Genus Knema: An Extensive Review on Traditional Uses, Phytochemistry, and Pharmacology

Background: Knema (the Myristicaceae family) is a large genus of small-medium trees found in Southeast Asia, Africa, and Australia. Historical records dealt with the uses of Knema species as medicinal plants against various diseases, especially cancer remedies, or their application as tonic agents in Asian communities Objective: The aim of this review is to provide the most current knowledge on the traditional uses, chemical profiles, as well as pharmacological values of Knema plants. Methods: Through electronic search, the literature materials on Knema plants were acquired from scholarly journals, books, and internationally recognized scientific databases, such as PubMed, ScienceDirect, Sci-Finder, Web of Science, and Google Scholar. All full-text articles and abstracts on Knema were screened. Genus Knema, traditional use, phytochemistry, and pharmacology were the first selective keywords to search for references. Results: Since the 1970s, more than 185 metabolites have been isolated from Knema plants and structurally elucidated. Among them, phenolic lipids, flavonoids, and lignans are the principal metabolites. Crude extracts, fractions, and isolated compounds of Knema species possess a wide variety of pharmacological properties, such as antioxidative, antidiabetic, antimicrobial, antiinflammatory, antimalarial, neuroprotective, and hepatoprotective activities, but cytotoxicity is the most striking feature. Phenolic lipids containing long alkyl side chains and polar hydroxyl or acyl groups are found as the most active molecules in cytotoxic assays. Conclusion: Further studies on phytochemistry and pharmacological activities, toxicological assessments, pharmacological mechanisms, and pharmacokinetics are urgently needed.