Two antidiabetic constituents from Roylea cinerea (D.Don) Baill.

Two antidiabetic compounds named 4-methoxybenzo[b]azet-2(1H)-one (1) and 3β-hydroxy-35-(cyclohexyl-5′-propan-7′-one)-33-ethyl-34-methyl-bacteriohop-16-ene (2) together with stigmasterol and β-sitosterol were isolated from the aerial part of Roylea cinerea (D.Don) Baill. The structures of these compounds were elucidated by advanced spectroscopic methods, including two-dimensional NMR and MS techniques. These compounds were evaluated for their antidiabetic efficacy using in vitro and in vivo methods. Both compounds (1 and 2) showed a significant decline in blood glucose level of alloxan-induced diabetic rats at 10 mg/kg, p.o. when compared with glibenclamide at a similar dose. The in vitro studies revealed that compound 1 reduced α-amylase and α-glucosidase by 83.0 and 78.5%, respectively, whereas compound 2 reduced the same by 58.2 and 58.4%, respectively, at 100 μM. The present study supports the role of R. cinerea in Ayurvedic medicine for diabetes.