~ 372 ~ Journal of Pharmacognosy and Phytochemistry 2021; 10(6): 372-378 E-ISSN: 2278-4136 P-ISSN: 2349-8234 www.phytojournal.com JPP 2021; 10(6): 372-378 Received: 22-09-2021 Accepted: 24-10-2021 Moumita Saha Department of Biotechnology, Techno India University, West Bengal, EM-4, Salt Lake, Sector- V, Kolkata, West Bengal, India Isha Roychowdhuri Department of Biotechnology, Techno India University, West Bengal, EM-4, Salt Lake, Sector- V, Kolkata, West Bengal, India Chandreyi Ghosh Department of Biotechnology, Techno India University, West Bengal, EM-4, Salt Lake, Sector- V, Kolkata, West Bengal, India Sohini Kulavi Department of Biotechnology, Maulana Abul Kalam Azad University of Technology, West Bengal, India Amrita Chakraborty Department of Biotechnology, Techno India University, West Bengal, EM-4, Salt Lake, Sector- V, Kolkata, West Bengal, India Anirban Roy Department of Food Technology & Biochemical Engineering, Jadavpur University, Kolkata- 700032, West Bengal, India Sirshendu Chatterjee Department of Biotechnology, Techno India University, West Bengal, EM-4, Salt Lake, Sector- V, Kolkata, West Bengal, India Corresponding Author: Sirshendu Chatterjee Department of Biotechnology, Techno India University, West Bengal, EM-4, Salt Lake, Sector- V, Kolkata, West Bengal, India Medicinal herbs and its bioactive ingredients: The alternative green resources against viruses Moumita Saha, Isha Roychowdhuri, Chandreyi Ghosh, Sohini Kulavi, Amrita Chakraborty, Anirban Roy and Sirshendu Chatterjee DOI: https://doi.org/10.22271/phyto.2021.v10.i6e.14314 Abstract In nature, there are plenty of medicinal herbs and plants which contain active compounds decisive for their diverse prophylactic/ therapeutic behaviour against many human diseases. A thorough analysis of these phyto-compounds for antimicrobial activities has considered greater importance in the context of recent days. There is an urgent need for alternative medicine to control the current pandemic of SARS- CoV-2 and its different variants, including delta strain and Omicron. Extensive research has revealed that identification and establishment of anti-viral activities of various prospective medicinal plants were limited due to: (a) infectious nature of viruses (b) absence of uncoupling techniques for the invention of anti-viral components from plants. With time progression of vector-based attempts, during which non- infectious molecular replica of an epidemic might be utilised for beneficial screening purposes alongside the development of separation techniques, offers the prospect for medicinal plants usage in current drug for the betterment of the society generally. The anti-viral mechanism of those agents could also be elucidated based on their scavenging abilities, inhibiting viral DNA replication, antioxidant activities, RNA synthesis, inhibition of the viral invasion, or inhibiting the viral propagation. A sizable amount of testing substances like phytochemicals and their synthetic residues are identified by consolidating in vitro and in vivo studies in various biological assays. In this review, comprehensive information on the recent advancement of plant-derived divergent phytochemicals as a probable non-conventional anti-viral substitute has been well explained. Keywords: medicinal plants, synthetic drugs, antiviral, novel coronavirus, cytotoxicity, screening methods for new drugs Introduction Viruses are intracellular obligate parasites, constitute a small cluster of RNA or DNA gene strands, and should be enclosed by a lipid-containing bilayer envelope. Viruses are complex in nature. It uses the host cell environment to strengthen its effects on the physical body, whereas bacterial cells are lifestyle organisms. Numerous invasive strategies are utilised, and every strain of the virus has its own exclusive configuration of surface molecules [1] . These surface molecules work like keys and locks, allowing viruses to enter into hosts by the definite fitting of the surface molecules to those on the membranes of target cells. Four general characteristics: efficient multiplication within host cells, genetic variation, variety in transmission, and therefore the capability to persevere within the host cell results in the success of viruses in progression [2] . Many viruses encode proteins that enhance virulence by modulating host immune responses. For example, influenza A NS1 protein interferes with activation of cellular innate immune responses to viral infection, [3] and thereafter the translation products of the adenovirus E3 transcriptional unit, which serve to prevent cytotoxic T-cell recognition of virally infected cells and block immunologically activated signalling pathways that lead to infected-cell death [4, 5] . These proteins are dispensable for viral replication in cultured cells in many cases. In this way, immunomodulatory viral virulence determinants resemble classic bacterial virulence factors such as various secreted toxins. Medicinal plants have played a significant role since the emergence of human civilisation on earth. Most of those plants were used to treat contagious virus infections in the past. However, the Boots pharmaceutical company (Nottingham, England) was the primary organisation to acknowledge their interest in developing anti-viral and screen 288 plants for anti-influenza activity [6] . Secondary metabolites from plant extracts have inhibitory effects on various virus types found in later studies. Viruses that showed potent inhibition against plant extracts are- Human Immunodeficiency Virus type1 [7] , Herpes Simplex Virus type2, poxvirus and Severe acute respiratory syndrome (SARS) virus stomatitis virus, Ebola [8] .