Three new methylene-bridged bisflavonoid glycosides with cardioprotective activity from Suaeda glauca

Abstract

A comprehensive phytochemical and pharmacological investigation of the n-BuOH fraction derived from an aqueous ethanol extract of Suaeda glauca (Bunge) Bunge led to the identification of twenty-two compounds. These include five methylene-bridged dimeric flavonol glycosides (1–5), three mono-flavonol glycosides (6–8), three phenylacrylic acids (9–11), three benzoic acids (12–15), and seven alkaloids (16–22). Notably, compounds 1–3 are newly reported. Furthermore, compounds 4, 5, 9–12, and 16–22 are reported for the first time from the genus Suaeda, with compounds 4 and 16 identified as new natural products. Compounds 1–9 and 16–20 demonstrated the ability to ameliorate pericardial edema and venous congestion in zebrafish embryos induced by verapamil hydrochloride (VH) at a concentration of 50 μM. In contrast, other compounds at this concentration exhibited lethal or teratogenic effects. Importantly, compounds 3 and 4 displayed superior efficacy in alleviating venous congestion in zebrafish embryos compared to the positive control, digoxin. These findings provide a theoretical foundation for the high-value utilization of the constituents of S. glauca.