Ursane-type Triterpene Glycosides from Rubus cochinchinensis Exhibited Insulin-Mimetic Activities in Differentiated 3T3-L1 Adipocytes

ABSTRACT

Diabetes mellitus is characterized by hyperglycemic due to impaired insulin secretion or resistance. In our search for anti-diabetic agents, we found that a 70% EtOH extract of Rubus cochinchinensis(Tratt) enhances glucose uptake in 3T3-L1 adipocytes. R. cochinchinensis is predominantly found in East Asia, particularly in Vietnam, Laos, Cambodia, and southern in China. Despite its widespread distribution, there have been few studies on its bioactivity or chemical constituents. In this study, activity-guided fractionation of 70% EtOH extract from the leaves of R. cochinchinensis resulted in the isolation of one new ursane-type glycoside, 3-O-β-acetyl-28-O-β-D-glucopyranosyl-rotundioic acid (1), along with four known compounds (2–5). The structures of these compounds were elucidated using 1D and 2D NMR and HRESIMS data. Notably, compound 4 significantly increased the uptake level of 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG) in differentiated 3T3-L1 adipocytes. This study suggests the potential of R. cochinchinensis as a promising medicinal plant for treating diabetes via glucose uptake.