Isolation of Apigenin Derivatives from the Leaves of Chorisia speciosa, Cordia dichotoma, Mentha piperita and Roots of Pluchea lanceolata

doi.org/10.26538/tjnpr/v1i6.4

Abstract

Apigenin (4′,5,7-trihydroxyflavone) is a plant-derived skin cancer chemopreventive flavonoid that has anti-allergic, anti-depressant, anti-inflammatory, antimetastatic, antioxidant and anti-cancer properties. Our study was planned to isolate the apigenin derivatives from the leaves of Chorisia speciosa A. St. Hil.(Bombacaceae, Malvaceae), Cordia dichotoma G. Forst. (Boraginaceae) and Mentha piperita L. (Lamiaceae) and the roots of Pluchea lanceolata (DC.) C. B. Clarke (Asteraceae). The air-dried plant materials were exhaustively extracted with methanol in a Soxhlet apparatus. The concentrated methanol extracts were adsorbed on silica gel (60-120 mesh) for the preparation of slurries. The dried slurries were chromatographed over silica gel columns individually. The columns were eluted with petroleum ether, chloroform and methanol, successively, in order of increasing polarity to isolate the apigenin derivatives. Phytochemical investigation of the methanol extract of the leaves of C. speciosa afforded β-sitosterol 3-β-Lglucopyranoside (1) and apigenin 4′-O-α-L-glucopyranosyl-(6′′→1′′′)-α-L-rhamnopyranoside (2). Column chromatography of the methanol extract of the leaves of C. dichotoma gave α-L-arabinose (3), β-D-arabinose (4) and acacetin-7-O-β-D-glucopyranosyl-(6a→1b)-O-β-D-glucopyranosyl-
(6b→1c)-O-β-D-glucopyranosyl-2c-linolenate (5). The methanol extract of the leaves of M. piperita on subjection to silica gel column furnished 5-hydroxy-6, 7, 3′, 4′-tetramethoxy-8-(1′′- gerananyl)-flavone or 8-(1′′-gerananyl)-5-demethylsinensetin (6) and 3′,4′-dihydroxy-β-phenylethyl caffeate-4-(3′′′-menthyl)-4′-β-D-glucopyranoside or 4-(3′′-menthyl) teucrol 4′-O-β-Dglucoside, 7). The chemical constituents isolated from the methanol extract of the roots of P. lanceolata included n-tridecyl stearate (8), n-nonadecanol (9) and 8-isobutyl apigenin (10). Apigenin derivatives were isolated from the investigated medicinal plants. Their structures were
established on the basis of spectral data analysis and chemical reactions.