Bioactive compounds from neem tissue cultures and screening against insects
✍ Scribed by Zounos, Athanassios K; Allan, Eunice J; MordueLuntz, A Jennifer
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 118 KB
- Volume
- 55
- Category
- Article
- ISSN
- 1526-498X
No coin nor oath required. For personal study only.
✦ Synopsis
Rocaglamide and the analogues 2-13 have been tested against the following insects : Heliothis virescens F -Hel.e/l egg-larval on artiücial diet -Hel.L1 ürst instar on soybean -Hel.L3 third instar on soybean Spodoptera littoralis Boisd -Spo.L3 third instar on soybean Plutella xylostella L -Plu.L2/3 second/third instar on cabbage Diabrotica balteata Lec -Dia.L2 second instar on maize seedlings
The compounds were tested either as a 500 g litre~1 emulsiüable concentrate or in acetone ] water solutions.
RESULTS
3.1 Structure-activity relationship
The compounds 1 to 5, bearing the cyclopentatetrahydrobenzofuran ring (Fig 1 ) show potent insecticidal activities, rocaglamide being the most active (Table 1). This cyclopentatetrahydrobenzofuran moiety is also present in the pyrimidinone analogues 7 to 10, (Fig 2). However, due to the planar pyrimidinone ring, these compounds display a completely diþerent steric conüguration, but are still active.
The cyclopentatetrahydrobenzopyran derivatives 11 to 16 (Fig 3) are inactive. They may be formed by addition of a ýavone (kaempferol ?) and odorine, a natural diamine also found in Aglaia species.
4 CONCLUSION
We have isolated 15 new analogues of rocaglamide. Rocaglamide and the furan analogues 2 to 5 are the most active compounds isolated. However, the insecticidal activity of rocaglamide could not be improved upon.
Meaningful information on structure-activity relationships can be uncovered by the detailed study of the complete spectrum of natural products occurring in biologically active extracts.
REFERENCES