Secolignans with antiangiogenic activities from Peperomia dindygulensis

Two new secolignans, peperomins G and H ( 1 and 2 , resp.), were isolated from the whole plant of Peperomia dindygulensis, together with five known secolignans, peperomin A ( 3 ), peperomin E ( 4 ), peperomin B ( 5 ), 2,3‐trans‐2‐methyl‐3‐{(3‐hydroxy‐4,5‐dimethoxyphenyl)[5‐methoxy‐3,4‐(methylenedioxy)phenyl]methyl}butyrolactone ( 6 ), 2,3‐cis‐2‐(hydroxymethyl)‐3‐{bis[5‐methoxy‐3,4‐(methylenedioxy)phenyl]methyl}butyrolactone ( 7 ). Their structures and configurations were elucidated by spectroscopic methods including 2D‐NMR techniques. Antiangiogenic effects of all compounds were evaluated using human umbilical vein endothelial cells (HUVEC) proliferation and tube‐formation tests, with compounds 4 and 5 being active in the bioassay. Compounds 4 and 5 induced obvious cell toxicity to HUVEC with IC₅₀ values of 1.64±0.19 and 8.44±0.4 μM , respectively. Compounds 4 and 5 also exhibited significant HUVEC tube formation‐inhibiting activity with IC₅₀ values of 3.13±0.09 and 6.24±0.12 μM , respectively.     

7,8-secolignans from Schisandra wilsoniana and their anti-HIV-1 activities

Two new 7,8‐secolignans, marphenols A and B ( 1 and 2 , resp.), together with a known related derivative, 7,8‐secoholostylone B ( 3 ), were isolated from the stems of Schisandra wilsoniana. The structures of 1 and 2 were elucidated by spectroscopic methods, including extensive 1D‐ and 2D‐NMR techniques. The anti‐HIV‐1 activities of 1 – 3 were evaluated. Compound 1 inhibited HIV‐1_IIIB‐induced syncytia formation with an EC₅₀ value of 0.55 μg ml^?1. It reduced p24 antigen expression in acutely HIV‐1_IIIB‐infected C8166 cells and primary isolate HIV‐1_TC‐2‐infected peripheral blood mononuclear cells (PBMCs), with EC₅₀ values of 3.34 and 0.52 μg ml^?1, respectively. It showed no effects on the HIV‐1_IIIB replication in chronically infected H9 cells as well as fusion inhibition.