Natural Products as Anti-HIV Agents and Role in HIV-Associated Neurocognitive Disorders (HAND): A Brief Overview

Abstract

As the threat of Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency Syndrome (AIDS) persists to rise, effective drug treatments are required to treat the infected people. Even though combination antiretroviral therapy (cART) provides stable viral suppression, it is not devoid of undesirable side effects, especially in persons undergoing long-term treatment. The present therapy finds its limitations in the emergence of multidrug resistance and accordingly finding new drugs and novel targets is the need of the hour to treat the infected persons and further to attack HIV reservoirs in the body like brain, lymph nodes to achieve the ultimate goal of complete eradication of HIV and AIDS. Natural products such as plant-originated compounds and plant extracts have enormous potential to become drug leads with anti-HIV and neuroprotective activity. Accordingly, many research groups are exploring the biodiversity of the plant kingdom to find new and better anti-HIV drugs with novel mechanisms of action and for HIV-associated neurocognitive disorders (HAND). The basic challenge that still persists is to develop viral replication-targeted therapy using novel anti-HIV compounds with new mode of action, accepted toxicity and less resistance profile. Against this backdrop, the World Health Organization (WHO) suggested the need to evaluate ethno-medicines for the management of HIV/AIDS. Consequently, there is need to evaluate traditional medicine, particularly medicinal plants and other natural products that may yield effective and affordable therapeutic agents. Although there are a good number of reports on traditional uses of plants to treat various diseases, knowledge of herbal remedies used to manage HIV/AIDS and HAND are scanty, vague and not well documented. In this review, plant substances showing a promising action that is anti-HIV and HAND will be explored along with what they interact. Since some plant substances are also known to modulate several cellular factors which are also involved in the replication of HIV and hence their role as potential candidates will be discussed. HIV/AIDS being an exceptional epidemic, demands an exceptional approach and that forms very much focus for the current review.

Chemical Composition of Essential Oils from Thymus vulgaris, Cymbopogon citratus, and Rosmarinus officinalis, and Their Effects on the HIV‐1 Tat Protein Function

“…In addition to crude extracts, essential oil (EO) isolated from aromatic plants by steam or hydro‐distillation showed specific antiviral activity . Although EOs are complex natural mixtures of about 20 – 60 different components, a few major low molecular weight terpenes and terpenoids present at high concentrations determine the biological activity …”

“…[15] [16] In addition to crude extracts, essential oil (EO) isolated from aromatic plants by steam or hydro-distillation showed specific antiviral activity. [17] Although EOs are complex natural mixtures of about 20 -60 different components, a few major low molecular weight terpenes and terpenoids present at high concentrations determine the biological activity. [18] New molecules, capable of interfering with essential viral functions different from those targeted by actual antiviral drugs, would be beneficial to fight resistant HIV strains.…”

Antiviral activity of plants and their isolated bioactive compounds: An update

“…Taxifolin, thanks to the presence of one OH group in C-3′ position, inhibits viral PR and RT as well as it can prevent the interaction between the viral envelope glycoprotein Gp120 and CD4 receptor on T lymphocytes, involved in the virus entry into the host cell. On the contrary, aromadendrin, which does not contain the OH group in C-3′ position, did not show PR and RT inhibition but showed a more specific inhibition of Gp120/CD4 interaction (Kurapati, Atluri, Samikkannu, Garcia, & Nair, 2016).…”

The potential of plant systems to break the HIV‐TB link

“…These valuable compounds could be extracted from different parts of plants, such as leaves, shoots, roots and flowers, and investigated for their potential as anti-HIV and anti-TB drugs. Phenolic compounds, flavonoids, triterpenes, coumarins and alkaloids are examples of prominent natural products with anti-HIV and TB activity (Kurapati et al, 2016). A condensed summary of the most active plant secondary metabolites against HIV and TB is provided in Tables 1 and 2, respectively.…”