Abstract: Twenty-four constituents were isolated from the root of Aristolochia versicolar S. M. Hwang (collected from Guangxi province, China). Ten of them (two novel sesquiterpene lacrones and eight known compounds) were reported recently. This paper deals with the other eight compounds. From the petroleum ether extraction a sesquiterpene lactone, C15H20O2, mp. 94–95℃ [α]D36 –49˚ (C=1.8, EtOH), confirmed to be isoaristolactone, was obtained from plants for the first time. On the basis of spectral analysis (UV, IR, 1HNMR, 13CNMR, MS) and chemical reactions its structure was determined as B2. From the petroleum enter unsoluble sec- tion 6-methoxyaristolic acid methyl ester (D1), aristolic acid (D3), 6-methoxyaristolic acid (ari- stolinic acid) (D4f), 6-methoxyaristolochic acid methyl ester (D4y), aristolochic acid A(D5), β-sitosterol-D-glucoside (D10) and allantoin (C2) were isolated and identified. Dx, Ds, and Ds show ed antifertility activity in mice.

Key words: Aristolochia versicolar, Isoaristolactone, Sesquiterpene lactone, 6-methoxyaristolic acid