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

Abstract

Averrhoa carambola 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 (1–4) and ten dihydrochalcone glycosides (5–12), were isolated and identified using spectroscopic techniques. New compounds identified in planta included (1) apigenin 6-C-(2-deoxy-β-D-galactopyranoside)-7-O-β-D-quinovopyranoside, (8) phloretin 3′-C-(2-O-(E)-cinnamoyl-3-O-β-D-fucopyranosyl-4-O-acetyl)-β-D-fucopyranosyl-6′-O-β-D fucopyranosyl-(1/2)-α-L arabinofuranoside, (11a) phloretin3′-C-(2-O-(E)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside, (11b) phloretin3′-C-(2-O-(Z)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside. Carambolaside M (5), carambolaside Ia (6), carambolaside J (7), carambolaside I (9), carambolaside P (10a), carambolaside O (10b), and carambolaside Q (12), which are reported for the first time from A. carambola L. leaves, whereas luteolin 6-C-α-L-rhamnopyranosyl-(1-2)-β-D-fucopyranoside (2), apigenin 6-C-β-D-galactopyranoside (3), and apigenin 6-C-α-L-rhamnopyranosyl-(1-2)-β-L-fucopyranoside (4) are isolated for the first time from Family. Oxalidaceae. In vitro α-glucosidase inhibitory activity revealed the potential efficacy of flavone glycosides, viz., 1, 2, 3, and 4 as antidiabetic agents. In contrast, dihydrochalcone glycosides (5–11) showed weak activity, except for compound 12, which showed relatively strong activity.

Effect of optimized germination technology on polyphenol content and hypoglycemic activity of mung bean

“…The experimental method was based on the protocol of others with modifications ( 19 , 20 ). The lyophilized germinated mung bean polyphenols were prepared into solutions with different mass concentrations.…”

Averrhoa carambola L. fruit polyphenols ameliorate hyperlipidemia, hepatic steatosis, and hyperglycemia by modulating lipid and glucose metabolism in mice with obesity

“…10 Averrhoa carambola L. leaf extract can reduce high-fat diet (HFD)-induced obesity and improve dyslipidemia, insulin resistance, and oxidative stress in rats. 11 Averrhoa carambola L. juice treatment can decrease hyperglycemia and hyperlipidemia and inhibit the progression of diabetic nephropathy. 12 However, the effects of A. carambola L. fruit polyphenols (ACFP) on obesity-associated hyperlipidemia, hepatic steatosis, and hyperglycemia and the underlying mechanisms remain unclear.…”

“…Micronized insoluble fiber‐rich fraction of A. carambola L. can exhibit serum hypolipidemic effect and prevent the development of the non‐alcoholic fatty liver 10 . Averrhoa carambola L. leaf extract can reduce high‐fat diet (HFD)‐induced obesity and improve dyslipidemia, insulin resistance, and oxidative stress in rats 11 . Averrhoa carambola L. juice treatment can decrease hyperglycemia and hyperlipidemia and inhibit the progression of diabetic nephropathy 12 .…”