Four new terpenoids and other metabolites with potential anti-complementary activities from the aerial parts of Dracocephalum moldavica (Lamiaceae)

In the course of our continuing search for biologically active compounds from medicinal herbs, four undescribed terpenoids including one monoterpenoid glycoside, (1 R, 3S, 4S, 5 R)-(-)-1,8-epoxy-p-menthan-5-ethoxycarbonyl-3-O-β-D-glucopyranoside (1), one iridoid glycoside, 3′-O-β-D-glucopyranosyl-melampyroside (2), one sesquiterpene, 1-(2-methylbutanol)-2-pentyl-1,3-cyclohexadiene (3), and one triterpenoid, 28-nor-3β,18β-dihydroxyurs-12-ene (4), together with nine known terpenoids (5–13) were isolated from the dried aerial parts of Dracocephalum moldavica (Lamiaceae). Their chemical structures were elucidated by detailed spectroscopy (1 D and 2 D NMR), HRESIMS data analysis and acid hydrolysis. Among them, compounds 9 and 10 were isolated from the family Lamiaceae, compounds 5, 6 and 11–13 were identified from the genus Dracocephalum and compounds 7 and 8 were reported from the D. moldavica for the first time. The biological evaluation of anti-complementary activity revealed that some compounds, 4, 6 and 12 exhibited anti-complementary activity with CH50 and AP50 values ranging from 0.67–1.43 and 1.12–1.55 mM, respectively.