Ethnomedicinal Antivirals: Scope and Opportunity

Abstract

Viral diseases, including emerging, reemerging, and chronic infections, are an increasing health concern throughout the world. As a consequence, the development of new antivirals from plants, particularly from ethnomedicinal practices, has assumed more urgency today. Ethnomedicines provide a diverse range of natural products with antimicrobial and immunomodulating potential. A wide variety of active phytochemicals such as alkaloids, coumarins, essential oils, flavonoids, phytosterols, polysaccharides, polyphenols, tannins, saponins, proteins, and peptides from hundreds of plants, culinary herbs, spices and teas have complementary and overlapping mechanisms of action, including inhibition of viral reproduction or genome formation. Immune-related conditions with a high unmet clinical need still exist, along with the problem of increasing antiviral resistance in many viral infections. The ethnomedicinal phytochemicals might be able to provide an alternative to the costly antivirals and immunotherapeutics.Assay methods to determine in vitro and in vivo antiviral activity are needed to link antiviral efficacy or potency and laboratory-based research. The relative success achieved in the last two decades with such plant extracts which are capable of acting therapeutically in various viral infections, has raised optimism about the future of phytoantiviral agents. This chapter reviews some potentially useful ethnomedicinal plants and compounds, evaluated and exploited for therapeutic applications against genetically and functionally diverse virus families including Retroviridae, Hepadnaviridae, and Herpesviridae causing sexually transmitted viral infections. 15.1

Recent advancements for the evaluation of anti-viral activities of natural products

“…Owing to the amazing structural diversity and broad range of bioactivities natural products can be explored as a source of complementary anti-virals, as many of them are reported to inhibit several steps of replication cycle and certain cellular factors of many DNA and/or RNA viruses. Many traditional medicinal plants used in Indian (Ayurveda) or TCM have been reported to have strong antiviral activity and are used to reduce the disease severity [4,6,[10][11][12]. Research interests for anti-viral agents started after Second World War in Europe, and in 1952 12 out of 288 plants were found to be effective against influenza viruses in embryonated eggs [13].…”

“…The discovery of novel anti-viral drugs deserves great efforts. There are several reviews been published in recent years stating discovery of new drugs against different viral infections from natural resources [5][6][7]. The role of traditional medicine for the development of anti-viral compounds is also been discussed in different reviews.…”

“…Interestingly, it was found that traditional medicines, like Ayurvedic, traditional Chinese medicine (TCM), Chakma medicines, are good sources for potential antiviral drugs [5]. A wide variety of active phytochemicals, including the flavonoids, terpenoids, organosulfur compounds, limonoids, lignans, sulfides, polyphenolics, coumarins, saponins, chlorophyllins, furyl compounds, alkaloids, polyines, thiophenes, proteins and peptides have been found to have therapeutic applications against different genetically and functionally diverse viruses [3][4][5][6][7]. The anti-viral mechanism of these agents may be explained on basis of their antioxidant activities, scavenging capacities, inhibiting DNA, RNA synthesis, inhibition of the viral entry, or inhibiting the viral reproduction and so on [4,7,8].…”

The human rhinovirus: human‐pathological impact, mechanisms of antirhinoviral agents, and strategies for their discovery

“…A wide variety of natural preparations showed to be acting therapeutically in HRV and other viral infections with often complementary and overlapping antiviral mechanisms of action. [274][275][276] Most of these remedies are described in ethnopharmacological sources or handed down for generations. They usually consist of simply prepared natural items whose chemical composition is complex.…”

Prospects of Essential Oils in Drug Discovery

“…Essential oils have been proved to demonstrate anti-microbial, anti-inflammatory, antioxidant, antitumorigenic and anti-carcinogenic properties as well as antibacterial, antiviral, antifungal and anti-parasitic properties. 3 In this review, emphasis will be laid on the microbiological importance of essential oils in the development of novel antimicrobials and production of antibiotics.…”