Effects of Food Processing on In Vivo Antioxidant and Hepatoprotective Properties of Green Tea Extracts

Abstract

Food processing can affect the nutrition and safety of foods. A previous study showed that tannase and ultrasound treatment could significantly increase the antioxidant activities of green tea extracts according to in vitro evaluation methods. Since the results from in vitro and in vivo experiments may be inconsistent, the in vivo antioxidant activities of the extracts were studied using a mouse model of alcohol-induced acute liver injury in this study. Results showed that all the extracts decreased the levels of aspartate transaminase and alanine aminotransferase in serum, reduced the levels of malondialdehyde and triacylglycerol in the liver, and increased the levels of catalase and glutathione in the liver, which can alleviate hepatic oxidative injury. In addition, the differences between treated and original extracts were not significant in vivo. In some cases, the food processing can have a negative effect on in vivo antioxidant activities. That is, although tannase and ultrasound treatment can significantly increase the antioxidant activities of green tea extracts in vitro, it cannot improve the in vivo antioxidant activities, which indicates that some food processing might not always have positive effects on products for human benefits.

Antioxidant activity and hepatoprotective effect of 10 medicinal herbs on CCl4-induced liver injury in mice

“…In this study, the antioxidant activities of selected medicinal herbs were determined by using the FRAP assay and the TEAC assay. The former indicates the antioxidant activity that is dependent on the capacity to reduce [Fe (TPTZ) 2 ] 3+ to [Fe (TPTZ) 2 ] 2+ [ 25 ], whereas the latter is based on the ability to scavenge ABTS •+ [ 24 , 44 ].…”

“…Two slides of liver were sampled from the middle of the left lobe of the liver, one for histopathologic examination (hematoxylin and eosin staining) and the other for biomarker assessment. Liver homogenate was prepared from liver tissue (0.2 g) and physiological saline (ice-cold, 1.8 mL), centrifuged at 2500 g for 10 min and then examined for the activities of SOD and CAT and the levels of GSH, MDA, and TG in accordance with the manufacturer’s instructions and as described in our previous publications[ 24 ].…”

The In Vivo Antioxidant and Hepatoprotective Actions of Selected Chinese Teas

“…The levels of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), triacylglycerol (TG), total bilirubin (TBIL), and total protein (TP) were measured by a Hitachi-7180 automated biochemistry analyzer with a diagnostic reagent kit according to the literature [22,26].…”

“…Although there have been several studies reporting the in vivo antioxidant effects of tea against alcoholic liver injuries, most of them focus on a single tea category, such as green tea or black tea, or a single component such as epigallocatechin gallate (EGCG) [17][18][19][20]. Besides, the in vitro antioxidant activity of natural products may be very different from the in vivo antioxidant activity, due to the differences of the bioavailability of bioactive compounds [21,22]. Therefore, it is very important to systematically evaluate the in vivo antioxidant activity of six categories of tea.…”

Antioxidant, Anti-Aging and Organ Protective Effects of Total Saponins from Aralia taibaiensis

“…ALT and AST are effective markers for evaluating liver function injury. 29 As shown in Figure 10 , compared with those in the normal group of rats, the levels of ALT and AST in the untreated model group were significantly increased (p<0.01), indicating that the liver was damaged by D-gal stimulation. In contrast, after administration of TSAT, the levels of ALT and AST in the livers of aging rats were significantly reduced (p<0.05).…”