A Adesida1, E O Farombi. 1. Drug Metabolism and Toxicology Unit, Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Ibadan, Ibadan, Nigeria.
Abstract
INTRODUCTION: Psidium guajava (guava) is used in folk medicine in treating diverse human ailments. The therapeutic benefit of medicinal plants is often attributed to their antioxidant properties. OBJECTIVES: This study evaluated the radical scavenging potentials of ethanolic extract of Psidium guajava (EEPG) in vitro. METHOD: Radical scavenging potential of EEPG was determined by assessing its reducing power, extent of LPO, NO, H2O2, DPPH inhibition and TEAC. RESULT: AAPH-induced LPO was significantly (P < 0.05) inhibited by 56.5%, 65.3%, 55.1%, 54.4%, 53.1%, at 25-400 micro/g of EEPG. The reference drug, catechin at 50 microg, produced 39.5% inhibition of LPO induced by AAPH respectively with respect to control. EEPG produced significant (p < 0.05) inhibition of deoxyribose degradation at 100-800 microg concentrations by 30.9% (p < 0.01), 42.5%, 55.7%, 72.8% (p < 0.001) respectively with respect to control. Catechin also show potency, producing 55.5% at 25 microg (p < 0.001). Furthermore, the antioxidant activity of EEPG ranged from 763.08 to 1206.2 micromol trolox equivalent in the TEAC assay at 50-200 microg (p < 0.001) and 24.62 to 14.77 micromol trolox equivalent at 800-2000 microg (p < 0.001). Catechin exhibited a TEAC value of 2338.5 micromol trolox equivalent (p < 0.001). EEPG exhibited maximum radical scavenging activities of 30.1% on NO radical (p < 0.01), 98.72% on H2O2 (p < 0.001), at 50 microg and 70.45% on DPPH radical (p < 0.001) at 100 microg. EEPG also demonstrated marked reducing power, increasing absorbance values from 0.24 +/- 0.01 to 1.86 +/- 0.20 at 25-160 microg. The reducing power of EEPG at 200 microg (0.41 +/- 0.07) almost compares with that of catechin at 50 microg (0.45 +/- 0.028). CONCLUSION: These results demonstrate that the ethanolic extract of Psidium guajava (EEPG) exhibited significant free radical scavenging and antioxidant activities in vitro.
INTRODUCTION:Psidium guajava (guava) is used in folk medicine in treating diverse human ailments. The therapeutic benefit of medicinal plants is often attributed to their antioxidant properties. OBJECTIVES: This study evaluated the radical scavenging potentials of ethanolic extract of Psidium guajava (EEPG) in vitro. METHOD: Radical scavenging potential of EEPG was determined by assessing its reducing power, extent of LPO, NO, H2O2, DPPH inhibition and TEAC. RESULT: AAPH-induced LPO was significantly (P < 0.05) inhibited by 56.5%, 65.3%, 55.1%, 54.4%, 53.1%, at 25-400 micro/g of EEPG. The reference drug, catechin at 50 microg, produced 39.5% inhibition of LPO induced by AAPH respectively with respect to control. EEPG produced significant (p < 0.05) inhibition of deoxyribose degradation at 100-800 microg concentrations by 30.9% (p < 0.01), 42.5%, 55.7%, 72.8% (p < 0.001) respectively with respect to control. Catechin also show potency, producing 55.5% at 25 microg (p < 0.001). Furthermore, the antioxidant activity of EEPG ranged from 763.08 to 1206.2 micromol trolox equivalent in the TEAC assay at 50-200 microg (p < 0.001) and 24.62 to 14.77 micromol trolox equivalent at 800-2000 microg (p < 0.001). Catechin exhibited a TEAC value of 2338.5 micromol trolox equivalent (p < 0.001). EEPG exhibited maximum radical scavenging activities of 30.1% on NO radical (p < 0.01), 98.72% on H2O2 (p < 0.001), at 50 microg and 70.45% on DPPH radical (p < 0.001) at 100 microg. EEPG also demonstrated marked reducing power, increasing absorbance values from 0.24 +/- 0.01 to 1.86 +/- 0.20 at 25-160 microg. The reducing power of EEPG at 200 microg (0.41 +/- 0.07) almost compares with that of catechin at 50 microg (0.45 +/- 0.028). CONCLUSION: These results demonstrate that the ethanolic extract of Psidium guajava (EEPG) exhibited significant free radical scavenging and antioxidant activities in vitro.