HIV-1 Reverse Transcriptase Inhibitory Activity Research Articles

Pleurotus citrinopileatus Extracts in HepG2 Cancer Cell Study

Introduction: Pleurotus citrinopileatus is a mushroom with n-number of biomolecules expressing both nutraceutical and pharmaceutical qualities. In recent years, there are many medicinal properties of the mushroom brought to light, be it the biomolecules that inhibits fat-induced weight gain; cancer treatments for hepatoma, colon or HIV-1 reverse transcriptase inhibitory activity by novel lectins present in it. Objective: The present study is to find the degree of cell damage in HepG2 cancer cell lines caused by the extracts of Pleurotus citrinopileatus. Method: Herein, we are going to compare the level of cell damage caused by acetone, ethanol and aqueous extracts of Pleurotus citrinopileatus using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Result: Acetone extracts of the mushroom showed higher cell damage in HepG2 cell line, indicated by MTT assay with the half-maximal inhibitory concentration (IC50) value of 37.03µg/ml, compared to the ethanolic and aqueous extracts of Pleurotus citrinopileatus. Conclusion: The acetone extract appears to possess biologically active compounds that might help reduce the viable cancer cells. If used as an adjuvant drug with cisplatin can reduce the effects caused by it and activate P53 action. Novelty: Further study on the biomolecules present in oyster mushrooms can give us an insight into the apoptotic behavior of cancer cells.

Insights into the key structural features of triazolothienopyrimidines as anti-HIV agents using QSAR, molecular docking, and pharmacophore modeling

The development of severe drug resistance caused by the extensive use of anti-HIV agents has resulted in resistance mutation that compromise efficacy of anti-retroviral. We have selected triazolothienopyrimidine derivatives for our study since these derivatives have potentially inhibited HIV-1 replication. The objectives of our study were to identify the important pharmacophoric features and correlate 3D chemical structure of of triazolothienopyrimidines and predict their anti-HIV activity using 2D-, 3D-QSAR, pharmacophore modeling, and docking studies to explore their binding to HIV-1 reverse transcriptase. Partial least square and k-nearest neighbor methodology were used to develop 2D-QSAR and 3D-QSAR models. The statistical significance of developed QSAR models was checked by internal and external validation. The developed 2D-QSAR model indicated that a significance of presence of electron withdrawing groups, number of hydrogen bond acceptor, Z component dipole moment, and the moment of inertia at X axis of the compounds on their anti-HIV potential. 3D-QSAR results indicated the influence of electrostatic and steric field descriptors in the anti-HIV potential of triazolothienopyrimidines. The pharmacophore mapping represented the importance of aromatic and hydrogen bond acceptor features of compounds to interact with the target. Docking studies revealed that the binding of the triazolothienopyrimidines to HIV-1 reverse transcriptase involved extensive hydrophobic and polar interactions. Collectively, the results of QSAR, pharmacophore mapping, and the docking studies provide an insight into the understanding of the relationship between triazolothienopyrimidines and anti-HIV activity, which may assist in designing new triazolothienopyrimidines with enhanced HIV-1 reverse transcriptase inhibitory and anti-HIV activity.

A Novel Peroxidase from Fresh Fruiting Bodies of the Mushroom Pleurotus pulmonarius

A novel peroxidase has been isolated from fresh fruiting bodies of the mushroom Pleurotus pulmonarius, with a purification protocol of ion exchange chromatography on DEAE-cellulose, affinity chromatography on ConA-Sepharose, ion exchange chromatography on CM-cellulose, and gel filtration by FPLC on Superdex 75. The peroxidase was unadsorbed on either DEAE-cellulose or ConA-Sepharose, but was adsorbed on CM-cellulose. It exhibited a molecular mass of 55 kDa in gel filtration and also in sodium dodecyl sulfate–polyacrylamide gel electrophoresis, indicating that it is a monomeric protein. It possessed a distinctive N-terminal amino acid sequences from other isolated mushroom peroxidases. The optimal pH and temperature for the enzyme were 4.0 and 70 °C, respectively. All enzyme activity was destroyed after exposured in 100 °C for 10 min. The peroxidase did not exhibit HIV-1 reverse transcriptase inhibitory activity and antifungal activity. The stability against high temperature and extreme pH supported that the enzyme could be a potential peroxidase source for special industrial applications.

