COVID-19 is a viral disease, infect humans and highly pathogenic caused by SARS-CoV-2. It has developed in Wuhan, China and spreads around the world. It has a phylogenetic similarity to the severe acute respiratory syndrome like bat viruses. Therefore, the primary reservoir may be the bat. The origin and transmission of the viral infection to humans is not clear, but human to human transmission of the virus has been confirmed widely. There is no antiviral drug or any vaccines has been clinically approved to treat or cure the viral infection. Thus, the present study reviewed about the antiviral activity of the naturally available medicinal plants viz., Curcuma longa, Zingiber officinale, Andrographis paniculata, Azadirachta indica, Piper nigrum, Allium sativum, Aloe vera, Citrus latifolia, Eucalyptus globulus and Vitex negundo. The bioactive compounds like anthraquinones isolated from aloe plant has been documented against influenza virus infection in humans. Two anthraquinones, aloesaponarin-I (1) and aloesaponarin-II (2) and its six derivatives were obtained from vera roots. All these compounds are tested against two different strains of influenza virus and it showed the potent antiviral activity. In the same way, neem seed kernel may also possess the antiviral activity which decreases the cytopathic effects of DPV and the amount of virus protein expressed in cells infected with viruses. The isolated compounds from ginger has proven to be effective on different viral infection. Curcumin, a bioactive compound isolated from turmeric, having multiple functions in disease prevention or treatment, including different types of cancer and viral infections. Extracts of A. Paniculata regulates both classical and alternative macrophage activation and production of specific antibodies, thus it was able to modulate the immune response, and still it showed antiviral activity. All the plants mentioned above have potent antiviral activity and these results are obtained by the survey carried out in the rural peoples and compared it with the scientific evidence. Thus, the review revealed that naturally available dietary plants and their bioactive compounds are used to control the viral replication, which may also apply to control the replication of Covid-19 virus.
Keywords: Covid-19, Tranmission, Antiviral activity, Medicinal plants, Bioactive compounds.