Comparative evaluation of α-glucosidase inhibitory potential of six Berberis species from the Nepal Himalaya

TRISHNA GOSWAMI (Central Department of Botany, Tribhuvan University. University Street, Kritipur, 44613 Kathmandu, Nepal)
DEEPAK RAJ PANT (Central Department of Botany, Tribhuvan University. University Street, Kritipur, 44613 Kathmandu, Nepal)
GIRI PRASAD JOSHI (Central Department of Botany, Tribhuvan University. University Street, Kritipur, 44613 Kathmandu, Nepal)

Biodiversitas Journal of Biological Diversity
Vol. 27 No. 8 (2026)

Abstract. Goswami T, Pant DR, Joshi GP. 2026. Comparative evaluation of α-glucosidase inhibitory potential of six Berberis species from the Nepal Himalaya. Biodiversitas 27 (8): d270818. https://doi.org/10.13057/biodiv/d270818. The present study evaluated the in vitro α-glucosidase inhibitory activity of methanolic stem bark extracts from Berberis angulosa, B. aristata, B. asiatica, B. glaucocarpa, and B. thomsoniana, and extracts of the entire stem (stem and leaves) of B. karnaliensis. Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) were determined using the Folin-Ciocalteu method and aluminum chloride colorimetric methods, respectively, while in vitro α-glucosidase inhibitory activity was assessed through an α-glucosidase inhibitory assay. All quantitative data were measured in triplicate. Among the species, the highest TPC was recorded in B. aristata extract (23.6±0.78 mg GAE g-1 extract), while the lowest was observed in B. karnaliensis extract (10.65±0.16 mg GAE g-1 extract). B. aristata extract had the highest TFC (27.37±0.22 mg QE g-1 extract), and the lowest in B. angulosa extracts (0.65±0.10 mg QE g-1 extract). Of the six tested species, B. karnaliensis exhibited the strongest α-glucosidase inhibitory activity, with an IC50 value of 14.72±3.15 μg/mL), significantly lower than that of Acarbose (p≤0.05). Further fractionation revealed that the hexane fraction of B. karnaliensis possessed the highest inhibitory activity. LC-MS annotation of the hexane fraction suggested the presence of two compounds (isosakuranetin and reserpine) previously associated with α-glucosidase inhibitory activity. Comparative evaluation of the bark extracts revealed that all investigated Berberis species, except B. aristata and B. thomsoniana, exhibited stronger α-glucosidase inhibitory activity than acarbose. Notably, the aerial parts of B. karnaliensis showed the highest inhibitory activity, suggesting that this species may be a promising alternative to B. aristata, which has long been used in traditional medicine for diabetes management. The findings indicate that B. karnaliensis warrants further investigation as a potential source of α-glucosidase inhibitory constituents.