Aqueous two phase partitioning of Pisum sativum lectin in PEG/citrate salt system

Pisum sativum lectin (Psl) is a metalloprotein which is in the center of research interest because of its HIV-1 reverse transcriptase inhibitory activity and mitogenic activity. The application of this lectin in various fields demands the economically feasible and scalable purification strategy other than affinity chromatography. The suitability of aqueous two phase system (ATPS) composed of poly ethylene glycol (PEG) with different salts (sodium citrate, potassium citrate, and ammonium citrate) was evaluated for better partitioning of Psl. The significant factors such as molar mass and concentration of PEG, type and concentration of salts, the effect of tie line length (TLL), ionic strength, and pH were studied to select a suitable system for better partitioning of Psl. ATPS comprising of 18% PEG 6000, 16% sodium citrate, 1% NaCl at the operating condition of pH 8, 40.23% of TLL, and the volume ratio of 1.32 was found to be the best system which gave a maximum partition coefficient and yield of 14.5% and 98.66%, respectively.

First discovery of a potential carbonate prodrug of NNRTI drug candidate RDEA427 with submicromolar inhibitory activity against HIV-1 K103N/Y181C double mutant strain

In the present work, we described the synthesis, antiviral profiles and metabolic stability in human plasma of compound 6, a potential carbonate prodrug of HIV-1 NNRTI drug candidate RDEA427. Compound 6 was found to inhibit the wild-type (WT) and K103N/Y181C double mutant HIV-1 strains at nano- and submicromolar concentrations, respectively. Moreover, it displayed potent HIV-1 reverse transcriptase inhibitory activity (IC50 = 0.264 μM). Further stability test in human plasma showed that 6 could release its active form RDEA427 in a linearly time-independent manner, possibly acting as a potential prodrug.

Purification and Characterization of a White Laccase with Pronounced Dye Decolorizing Ability and HIV-1 Reverse Transcriptase Inhibitory Activity from Lepista nuda.

A strain LN07 with high laccase yield was identified as basidiomycete fungus Lepista nuda from which a white laccase without type I copper was purified and characterized. The laccase was a monomeric protein with a molecular mass of 56 kDa. Its N-terminal amino acid sequence was AIGPAADLHIVNKDISPDGF. Besides, eight inner peptide sequences were determined and lac4, lac5 and lac6 sequences were in the Cu2+ combination and conservation zones of laccases. HIV-1 reverse transcriptase was inhibited by the laccase with a half-inhibitory concentration of 0.65 μM. Cu2+ ions (1.5 mM) enhanced the laccase production and the optimal pH and temperature of the laccase were pH 3.0 and 50 °C, respectively. The Km and Vmax of the laccase using ABTS as substrate were respectively 0.19 mM and 195 μM. Several dyes including laboratory dyes and textile dyes used in this study, such as Methyl red, Coomassie brilliant blue, Reactive brilliant blue and so on, were decolorized in different degrees by the purified laccase. By LC-MS analysis, Methyl red was structurally degraded by the laccase. Moreover, the laccase affected the absorbance at the maximum wavelength of many pesticides. Thus, the white laccase had potential commercial value for textile finishing and wastewater treatment.

4-Thiazolidinone derivatives as potent antimicrobial agents: microwave-assisted synthesis, biological evaluation and docking studies

A series of ten thiazolidin-4-one derivatives was synthesized and evaluated for their antibacterial, antifungal and HIV-1 reverse transcriptase (RT) inhibitory activity.

Isolation of a ribonuclease with antiproliferative and HIV-1 reverse transcriptase inhibitory activities from Japanese large brown buckwheat seeds.

A ribonuclease, with a molecular mass of 22.5 kDa and an N-terminal sequence exhibiting resemblance to previously isolated buckwheat storage proteins and allergens, was isolated from Japanese large brown buckwheat seeds. The ribonuclease was purified using a simple protocol that comprised ion exchange chromatography on Q-Sepharose and DEAE-cellulose and gel filtration on Superdex 75. The ribonuclease exhibited low activity toward poly U, lower activity toward poly C, and very low activity toward poly A and poly G. The enzyme was activated upon exposure to 10 mM of Fe(2+) and Zn(2+) ions but was inhibited by Ca(2+), Mg(2+), and Mn(2+) ions at the same concentration. The optimum pH and optimum temperature for the enzyme were pH 9 and 60 °C, respectively. It inhibited proliferation of HepG2 hepatoma and MCF 7 breast cancer cells, with an IC50 value of 79.2 and 63.8 μM, respectively. It potently inhibited HIV-1 reverse transcriptase activity with an IC50 of 48 μM. However, there were no antifungal and mitogenic activities.

