Comprehensive phytochemical profiling and dual enzyme inhibitory activities of Coleus rotundifolius leaves and ursolic acid quantification as a bioactive marker

Coleus rotundifolius leaves, typically discarded after tuber harvest, present an unexplored phytochemical potential despite the crop’s established ethnobotanical use in diabetes management. This study presents the first preliminary phytochemical characterisation of C. rotundifolius leaves using authenticated plant, incorporating physicochemical characterisation, nutritional profiling, GC-MS identification, and quantitative antioxidant and antidiabetic enzyme inhibition assays. Physicochemical analysis confirmed phenolic, terpenoid, and polysaccharide functional groups. Proximate analysis revealed high dietary fibre, essential minerals, and minimal anti-nutritional factors. GC-MS identified 6 bioactive phytochemicals, dominated by polyunsaturated fatty acids. Moderate phenolic and flavonoid content with concentration-dependent scavenging activity were recorded. The extract exhibited inhibitory activity of α-amylase and α-glucosidase inhibition with high cell viability. Ursolic acid was quantified via a previously established HPLC method. Collectively, these findings establish C. rotundifolius leaves may represent a candidate source of bioactive compounds with potential relevance to postprandial glycemic management, warranting further investigation with larger sample sets and standard confirmation.