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

Abstract

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.

Keywords::

• lichen
• nutraceuticals
• antioxidants
• α-amylase
• α-glucosidase
• hyperglycaemia

Acknowledgements

We thank the Council of Scientific and Industrial Research (CSIR) for financial support (BSC 0106) and the Director, CSIR-NIIST for providing the necessary facilities. We also thank Mr M.S. Ajayan (Senior Research Fellow, CUSAT) for his technical assistance. There is no conflict of interest between any of the authors.

Notes

^1. P. Salin Raj and A. Prathapan contributed equally to this work.