ABSTRACT
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.
Subject(s)
Abelmoschus/chemistry , Fruit/chemistry , Lipase/antagonists & inhibitors , alpha-Amylases/antagonists & inhibitors , alpha-Glucosidases/chemistry , Animals , Antioxidants/chemistry , Antioxidants/classification , Antioxidants/isolation & purification , Benzothiazoles/antagonists & inhibitors , Benzothiazoles/chemistry , Biphenyl Compounds/antagonists & inhibitors , Biphenyl Compounds/chemistry , Disaccharides/chemistry , Disaccharides/isolation & purification , Flavonoids/chemistry , Flavonoids/classification , Flavonoids/isolation & purification , Hydroxybenzoates/chemistry , Hydroxybenzoates/isolation & purification , Lipase/chemistry , Phenols/chemistry , Phenols/classification , Phenols/isolation & purification , Picrates/antagonists & inhibitors , Picrates/chemistry , Plant Extracts/chemistry , Quercetin/analogs & derivatives , Quercetin/chemistry , Quercetin/isolation & purification , Rutin/chemistry , Rutin/isolation & purification , Sulfonic Acids/antagonists & inhibitors , Sulfonic Acids/chemistry , Sulfonic Acids/isolation & purification , Swine , Thiazoles/chemistry , Thiazoles/isolation & purification , alpha-Amylases/chemistryABSTRACT
Chuanminshen violaceum has been used as an important traditional Chinese medicine and a popular tonic food in China. Polysaccharides are considered the major bioactive components in C. violaceum. In this study, in order well understand the chemical structures and bioactivities of non-starch polysaccharides in C. violaceum (CVPs), the physicochemical structures, antioxidant activities, and immunomodulatory activities of CVPs in C. violaceum collected from different regions of China were investigated and compared. Results showed that the constituent monosaccharides and Fourier transform infrared spectra of CVPs in C. violaceum collected from different regions were similar. However, their molar ratios of constituent monosaccharides, molecular weights, and contents of uronic acids were different. Furthermore, CVPs exerted remarkable antioxidant activities (ABTS and nitric oxide radical scavenging capacities) and immunomodulatory activities (promoted production of nitric oxide, IL-6, and TNF-α from RAW 264.7 macrophages in vitro). Meanwhile, the antioxidant and immunomodulatory activities of CVPs extracted from C. violaceum also varied by cultivated regions. Moreover, results indicated that the antioxidant and immunomodulatory activities of CVPs were closely correlated to their α-1,4-d-galactosiduronic linkages. Results are helpful for better understanding of the structure-bioactivity relationships of CVPs, and beneficial for the improvement of their applications in pharmaceutical and functional food industries.