To identify substances with anti-human immunodeficiency virus (HIV) activity in traditional medicines, water and methanol extracts of crude drugs used in Indian traditional medicine (Ayurveda) were subjected to screening for their inhibitory effects on HIV type 1 protease (PR). The enzyme activity was determined by HPLC and of the 39 crude drugs tested, the extracts of the seeds of Areca cutechu, the bark of Eugenia jambohnu, the bark of Saruca indica and the stem bark of Terminuliu arjuna inhibited the HIV-1 PR activity by more than 70% at a concentration of 0.2 mg/mL. The most potent inhibition was shown by the A. cutechu extract, from which some procyanidins were isolated. One of them, arecatannin B1 showed significant HIV-1-PR inhibitory activity.
Extracts of 41 medicinal plants used in Egyptian folk medicine were screened for their inhibitory effects on human immunodeficiency virus-1 reverse transcriptase. The extracts of fruits of Phyllanthus emblica, Quercus pedunculata, Rumex cyprius, Terminalia bellerica, Terminalia chebula and Terminalia horrida showed significant inhibitory activity with IC50 < or = 50 micrograms/ml. Through a bioassay guided-fractionation of the methanol extract of the fruit of P. emblica, putranjivain A (1) was isolated as a potent inhibitory substance with IC50 = 3.9 microM, together with 1,6-di-O-galloyl-beta-D-glucose (2), 1-O-galloyl-beta-D-glucose (3), kaempferol-3-O-beta-D-glucoside (4), quercetin-3-O-beta-D-glucoside (5) and digallic acid (6). The inhibitory mode of action by 1, 2 and 6 was non-competitive with respect to the substrate but competitive with respect to a template-primer. Furthermore, the stereochemistry of 1 was established in this paper by nuclear magnetic resonance spectroscopy.
Of 30 Indonesian plant extracts tested for their human immunodeficiency virus type-1 (HIV-1) inhibitory activities, six were shown to be effective by assays using HIV-1-infected MT-4 cells: a methanol extract of mahoni (bark of Swietenia rnahagoni) and water extracts of benalu teh (stems and branches of Loranthus parasiticus), kiules (fruit of Helicteres isora), supratul (fruits of Sindoru surnalranu), sambiloto (leaves of Andrographis paniculata) and temu ireng (rhizoma of Curcurna aeruginosa). Their EDs values ranged from 4.2 to 175 pg1mL. The samples also suppressed the formation of syncytia in co-cultures of MOLT-4 and MOLT41HIV-1 cells. The most potent inhibitor was a methanol extract of mahoni, which also showed a significant inhibition of HIV-1 protease.
Methanol and water extracts of 30 Indonesian medicinal plants were tested for inhibitory activity on avian myeloblastosis virus (AMV)-reverse transcriptase (RT). The most potent inhibition was shown by extracts of Lorunthus purusiticus (whole plant), Helicteres isoru (fruit), Terminaliu belericu (fruit peel), Strobilanthes crispus (leaves) and Woodfordiu jloribundu (flower and leaves). Two kinds of template-primers, (rA)n-(dT)lz-and (rC)n-(dG)12-18 were examined for polymerization reaction but the inhibitory activity was stronger in the (rC)n-(dG)lz-18 directed reaction in most of the samples. These extracts showed no appreciable cytotoxicity at concentrations where over 90% of RT activity was inhibited.
Inhibitory effects of 18 condensed tannins and related compounds on reverse transcriptase from an RNA tumour virus were examined in the presence of poly(riboadeny1ic acid) oligo(deoxythymidy1ic acid) ((rA)n(dT)lt-18) or poly(ribocytidy1ic acid) oligo(deoxyguany1ic acid) ((rC)m(dG),t-18) as a template-primer. A potent inhibitory effect was found in galloylated monomers and oligomers as well as non-galloylated tetramer, trimer and two of three dimers. The mode of the inhibition of one of them, procyanidin B-2, was competitive with regard to the template-primer.
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