Bioquímica e Farmacologia: Acesso Aberto
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Abstrato

Concentration and Differential fractions of Saponin Rich Aframomum melegueta Extract Influences In-Vitro Antioxidant Activities, and Silver Nitrate can Stimulate such Activities in the Plant

John Ajayi, Ibraheem Omodele

Free radicals are generated during normal metabolic activities of the body, and are capable of causing damage to cells and tissues when their rate of production exceeds their removal from the body, a pathologic condition commonly referred to as oxidative damage. Plant secondary metabolites, are proved to be effective in scavenging such free radicals. The plant saponin extracts were prepared using different solvent extraction fractions. It was intended at determining what fractions of the solvents would be best suitable for the extraction of the plant’s saponin rich fraction. Different concentrations were then prepared from the stock saponin solution, to evaluate the most potent concentration. Total phenolics, antioxidant activity using DPPH, chelating activity, hydrogen peroxide scavenging activity and the effect of silver nitrate on the plant’s activity were then evaluated. The 80% saponin fraction at the 150µg/ml concentration demonstrated the highest antioxidant activities using DPPH with a value of 46.88 and the 100% SF at the 100 µg/ml had the least antioxidant activity with a value of 10.55%. The 80% extract also had the highest total phenolic content, and iron chelating activity at higher concentrations. While the highest saponin extraction yield was obtained by 100% fraction. The effect of 1mM Silver nitrate (AgNO3 ) was evaluated for five minutes, and it was found to have stimulatory effect by remarkably increasing the antioxidant activities of each concentration tested from 86.08 to 65.29. The results from this study indicate that polyphenols could be better extracted using a correct mixture of acetone, methanol, ethanol and water because of polarity, and plant’s saponin, being an effective antioxidant, could protect the body from oxidative damage by enhancing the antioxidant defence mechanism of the body system, and its antioxidant activity can be stimulated using silver nitrate or its nanoparticles.