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

• Main Authors: Reuben Agada, Dluya Thagriki, D. Esther Lydia, Ameer Khusro, Jawaher Alkahtani, Manal M. Al Shaqha, Mona S. Alwahibi, Mohamed Soliman Elshikh
• Format: Article
• Language: English
• Published: Elsevier 2021-03-01
• Series: Journal of King Saud University: Science
• Subjects: Antioxidant; Carica papaya seeds; Diabetes mellitus; Gas chromatography-mass spectrometry
• Online Access: http://www.sciencedirect.com/science/article/pii/S1018364721000033

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 α-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 α-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 α-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 α-amylase (IC50 = 156.15 mg/ml) and intestinal α-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 α-amylase and α-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.