Acacia leucophloea (Roxb.). Willd.: Multi-targeted therapeutic efficacy against type 2 diabetes mellitus

Introduction

Acacia leucophloea (AL) has been used traditionally to treat diabetes, cancer, inflammation, ophthalmia, haemorrhoids and leukoderma, however the scientific evidence validating its antidiabetic activity is limited. Employing a multi-targeted therapeutic strategy could be advantageous for the management of type 2 diabetes mellitus which is strongly correlated with oxidative stress-induced pathways. The present study was intended to evaluate the antidiabetic and antioxidant potential of AL via in vitro assays, validating its traditional medicinal significance.

Methods

Anti-diabetic potential of the AL extract, its fractions and isolated compounds was assessed through the determination of α-glucosidase, DPP-IV inhibition, anti-glycation activity, and glucose uptake using 2-NBDG in differentiated L6 myoblast, along with cytotoxicity studies. Total phenolic and flavonoid content was measured and the antioxidant potential was evaluated using in vitro assays i.e., DPPH, ABTS and FRAP. In addition, quantitative determination of isolated compounds and their purity was analysed using HPLC-DAD.

Results

Fractions with the highest phenolic/flavonoid content (VI to XIII of AL) demonstrated substantial antioxidant and antidiabetic potential across selected therapeutic targets and these active fractions yielded six compounds upon fractionation using column chromatographic techniques. Structures of these compounds were examined using spectroscopic techniques and were identified as isoquercitrin, quercitrin, luteolin, epigallocatechin-3-O-(3″-O-methyl)-gallate, apigenin-7-O-glucoside and ethyl gallate. Isolated compounds showed significant DPP-IV inhibitory activity in a concentration-dependent manner with the highest activity with minimum IC₅₀ being possessed by isoquercitrin (IC₅₀ 4.28 ± 0.32 µM). At a concentration of 200 µM, apigenin-7-O-glucoside displayed a considerable glycation inhibitory effect (81.57 ± 2.66 %), surpassing the effect of other compounds. Moreover, at a concentration of 50 μM, the compounds apigenin-7-O-glucoside and isoquercitrin have increased the glucose uptake in L6 myotubes by 11.5 % and 11 % respectively, compared to a 6.1 % increase by the standard drug metformin. Notably, this study reveals for the first time the potential of both apigenin-7-O-glucoside and isoquercitrin to enhance glucose uptake in L6 myotubes.

Conclusion

AL and its isolated compounds exhibit promising effects in ameliorating post-prandial hyperglycemia. Their multifaceted therapeutic potential prompts further investigation to elucidate the underlying molecular mechanisms.