Venom components of Iranian scorpion hemiscorpius lepturus inhibit the growth and replication of human immunodeficiency virus 1 [HIV-1]

Background: During the recent years, significant progress has been achieved on development of novel anti-viral drugs. Natural products are assumed as the potential sources of novel anti-viral drugs; therefore, there are some previous studies reporting the anti-viral compounds from venomous animals. Based on the significant value for tracing of non-toxic anti-viral agents from natural resources, this study was aimed to investigate the anti-viral activity of some HPLC purified fractions derived from the venom of Iranian scorpion, Hemiscorpius lepturus, against human immunodeficiency virus 1 [HIV-1] and herpes simplex virus 1 [HSV-1]

Methods: H. Lepturus crude venom was subjected to reverse phase HPLC analysis to determine its active components precisely where four dominant fractions obtained at retention time of 156-160 minutes. The phospholipase A2 and hemolytic activities of the purified fractions were first evaluated. Then the anti-viral activity was measured using single cycle HIV [NL4-3] replication and HSV [KOS] plaque reduction assays

Results: The H. lepturus crude venom inhibited HIV replication by 73% at the concentration of 200 micro g/ml, while it did not show significant anti-HSV activity. It also inhibited the cell-free viral particles in a virucidal assay, while it showed no toxicity for the target cells in a proliferation assay. The four HPLC fractions purified from H. lepturus inhibited HIV with IC50 of 20 micro g/ml

Conclusion: H. lepturus venom contains components with considerable anti-HIV activity insofar as it has virucidal activity that offers a novel therapeutic approach against HIV infection. Our results suggest a promising pilot for anti-HIV drug discovery with H. lepturus scorpion venom

Inhibitory activity of Avicennia marina, a medicinal plant in Persian folk medicine, against HIV and HSV

Avicennia marina [Avicenniaceae] is a species of mangrove tree used for treatment of small pox lesions in Persian folk medicine. The antiviral activity of methanol, ethanol, water, chloroform and n-hexane extracts was evaluated against HIV-1 and HSV. Methanol extract had the highest antiviral activity and the most polar fraction of this extract [fraction D] inhibited HSV with TI and SI values of 57.1 and 133; however, it showed mild activity against HIV with SI value of 6.25 [fraction 3]. The anti-HSV activity of active fraction was confirmed using FLASH-PCR. Phytochemical investigation revealed that fraction D encompasses flavonoids compounds. The time-of-addition study demonstrated that fraction D disturbs viral replication after penetrating to the cell. A. marina was endowed with fragments by which found to be able to inhibit replication of HSV after entry but did not show significant potency against HIV-1. This promotes further investigation in anti-HSV drug discovery

Design of small molecules with HIV fusion inhibitory property based on Gp41 interaction assay

Gp41 of HIV [Human Immunodeficiency Virus] is a protein that mediates fusion between viral and cellular membranes. The agent, T-20, which has been approved for HIV inhibition, can restrain Gp41 function in the fusion process; nevertheless, it has disadvantages like instability, high cost of production and injection form to be delivered twice a day. Several molecules like NB-2 and NB-64 have been discovered that can inhibit HIV infection. These molecules were used as template compounds to design and develop more effective small molecules functioning as HIV-1 fusion inhibitors targeting Gp41. The process included in silico docking protocols using HEX and ArgusLab applications. A multisource database was created, after choosing the best molecules; they were tested in vitro for inhibitory activity by HIV-1 single-cycle model, transfected in HEK cells [293T]. Computational analysis and experimental data were combined to explore molecular properties and the most potent ones were found, with the best suitable criteria for interaction with Gp41. Several examples [DAA-6, DAA-9 and DAA-12] could inhibit infection in vitro as effective as NB-2, NB- 64. Since disadvantages of available fusion inhibitor [T-20], it seems necessary to find similar molecules to be approved and have small size providing suitable bioactivity profile. The molecules explored in this study can be good candidates for further investigations to be used as oral HIV fusion inhibitors in the future

Optimization of human immunodeficiency virus type one replication assay using single cycle replicable virions

HIV virions with replication capacity are needed for HIV researches, like investigating for new anti HIV agents. Here HIV-1 replication assay was optimized with HIV-1 single cycle replicable [SCR] virions to improve biological safety condition. pSPAX2, pmzNL4-3 and pMD2G plasmids were co-transfected to the HEK293T by using polyfect reagent to produce the SCR HIV-1 virions. Virions were quantified using capture ELISA P24. Different MOI of SCR virions were used for infecting of Target cells [HEK] and the load of the supernatant P24 was monitored days after infection. Single cycle replication assay [SCRA] was developed using kinetic studies data. The P24 load of the infected cells supernatant has linear relation to the beginning infectious MOI. 24 hours post infection with HIV-1 SCR virions the viral particle production was detectable. The highest load of P24 in infected cells supernatant was detected 48 hours after infection. Using this developed method, the 50 and 95 percent inhibitory concentration of [IC[95] and IC[50]] Indinavir and Nevirapine were calculated as 25nM and 50nM. In this study, using SCR HIV-1 virions the SCRA was developed. SCR HIV-1 virions are replicable only for one cycle and this improves the safety of developed assays. The accuracy of assay was examined by quantifying the anti HIV-1 potential of two commercial anti-AIDS drugs and the calculated activity for test agents was equal to previously known amounts