Phenolic Compounds, Antioxidant Activities, and Inhibitory Effects on Digestive Enzymes of Different Cultivars of Okra (Abelmoschus esculentus).

In this study, the phenolic profiles and bioactivities of five representative cultivars of okra collected in China were investigated. Noticeable variations of phenolic compounds and their bioactivities were observed among these different cultivars of okra. The contents of total flavonoids (TFC) in "Shuiguo", "Kalong 8", "Kalong 3", "Wufu", and "Royal red" ranged from 1.75 to 3.39 mg RE/g DW, of which "Shuiguo" showed the highest TFC. Moreover, five individual phenolic compounds were found in okra by high performance liquid chromatography analysis, including isoquercitrin, protocatechuic acid, quercetin-3-O-gentiobioside, quercetin, and rutin, while isoquercitrin and quercetin-3-O-gentiobioside were detected as the main phenolic compounds in okra. Moreover, all tested okra exhibited significant antioxidant activities (2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, 2,2'-azino-bis (3-ethylenzthiazoline-6-sulphonic acid) radical scavenging capacity, and ferric reducing antioxidant power) and inhibitory effects on digestive enzymes (lipase, α-glucosidase, and α-amylase). Indeed, "Shuiguo" exhibited much better antioxidant activities and inhibitory activities on digestive enzymes, which might be attributed to its high TFC. Results suggested that okra, especially "Shuiguo", could be developed as natural antioxidants and inhibitors against hyperlipidemia and hyperglycemia in the fields of functional foods and pharmaceuticals, which could meet the increasing demand for high-quality okra with health-promoting properties in China.

Physicochemical characteristics and biological activities of polysaccharides from the leaves of different loquat (Eriobotrya japonica) cultivars.

In order to explore polysaccharides from loquat leaves (LLPs) as functional food ingredients for prevention and treatment of obesity and type 2 diabetes, the physicochemical characteristics, in vitro binding properties, and inhibitory effects on α-amylase and α-glucosidase of polysaccharides from the leaves of different loquat cultivars, including 'Baiyu', 'Chuannong8', 'Yuanbao', and 'Dawuxing', were investigated and compared. Results showed that the contents of total uronic acids and degree of esterification in LLPs ranged from (27.04 ±â€¯1.76)% to (41.46 ±â€¯1.91)%, and from (20.54 ±â€¯0.11)% to (26.90 ±â€¯0.10)%, respectively. The weight-average molecular weights of LLPs ranged from 4.307 × 106 Da to 5.101 × 106 Da, and the major constituent monosaccharides of LLPs were rhamnose, galacturonic acid, arabinose, and galactose. Furthermore, LLPs exerted strong in vitro fat binding, cholesterol binding, and bile acid binding capacities, as well as remarkable inhibitory effects on α-amylase and α-glucosidase, which might be attributed to their molecular weights, molecular weight distributions, and degree of esterification. Results are helpful for better understanding of chemical structures and bioactivities of polysaccharides from loquat leaves, and LLPs had good potential to be explored as functional food ingredients for prevention and treatment of obesity and type 2 diabetes.

Phenolic Profiles, Antioxidant Capacities, and Inhibitory Effects on Digestive Enzymes of Different Kiwifruits.

In order to obtain high-quality kiwifruits with health-promoting characteristics, physicochemical properties, phenolic profiles, antioxidant capacities, and inhibitory effects on digestive enzymes (pancreatic lipase and α-glucosidase), of fourteen different types of kiwifruit obtained from China were systematically investigated and compared. Noticeable variations in the fruits' physicochemical properties and phenolic profiles were observed among them. The total phenolic content of Actinidia chinensis cv. Hongshi, A. chinensis cv. Jinshi, and A. chinensis cv. Jinlong were 16.52 ± 0.26 mg GAE/g DW (dry weight), 13.38 ± 0.20 mg GAE/g DW, and 11.02 ± 0.05 mg GAE/g DW, respectively, which were much higher than those of the other tested kiwifruits. According to high performance liquid chromatography (HPLC) analysis, phenolic compounds, including procyanidin B1, procyanidin B2, (-)-epicatechin, chlorogenic acid, gallic acid, and quercetin-3-rhamnoside, were found to be the major compounds in kiwifruits, while procyanidin B1, procyanidin B2, and chlorogenic acid were the most abundant phenolic compounds. Furthermore, all the tested kiwifruits exerted remarkable antioxidant capacities and inhibitory effects on pancreatic lipase and α-glucosidase. Indeed, A. chinensis cv. Hongshi, Actinidia chinensis cv. Jinshi, and Actinidia chinensis cv. Jinlong exhibited much better antioxidant capacities and inhibitory effects on digestive enzymes than those of the other tested kiwifruits. Particularly, A. polygama showed the highest inhibitory activity on α-glucosidase. Therefore, Actinidia chinensis cv. Hongshi, Actinidia chinensis cv. Jinshi, and Actinidia chinensis cv. Jinlong, as well as A. polygama could be important dietary sources of natural antioxidants and natural inhibitors against pancreatic lipase and α-glucosidase, which is helpful for meeting the growing demand for high-quality kiwifruits with health-promoting characteristics in China.