Two Gynura species, G. bicolor and G. divaricata, are used in folk recipes for the treatment of diabetes mellitus in south China.
Our previous pharmacological study proved that both plants showed significant hypoglycemic
activity on normal and alloxan-diabetic mice. Sixteen chemical constituents were isolated
from the CH2Cl2 and EtOAc extracts of the aerial parts of G. bicolor. Their structures were determined spectroscopically as hydroxymethylfurfural, benzoic
acid, 4-hydroxybenzoic acid, protocatechuic acid, vanillic acid, 4-hydroxybenzaldehyde,
kaempferol, 3,3'-di-O-methylellagic acid-4-O-β-D-xylopyranoside, loliolide, ficusic
acid, vomifoliol, dehydrovomifoliol, boscialin, (6S,9S)-roseoside, benzyl-β-D-glucopyranoside,
and 2-phenylethyl-β-D-glucopyranoside. Fractionation and isolation of the EtOAc extract
of aerial parts of G. divaricata yielded six compounds [succinic acid, ethyl methyl succinate, salicylic acid, isovanillic
acid, 4-hydroxycinnamic acid, esculetin]. All compounds, except 4-hydroxybenzoic acid
and kaempferol, were isolated for the first time from these two plant sources.