Antioxidant and anti-diabetic activities of bioactive fractions of Carica papaya seeds extract

Carica papaya has tremendous medicinal applications against diverse diseases since ancient period. Considering this, the present study was aimed to assess in vitro antioxidant and anti-diabetic activities of bioactive fractions of C. papaya seed extracts. Initially, the shade-dried ripen seeds of C. papaya were powdered and extracted via soxhlet protocol to obtain crude extracts. The crude extracts were then fractionated using different solvents viz. hexane, ethyl acetate, methanol, and water. Fractions obtained were assessed for a-glucosidase and amylase inhibitory activities using standard methodologyies. Results revealed that ethyl acetate fraction C (83.66 +/- 0.10%) and D (84.56 +/- 0.23%) showed maximum inhibition of a-amylase with an IC50 value of 36.84 and 36.86 mg/ml, respectively. Likewise, ethyl acetate fraction C (48.72 +/- 0.10%) and D (51.81 +/- 0.45%) exhibited alpha-glucosidase inhibition with an IC50 value of 83.54 and 82.33 mg/ml, respectively. The ethyl acetate fractions C and D were further purified to obtain sub-fraction K, L, M, and N and evaluated for in vitro antioxidant and anti-diabetic activities. The sub-fraction K demonstrated maximum antioxidant activity against DPPH and TBA radicals (IC50 = 41.37 and 53.98 mg/ml) respectively. However, the sub-fraction K elicited the most conspicuous anti-diabetic activity towards alpha-amylase (IC50 = 156.15 mg/ml) and intestinal alpha-glucosidase (IC50 = 70.89 mg/ml). The mode of inhibition was determined using the Lineweaver- Burk plot. Sub-fraction K exhibited a competitive mechanism of inhibition on both alpha-amylase and alpha-glucosidase. The GC-MS profile confirmed the presence of diverse metabolites in the sub-fraction and the major bioactive compounds detected were hexadecanoic acid, methyl ester, 11-octadecenoic acid, methyl ester, N, N-dimethyl, n-hexadecanoic acid, and oleic acid. Our findings suggested the folklore medicinal use of C. papaya seeds as an effective antioxidant and anti-diabetic agents. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of King Saud University.