HIV-1 reverse transcriptase inhibitory activity of Aerva lanata plant extracts

Background HIV-1 reverse transcriptase (HIV-1 RT) is an essential enzyme for the replication cycle of HIV. HIV-1 RT inhibitors have been extensively investigated for their antiHIV properties. However, emergence of HIV drug resistance and side effects are the main reasons for failure of anti-HIV therapy. The aim of the present study was to evaluate the HIV reverse transcriptase inhibitory activity of Aerva lanata plant extracts.

Synthesis, in-vitro reverse transcriptase inhibitory activity and docking study of some new imidazol-5-one analogs

Non-nucleoside reverse transcriptase inhibitors have a definitive role and most commonly used in treatment of HIV-1 infection. A new series of 4-ethylidene/substituted-benzylidene-1-(4-hydroxy/chloro-6-methylpyrimidin-2-yl)-2-ethyl/phenyl-1H-imidazol-5(4H)-one were designed, synthesized, and evaluated for HIV-1 reverse transcriptase (RT) inhibitory activity. The results of in-vitro HIV-1 RT assay showed that some of the new compounds, such as 4c, 4d, 4e, 5a, and 5e effectively inhibit HIV-1 RT activity. 1-(4-Chloro-6-methylpyrimidin-2-yl)-4-(furan-2-ylmethylene)-2-methyl-1H-imidazol-5(4H)-one (5e) exerted most potent in-vitro HIV-1 RT inhibitory activity, among the group of compounds. Molecular docking studies were carried out to explore the binding affinity of imidazole-5-one analogs in active site of HIV-1 RT enzyme.

A novel hemagglutinin with antiproliferative activity against tumor cells from the hallucinogenic mushroom Boletus speciosus.

Little was known about bioactive compounds from the hallucinogenic mushroom Boletus speciosus. In the present study, a hemagglutinin (BSH, B. speciosus hemagglutinin) was isolated from its fruiting bodies and enzymatic properties were also tested. The chromatographic procedure utilized comprised anion exchange chromatography on Q-Sepharose, cation exchange chromatography on CM-Cellulose, cation exchange chromatography on SP-Sepharose, and gel filtration by FPLC on Superdex 75. The hemagglutinin was a homodimer which was estimated to be approximately 31 kDa in size. The activity of BSH was stable up to 60°C, while there was a precipitous drop in activity when the temperature was elevated to 70°C. BSH retained 25% hemagglutinating activity when exposed to 100 mM NaOH and 25 mM HCl. The activity was potently inhibited by 1.25 mM Hg2+ and slightly inhibited by Fe2+, Ca2+, and Pb2+. None of the sugars tested showed inhibition towards BSH. Its hemagglutinating activity towards human erythrocytes type A, type B, and type AB was higher than type O. The hemagglutinin showed antiproliferative activity towards hepatoma Hep G2 cells and mouse lymphocytic leukemia cells (L1210) in vitro, with IC50 of 4.7 μM and 7.0 μM, respectively. It also exhibited HIV-1 reverse transcriptase inhibitory activity with an IC50 of 7.1 μM.

Antiplasmodial, HIV-1 reverse transcriptase inhibitory and cytotoxicity properties of Centratherum punctatum Cass. and its fractions

The hexane, dichloromethane, ethyl acetate and aqueous fractions of an ethanolic extract of Centratherum punctatum leaves were screened for antiplasmodial, HIV-1 reverse transcriptase inhibitory and cytotoxicity properties. The crude extract exhibited both antiplasmodial (IC50=3.2μg/ml) and HIV-1 reverse transcriptase inhibitory (IC50=72.8μg/ml) activities. A remarkable improvement in both antiplasmodial (IC50=0.419μg/ml) and HIV-1 reverse transcriptase inhibitory (IC50=52.4μg/ml) activities was observed with dichloromethane fraction. The study revealed the antiplasmodial and HIV-1 RT inhibitory effects of C. punctatum and its fractions, especially the dichloromethane fraction. However, its safety index values [antiplasmodial (0.2), HIV-1 reverse transcriptase inhibition (0.0017)] indicate that the fraction is cytotoxic.

