Transcriptional suppression of the HIV promoter by natural compounds

Abstract

Tannins and lignins are natural compounds contained in plants such as tea leaves. Previously, we demonstrated that tannic acid represses 12- o-tetra-decanoyl phorbol-13-acetate (TPA)-induced human immunodeficiency virus (HIV) promoter activity. Furthermore, we demonstrated that a 30-bp element located just downstream of the NF-κB element in the HIV promoter responds negatively to tannic acid. However, the kinds of molecules responsible for this suppressive effect have remained unknown, because tannic acid is a mixture of various galloylglucoses. Here, we examined structure-defined natural compounds for HIV promoter-suppressive effects. We found that ellagitannins suppress TPA-induced HIV promoter activity to the same extent as tannic acid. 3-Phenylcoumarins, isoflavone and chalcones have more suppressive effects than ellagitannins. On the other hand, other flavonoids and acetogenins have no suppressive effect. 3-Phenylcoumarins and chalcones showed no suppressive effect on the cytomegalovirus (CMV) promoter, suggesting that they act specifically on the HIV promoter. These results suggest that 3-phenylcoumarin or chalcone compounds could be used to develop novel anti-HIV drugs with an action targeted at HIV promoter activity.