Antioxidant and anti-glycation capacities of some medicinal plants and their potential inhibitory against digestive enzymes related to type 2 diabetes mellitus.

BACKGROUND

Plants preparations are used by traditional medicine in the treatment of various diseases, such as type-2 diabetes mellitus. Some medicinal plants are capable of controlling the complications of this metabolic disease at different levels, for example, providing antioxidant compounds that act against oxidative stress and protein glycation and others which are capable of inhibiting the catalysis of digestive enzymes and thus contribute to the reduction of hyperglycemia and hyperlipidemia. Our objective was to investigate the antioxidant and anti-glycation activities of some medicinal plants and their potential inhibitory against α-amylase, α-glucosidase and pancreatic lipase activities.

METHODS

Based on the ethnobotanical researches carried out by academic studies conducted at the Federal University of Uberlandia, ten plants traditionally used in the treatment of type-2 diabetes mellitus were selected. Ethanol (EtOH) and hexane (Hex) extracts of specific parts of these plants were used in enzymatic assays to evaluate their inhibitory potential against α-amylase, α-glucosidase and lipase, as well as their antioxidant (DPPH, ORAC and FRAP) and anti-glycation (BSA/fructose model) capacities.

RESULTS

The results indicate that EtOH extract of four of the ten analyzed plants exhibited more than 70% of antioxidant and anti-glycation capacities, and α-amylase and lipase inhibitory activities; no extract was able to inhibit more than 40% the α-glucosidase activity. The EtOH extracts of Bauhinia forficata and Syzygium. cumini inhibited α-amylase (IC50 8.17 ± 2.24 and 401.8 ± 14.7 μg/mL, respectively), whereas EtOH extracts of B. forficata, Chamomilla recutita and Echinodorus grandiflorus inhibited lipase (IC50 59.6 ± 10.8, 264.2 ± 87.2 and 115.8 ± 57.1 μg/mL, respectively). In addition, EtOH extracts of B. forficata, S. cumini, C. recutita and E. grandiflorus showed, respectively, higher antioxidant capacity (DPPH IC50 0.7 ± 0.1, 2.5 ± 0.2, 1.3 ± 0.2 and 35.3 ± 9.0 μg/mL) and anti-glycation activity (IC50 22.7 ± 4.4, 246.2 ± 81.7, 18.5 ± 2.8 and 339.0 ± 91.0 μg/mL).

CONCLUSIONS

EtOH extracts of four of the ten species popularly cited for treatment of type 2 diabetes mellitus have shown promising antioxidant and anti-glycation properties, as well as the ability to inhibit the digestive enzymes α-amylase and lipase. Thus, our results open new possibilities for further studies in order to evaluate the antidiabetic potential of these medicinal plants.