## 2 Bioactive Compounds Commonly Found in Green-Colored Fruits and Vegetables
### Potential Health Benefits  
Among numerous polyphenols, GA is a low-molecular-weight phenolic compound with outstanding anti-antioxidant, inflammatory, antimicrobial, anticancer, cardioprotective, gastroprotective, and neuroprotective properties in humans [198]. In metabolic syndrome and obesity mice, GA appeared to improve the plasma concentrations of TG and glucose as well as the recovery of glucose tolerance and lipid metabolism [180; 199; 200]. In addition, it has been shown to specifically target adipose tissue to inhibit lipogenesis, promote insulin signaling, and concomitantly combat raised proinflammatory response and oxidative stress in mice [180]. The anti-obesity effects of GA can be harnessed either directly by inhibiting the generation of lipid droplets in the liver or adipose tissue, or indirectly by ameliorating the serum levels of TG and LDL of rats [201; 202]. GA could exert its protective effects on the cardiovascular system under oxidative stress [203] by restoring a series of enzymic and nonenzyme antioxidants and attenuating cardiotoxic content and ROS generation. Thus, the preclinical data support the beneficial effects of GA in preventing obesity-associated complication as well as CVDs. In a clinical trial, a placebo-controlled pilot study with 19 patients with type 2 diabetes showed that GA supplementation (15 mg/day for 7 days which was in the range of daily consumption in Europeans) prevented oxidative DNA damage and reduced the levels of inflammatory biomarkers, including C-reactive protein [204]. However, in order to provide meaningful data in determining the efficacy and safety of a given GA treatment, well-designed clinical trials should be necessary. PCA is the main metabolite of anthocyanins and presents a variety of beneficial physiological activities for potential health benefits in humans such as cardiovascular-protective, anti-diabetic, and anti-obesity effects [205; 206]. For example, a previous study has shown that PCA can reduce the risk of CVDs and protect myocardial injury [207]. The mechanism of this rests on the ability of PCA to significantly reduce myocardial infarction size, serum TNF-a levels, and platelet aggregation and significantly inhibit the apoptosis rate and cleaved caspase-3 expression of damaged myocardial cells. In addition, PCA exerts positive effects on insulin resistance and other metabolic and vascular disorders related to type 2 diabetes, partially by enhancing the insulin reaction to manage blood glucose stability of rats [208] as well as by upregulating the expression of phosphorylated Akt [207]. Some studies have proposed a possible anti-diabetes mechanism of PCA, which may improve hepatic insulin resistance and vascular oxidation state by regulating insulin signaling pathway and age-rage-NOX (NADPH oxidase) 4 pathways, respectively, thus exerting its hypoglycemic effect in rats [208]. SA has a wide range of therapeutic applications in preventing diabetes and CVDs, besides having antioxidant, antimicrobial, neuroprotective, and hepatotoxicity activities [184]. In addition, SA exerts health-promoting effects on hyperlipidemia and NAFLD. Briefly, the SA treatment (0.05%, wt/wt) not only lowers the serum glucose and insulin lev els, but also increases the adiponectin levels of HFD-fed rats [209]. Moreover, SA appeared to reduce the expression of inflammatory and lipogenic genes and increase the expression of fatty acid oxidation-related genes in the liver of an NAFLD mouse model [209]. The oral administration of SA (50 mg/kg body weight) for 30 days significantly improved the glycemic status of alloxan-induced diabetic Wistar rats, as indicated by the decreased plasma glucose and glycoprotein levels of the liver and kidney [210]. Extensive investigations have shown that VA exhibits various bioactivities, such as anti-obesity, anti-diabetes, antioxidant, anti-inflammatory, hepatocyte, cardioprotective, and hypolipidemic effects [211].