A new steroidal compound (β-sitosterol-3-O-butyl) isolated from Caesalpinia gilliesii flowers

Summary. The study aimed to evaluate the cytotoxic activity of total extracts from leaves, flowers and pods of Caesalpinia gilliesii (Fabaceae, Caesalpinoideae). In addition, a detailed phytochemical investigation of flower extracts was carried out to isolate and elucidate the structures of the bioactive compounds. Flower extract was the most cytotoxic against MCF7 and HepG2 cancer cells with IC 50 values of 10 and 15.6 µ g/mL, respectively. A new β- sitosterol-3 -O- butyl was isolated from dichloromethane fraction of flowers together with another known sterol (daucosterol), and two flavonoids (isorhamnetin and isorhamnetin 3- O -rhamnoside). β- sitosterol-3 -O- butyl was the most active compound against both HepG2 and MCF7 cells with IC 50 values of 13.1 and 14.4 µ g/mL, respectively. Isorhamnetin possesses a moderate antioxidant activity with an IC 50 value 370 µ g/mL as determined by DPPH radical scavenging assay. Industrial relevance. β- sitosterol-3 -O- butyl and the other phytosterols are responsible for the cytotoxicity of the extracts which would correlate with the known abortifacient, antimalarial and anthelmintic properties, which can provide a cheap alternative drug. Keywords. Cytotoxicity, antioxidant; Caesalpinia gilliesii; β- sitosterol-3 -O- butyl; daucosterol; isorhamnetin-3- O -rhamnoside