Two new dibenzyl derivatives, dendrocandins V-W (1-2), together with six known compounds (3-8), have been isolated from the dried stems of Dendrobium catenatum. Their structures were mainly elucidated on the basis of HRESIMS, one- and two-dimensional NMR techniques. The isolated compounds 5-8 were evaluated in vitro for their antioxidant and hypoglycemic activities. Compound 8 showed moderate potent DPPH scavenging activity with IC50 value of 34.45 ± 1.07 µM. And compounds 5, 7-8 exhibited significant ABTS radical scavenging activities with IC50 values of 10.03 ± 0.88, 5.32 ± 1.13 and 9.01 ± 1.39 µM. Compounds 6-7 showed potent α-glucosidase inhibitory activities with IC50 values of 36.05 ± 0.67 and 159.59 ± 0.86 µM.
Keywords: Dendrobium catenatum; Orchidaceae; antioxidant activity; dibenzyl derivatives; α-glucosidase inhibitory activity.