Lipid Metabolism-Related Enzyme Inhibition and Antioxidant Potential of the Extracts and Phytochemical Compounds from Trachystemon orientalis (L.) D.Don.

Trachystemon orientalis (L.) D.Don is a perennial herb extensively utilized for culinary purposes and the treatment of numerous ailments. Hyperlipidemia is a significant risk factor for atherosclerosis, diabetes, obesity, and coronary heart disease. The inhibition of pancreatic lipase (PL) and cholesterol esterase (CE) aims to mitigate problems associated with lipid metabolism disorders by decreasing hyperlipidemia. In this context, enhancing antioxidant capability is an additional objective. This study assessed the PL and CE inhibitory actions of extracts and compounds from the aerial parts of T. orientalis, utilizing ferric reducing antioxidant power (FRAP) and cupric-reducing antioxidant capacity (CUPRAC) assays to measure antioxidant capabilities. Rosmarinic acid, a combination of rosmarinic acid and danshensu (phenolic acids), and β-sitosterol (phytosterol) were isolated. β-sitosterol (IC₅₀: 41.698 ± 1.982 µg/mL, 14.249 ± 1.209 µg/mL, respectively) followed by rosmarinic acid (IC₅₀: 48.213 ± 2.490 µg/mL, 21.941 ± 3.785 µg/mL, respectively) demonstrated significant inhibitory effects on PL and CE. Additionally, rosmarinic acid (FRAP: 1274.400 ± 1.633 µM TEAC, CUPRAC: 1801.389 ± 5.500 µM TEAC) and its combination with danshensu (FRAP: 1405.067 ± 4.491, CUPRAC: 2174.167 ± 9.647 µM TEAC) exhibited high antioxidant activity. The ethyl acetate subextract (TOE) from which rosmarinic acid was isolated showed considerable enzyme inhibitory (IC₅₀: 47.577 ± 0.931 µg/mL, 12.443 ± 1.233 µg/mL, for PL and CE inhibition, respectively) and antioxidant activity (FRAP: 1770.021 ± 4.583, CUPRAC: 2189.167 ± 5.401 µM TEAC). T. orientalis has been identified as a promising natural resource for the management of lipid metabolism-related disorders and for enhancing antioxidant activity.