Phytochemical analysis and anti-oxidant activities of Albuca bracteata Jacq. and Albuca setosa Jacq bulb extracts used for the management of diabetes in the Eastern Cape, South Africa

ABSTRACT

Objective The bulb of Albuca bracteata Jacq., and Albuca setosa commonly used in Eastern Cape Province of South Africa for the treatment of several types of disease conditions including diabetes, was investigated for their phytochemical contents and antioxidant activities. Methods The antioxidant activity was determined by evaluating the effect of various solvent extracts (acetone, methanol, ethanol and water) on 2,2 – diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, 2,2′ – azino-bis (3-ethylbenzthiazoline-6-sulfonic acid diammonium salt (ABTS), ferric reducing power, hydrogen peroxide and nitric oxide scavenging activity while the various extracts were also analysed for phytochemical their contents. Results The results obtained indicate that polyphenols, proanthocyanidins, saponins and alkaloids are present in higher concentrations. The composition of phenols (117 mg/g), flavonols (26.28 mg/g), proanthocyanidins (84.85 mg/g) and flavonoids (5.36 mg/g) were significantly higher in the acetone extract while saponin and alkaloids contents were higher in the aqueous extract. Antioxidant studies of the extracts for nitric oxide, hydrogen peroxide, ABTS and DPPH showed high antioxidant potential in a concentration-dependent manner that was not significantly different from Vitamin C, BHT and Rutin used as standard references. The methanol extract showed higher ferric reducing potential compared to the aqueous extract but was significantly different from Vitamin C, BHT and Rutin. Conclusion This implies that the bulb of Albuca bracteata may serve as a natural source of antioxidants, which together with the numerous phytochemicals present, could account for its folkloric use as a medicinal plant.