Abstract
Thailand is located in the tropics and a wide variety of fruits are grown commercially. However, studies regarding the phytonutrients, anti-mutagenic and chemopreventive effects of these fruits are limited. Thus, phytochemical profiles and inhibition of key enzymes involved in obesity and diabetes, together with anti-mutagenic and chemopreventive properties of eight tropical fruit extracts cultivated in Thailand, including Psidium guajava 'Kimju', Psidium guajava 'Keenok', Ananas comosus 'Pattavia', Ananas comosus 'Phulae', Durio zibethinus 'Chanee', Durio zibethinus 'Monthong', Carica papaya 'Khaekdum' and Mangifera indica 'Namdokmai' were investigated. Different cultivars were also compared. Results showed that M. indica 'Namdokmai' was the most antioxidant-rich extract containing abundant 4-hydroxybenzoic acid and its derivative, gallic acid, as the main phenolics. M. indica 'Namdokmai' also exhibited high inhibitory capacities (>60% inhibition under studied conditions) against lipase, α-amylase and α-glucosidase, key enzymes as drug targets for controlling obesity and type 2 diabetes. Interestingly, all fruit extracts suppressed food mutagen-induced DNA mutations assayed by the Ames test, especially M. indica 'Namdokmai' and C. papaya 'Khaekdum' (>50% inhibition at 200 µg/plate). The M. indica 'Namdokmai' was also the most potent extract for suppression of cancer promotion (>90% inhibition at 200 µg/mL) followed by P. guajava 'Kimju', P. guajava 'Keenok' and C. papaya 'Khaekdum'. Results potentially indicated that fruit intake after overcooked meat consumption might supplement nutrients and fiber and also reduce DNA mutation sources.