Minor Sesquiterpenoid and Steroid Constitutes from Azadirachta indica A. Juss and Their Cytotoxic Activity

Abstract

Background  Neem (Azadirachta indica A. Juss) is a plant belonging to the meliaceae family. It was used widely as herbal medicine in ancient India and Burma. It possesses a variety of chemical constitutes. Recent studies showed that some of major constitutes have remarkable anticancer activities. However, the minor constitutes in neem are still studied insufficiently.

Aim The aim of the study is to identify the minor constitutes in neem, and investigate their cytotoxic activity.

Material & methods The dry seeds of neem were extracted with 95% ethanol. The ethyl acetate fraction of the extract was systematically separated by silica gel, Sephadex LH-20, High Performance Liquid Chromatography (HPLC) and other chromatographic techniques. The structures of the resulting isolates were elucidated by spectroscopic methods, such as mass spectrum (MS), nuclear magnetic resonance spectrum (NMR), etc.

Results A sesquiterpenoid, 11,13-dihydroqinghaosu V (1), together with two known steroids, (24R)-ergosta-5,7,22E-trien-3 beta-ol (2) and 5 alpha,8 alpha-epidioxiergosta-6,22-dien-3 beta-ol (3), was isolated from the dry seeds of neem. 1 is a compound which is isolated from nature for the first time. In vitro cytotoxic bioassays showed that compound 1 selectively inhibited the growth of Hela cell lines, with an IC₅₀ value of 37.26 ±6.02 µM.

Conclusion The study indicated that besides some major constituents of neem possessing anticancer activity, its minor metabolites may also inhibit growth of cancer cells.