BIONATURE

Depression, anxiety, stress, and other mental disorders, which are on the rise worldwide, are indications that pharmacological therapy can have serious adverse effects, which is why many patients prefer to use herbal products to treat these symptoms. Mental health disorders — particularly anxiety, insomnia and depression — represent a major and escalating burden on global public health. Collectively, they account for a disproportionate share of years lived with disability worldwide and remain substantially undertreated across all income settings. Long before the advent of synthetic psychopharmacology, human societies relied upon the plant kingdom to manage disturbances of the mind and sleep. Today, this inherited knowledge constitutes an invaluable resource for drug discovery, integrative medicine and the development of accessible, culturally grounded therapeutics. The present review systematically examines peer-reviewed ethnobotanical and ethnopharmacological literature published between 2000 and 2026 alongside selected authoritative international reports, aiming to document the major plant taxa employed for these three conditions across Africa, Asia, Europe, the Americas and Oceania. Species belonging to the families Lamiaceae, Valerianaceae, Hypericaceae, Passifloraceae, Asteraceae, Apiaceae, Solanaceae and Fabaceae emerge as the most cross-culturally consistent contributors. A systematic search of the peer-reviewed literature was conducted across PubMed/MEDLINE, Web of Science, Scopus, Google Scholar, EMBASE and the WHO Global Index Medicus. Key bioactive secondary metabolites including valepotriates, naphthodianthrones, phloroglucinols, flavonoids, withanolides, kavalactones, bacosides and crocins are discussed in relation to their documented pharmacodynamic interactions with GABAergic, serotonergic, adrenergic and hypothalamic-pituitary-adrenal (HPA) axis systems. Convergent cross-cultural use patterns are interpreted as indirect pharmacological validation and as primary indicators for future clinical investigation. The review also addresses methodological standards for rigorous ethnobotanical fieldwork, the intersection of traditional knowledge with intellectual property and biodiversity law, safety and toxicology considerations, standardisation and quality control, and the principal pathways through which documented ethnobotanical knowledge may be translated into evidence-based therapeutics. Critical research gaps, including the underrepresentation of sub-Saharan African, Pacific and indigenous Amazonian traditions in the peer-reviewed literature, are highlighted.