Molecular Docking Studies of Marine Diterpenes as Inhibitors of Wild-Type and Mutants HIV-1 Reverse Transcriptase

AIDS is a pandemic responsible for more than 35 million deaths. The emergence of resistant mutations due to drug use is the biggest cause of treatment failure. Marine organisms are sources of different molecules, some of which offer promising HIV-1 reverse transcriptase (RT) inhibitory activity, such as the diterpenes dolabelladienotriol (THD, IC50 = 16.5 µM), (6R)-6-hydroxydichotoma-3,14-diene-1,17-dial (HDD, IC50 = 10 µM) and (6R)-6-acetoxydichotoma-3,14-diene-1,17-dial (ADD, IC50 = 35 µM), isolated from a brown algae of the genus Dictyota, showing low toxicity. In this work, we evaluated the structure-activity relationship (SAR) of THD, HDD and ADD as anti HIV-1 RT, using a molecular modeling approach. The analyses of stereoelectronic parameters revealed a direct relationship between activity and HOMO (Highest Occupied Molecular Orbital)-LUMO (Lowest Unoccupied Molecular Orbital) gap (ELUMO–EHOMO), where antiviral profile increases with larger HOMO-LUMO gap values. We also performed molecular docking studies of THD into HIV-1 RT wild-type and 12 different mutants, which showed a seahorse conformation, hydrophobic interactions and hydrogen bonds with important residues of the binding pocket. Based on in vitro experiments and docking studies, we demonstrated that mutations have little influence in positioning and interactions of THD. Following a rational drug design, we suggest a modification of THD to improve its biological activity.

A sorghum xylanase inhibitor-like protein with highly potent antifungal, antitumor and HIV-1 reverse transcriptase inhibitory activities

A 25-kDa protein, with an N-terminal amino acid sequence homologous to that of xylanase inhibitor and designated as xylanase inbibitor-like protein (XILP) was purified from sorghum seeds. The isolation protocol consisted of affinity chromatography, ion exchange chromatography, and gel filtration. XILP inhibited mycelial growth in various phytopathogenic fungi. The antifungal activity was thermostable and pH-stable. XILP inhibited proliferation of various cancer cell lines but did not do so in human embryonic liver (WRL 68) cells. There was no mitogenic activity toward mouse splenocytes. XILP reduced the activity of HIV-1 reverse transcriptase with an IC50 of 11.1μM, but lacked inhibitory activity toward HIV-1 integrase and SARS coronavirus proteinase. In conclusion, sorghum XILP is thermostable and pH stable and exhibits potent antifungal, antiproliferative, and HIV-1 reverse transcriptase inhibitory activities.

Purification and Characterization of an Antifungal Peptide with Potent Antifungal Activity but Devoid of Antiproliferative and HIV Reverse Transcriptase Activities from Legumi Secchi Beans

A monomeric 9.4-kDa peptide with antifungal activity was isolated from seeds of Phaseolus vulgaris cv Legumi secchi by using a protocol that involved affinity chromatography on Blue-Sepharose, ion exchange chromatography on Q-Sepharose, and gel filtration on Superdex 75. It was adsorbed on Blue-Sepharose and unadsorbed on Q-Sepharose. Its N-terminal sequence resembled those of other leguminous defensins. It impeded mycelial growth in the fungi Helminthosporium maydis, Rhizoctonia solani, Mycosphaerella arachidicola, and Fusarium oxysporum with an IC(50) value of 9.5, 3.5, 1, and 9.2 μM, respectively, but there was no effect on Valsa mali. SYTOX Green uptake by R. solani indicated that the antifungal peptide induced fungal membrane permeabilization. In contrast to the majority of previously reported defensins/defensin-like peptides, Legumi secchi antifungal peptide did not reduce the viability of MCF-7 breast cancer cells and HepG2 hepatoma cells or inhibit HIV-1 reverse transcriptase, indicating a dissociation between antifungal, antiproliferative and HIV-1 reverse transcriptase inhibitory activities.

A Novel Aspartic Protease with HIV-1 Reverse Transcriptase Inhibitory Activity from Fresh Fruiting Bodies of the Wild MushroomXylaria hypoxylon

A novel aspartic protease with HIV-1 RT inhibitory activity was isolated and characterized from fruiting bodies of the wild mushroom Xylaria hypoxylon. The purification protocol comprised distilled water homogenization and extraction step, three ion exchange chromatographic steps (on DEAE-cellulose, Q-Sepharose, and CM-cellulose in succession), and final purification was by FPLC on Superdex 75. The protease was adsorbed on all the three ion exchangers. It was a monomeric protein with a molecular mass of 43 kDa as estimated by SDS-PAGE and FPLC. Its N-terminal amino acid sequence was HYTELLSQVV, which exhibited no sequence homology to other proteases reported. The activity of the protease was adversely affected by Pepstatin A, indicating that it is an aspartic protease. The protease activity was maximal or nearly so in the pH range 6–8 and in the temperature range 35–60°C. The purified enzyme exhibited HIV-1 RT inhibitory activity with an IC50 value of 8.3 μM, but was devoid of antifungal, ribonuclease, and hemagglutinating activities.

