Open AccessEvaluation of in vitro antioxidant activities of selected commercial tea brands
Author(s) -
Habibu Tijjani,
Sherifdeen Jibrin,
Chukwuebuka Egbuna
Publication year - 2022
Language(s) - English
DOI - 10.54117/gjpas.v1i1.1
Subject(s) - chemistry , antioxidant , dpph , ascorbic acid , food science , ic50 , ethanol , vitamin c , hydrogen peroxide , vitamin , biochemistry , in vitro
The generation of reactive oxygen species requires the availability of antioxidants to ensure a balance between oxidants and prooxidants. Teas are commonly consumed due to their beneficial antioxidant effects. This study evaluated the in vitro antioxidant effects of aqueous and ethanol extracts of five selected commercial tea brands using ascorbic acid as the reference standard. The results showed that total antioxidant capacity (TAC) of aqueous extract of brand 1 was significantly lower (p<0.05) compared to brand 2 with half maximal inhibitory concentration (IC50) values of 96.82 and 25.60 mg/mL respectively while the ethanol extract of all tea brands (IC50 values between 53.94 to 120.40 mg/mL) were significantly lower (p<0.05) to vitamin C with IC50 of 22.72 mg/mL. In the ferric ion reducing antioxidant property (FRAP), four of the tea brands expressed none significant FRAP activities with IC50 values between 12.84 and 14.97 mg/mL compared with vitamin C with IC50 values of 17.16 mg/mL, while the ethanol extract of the brand expressed none significant FRAP activities at higher concentrations. Hydrogen peroxide scavenging activities of aqueous and ethanol extracts of all tea brands were significantly lower (p<0.05) with IC50 values between 20.23 - 44.56 mg/mL and 30.53 - 36.01 mg/mL compared with vitamin C with IC50 values of 13.72 and 15.69 mg/mL respectively. Similarly, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging property of aqueous extracts of all brands were significantly lower (p<0.05) compared with vitamin C with IC50 values of 12.92 mg/mL. Furthermore, the nitric oxide scavenging property of aqueous extracts of three brands (IC50 = 18.65, 24.69 and 24.80 mg/mL) were significantly higher (p<0.05) than vitamin C (IC50 = 37.75 mg/mL), while ethanol extract of three brands (IC50 = 12.81, 12.84 and 13.89 mg/mL) were significantly higher (p<0.05) than vitamin C (IC50 = 32.80 mg/mL). The results of the study indicated that the selected commercial tea brands possess in vitro antioxidant properties with potential benefits of the removal of free radicals and thus the prevention of oxidative stress.