Anti-human Immunodeficiency Virus-1 Constituents of the Bark of Poncirus trifoliata

A total of 36 compounds (1-36) were obtained from the stem bark of Poncirus trifoliata including three new prenylated flavonoids, (-)-5,4'-dihydroxy-7,8-[(3 '',4 ''-cis-dihydroxy-3 '',4 ''-dihydro)-2 '',2 ''-dimethylpyrano]-flavone (1), (-)-5,4'-dihydroxy-7,8-[(3 ''-hydroxy-4 ''-one)-2 '',2 ''-dimethylpyrano]-flavone (2), and (-)-5,4'-dihydroxy-7,8-[(cis-3 ''-hydroxy-4 ''-ethoxy-3 '',4 ''-dihydro)-2 '',2 ''-dimethylpyrano]-flavone (3). The new structures were elucidated by means of spectroscopic methods. Compounds 1-20 were evaluated for their anti-human immunodeficiency virus-1 (HIV-1) activity, in which 2 showed significant anti-HIV-1 activity with high therapeutic index (T1) of 143.65.

This work has been supported by the program for New Century Excellent University Talents, State Education Ministry of China (NCET-06-0868), and the Key Project of Chinese Ministry of Education (No. 107105). We also would like to acknowledge Scientific and Technological Projects of China (2009ZX09501-029, 2008ZX10005-005) and Yunnan (2007BC006), 863 Program (2006AA020602), 973 Program (2009CB522306), the CAS (KSCX1-YW-R-24, KSCX2-YW-R-185), and the MRC AIDS Research Project and the NIH AIDS Research and Reference Reagent Program for providing cell lines and viruses.