Antihyperglycemic effects of Lysiphyllum strychnifolium leaf extract in vitro and in vivo

Abstract

Context

Lysiphyllum strychnifolium (Craib) A. Schmitz (LS) (Fabaceae) has traditionally been used to treat diabetes mellitus.

Objective

This study demonstrates the antidiabetic and antioxidant effects of aqueous extract of LS leaves in vivo and in vitro.

Materials and methods

The effects of aqueous LS leaf extract on glucose uptake, sodium-dependent glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2) mRNA expression in Caco-2 cells, α-glucosidase, and lipid peroxidation were evaluated in vitro. The antidiabetic effects were evaluated using an oral glucose tolerance test (OGTT) and a 28-day consecutive administration to streptozotocin (STZ)-nicotinamide (NA)-induced type 2 diabetic mice.

Results

The extract significantly inhibited glucose uptake (IC₅₀: 236.2 ± 36.05 µg/mL) and downregulated SGLT1 and GLUT2 mRNA expression by approximately 90% in Caco-2 cells. Furthermore, it non-competitively inhibited α-glucosidase in a concentration-dependent manner with the IC₅₀ and K_i of 6.52 ± 0.42 and 1.32 µg/mL, respectively. The extract at 1000 mg/kg significantly reduced fasting blood glucose levels in both the OGTT and 28-day consecutive administration models as compared with untreated STZ-NA-induced diabetic mice (p < 0.05). Significant improvements of serum insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and GLUT4 levels were observed. Furthermore, the extract markedly decreased oxidative stress markers by 37–53% reduction of superoxide dismutase 1 (SOD1) in muscle and malondialdehyde (MDA) in muscle and pancreas, which correlated with the reduction of MDA production in vitro (IC₅₀: 24.80 ± 7.24 µg/mL).

Conclusion

The LS extract has potent antihyperglycemic activity to be used as alternative medicine to treat diabetes mellitus.

Keywords:

• α-glucosidase
• glucose uptake
• GLUT4
• oral glucose tolerance test

Acknowledgements

We would like to express our sincere thanks to Assist Prof. Pilanthana Lertsatitthanakorn, Bansomdejchaopraya Rajabhat University, Thailand for providing the source of the LS leaf extract, Dr. Sumet Kongkiatpaiboon, Thammasat University for kindly providing the chemical standards.

Author contributions

GAS, SVH and MM made substantial contributions to the conception. GAS and MM implemented experiments. GAS, SVH, SH, TT, YJ and MP analyzed the data and made figures for this manuscript. GAS, SVH and SH wrote the original draft and substantively revised it. SVH, CS and LJ administrated this project. All authors read and approved the final manuscript.

Disclosure statement

The authors declare that this research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Additional information

Funding

This work was financially supported by a grant from the Thai Traditional Medical Knowledge Fund [42, 2563] and also partially supported by Mahidol University, Thailand.