Dihydrochalcone C-glycosides from Averrhoa carambola leaves.

Ten undescribed dihydrochalcone C -glycosides, carambolasides R1‒R3, S1, S2, T1‒T3, 3-hydroxycarambolaside T1, and 3-hydroxycarambolaside P were isolated along with carambolasides I and P from the leaves of Averrhoa carambola L. (Oxalidaceae). Their structures were determined by spectroscopic and chemical methods. Among them, carambolasides P, T1, T2, and I with contents of 22.78, 14.39, 4.93, and 1.87 mg g−1 dry wt., respectively, were shown to be abundant in the leaves by HPLC analysis. All the compounds showed more potent ABTS radical cation scavenging activity than l -ascorbic acid. 3-Hydroxycarambolaside T1 and 3-hydroxycarambolaside P also demonstrated moderate DPPH radical scavenging activity. Further, carambolaside R3, 3-hydroxycarambolaside T1, and 3-hydroxycarambolaside P exhibited weak in vitro porcine pancreatic lipase inhibitory activity. From Averrhoa carambola leaves, ten undescribed and two known dihydrochalcone C -glycosides were isolated, which showed potent antioxidant and weak pancreatic lipase inhibitory activities. The contents of five compounds were measured. Image 1 • Ten undescribed dihydrochalcone C -glycosides were isolated from A. carambola leaves. • The contents of five compounds were measured. • All the compounds showed potent ABTS radical cation scavenging activity. • Three compounds exhibited weak pancreatic lipase inhibitory activity. [ABSTRACT FROM AUTHOR]