Nicandra steroids

Nicandra steroids possess a 5 -hydroxy-6 a,7a-epoxy pattern. 

Nicandra steroids are closely related to withanolides (Chart I). 

Ecdysones which are yet another closely related group of polyoxy steroids and Nicandra steroids are knwon for their powerful... 

The 9(10-> l9)-abeo analogue (6) of oestrone methyl ether has been shown by X-ray crystallography to have the normal 9a -configuration, but because of the chair conformation of the enlarged ring b the molecule differs considerably in shape from oestrone methyl ether. X-Ray, n.m.r., and o.r.d. data establish the structures and absolute configurations of a series of insect-repellent steroids isolated from Nicandra physaloides. The structure and conformation of the 6-sila-steroid (7) have been determined. ... 

During an infestation by larvae of the Egyptian cotton leafworm Spodoptera littoralis (Boisd) in the summer of 1978, it was noticed that shrubs of Physalis peruviana L. (cape gooseberry) were not attacked, whereas other Physalis and Nicandra spp. suffered heavy damage. Asher and co-workers demonstrated that withanolide E (118) and 4(3-hydroxywithanolide E (119), isolated from P. peruviana, as well as several related steroids, had insect antifeedant properties. Further studies on other withanolides showed antifeedant effects and species-specific activity on three insects, S. littoralis (Boisd.) (Lepidoptera), the Mexican bean beetle, Epilachna varivestis Muls. (Coleoptera) and the red flour beetle, Tribolium castaneum (Herbst) [62]. 

Begley MJ, Crombie L, Ham PJ, Whiting DA (1972) Constitution of four novel methyl steroid relatives (ring D-anunatic) from the insect repellent plant Nicandra physaloides X-ray analysis of Nic-10. J Chem Soc Chem Commun 22 1250-1251... 

Co-occurrence of lactol-type withasteroids and steroidal alkaloids/glycoalkaloids has been demonstrated in two Solamm spp. S. ciliatum, S. sisymbrifolium). However, there is no report on co-occurrence of these alkaloids and withanolides. In a few taxa even withanolides co-occur surprisingly with different types of tropane alkaloids, i.e., hyoscyamine-type tropanes fowDatura spp., Hyoscyamus niger) or non-hyoscyamine-type tropanes and related alkaloids Nicandra physalodes, Physalis alkekengi, P. peruviana, Withania somnifera) for details see Tables 3.1 and 3.8. 

---