Antioxidant and Inhibitory Effects of Saponin Extracts from Burtt Davy on Key Enzymes Implicated in Type 2 Diabetes .

CONTEXT

is a plant of South African origin with various acclaimed pharmaceutical potentials.

AIMS

This study explored the antioxidant and antidiabetic activities of saponin extract from .

MATERIALS AND METHODS

Antioxidant activity of saponin was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (*NO)-free radical scavenging activity while antidiabetic potentials were measured by the α-amylase and α-glucosidase inhibitory activities of the saponin extract.

RESULTS

The results showed that the saponin extract, compared with quercetin, displayed better DPPH (IC = 6.95 mg/ml) and NO (IC = 3.31 mg/ml) radical scavenging capabilities. Similarly, the saponin extracts elicited stronger α-glucosidase (IC = 3.80 mg/ml) and moderate α-amylase (IC = 4.18 mg/ml) inhibitory activities as compared to acarbose. Saponin exhibited a competitive mode of inhibition on α-amylase with same maximum velocity (Vmax) of 0.0093 mM/min for saponin compared with control 0.0095 mM/min and different the Michaelis constant (Km) values of 2.6 × 10 mM and 2.1 × 10 mM, respectively, while for α-glucosidase, the inhibition was uncompetitive, Vmax of 0.027 mM/min compared with control 0.039 mM/min and Km values of 1.02 × 10 mM and 1.38 × 10 mM, respectively. The gas chromatography-mass spectrometric analysis revealed the presence of bioactive like β- and α-amyrin, 3-O-methyl-D-glucose, methyl commate, and olean-12-en-3-beta-ol.

CONCLUSION

Overall, the data suggested that the saponin extract from has potentials as natural antioxidants and antidiabetics.

SUMMARY

Saponin extract from displayed promising antidiabetic and antioxidant activitySaponin competitively and uncompetitively inhibited a-amylase and a-glucosidase, respectivelyThe stronger inhibition of α-glucosidase and moderate inhibition of α-amylase by saponin extract from is promising good antidiabetes compared with existing drugs with associated side effects. DPPH: 2,2-diphenyl-1-picrylhydrazyl, Km: The Michaelis constant, Vmax: Maximum velocity, ROS: Reactive oxygen species, NIDDM: Non-insulin-dependent diabetes mellitus, UFS: University of the Free State, GC-MS: Gas chromatography-mass spectrometric, MS: Mass spectrometry, NIST: National Institute of Standards and Technology, DNS: 3,5-dinitrosalicylic acid, NO: Nitric oxide, RNS: Reactive nitrogen species, PNPG: p-Nitrophenyl-α-D-glucopyranoside.