2009 Volume 57 Issue 2 Pages 218-219
Three new compounds were isolated from the stems of Dendrobium candidum: (S)-3,4,4′-trihydroxy-5,α-dimethoxybibenzyl (1), named dendrocandin C; (S)-3,4,4′-trihydroxy-5-methoxy-α-ethoxybibenzyl (2), named dendrocandin D; and 3,3′,4,4′-tetrahydroxy-5-methoxybibenzyl (3), named dendrocandin E. Their structures were elucidated by 1D- and 2D-NMR spectroscopy and mass spectroscopy. The isolated compounds exhibited potent antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test, with IC50 values of 34.2, 34.5, and 15.6 μM for compounds 1, 2, and 3, respectively. Vitamin C was used as positive control with IC50 23.2 μM.
