The medicinal uses, chemistry and phylogenetic relationships of ethnobotanically relevant South African Stachys species

Ethnopharmacological relevance: The genus Stachys L. (Lamiaceae) has a rich global history of traditional medicinal use. In South Africa, several species of Stachys are used ethnomedicinally to treat various ailments, including respiratory and urinary conditions, pain relief, and drunk as herbal teas and tonics. Despite their traditional use, research on their phytochemistry and pharmacological properties remains limited, warranting the need for a broad investigation that integrates ethnobotanical knowledge with phytochemical and genetic data. Aim of the study: This study aimed to document the traditional uses of ten South African Stachys species, analyse their chemical composition, and explore phylogenetic relationships to enhance understanding of their therapeutic potential. Materials and methods: Ethnobotanical information on the medicinal uses of Stachys species was collected from several scientific databases, including Scopus, Web of Science, Google Scholar and PubMed. Chemical analyses were performed using ultra-high-performance liquid and gas chromatography coupled with mass spectrometry. Phylogenetic analysis was conducted using DNA sequencing of plastid and nuclear markers, allowing for the classification of species into distinct clades and linking these with chemical profiles. Results: Ethnobotanical data showed that South African Stachys species are used in a similar manner, consistent with their global counterparts, particularly for their analgesic and anti-inflammatory properties. These applications are frequently administered as herbal teas and are traditionally used to address respiratory and urinary ailments, mirroring patterns of use observed worldwide. Our chemical analyses identified a total of 83 volatile and 24 non-volatile compounds, with prominent volatile constituents including linalyl acetate, limonene, and caryophyllene oxide, while verbascoside, ipolamiide, and harpagide emerged as the major non-volatile compounds. Phylogenetic analyses resolved three distinct clades among the South African Stachys species, with these groupings correlating strongly with their respective chemical profiles. Conclusion: This integrative study connects ethnobotanical knowledge with chemical and phylogenetic analyses, providing a comprehensive framework for understanding the therapeutic potential of South African Stachys species. The findings highlight the necessity of safeguarding traditional knowledge while underscoring the need for further pharmacological research to validate and clarify the medicinal properties of Stachys species in the South African context.