•Three different methods were used to extract longan polysaccharide.•Compared with LP-H and LP-S, LP-SE had a unique structure11LP-H, LP-S, LP-SE: longan pulp polysaccharides extracted with hot ...water, superfine grinding, superfine grinding-assisted enzymatic treatments, respectively..•LP-SE exhibited the strongest stimulation on proliferation of probssiotic.
Longan pulp polysaccharides were extracted with hot water (LP-H), superfine grinding (LP-S) and superfine grinding-assisted enzymatic treatments (LP-SE). The yields, physicochemical properties and prebiotic activities of polysaccharides were investigated. Compared with LP-H and LP-S, the yield, sugar content, solubility, arabinose and mannose percentage of LP-SE increased while its apparent viscosity, particle size, Mw and glucose percentage declined. Three LPs contained similar glycosidic linkage of →3)-α-l-Araf-(1→, →3,6)-β-d-Galp-(1→ and α-l-Rhap(l→, while they each contained specific glycosidic linkage of →4)-β-d-Glcp(l→, →4)-β-d-Galp-(1→ and →5)-α-l-Araf-(1→ in LP-H, LP-S and LP-SE, respectively. Moreover, LP-SE exhibited stronger stimulation than LP-H and LP-S on the proliferation of Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus fermentum and Leuconostoc mesenteroides. The results indicated three extraction methods had some effect on chemical composition and structure of polysaccharide. LP-SE extracted by superfine grinding-assisted enzymatic treatment exhibited the highest prebiotic activities, which have a great potential in applying in functional food and medical industry.
•Free & bound phytochemicals in milled fractions of black rice exist differences.•The changing ranges of free & bound phytochemicals varied after extrusion.•Extrusion slightly increases the release ...of phytochemicals in black rice bran fraction.•Extrusion causes significant phytochemical loss in polished/brown rice fractions.•Free fractions contributes most to total phytochemicals before and after extrusion.
The phytochemical profile and antioxidant activities of unprocessed and extruded milled fractions of black rice were investigated. Extrusion increased the free phenolics, anthocyanins and oxygen radical absorbance capacity (ORAC) and decreased the bound forms. The total phenolics, anthocyanins and ORAC increased by 12.6%, 5.4% and 19.7%, respectively, in bran. Extrusion decreased both free and bound phenolics and anthocyanins while ORAC values decreased by 46.5%, 88.4% and 33.1%, respectively, in polished rice and by 71.2%, 87.9% and 14.7%, respectively, in brown rice. A total of seven phenolics, gallic, chlorogenic, vanillic, caffeic, syringic, p-coumaric and ferulic acids, were detected in both forms. Cyanidin 3-glucoside (Cy-3-G), cyanidin 3-rutinoside and peonidin 3-glucoside were also detected with Cy-3-G found in the highest amounts in unprocessed and extruded rice bran. These results provide the basis for the development of different milled fractions of extruded black rice with balanced nutritional characteristics for today’s functional food markets.
•Free & bound antioxidant phenolics in endosperm and bran of indica rice investigated.•Phenolic content and antioxidant activity of bran/embryo mainly exist in free form.•The endosperm fraction ...contains both free and bound forms of phenolics.•Bran/embryo fraction contributes most to phenolics content and total antioxidant activity.•Ferulic and coumaric acid in bound forms were distributed mainly in bran/embryo.
This study quantified free and bound phytochemicals and their antioxidant activity in the endosperm and bran/embryo of different indica rice varieties. Phytochemicals mainly existed as free form in the bran/embryo and as both free and bound forms in the endosperm. The average values of total phenolic content, flavonoid content, FRAP, ABTS and ORAC values in the bran/embryo were 3.1, 10.4, 8.2, 11.2 and 11.4 times higher than those in the endosperm, respectively. In whole brown rice, the bran contributed 59.2%, 53.7%, 47.7%, 55.5% and 56.9% of total phenolics, flavonoids, FRAP, ABTS and ORAC values, respectively. Seven individual phenolics (gallic, protocatechuic, chlorogenic, caffeic, syringic, coumaric and ferulic acids) were detected with most coumaric and ferulic acids in the bran. All measurements exhibited varietal differences. These findings provide important information for improving human health by encouraging the consumption of whole brown rice and its use in food product development.
