 5; Oils Oilseeds J, 1965-66, 18(3), 10; Kraus & Cramer, Tetrahedron Lett, 1978, 2395; Lavie et al, Tetrahedron, 1971, 27, 3927; Chowdhuri et al, Chem & Ind, 1958, 634; Butterworth & Morgan, J Chem Soc, Chem Comm, 1968, 23; Dictionary Zrg Compds, 1969, 80; Qadri & Narsaiah, Indian J Exp Biol, 1978, 16, 1141].

 

50. The kernels yield a greenish yellow to brown, acrid, bitter fixed oil (40.0-48.9%), known as OIL OF MARGOSA, having a strong, disagreeable odour resembling garlic. The yield is equivalent to c 23.5 per cent of the whole seed. The kernels from Sri Lanka have been reported to yield 59.25 per cent oil which is equivalent to c 31 per cent of the whole seed. The kernels are crushed in local crushers (wooden ghanis) or expellers, giving 30-40 per cent oil. The local oil-presses yield c three per cent less than the expellers. The residual oil may be recovered by solvent extraction method. The oil is sometimes extracted by boiling the crushed kernels with water. The oil should be stored in well-closed containers, in cool places. The oil has a high total tocopherol content (1.17 mg/g), made up almost equally of gand b-form, with just a trace of -form. The crude oil is used as illuminant, although it smokes badly. The oil is simultaneously purified and refined by the separation of the bitter and odorous constituents by repeated extraction with water-miscible solvents, such as dilute alcohol, methanol, dilute acetone or with a mixture of such solvents (Ketkar, 1976, 5; Mitra, C.R., 15, 112-27; Dutt et al, Indian Soap J, 1950-51, 16, 72; 1951-52, 17, 105; I.P., 1966, 324; Rao & Seshadri, Proc Indian Acad Sci, 1942, 15A, 161; Rao et al, J Sci Fd Agric, 1965, 16, 121; Mitra, Indian Oilseeds J, 1961, 5, 204; Mitra & Pandey, ibid, 1963, 7, 96; Mitra, J Oil Technol Assoc India, Kanpur, 1963, 18, 102).

 

51. The refined and purified oil has the following characteristics: sp gr 30, 0.9087; nD30, 1.4612; iod val (Wij's),66.4; sap val, 290.9; and unsapon matter, 0.8%. The fatty acid composition of the oil is as follows: myristic, 0.2; palmitic, 16.2; stearic, 14.6; arachidic, 3.4; oleic, 56.6; and linoleic, 9.0%. The component glycerides are: palmitodistearin, 0.2; oleopalmitostearin, 20.3; oleodistearin, 1.6; palmito-oleolinolein, 6.6; palmitodiolein, 26.3; stearo-oleolinolein, 3.6; stearodiolein, 24.9; and linoleodiolein, 16.5%. The refined oil is stable and does not become rancid on storing (Indian Pat. No. 46713, 1952; Gupta & Mitra, J Sci Fd Agric, 1953, 4, 44; Mitra, Indian Oilseeds J, 1956-57, 1, 256).

 

52. The oil has many therapeutic uses and is official in I.P. Medicinal properties of the oil are attributed to the presence of bitter principles and odorous compounds. The bitter principles are used in pharmaceutical industry. The alcoholic extract, after removal of the bitter principles, can be used as an agrochemical for the preparation of water-based pesticidal spray for common agricultural and horticultural pests. The oil is a useful remedy in some chronic skin diseases and ulcers. It is a common external application for rheumatism, leprosy and sprain. Intrauterine medication of oil controls different types of metritis. The warm oil relieves ear trouble; the oil also cures dental and gum troubles. A few drops of oil taken in betel-leaf provides relief in asthma. The oil is reported to have anti-fertility properties. It possesses antiseptic and anti-fungal activity and is found to be active against both gram-positive and gram- negative organism.

 

53. The bitter principles of the oil have been obtained by extraction with alcohol in a yield of two percent. Nimbidin (yield, 1.2-1.6%), the main constituent, is highly bitter and contains sulphur. On hydrolysis it gave neutral nimbidinin and nimbidic acid. Besides nimbidin, two bitter constituents, free from sulphur, nimbin (yield, 0.1%) and nimbinin (yield, 0.01%) have been obtained. The presence of gedunin, meldenin, desacetylgedunin, salannin, azadirone, epoxyazadiradione and a new minor product, vepinin (C28H36O5; yield, 0.15%) is also reported in the oil. The oil also contains nimbinene, 6-O-acetylnimbandiol (C28H32O7, m p 121), 6-desacetylnimbinene, 3-desacetylsalanin, salannol and 1,3-diacetylvilasinin (C30H40O7, mp157). The diterpenoids, margolone, nimbogone, nimbonolone and nimbolinin have been isolated from the plant (Hanson, Nat Prod Rep,1991, 54, 6).

