Parmotrema tinctorum exhibits antioxidant, antiglycation and inhibitory activities against aldose reductase and carbohydrate digestive enzymes: an in vitro study

This study evaluated the inhibitory potential of ethyl acetate extract of Parmotrema tinctorum (PTEE), an edible lichen, against aldose reductase (AR) and carbohydrate digestive enzymes such as α-glucosidase and α-amylase. It was also screened for antioxidant activities by using DPPH, ABTS, superoxide and hydroxyl radical-scavenging assays. PTEE exhibited α-glucosidase, α-amylase and AR inhibition along with significant antiglycation potential with an estimated IC50 value of 58.45 ± 1.24, 587.74 ± 3.27, 139.28 ± 2.6 and 285.78 ± 1.287 μg/mL, respectively. Antioxidant activity of PTEE against DPPH (IC50 396.83 ± 2.98 μg/mL), ABTS (151.34 ± 1.79 μg/mL), superoxide (30.29 ± 1.17 μg/mL) and hydroxyl (35.42 ± 1.22 μg/mL) radicals suggests the antioxidant potential of P. tinctorum. Significant antioxidant activity and inhibitory potential against carbohydrate digestive enzymes and AR suggest that P. tinctorum can be developed as functional food/nutraceuticals for diabetes after detailed study.