α‐glucosidase, α‐amylase inhibitory potential and antioxidant activity of fragrant black rice (Thai coloured rice)

• Published in: Flavour and fragrance journal Vol. 35; no. 4; pp. 376 - 386
• Main Authors: Sansenya, Sompong, Nanok, Kesinee
• Format: Journal Article
• Language: English
• Published: Chichester Wiley Subscription Services, Inc 01.07.2020
• Subjects: 2,2-diphenyl-1-picrylhydrazyl; Acarbose; alpha-amylase; alpha-glucosidase; Amylases; antioxidant activity; antioxidant potential; Antioxidants; Bioactive compounds; black rice; carbohydrate hydrolysis enzyme; color; Diabetes mellitus; drugs; enzyme inhibition; Enzymes; Flavonoids; Glucosidase; Inhibition; inhibitory concentration 50; Pharmaceutical industry; Rice; Thai fragrant rice; type 2 diabetes mellitus; α-Amylase; α-Glucosidase
• ISSN: 0882-5734; 1099-1026
• DOI: 10.1002/ffj.3572

Coloured rice is the source of bioactive compounds related to medicinal treatment. This study aimed to investigate α‐glucosidase and α‐amylase inhibitory activity and antioxidant properties of purified coloured rice extract (Thai fragrant black rice). The results reveal that seven purified fractions; rice fractions 1‐7 (RF1‐RF7) contained several phytochemical compounds especially flavonoids, which were presented in all purified fractions. The percentage inhibition on α‐glucosidase and α‐amylase of fractions RF1, RF2, RF4, RF5 and RF6 had higher potential than acarbose. RF4, RF5 and RF6 contained the highest inhibition potential, which further determined the IC50 values, kinetic analysis and antioxidant properties. The IC50 values of all three fractions indicated that the inhibition potential of purified fraction had higher potential than acarbose, and the highest inhibition potential for both enzymes was obtained from fraction RF5. The kinetic analysis of the three fractions indicated that they are against both enzymes' function in mixed‐type inhibition. Moreover, all three fractions also showed good antioxidant activity, and the highest potential was obtained from fraction RF6. This study presents the inhibition efficiency of fragrant black rice extract on α‐glucosidase and α‐amylase enzymes. The inhibitory activity of rice extract on both enzymes had higher potent than commercial standard drug acarbose. Moreover, the rice extract also shown the high‐efficiency antioxidant activity on DPPH and ABTS assay. We suggest the application of these results in the development of anti‐diabetes drug for pharmaceutical industry. The bioactive compounds content and inhibitory activity against α‐glucosidase, α‐amylase and tyrosinase of fragrant black rice extract.