•Increasing degrees of milling significantly reduces phenolics in brown rice.•Ratios of bound:total forms of phenolics and flavonoids decreased during milling.•Nine individual phenolics decreased to ...different extents during milling.•Milling significantly decreased the cellular antioxidant activity of brown rice.
The impact of increasing degree of milling (DOM) on free and bound phenolics and flavonoids and on cellular antioxidant activity (CAA) of japonica and indica brown rice was investigated. As the average DOM increased from 0 to 2.67, 7.25 and 9.60%, the average total phenolic content decreased by 21.1, 42.6 and 55.6%, and the average total CAA value decreased by 37.4, 84.0 and 92.8%, respectively. Furthermore, the percentage contributions of bound forms to total phenolics and flavonoids decreased with increasing DOM. The contents of nine phenolic compounds significantly decreased with increasing DOM, including quercetin, ferulic and coumaric acids. Interestingly, as the DOM increased to 9.6%, free ferulic and coumaric acids were undetectable in japonica rice, while neither free nor bound caffeic acid was detectable in indica rice. These findings indicate that DOM should be carefully controlled for acceptable sensory quality and retention of phytochemicals during brown rice milling.
Citrus plants are rich in flavonoids and beneficial for lipid metabolism. However, the mechanism has not been fully elucidated. Both citrus peel flavonoid extracts (CPFE) and a mixture of their ...primary flavonoid compounds, namely, nobiletin, tangeretin and hesperidin, citrus flavonoid purity mixture (CFPM), were found to have lipid-lowering effects on oleic acid-induced lipid accumulation in HepG2 cells. The carnitine palmitoyltransferase 1α (CPT1α) gene was markedly increased, while the fatty acid synthase (FAS) gene was significantly decreased by both CPFE and CFPM in oleic acid-treated HepG2 cells. Flavonoid compounds from citrus peel suppressed miR-122 and miR-33 expression, which were induced by oleic acid. Changes in miR-122 and miR-33 expression, which subsequently affect the expression of their target mRNAs FAS and CPT1α, are most likely the principal mechanisms leading to decreased lipid accumulation in HepG2 cells. Citrus flavonoids likely regulate lipid metabolism by modulating the expression levels of miR-122 and miR-33.
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•UAE with deep eutectic solvent (DES) extracted polyphenols of P. scandens.•Chcl-EG afforded the highest TFC among 16 DESs coupled with UAE.•Optimization of Chcl-EG-UAE was studied by ...two-level factorial experiment and RSM.•Chcl-EG-UAE had the highest extractability compared with other methods.•30 polyphenols extracted by Chcl-EG-UAE were identified and quantified by UHPLC-MS.
Ultrasonic-assisted extraction (UAE) coupled with deep eutectic solvent (DES) is a novel, efficient and green extraction method for phytochemicals. In this study, the effects of 16 DESs coupled with UAE on the extraction rate of polyphenols from Paederia scandens (Lour.) Merr. (P. scandens), an edible and medicinal herb, were investigated. DES synthesised with choline chloride and ethylene glycol at a 1:2 M ratio resulted in the highest extractability. Moreover, the effects of extraction parameters were investigated by using a two-level factorial experiment followed by response surface methodology The optimal parameters (water content in DES of 49.2%, the actual ultrasonic power of 72.4 W, and ultrasonic time of 9.7 min) resulted in the optimal total flavonoid content (TFC) (27.04 mg CE/g DW), ferric-reducing antioxidant power (FRAP) value (373.27 μmol Fe(Ⅱ)E/g DW) and 2,2′-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS+) value (48.64 μmol TE/g DW), closely matching the experimental results. Furthermore, a comparison study demonstrated that DES-UAE afforded the higher TFC and FRAP value than traditional extraction methods. 36 individual polyphenolic compounds were identified and quantified by ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) in P. scandens extracts, and of which 30 were found in the extracts obtained by DES-UAE. Additionally, DES-UAE afforded the highest sum of individual polyphenolic compound content. These results revealed that DES-UAE enhanced the extraction efficiency for polyphenols and provided a scientific basis for further processing and utilization of P. scandens.
