Ethnobotany, chemical analysis, and antiglycation activity of Elsholtzia species from Northern Thailand

Seven species of <i>Elsholtzia</i> from upper northern Thailand were ethnobotanically surveyed, and the plant parts utilized by local communities were collected for chemical analysis and antiglycation activity evaluation. The 80% methanol extracts were concentrated and analyzed for total soluble phenolic content using the Folin-Ciocalteu reagent, and phytochemical profiling was performed by high-performance liquid chromatography (HPLC) against standard phenolic compounds. In addition, the extracts were investigated for antiglycation activity using the methylglyoxal (MGO)-BSA method, with aminoguanidine as a positive control. According to the ethnobotanical survey, the seven <i>Elsholtzia</i> species were traditionally used as food, medicine, and insect repellents by seven ethnic groups: Akha, Hmong, Karen, Lawa, Lisu, Tai Lue, and Tai Yai. Most species were cultivated and commonly found in agricultural areas, including upland rice fields and home gardens. HPLC analysis identified three major phenolic compounds-rosmarinic acid, ferulic acid, and luteolin-showing species- and plant part-specific variations. The leaf extract of <i>E. beddomei</i> contained the highest rosmarinic acid (667.9 mg/100 g), <i>E. griffithii</i> exhibited the highest ferulic acid (2.25 mg/100 g), and luteolin was detected exclusively in <i>E. stachyodes</i> (15.4 mg/100 g). Consistently, <i>E. beddomei</i> also had the highest total phenolic content (36.04 mg GAE/g) and the strongest antiglycation activity, with an IC₅₀ value of 1.65 mg/mL. The observed trend suggests that phenolic-rich extracts, particularly those with elevated rosmarinic acid content, are strongly associated with enhanced anti-glycation potential. These findings validate local ethnobotanical practices and highlight the species-specific potential of <i>Elsholtzia</i> as sources of bioactive compounds, supporting their further development for pharmaceutical and nutraceutical applications.