Anti-obesity evaluation of Averrhoa carambola L. leaves and assessment of its polyphenols as potential α-glucosidase inhibitors

authored by

Nehal S Ramadan, Nabil H El-Sayed, Sayed A El-Toumy, Doha Abdou Mohamed, Zeinab Abdel Aziz, Mohamed Sobhy Marzouk, Tuba Esatbeyoglu, Mohamed A Farag, Kuniyoshi Shimizu

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 (

4) and ten dihydrochalcone glycosides (

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.,

3, and

4 as antidiabetic agents. In contrast, dihydrochalcone glycosides (

11) showed weak activity, except for compound

12, which showed relatively strong activity.

Organisation(s)

Institute of Food Science and Human Nutrition
Molecular Food Chemistry and Food Development

External Organisation(s)

National Research Centre (NRC)
Cairo University
Kyushu University

Type

Article

Journal

Molecules

Volume

ISSN

1420-3049

Publication date

12.08.2022

Publication status

Published

Peer reviewed

Yes

Sustainable Development Goals

SDG 3 - Good Health and Well-being

Electronic version(s)

https://doi.org/10.3390/molecules27165159 (Access: Open)