Comparative Phytochemical Analyses and in-vitro Antioxidant Activity of Aqueous and Ethanol Extracts of Simarouba glauca (Paradise Tree)

Abstract

Aims: The study was conducted to evaluate the phytochemical and antioxidant potentials of ethanol and aqueous leaf extracts of Simarouba glauca vis-à-vis standard antioxidants. Study Design: True experimental study. Place and Duration of Study: Department of Biochemistry, University of Benin, Benin City. Nigeria, between August and October 2015. Methodology: Samples were harvested, air dried, pulverized and extracted with aqueous and absolute ethanol; freeze dried at the National energy commission centre, University of Benin. Total phenol content was determined by Folin-ciocalteau method, tannin determined according to Folin and Denis methods while flavonoids content was determined according to the methods described by Ebrahimzadeh et al. DPPH radical scavenging activity was conducted based on the ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH), a stable free radical, to decolorize in the presence of antioxidants. Reducing power activity of extracts was conducted based on test samples extract’ ability to reduce ferricyanide to ferrocyanide indicated in the colour change. Total antioxidant activity of ethanol and aqueous leaf extracts was determined based on the ability of the sample to reduce the ferric-tripyridyltriazine (Fe (III)-TPTZ) complex to ferrous tripyridyltriazine (Fe(II)-TPTZ) at low pH. Hydroxyl radical activity of extracts was conducted on the principle based on the ability of test samples to reduce H2O2 in the presence of 1,10-phenanthroline. Trolox equivalent antioxidant activity of extracts was conducted based on the ability of test sample to scavenge 2,2’azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS+) radical generated based on the principle of decolourization. Nitric oxide (NO.) radical scavenging activity of S, glauca leaf extracts was estimated based on the ability of test samples to scavenge radicals generated by the reaction of naphthylethylenediamine dihydrochloride. Butylated hydroxytuolene (BHT), Ascorbate, Quercetin and Trolox were standard antioxidant. Results: DPPH radical scavenging activity yielded aqueous and ethanol extracts IC50 values of 3.2144 and 4.9100 µg/ml respectively. Reducing power activity yielded (aqueous and ethanol extracts) EC50 of values 60.3233 and 60.1000 µg/ml respectively. Total antioxidant activity yielded (ethanol and aqueous extracts) IC50 values of 52.4320 and 68.8201 µg/ml respectively. Hydroxyl radical activity yielded (ethanol and aqueous extracts) IC50 values of 49.3130 and 50.2341 µg/ml respectively. Trolox equivalent antioxidant activity yielded (ethanol and aqueous extracts) IC50 values of 45.2015 and 52.0721 µg/ml respectively. Nitric oxide scavenging activity yielded aqueous IC50 value of 14.2102 µg/ml but ethanol extract yielded no inhibition concentration at 50 percent. Conclusion: The study showed that aqueous and ethanol leaf extracts of S. glauca demonstrated substantial amount of biochemically valuable phytochemicals and antioxidant potential capable of scavenging reactive oxygen species.