Phytochemical and biological study of the aerial parts of lotus lalambensis growing in Saudi Arabia

ABSTRACT

Phytochemical investigation of the aerial parts of Lotus lalambensis Schweinf resulted in the isolation and identification of 20 known compounds. Liquid-Liquid fractionation of the crude extract followed by chromatographic purification resulted in the isolation of lupeol, beta-sitosterol, oleanolic acid, beta-sitosterol glucoside and stigmasterol glucoside from the petroleum ether fraction. The chloroform fraction afforded heptadecanol, kaempferol [1], kaempferol-3-O-alpha-L-rhamnoside [2], lotaustralin [3], epilotaustralin [4], linamarin [5], kaempferol-3,7-di-O-alpha-L-rhamnopyranoside [kaempferitin] [6] and ethyl-O-beta-D-glucopyranoside [7]. From the ethyl acetate fraction three simple rhamnosyl derivatives; butyl-O-alpha-L-rhamnopyranoside [8] methyl-O-alpha-L-rhamnopyranoside [9] and methyl-O-beta-L-rhamnopyranoside [10] were obtained. Kaempferol-3-0-beta-D-glucopy-ranoside-7-O-alpha-L-rhamnopyranoside [11], kaempferol-3-O-alpha- [beta-D-glucopyranosyl-[1""->2'"]- L-rhamnopyranoside]-7-O-alpha-L-rhamnopyranoside [12], kaempferol-3-O-beta-D-glucopyranoside-7-O-alpha-[beta-D-glucopyranosyl-[1""->2'"]-L-rhamnopyranoside] [13] and the myo-inositol [+] D-pinitol [14] were isolated from the butanol extract. The total extract and different fractions were evaluated for their possible estrogenic, anti-inflammatory and anti-platelets aggregation activities. The chloroform extract showed the highest estrogenic activity, while the petroleum ether was the best in protection against inflammation induced by carrageenan. The strongest inhibition of platelet aggregations was observed with the aqueous fraction