Anti-Obesity Evaluation of L. Leaves and Assessment of Its Polyphenols as Potential α-Glucosidase Inhibitors.

L. is reported for its anti-obese and anti-diabetic activities. The present study aimed to investigate its aqueous methanol leaf extract (CLL) in vivo anti-obese activity along with the isolation and identification of bioactive compounds and their in vitro α-glucosidase inhibition assessment. CLL improved all obesity complications and exhibited significant activity in an obese rat model. Fourteen compounds, including four flavone glycosides (-) and ten dihydrochalcone glycosides (-), were isolated and identified using spectroscopic techniques. New compounds identified in planta included () apigenin 6--(2-deoxy--D-galactopyranoside)-7---D-quinovopyranoside, () phloretin 3'--(2--()-cinnamoyl-3---D-fucopyranosyl-4--acetyl)--D-fucopyranosyl-6'---D fucopyranosyl-(1/2)-α-L arabinofuranoside, () phloretin3'--(2--()-p-coumaroyl-3--D-fucosyl-4--acetyl)--D-fucosyl-6'--(2---D-fucosyl)-α-L-arabinofuranoside, () phloretin3'--(2-O--coumaroyl-3---D-fucosyl-4--acetyl)--D-fucosyl-6'--(2---D-fucosyl)-α-L-arabinofuranoside. Carambolaside M (), carambolaside Ia (), carambolaside J (), carambolaside I (), carambolaside P (), carambolaside O (), and carambolaside Q (), which are reported for the first time from L. leaves, whereas luteolin 6--α-L-rhamnopyranosyl-(1-2)--D-fucopyranoside (), apigenin 6---D-galactopyranoside (), and apigenin 6---L-rhamnopyranosyl-(1-2)--L-fucopyranoside () are isolated for the first time from Family. Oxalidaceae. In vitro α-glucosidase inhibitory activity revealed the potential efficacy of flavone glycosides, viz., , , , and as antidiabetic agents. In contrast, dihydrochalcone glycosides (-) showed weak activity, except for compound , which showed relatively strong activity.