Abstract: The present invention reveals the isolation, purification and characterization from the creosote bush Larrea tridentata of compounds of the structural formula: where R1, R2, R3 and R4 are each selected from the group consisting of HO—, CH3O— and CH3(C═O)O—, provided that R1, R2, R3 and R4 are not each HO—0 simultaneously. Each compound is a derivative of 1,4-bis-(3,4-dihydroxyphenyl)-2,3-dimethylbutane (nordihydroquaiaretic acid, NDGA). In addition, NDGA and each derivative can be used in a method to suppress Tat transactivation of a lentivirus, including the HIV virus, in a cell by administering NDGA or a derivative of NDGA to the cell.

Abstract: A method for suppressing undesired viral growth in a host which comprises administering to the host an effective amount of a compound of the formula: wherein R1, R2, R3 and R4 are independently selected from the group consisting of HO—, CH3O— and CH3(C═O)O—. The method is exemplified by inhibiting Tat transactivation of a lentivirus and in suppressing Herpes simplex virus.

Abstract: Larrea tridentata and Ambrosia deltoidea are shown to produce compounds that inhibit replication of HIV. The compounds can be extracted by differential fractionation and by counter-current chromatographic methods described herein. Extracts prepared from L. tridentata and A. deltoidea are found to be effective in inhibiting viral replication. The extracts from L. tridentata have been characterized and found to contain tricyclic lignans. The extracts can be administered to subjects for treatment of viral infection.

Abstract: The present invention reveals the isolation, purification and characterization from the creosote bush Larrea tridentata of compounds of the structural formula: ##STR1## where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each selected from the group consisting of HO--, CH.sub.3 O-- and CH.sub.3 (C.dbd.O)O--, provided that R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are not each HO-- simultaneously. Each compound is a derivative of 1,4-bis-(3,4-dihydroxyphenyl)-2,3-dimethylbutane (nordihydroquaiaretic acid, NDGA). In addition, NDGA and each derivative can be used in a method to suppress Tat transactivation of a lentivirus, including the HIV virus, in a cell by administering NDGA or a derivative of NDGA to the cell.

Abstract: A method for suppressing undesired viral growth in a host which comprises administering to the host an effective amount of a compound of the formula: wherein R1, R2, R3 and R4 are independently selected from the group consisting of HO—, CH3O— and CH3(C?O) O—. The method is exemplified by inhibiting Tat transactivation of a lentivirus and in suppressing Herpes simplex virus.