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Polygonumins A, a new compound, was isolated from the stem of Polygonum minus. Based on NMR results, the compound’s structure is identical to that of vanicoside A, comprising four phenylpropanoid ester units and a sucrose unit. The structure differences were located at C-3″″′. The cytotoxic activity of polygonumins A was evaluated on several cancer cell lines by a cell viability assay using tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The compound showed the highest antiproliferative (p < 0.05) activities against K562 (Human Leukaemia Cell Line), MCF7 (Human breast adenocarcinoma cell line), and HCT116 (Colorectal cancer cells) cells. Cytotoxic studies against V79–4 cells were carried out and showed that polygonumins A was toxic at 50 µg/ml, suggesting that this compound may be used as an anticancer drug without affecting normal cells. Polygonumins A also showed promising activity as an HIV-1 protease inhibitor with 56% relative inhibition. Molecular docking results indicated that the compound possesses high binding affinity towards the HIV protease over the low binding free energy range of -10.5 to -11.3 kcal/mol. P. minus is used in Malaysian traditional medicine for the treatment of tumour cells. This is the first report on the use of P. minus as an HIV-1 protease inhibitor.

Background and aim Lignosus rhinocerus (LR) is an edible mushroom with a variety of medicinal properties such as neurostimulation, immunomodulation, anti-inflammation, anti-oxidation, anti-proliferation, anti-diabetes and especially antiviral activity. Human immunodeficiency virus type-1 (HIV-1) needs the HIV-1 protease (PR) and reverse transcriptase (RT) for its replication. Therefore, both HIV-1 PR and RT are important targets for antiretroviral drug development. Experimental procedure The crude hexane (LRH), ethanol (LRE) and water (LRW) extracts of LR were in vitro screened for inhibitory activity against HIV-1 PR and RT, then anti-HIV-1 activity on the infected MOLT-4 cells were determined. Chemical constituents of the extracts were identified by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC)-MS. The identified compounds were in silico analysed for drug-likeness property and molecular modelling. Results and conclusion According to our screening assays, LRE and LRW significantly inhibited both enzymes (25–55%), while LRH suppressed only the HIV-1 PR activity (88.97%). At 0.5 mg/ml of LRW showed significant inhibition of HIV-1 induced syncytial formation and p24 production in the infected MOLT-4 cells. Investigation of chemical analysis revealed that major groups of identified constituents found in the extracts were fatty acids, peptides and terpenoids. In silico analysis showed that heliantriol F and 6 alpha-fluoroprogesterone displayed great binding energies with HIV-1 PR and HIV-1 RT, respectively. These findings suggest that LR could be a potential source of compounds to inhibit HIV-1 PR and/or RT activities in vitro . Furthermore, our results provide beneficial data for the development of novel HIV-1 PR and RT inhibitors.

BackgroundAcquired immunodeficiency syndrome (AIDS) is caused by the Human immunodeficiency virus type-1 (HIV-1). HIV-1 protease (HIV-1 PR) is an essential enzyme for the HIV replication, and therefore, it is an important target for antiretroviral drugs development, particularly from natural products. Auricularia polytricha (AP) is an edible mushroom with several important therapeutic properties. These properties will be investigated as HIV-1 PR inhibitors.MethodsThe sequential hexane (APH), ethanol (APE) and water (APW) extracts from AP were screened for inhibitory activity against HIV-1 PR. The extract that consistently showed the strong HIV-1 PR inhibition was further investigated for its phytochemical constituents. The compounds were purified by column chromatography. The isolated compounds were structurally elucidated using 1D and 2D NMR, HRMS, FTIR, and GC/MS techniques. Each compound was screened against HIV-1 PR to determine its inhibitory activity and to provide an explanation for the activity found in the extract.ResultsHexane crude extract of AP (APH) exhibited significant inhibition on HIV-1 PR activity. Four major compounds isolated from APH fraction were identified to be two triacylglycerols, linoleic acid and ergosterol. Moreover, all four compounds showed significant inhibition of HIV-1 PR activity.ConclusionThe findings from this study suggest that AP is a good source of fatty esters, fatty acids and ergosterol. These natural products exhibit anti-HIV-1 properties by blocking HIV-1 PR. These important biological results warrant further development of AP as an alternative antiretroviral drug.