 

54. The ethanolic extract of the stembark contains two isomeric diterpenoids, nimbonone and nimbonolone, the methyl derivtives of grevillic acid, the grevillate, three new tricyclic diterpenoids, nimbosodione, nimbisonol and methyl nimbionol, phenols namely nimbione, nimbinone and nimbionone,two fatty acid derivatives and ( polyacetates) margosinone and margosinolone. The pentacyclic nortriterpenoids, 6-desacetylnimbinen, nimbiol, nimbinen and 6-desacetylnimbinen have also been isolated from the stembark. The methanolic extract of the bark also contains gedunin, which showed antimalarial activity against Plasmodium falciparum. The tricyclic diterpenoids, margocin, margocinin, margocilin and nimobinin and a tetranor triterpenoid, nimbilin have been isolated from the rootbark. These terpenoids exhibited antitumour, antileukaemic, antibiotic and insecticidal properties (Ara et al, Phytochemistry 1989, 28, 1177; 1990, 29, 911; J Nat Prod, 1989, 52, 1209; 1990, 53, 816; Fitoterapia, 1989, 60, 519; Van der Nat, J Ethnopharmacol, 1991, 35, 1; Hanson, Nat Prod Rep, 1991, 54, 155).

 

55. The fresh undried winter leaves contain stigmasterol, nimbocinone, nimbocinolide, isonimbocinolide, nimocinol, isonimocinolide and isoazadirolide. The fresh green leaves yield meldenindiol, vilasinin, azadirachtanin, margosinolide, isomargosinolide, desacetyldihydronimbic acid. The dried leaves contain 4a, 6a-dihydroxy-A-homoazadiron, nimbinen, 6-desacetylnimbinen, 3-desacetylsalannin and 2',3''dehydrosalannol. The fallen yellow leaves contain isomeldenin. Nimbolide and 28-deoxonimbolide isolated from the leaves, showed significant cytotoxic activity. A new isoprenylated flavonone, 8-prenyl-5,7-dihydroxy-3'(3-hydroxy-3,3-dimethylbutyl)-4'methoxyflavanone (C26H32O6) has been isolated from the exudate of the resineous glands (Van der Nat, J Ethnopharmacol, 1991, 35, 1; Kigodi et al, J Nat Prod, 1989, 52, 1246; Balasubramanian et al Phytochemistry, 1993)

 

56. A new protolimonoid, naheedin along with azadirachtol, 7-desacetyl-7-benzoylazadiradion, nimocin, nimbocinol and nimbolicinol have been isolated from fresh ripe fruits. The ethanolic extract of fresh, undried and uncrushed ripe fruit coat yields terpenoids namely limoicinol, limocinone, limocin, limocin A, limocin B, azadirol, kulactone, desfurano-azadiradione [7a-acetoxy-4, 4, 8-trimethyl-5a-(13aMe)-androsta-1, 14-dien-3,16-dione], 7a-acetoxy-4,4,8-trimethyl- 5a-(13aMe)-17-oxa-androsta-1, 14-dien-3, 16-dione and 7a-acetoxy-4, 4, 8-trimethyl-5a-17-oxa-androsta-1, 14-dien-3, 16-dione. The cold water extract of the fruit pulp yields 17-a-hydroxyazadiradione and arabinogalactan. The latter contains D-galactose, L-arabinose, L- rhamnose and D-glucoronic acid (Van der Nat, J Ethnopharmacol, 1991, 35, 1; Siddiqui et al, J Nat Prod, 1992, 55, 303; 1991, 54, 408; Phytochemistry, 1991, 30, 1615; 1992, 31, 4275; Sen et al, Indian J Chem, 1993, 32B, 862).

 

57. On steam distilation seed yields an essential oil which contains, 2-methyl-2-pentenal, 31.2; 2,4-dimethylthiophene, 10.3; 3,4-dimethylthiophene, 10.5; cis -3,5-diethyl-1,2,4-trithiolane, 8.5; trans -3,5-diethyl-1,2,4-trithiolane, 14.1; dipropyl disulphide, 3.3; cis -1-propenyl-1-propyldisulphide, 0.8; and trans -1- propenyl-1-propyldisulphide, 2.8 percent volatile constituents. The ethanolic extract of the seed contains tetranortriterpenoids, 17-epiazadiradione, 17-hydroxyazadiradion 22,23-dihydro-23--methoxy-azadirachtin, 3-tigloylazadirachtol, nimbanal, ochchinolide B, 6-desacetylnimbin, azadiradione, nimbin, salannin, azadirachtin A to K; 3-acetyl, 1-tigloyl-3-acetyl-11-hydroxy-4-methyl-meliacarpin, 4-methyl azadirachtin, their analogues such as 1-cinnamoyl-3-feruloyl-11-hydroxy-meliacarpin (Mubarak & Kulatilleke, Phytochemistry, 1990, 29, 3351; Rojatker, ibid, 1989, 28, 203; 1993, 32, 313; Van der Nat, J Ethnopharmacol, 1991, 35 ; 1, Govindachari et al, Indian J Chem, 1992, 31B, 295; J Nat Prod. 1992, 55, 596).

