α-glucosidase is a therapeutic target for diabetes mellitus (DM) and α-glucosidase inhibitors play a vital role in the treatments for the disease. Furthermore, xanthine oxidase (XO) is a key enzyme that catalyzes hypoxanthine and xanthine to uric acid which at high levels can lead to hyperuricemia which is an important cause of gout. Pancreatic lipase (PL) secreted into the duodenum plays a key role in the digestion and absorption of fats. For its importance in lipid digestion, PL represents an attractive target for obesity prevention. The flowers essential oil of Rhaponticum acaule (L) DC (R. acaule) was characterized using gas chromatography-mass spectrometry (GC-MS). The antioxidant activities of R. acaule essential oil (RaEO) were also determined using 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), reducing power, phosphomolybdenum, and DNA nicking assays. The inhibitory power of RaEO against α-glucosidase, xanthine oxidase and pancreatic lipase was evaluated. Enzyme kinetic studies using Michaelis-Menten and the derived Lineweaver-Burk (LB) plots were performed to understand the possible mechanism of inhibition exercised by the components of this essential oil. The result revealed the presence of 26 compounds (97.4%). The main constituents include germacrene D (49.2%), methyl eugenol (8.3%), (E)-β-ionone (6.2%), β-caryophyllene (5.7%), (E,E)-α-farnesene (4.2%), bicyclogermacrene (4.1%) and (Z)-α-bisabolene (3.7%). The kinetic inhibition study showed that the essential oil demonstrated a strong α-glucosidase inhibiton and it was a mixed inhibitor. On the other hand, our results evidenced that this oil exhibited important xanthine oxidase inhibitory effect, behaving as a non-competitive inhibitor. The essential oil inhibited the turkey pancreatic lipase, with maximum inhibition of 80% achieved at 2 mg/mL. Furthermore, the inhibition of turkey pancreatic lipase by RaEO was an irreversible one. The results revealed that the RaEO is a new promising potential source of antioxidant compounds, endowed with good practical applications for human health.

Natural inhibitors of digestive lipases offer promising alternatives to conventional obesity medications. This study screened nine medicinal plant extracts, identifying the ethanolic bark extract of Cinnamomum cassia as the most potent inhibitor for gastric and pancreatic lipases. Using an integrated approach combining bioactivity-guided fractionation and mass spectrometry, we isolated the highly active fraction, F3-1-1, which exhibited dose- and time-dependent inhibitory effects against human and porcine pancreatic lipases, as well as dog gastric lipase (DGL). Further mass spectrometry and peptide mass fingerprint analysis putatively annotated cinncassiol A-19 glucoside as a bioactive constituent. Notably, this compound was likely bound covalently to the catalytic peptide containing the Ser153 residue in DGL, characterized by a mass shift of +553.10 Da. Molecular docking simulations supported these suggestions, demonstrating stable interactions within the catalytic pocket of DGL through hydrogen and hydrophobic bond interactions. These findings highlight C. cassia as a promising source of natural anti-obesity agents.

Natural inhibitors of digestive lipases offer promising alternatives to conventional obesity medications. This study screened nine medicinal plant extracts identifying the ethanolic bark extract of Cinnamomum cassia as the most potent inhibitor for gastric and pancreatic lipases. Using an integrated approach combining bioactivity-guided fractionation and mass spectrometry, we isolated the highly active fraction, F3-1-1, which exhibited dose- and time-dependent inhibitory effects against human and porcine pancreatic lipases, as well as dog gastric lipase (DGL). Further mass spectrometry and peptide mass fingerprint analysis identified cinncassiol A-19 glucoside as the main bioactive constituent. Notably, this compound forms covalent complexes with the catalytic peptide containing the Ser153 residue in DGL, characterized by a mass shift of +553.10 Da. Molecular docking simulations supported these results, demonstrating stable interactions within the catalytic pocket of DGL through hydrogen and hydrophobic bond interactions. These findings highlight C. cassia as a promising source of natural anti-obesity agents.