ABSTRACT
Objective:To evaluate the antioxidant potential of the phenolic extracts of Mimusops elengi (M. elengi) L. (Sapotaceae). Methods:The extract of stem bark and seeds of M. elengi were prepared in methanol and acetone:water (7:3). The acetone: water was further partitioned with ethyl acetate and n-butanol. Antioxidant activity of the extracts and partitioned fractions of M. elengi was evaluated in terms of radical scavenging potential (DPPH), inhibition of lipid peroxidation [ferric thiocyanate (FTC)], and total antioxidant activity (phosphomolybdate method). Total phenolics content were calculated using Folin-Ciocalteu reagent. Results:The stem bark extract partitioned with ethyl acetate exhibited highest amount of total phenols (98.0 mg GAE/g dry weight), among all other extracts, with 92.0%DPPH radical scavenging activity at concentration of 0.5 mg/mL, while methanol extract (stem bark) had maximum inhibition of lipid peroxidation (62.0%) and total antioxidant activity (771.0 mg/g GAE/g). A positive correlation occurred between total phenols and radical scavenging activity (R2= 0.922 9) and total antioxidant activity (R2= 0.945 1). Conclusions: Our study suggested that antioxidant activity of stembark extract of M. elengi is due the presence of phenolic compounds. Furthermore, the bark extract is a valuable source of natural antioxidants.
ABSTRACT
Objective: Eucalyptus and Curcuma species are well reputed for their traditional medicinal uses in south east Asia, therefore, the present study was designed to determine reducing potential of their essential oils. Method: Essential oils of the selected medicinal species Eucalyptussideroxylon, E. teriticornis, E. citriodora, Curcuma longa and C. aromatic were extracted using hydro distillation method, separated with diethyl ether and dried over anhydrous sodium sulphate. Column chromatography of Curcuma aromatica was carried out and six fractions were collected using gradient solvent system of n-hexane-ethyl acetate. Ferric reducing antioxidant power (FRAP) of oils were evaluated using standard protocol and results were expressed in μM equivalent to FeSO4.7H2O. Results: The essential oil of Eucalyptus sideroxylon was found to possess highest reducing potential among the Eucalyptus species. Curcuma longa essential oil showed most significant reducing potential with 138.4±1.1 FRAP equivalents. Conclusions:It was concluded that the all essential oil and the column fractions of C. aromatica possess significant reducing capacity ranged from 95.8±1.0 to 152.4±1.4 μM in a dose dependent manner.