Structure-activity relationship study of androstene steroids with respect to local anti-inflammatory activity.

A sex hormone, 3beta-acetoxy-17beta-hydroxy-androst-5-ene (1) (CAS 1639-43-6), was isolated from aerial parts of Acacia nilotica. This compound is reported to have anti-inflammatory activity. In view of this, considering this molecule as a lead molecule different androstene compounds were synthesized to study their potency and structure-activity relationship with respect to local anti-inflammatory activity. The experiments indicated that 17 ketonic compounds were more active towards inflammation than their oxime analogues. Similarly, for the compounds containing an acetyl group fixed at C-3 position a decreasing trend of activity was observed in the order of ketonic, hydroxyl, oxime and acetyl group, respectively, when these groups are at C-17 position.

Larvicidal activity of Acacia nilotica extracts and isolation of D-pinitol--a bioactive carbohydrate.

A low-molecular-weight, sugar-like compound other than glucose, fructose, sucrose, or myo-inositol showing lipophilic nature was isolated from the EtOH extract of Acacia nilotica. The structure of the compound was determined by spectral methods. This alicyclic polyalcohol was found to be D-pinitol (= 3-O-methyl-D-chiro-inositol; 1). The configuration of the compound was confirmed by single-crystal X-ray analysis. The compound 1 is known from Soybean, Australian mangroves, Fagonia indica, Arachis hypogaea, etc., but we have isolated this compound for the first time from the aerial parts of A. nilotica. Very few references have been cited for compound 1 for its entomological activity, and there are no reports on mosquitoes. Therefore, the crude extracts of A. nilotica were tested for its biological activity against mosquito larvae. Acetone extract at 500-ppm concentration showed chronic toxicity against Aedes aegypti and Culex quinquefasciatus IVth instar mosquito larvae. Such a biological activity has been observed for the first time for this plant. This study could be a stepping stone to a solution for destroying larval species as well as consumption of such a widely grown, problem weed, A. nilotica. This larvicidal agent, since it is derived from plant, is eco-friendly, cost effective, non-hazardous to non-target organisms and would be safe unlike commercially available insecticides.

Isolation and X-ray study of an anti-inflammatory active androstene steroid from Acacia nilotica.

3beta-Acetoxy-17beta-hydroxy-androst-5-ene was isolated from aerial parts of Acacia nilotica (L.) Willd (Mimosaceae). The structure of this compound was established by spectral analysis and single crystal X-ray diffraction analysis. The steroid showed dose-dependent anti-inflammatory activity against TPA-induced mouse earedema.