This study investigated the contents of saponins and phenolic compounds in relation to their antioxidant activity and α-glucosidase inhibition activity of 7 colored quinoa varieties. The total ...saponin content was significantly different among 7 varieties and ranged from 7.51 to 12.12 mg OAE/g DW. Darker quinoa had a higher content of phenolic compounds, as well as higher flavonoids and antioxidant activity than that of light varieties. Nine individual phenolic compounds were detected in free and bound form, with gallic acid and ferulic acid representing the major compounds. The free and bound phenolic compounds (gallic acid and ferulic acid in particular) exhibited high linear correlation with their corresponding antioxidant values. In addition, the free phenolic extracts from colored quinoa exhibited higher inhibitory activity against α-glucosidase than the bound phenolic extracts. These findings imply that colored quinoa with abundant bioactive phytochemicals could be an important natural source for preparing functional food.
► Phenolic and flavonoid contents in litchi pulp had significant varietal difference. ► Phenolics and flavonoids existed mainly in free form in litchi pulp. ► Six phenolic compounds were detected in ...litchi pulp by HPLC. ► Some litchi cultivars (Feizixiao and Nuomici) showed potent antioxidant activity.
The phenolic profiles and antioxidant activity of litchi pulp of 13 varieties were investigated. The free, bound and total phenolic contents were 66.17–226.03, 11.18–40.54, and 101.51–259.18mg of gallic acid equivalents/100g, respectively. The free, bound and total flavonoid contents were 16.68–110.33, 10.48–22.75, and 39.43–129.86mg of catechin equivalents/100g, respectively. Free phenolics and flavonoids contributed averagely 80.1% and 75% to their total contents, respectively. Six individual phenolics (gallic acid, chlorogenic acid, (+)-catechin, caffeic acid, (−)-epicatechin, and rutin) were detected in litchi pulp by HPLC. The contents of each compound in free and bound fractions were determined. Significant varietal discrepancy in antioxidant activity was also found by FRAP and DPPH scavenging capacity methods. Antioxidant activity was significantly correlated with phenolic and flavonoid contents. Thus, phenolics and flavonoids exist mainly in the free form in litchi pulp. There were significant varietal differences in phytochemical contents and antioxidant activity of litchi pulp.
The purpose of this study was to investigate the immunomodulatory and antioxidant activities of litchi pulp polysaccharides (LP) in cyclophosphamide (Cy)-induced mice. The administration of LP (50, ...100 and 200mg/kg/d) remarkably enhanced mesenteric lymph node cells proliferation and serum IgA. Moreover, IL-6, TNF-α, IgG and IgM levels in serum were significantly improved in a dose-dependent manner with LP treatment. Dietary LP induced systemic immune responses including stimulating the proliferation of splenocytes, balancing the ratio of spleen lymphocyte subsets, up-regulating the thymus and spleen indices. Thus, we speculate litchi polysaccharides would express their systemic immunomodulatory effects by triggering the intestinal mucosal immunity. Likewise, LP also significantly increased total antioxidant capacity, as well as superoxidase dismutase and glutathione peroxidase activity, while decreasing malondialdehyde levels in the serum and liver. The immunomodulatory activity of LP was accompanied with its antioxidant activity, which might be related with its structure and prebiotic effect. This is a novel study on the relationship between the immunomodulatory and antioxidant activities of litchi polysaccharides.
Changes of phenolic profiles and antioxidant activity of litchi pericarp during storage at 4 °C for seven days and at room temperature (RT) for 72 h were evaluated in this study. The contents of ...total phenolic and procyanidin decreased by 20.2% and 24.2% at 4 °C and by 37.8% and 47.8% at RT, respectively. Interestingly, the corresponding reductions of anthocyanins were 41.3% and 73%, respectively. Four phenolic compounds, including epicatechin, procyanidin A₂, procyanidin B₂, and quercetin-3-
-rutinoside-7-
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-l-rhamnosidase were detected in litchi pericarp. Their contents after storage at 4 °C and at RT were decreased by 22.1⁻49.7% and 27.6⁻48.7%, respectively. The oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) of litchi pericarp decreased by 17.6% and 58.7% at 4 °C, and by 23.4% and 66.0% at RT, respectively. The results indicated that storage at 4 °C preserved more phenolics and retained higher antioxidant activity in litchi pericarp compared to storage at RT, suggesting that storage at 4 °C should be considered as a more effective method for slowing down the degradation of litchi pericarp phenolics.
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