 

58. The powdered seeds mixed with honey are reported to be given in piles by the local people in U.P. An aqueous solution of seeds showed antiviral activity against Okra mosaic virus. Defatted neem kernel powder at 1.0% (wt/wt of Sorghum grain) was found fatal against rice Weevil Sitophilus oryzae Linn. Azadirachtin at 0.1 ppm dose was found to reduce servival of early nauplii (N1-N3) Mesocyclop leuckarti s.1., a major vector of quinea worm disease. It has been recommended for treatment of potable water to kill the mesocyclops [Maheshwari & Singh J Eon Bot Phytochem, 1991, 2, 16; Atiri et al, Trop Agric (Trinidad), 1991, 68, 178; Champange, et al, Phytochemistry, 1992, 31, 377; Susha & Karnavar, Indian J Exp. Biol, 1993, 31, 188; Mukherjee et al, Indian J Med Res, 1990, 91A, 461; Mohan et al Neem News Letter, 1990, 7, 1].

 

59. The nimbidin fraction of the oil contains tetranortriterpene alcohols, nimbocinol and 17-epinimbocinol. The tetranortriterpenoids, azadiradione, meliantriol, salannolide, nimbandiol, 4-epinimbin, nimbinen, 6-desacetylnimbinen, desacetylnimbin and 17- hydroxyazadiradione have also been isolated from the oil (Van der Nat, J Ethnopharmacol, 1991, 35, 1; Gaikwad, et al, Phytochemistry, 1990, 29, 3963; Siddiqui et al, J Nat Prod, 1992, 55, 303).

 

60. Neem oil has been found to be effective in preventing the multiplication of HIV-virus which causes AIDS. The oil is also reported to be a potent contraceptive. The emulsified oil is to control rust and powdery mildew in plants (East Pharmac, 1992, 35, 79; Stanley, Agric Res Wash, 1991, 39, 21).

 

61. A colourless, odourless and nonbitter edible oil has been extracted from neem oil by removing sulphur compounds that cause bitterness. A two stage process to extract both azadirachtin and edible oil from the crude neem oil has been developed at the Central Food Technological Research Institute, Mysore. Its fatty acid content is higher than that of palm oil (Res & Industr, 1993, 38, 283). The flower contains cholesterol and nimbin (Van der Nat, J Ethnopharmacol, 1991, 35, 1).

 

62. When the oil is given as an anthelmintic to humans it produces nausea and general discomfort. There are some indications that the oil may be involved in the etiology of Reyes syndrome, possibly because of a synergistic effect of afflatoxins in the oil (Koul, et al, Canad J Bot, 1990, 68, 1).

 

63. A glycoprotein containing carbohydrate and protein in ratio of 19:81 was isolated from neem gum; it contained mannose, glucosamine, arabinose, galactose, xylose and glucose in molar ratio of 4:3:3:2:2:1:1 (Indian J. Biochem. Biophys. 1981, 18, 202); two related arabinofucoglucans Gla and Glb were isolated from bark; hoth, composed of main chain of repeating (14)Iinked glucopyranosyl units with side chains of a-L-arabinofuranosyl units (Chem. Pharm. Bull. 1982, 30, 4025); a process for extracting an anti-inflammatory polysaccharide consisting of glucose, arabinose and fucose in molar ratio of 1:1:1 from bark was developed (Jpn. 58,225,021 (1983) Dec. 27).

 

64. Pentanortriterpenoids, nimbinene, 6-deacetylnimbinene, nimbandiol and 6-0-acety]- nimbandiol were isolated from seed oil; the first three compounds were also isolated from leaves whereas only first two compounds were found to be present in bark and their structures were established (Chem. Ber 1981, 114, 2375); six new tetranortriterpnoids, la-metboxy-1,2-dihydro-epoxyazdiradione, 14b,15b- diepoxyazadiradione, 7-acetylneotrichilenone and three C-7 benzoates of tetranortriterpenoids (I, II, III) - were isolated from seeds and their structures determined (Phytochemistry 1981,20,117); hyperoside, quercitrin and rutin were identified in leaves (Farmatsiya 1982,32, 24); nimbin and b-sitosterol from cotyledons (Indian Drug 1983, 20, 479), meldenindiol from green leaves, meldenin and isomeldenin from fallen yellow leaves and quercetin as a glycone from the glycosides of either type of leaves were reported(Acta Cienc. Indica, Ser. Chem. 1983, 9, 55; Chem. Abstr 1984,101, 51706 w); a new tetranortriterpenoid - 4a,6a-dihydroxy-A-homoazadirone (IV) was isolated from leaves and its structure was determined (Tetrahedron Lett. 1984, 25, 3691); nimolicinol was isolated from fresh, ripe. fruits and characterised (Heterocycles 1984, 22, 295).