Diverse lignans with protective effect against hypoxia/oxidative injuries to H9c2 cells from Syringa pinnatifolia Hemsl

A bioactivity-guided fractionation on the phenolic fractions from the peeled stems of Syringa pinnatifolia Hemsl., one of representative Mongolian folk medicine in China, led to the isolation and structural determination of 11 undescribed lignans and 12 known ones. These lignans cover diverse types, among them syringanones A and B represent an unprecedented carbon skeleton (proposed syringanane) and alashanenol A possesses a rare bicyclo [3.3.1]nonadienemethanol core. Their structures were established by extensive spectroscopic data analysis, X-ray diffraction, and quantum chemical calculations. All isolates were evaluated for their cardioprotective activities on H9c2 cardiomyocytes in vitro. The results showed that five lignans exhibited the protective effects against hypoxia-induced injury at the concentrations of 1.2–40 μM and six lignans exhibited anti-oxidative stress injury at 10–40 μM. These findings account to some extend for the traditional therapeutic effects of S. pinnatifolia for the treatment of ischemic heart diseases in clinic. Eleven undescribed lignans and twelve known ones were isolated from the stems of Syringa pinnatifolia Hemsl. by a bioactivity-guided approach. Their cadioprotective activities on H9c2 cells were evaluated. [Display omitted] •Eleven undescribed lignans were isolated from the stems of Syringa pinnatifolia.•Their structures with absolute configurations were completely resolved.•Syringanones A and B represent an unprecedented carbon skeleton.•Alashanenol A possesses a rare bicyclo [3.3.1]nonadienemethanol core.•These lignans exhibited cadioprotective effects on H9c2 cells.