Cherry tomatoes are abundant in Tianyang County, Guangxi. In this study, we investigated the nutritional composition, bioactive composition and antioxidant function of three widely grown cherry tomato varieties in Tianyang County. The nutrients included sugar, fats, proteins, and minerals, and the cherry tomatoes bioactive components included fat-soluble components and water-soluble components, such as lycopene, β-carotene, esculeoside A, glutathione (GSH), and vitamin C. In addition, antioxidant activities of the three cherry tomato varieties were evaluated by their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl free radicals in vitro, preventing lipid peroxidation in the liver of mice. The results showed that all three types of cherry tomatoes were all rich in water and dietary fiber, and the Jinbi cherry tomato variety showed the highest energetic value (36.69 kcal/100 g fresh weight), suggesting cherry tomatoes as a low-calorie diet food. Constituent studies revealed that all three cherry tomato varieties were rich in GSH, esculose A, vitamin C and rutin, and the Qianxi cherry tomato variety was also rich in lycopene. In vitro scavenging of DPPH and hydroxyl radicals revealed excellent free radical scavenging activity in all three cherry tomato fat-soluble and water-soluble components, with the best results in the Qianxi variety fat-soluble component. Experimental results suggested that cherry tomatoes reduced malondialdehyde (MDA) level and increased levels of superoxide dismutase (SOD), catalase (CAT) and GSH, and prevented lipid peroxidation in the liver of mice. Our study suggests that cherry tomatoes are not only a good low-calorie nutritional supplement, but also a functional antioxidant food.

Mogroside IIE is a bitter triterpenoid saponin which is the main component of unripe Luo Han Guo fruit and a precursor of the commercially available sweetener mogroside V. In this study, we developed an enzymatic glycosyl transfer method, by which bitter mogroside IIE could be converted into a sweet triterpenoid saponin mixture. The reactant concentration, temperature, pH and buffer system were studied. New saponins with the α-glucose group were isolated from the resulting mixtures, and the structures of three components of the extract were determined. The structure-taste relationships of these derivatives were also studied together with those of the natural mogrosides. The number and stereoconfiguration of glucose groups present in the mogroside molecules were found to be the main factor to determine the sweet or bitter taste of a compound. The antioxidant and food safety properties were initially evaluated by their radical scavenging ability and via 7 day mice survival tests, respectively. The results showed that the sweet triterpenoid saponin mixture has the same favorable physiological and safety characteristics as the natural mogrosides.

Litchi pericarp is the main byproduct of litchi processing and contains several polyphenols. However, the chemical constituents and the antioxidant effect in litchi pericarp extracts (LPE) have been rarely studied. The result of the quantitative analyses of the major monomers in LPE indicated that procyanidin A2, procyanidin B2, epicatechin, rutin, and catechin were the major polyphenol compounds of LPE. The LPE exhibited high radical scavenging activity, as indicated by the results of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ascorbic acid, 2,2′-Azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) tests. Moreover, administrating D-galactose in mice led to the reduced activity of antioxidant enzymes, aggravated lipid peroxidation, and induced protein oxidation. The results were improved in the aging mice after the LPE treatment was performed. The above results suggest that LPE has an excellent antioxidant effect. Accordingly, litchi pericarp can serve as a promising source of dietary antioxidants.

Tomato fruit (Lycopersicon esculentum Mill.) has been suggested to be useful for the prevention of diabetes. Esculeoside A is the main saponin compounds in tomatoes. This study investigated the hypoglycemic effects and the underlying mechanism of esculeoside A in C57BLKS/Leprdb (db/db) mice. Wild-type C57BLKS (db/dm) mice were used in the db/dm mouse group and db/db mice were randomly divided into 2 groups: untreated and treated db/db mouse groups. Esculeoside A (100 mg/kg) was administered by gavage for 56 days to the treated db/db mouse group. Distilled water was administered to the db/dm mouse group and the untreated db/db mouse group. The blood and liver biochemical parameters and the expression of liver insulin signaling-related proteins were examined. The results showed that esculeoside A reduced the fasting blood glucose (FBG) levels and improved the glucose tolerance. Further investigation revealed that hepatic protein expressions of total AMP-activated protein kinase (T-AMPK), phosphorylated AMP-activated protein kinase (p-AMPK), insulin receptor substrate-1 (IRS-1), and glucokinase (GCK) were significantly upregulated after esculeoside A treatment. In contrast, the hepatic protein expression of phosphoenolpyruvate carboxykinase (PEPCK) was significantly downregulated by esculeoside A treatment. These findings suggested that esculeoside A has a potential of alleviating the metabolic abnormalities in db/db mice via regulation of AMPK/IRS-1 pathway. Our findings supported a possible application of esculeoside A as a functional supplement for diabetes treatment.