Defensins and Other Biocidal Proteins from Bean Seeds with Medicinal Activities

It is well known that legumes, especially soybeans, are beneficial to health due to the presence of saponins and an abundance of fiber and proteins. Defensins and other related defense proteins with antifungal activity in legumes act against fungi which are human pathogens and also against phytopathogenic fungi. These proteins exhibit HIV-1 reverse transcriptase inhibitory and antitumor activities. Some of these proteins have remarkable stability to proteases, and changes in pH and temperature and are promising therapeutic candidates.

Cordysobin, a novel alkaline serine protease with HIV-1 reverse transcriptase inhibitory activity from the medicinal mushroom Cordyceps sobolifera

A novel serine protease, designated as cordysobin, was purified from dried fruiting bodies of the mushroom Cordyceps sobolifera. The isolation procedure utilized ion exchange chromatography on DEAE-cellulose and SP-Sepharose followed by gel filtration on Superdex 75. The protease did not adsorb on DEAE-cellulose but bound to SP-Sepharose. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the protease resolved as a single band with an apparent molecular mass of 31 kDa. Its optimal pH was 10.0, and the optimal temperature was 65°C. The protease displayed a K(m) value of 0.41 μM and 13.44 μM·min⁻¹ using Suc-Leu-Leu-Val-Tyr-MCA as substrate at pH 10.0 and 37°C. Protease activity was enhanced by the Fe²⁺ ion at low concentration range of 1.25-10 mM and was strongly inhibited by Hg²⁺ up to 1.25 mM. The protease was strongly inhibited by chymostatin and phenylmethylsulfonyl fluoride (PMSF), suggesting that it is a serine protease. It manifested significant inhibitory activity toward HIV-1 reverse transcriptase (RT) with an IC₅₀ value of 8.2×10⁻³ μM, which is the highest anti-HIV-1 RT activity of reported mushroom proteins.

A novel ribonuclease with potent HIV-1 reverse transcriptase inhibitory activity from cultured mushroom Schizophyllum commune

A 20-kDa ribonuclease (RNase) was purified from fresh fruiting bodies of cultured Schizophyllum commune mushrooms. The RNase was not adsorbed on Affi-gel blue gel but adsorbed on DEAE-cellulose and CM-cellulose. It exhibited maximal RNase activity at pH 6.0 and 70°C. It demonstrated the highest ribonucleolytic activity toward poly (U) (379.5 μ/mg), the second highest activity toward poly (C) (244.7 μ/mg), less activity toward poly (A) (167.4 μ/mg), and much weaker activity toward poly (G) (114.5 μ/mg). The RNase inhibited HIV-1 reverse transcriptase with an IC(50) of 65 μM. No effect on [(3)H-methyl]-thymidine uptake by lymphoma MBL2 cells and leukemia L1210 cells was observed at 100 μM concentration of the RNase. A comparison of RNases from S. commune and Volvariella volvacea revealed that they demonstrated some similarities in N-terminal amino acid sequence, optimum pH and polyhomoribonucleotide specificity. However, some differences in chromatographic behavior and molecular mass were observed.

Isolation of a polysaccharide with antiproliferative, hypoglycemic, antioxidant and HIV-1 reverse transcriptase inhibitory activities from the fruiting bodies of the abalone mushroom Pleurotus abalonus

The intent of this study was to purify and characterize a polysaccharide named LA from the fruiting bodies of the edible mushroom Pleurotus abalones. The 120-kDa polysaccharide was obtained by extraction with boiling water, ethanol precipitation, ion exchange chromatography on Diethylaminoethyl-cellulose and gel filtration on Sephadex G-200. The LA was composed of glucose, rhamnose, glucuronic acid, xylose, galactose and arabinose in the molar ratio of 26.3:2.7:1:1.4:1.8:1.2. The FITR and 1H-NMR spectrum of LA disclosed that it was a saccharide with an α-configuration. Its 13C-NMR spectrum revealed that its main chain was [→6)-α-D-Gly(1→]n. The LA exhibited antioxidant activities, especially in scavenging 1,1- diphenyl-2-picryl-hydrazyl radicals and hydroxyl radicals. It manifested antiproliferative activity towards breast cancer MCF7 cells with an IC50 of 3.7 µm, and also exerted some antiproliferative activity against HepG2 cells. It manifested a hypoglycemic action on diabetic mice. It inhibited HIV-1 reverse transcriptase with an IC50 of 8.7 × 10(-2) µm. The polysaccharide from the abalone mushroom.