Biphenyl derivatives from the twigs of Garcinia bracteata and their biological activities

Abstract Three new biphenyl derivatives, bractebiphenyls A–C ( 1 – 3 ), along with five known biphenyl derivatives ( 4 – 8 ) were isolated from the acetone extract of the twigs of Garcinia bracteata . Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. The anti-tobacco mosaic virus (anti-TMV) activities of 1 – 8 were evaluated. Compound 3 showed high anti-TMV activities with inhibition rates of 28.4%, which is close to that of Ningnanmycin (30.2%). Compounds 1 – 3 , 6 and 8 were also tested for their cytotoxicities against five human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7), and 3 showed high cytotoxicities against A549 and PC3 cell with IC 50 values of 3.6 and 2.7 μM, respectively.