A scoping review of five selected underutilized medicinal plants of Sri Lanka: Focusing on ethnobotany, phytochemistry and bioactivities, and evaluation of their potential for novel herbal product development

Ageratum conyzoides L., Artocarpus gomezianus Wall. ex Trécul, Euphorbia hirta L., Plectranthus zeylanicus Benth., and Piper sarmentosum Roxb. have long been utilized in traditional medical practices, particularly across South and Southeast Asia. Despite their significant ethnopharmacological potential to treat various disorders, these plants remain underutilized in Sri Lanka. This review aims to evaluate the habit, propagation, ethnomedicinal uses, phytochemistry, and pharmacological properties of these five underutilized medicinal plants to promote their sustainable utilization in the herbal products industry of Sri Lanka. The plants were selected based on data from pharmacopeias and interviews with traditional medical practitioners. Scientific information on their ethnomedicinal uses, phytochemical compositions, and pharmacological properties was gathered from key scientific databases, including PubMed, Scopus, ScienceDirect, and Google Scholar, as well as web references and books. This information was analyzed to assess the factors contributing to their underutilization and their potential for novel herbal product development in Sri Lanka. All five plants possess a wide range of ethnomedicinal uses and are rich in bioactive compounds, including alkaloids, terpenoids, stilbenoids, and polyphenolic compounds. These bioactive compounds have been scientifically validated for their pharmacological properties, making these plants strong candidates for the development of novel pharmaceuticals and cosmeceuticals. However, their full potential remains largely untapped, primarily due to the lack of detailed phytochemical characterization and bioactive studies specific to Sri Lanka. Further preclinical and clinical research is needed to evaluate their therapeutic outcomes within the local context. The findings of this scoping review will guide future research and encourage broader use of these underutilized plants. Promoting their use will provide a sustainable alternative to the overexploitation of commonly used medicinal plants and support effective biodiversity conservation and resource management.