Ethnobotany, Pharmacological Activities and Bioavailability Studies on "King of Bitters" (Kalmegh): A Review (2010-2020)

Background: Andrographis paniculata, commonly known as "Kalmegh", is an annual herbaceous plant from the family Acanthaceae. The whole plant of A. paniculata has been explored for multiple pharmacological activities and is scientifically recognized by in-vivo and in-vitro studies. Various biotechnologically engineered techniques have been explored to enhance the bioavailability of this plant. Objective: In this review, we aim to present comprehensive recent advances in ethnopharmacology, phytochemistry, specific pharmacology, safety and toxicology, and bioavailability of A. paniculata and its pure compounds. Possible directions for future research are also outlined in brief, which will encourage advance investigations on this plant. Methods: Information on the recent updates of the present review is collected from different electronic scientific databases such as Science Direct, PubMed, Scopus, and Google Scholar. All the composed information is classified into different sections according to the objective of the paper. Results: More than a hundred research and review papers have been studied and incorporated in the present manuscript. After a vast literature search on A. paniculata, we present a noteworthy report of various phytoconstituents present in the plant, which are accountable for the potential therapeutic properties of the plant. Forty-five of the studied articles gave general information about the introduction, ethnobotany, and traditional uses of the plant. Twenty-two papers enclosed information about the phytoconstituents present in different parts of A. paniculata and seventy-two papers briefly outlined the pharmacological activities like antioxidant, anti-dengue, anti-ulcerogenic, antifungal, some miscellaneous activities like activity against SARS-CoV-2, antidiarrhoeal. Nineteen studies highlighted the research work conducted by various researchers to increased the bioavailability of A. Paniculata and two studies reported the safety and toxicology of the plant. Conclusion: This review incorporated the scientifically validated research work encompassing the ethnobotanical description of the subjected plant, phytochemical profile, various pharmacological activities, and recent approaches to enhance the bioavailability of active metabolites.