•The physicochemical characterization and antioxidant activity of MP-A, MP-U and MP-C were analysed and compared.•MP-C showed the best antioxidant activity and protective effect on the injured cells induced by H2O2.•MP-C could potentially be used for the antioxidant food ingredient.Polysaccharides MP-A, MP-U and MP-C were extracted from Mesona chinensis Benth by hot-alkali extraction (HAE), ultrasonic-assisted extraction (UAE) and cellulose-enzyme assisted extraction (CAE), respectively. The yields, physicochemical properties and antioxidant of polysaccharides were investigated. Results showed that the yields of MP-A (11.14%), MP-U (10.62%) and MP-C (9.70%) were similar, and they were all heteropolysaccharides with average molecular weights of 1.9 × 105 Da, 1.5 × 105 Da, 1.4 × 105 Da. Glucose, galactose, and galacturonic acid were the main monosaccharides in MP-A, MP-U and MP-C with molar ratios of 1.00:1.34:0.25, 1.00:2.49:0.19 and 1.00:2.95:0.84, respectively. MP-C extracted by CAE exhibited higher antioxidant activities in FRAP, DPPH, hydroxyl radical assays and the H2O2-induced injury cell model. The three extraction methods had only slight effects on chemical composition, while MP-C extracted by CAE exhibited the highest antioxidant activity, which could potentially be used for an addition ingredient as it was previously shown to have good gelling property in food products.

•Characterizations of S-CP1-8 were elucidated by multiple techniques.•Immunomodulatory activity of S-CP1-8 is evaluated with RAW264.7 cells.•S-CP1-8 increases the cytokines levels and phagocytosis in RAW264.7 cells.•S-CP1-8 exhibits stronger immunomodulatory activity than CP.In this study, a sulfated polysaccharide (S-CP1-8) was obtained from Cyclocarya paliurus by chlorosulfonic acid-pyridine method. S-CP1-8 was chemical characterized and cultured with macrophage RAW264.7 cells to evaluate its immunomodulatory activity. Preliminary physicochemical analysis identified arabinose (Ara), galactose (Gal) and glucose (Glc) were the major monosaccharides of S-CP1-8, with average Molecular weight (Mw) of 970 kDa and contained sulfate with degree of substitution (DS) of 0.12. Meanwhile, our findings demonstrated that tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 secretion levels were significantly increased by S-CP1-8 treatment in RAW264.7 cells in a dose-dependent manner. Moreover, nitric oxide (NO) release and phagocytic activities of macrophages were significantly enhanced by the treatment of S-CP1-8 compared with native Cyclocarya paliurus polysaccharide (CP). The results indicated that S-CP1-8 could enhance the immunomodulatory effects on RAW264.7 macrophages, as comparison with CP group. S-CP1-8 could serve as potential immunomodulatory agents to be used as complementary medicine or functional foods.

•Ultrasonic effect had no obvious change on the physicochemical characterization of CP.•PCP exhibited antioxidant activities in a concentration-dependent manner.•Ultrasonic treatment can enhance antioxidant activities of polysaccharides.The effects of ultrasonic treatment on the physicochemical properties and antioxidant activities of the polysaccharide from Cyclocarya paliurus leaves were investigated. The physicochemical properties were detected by high-performance gel permeation chromatography (HPGPC), high-performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) and fourier transform infrared spectrometer (FT-IR) as well. The antioxidant activities were evaluated by the assay of DPPH, hydroxyl free radical, β-carotene-linoleic acid, respectfully. Results showed that no considerable change was observed on the structure between the polysaccharide of Cyclocarya paliurus (CP) and the ultrasonic polysaccharide of Cyclocarya paliurus (UCP) by FT-IR, and no apparent differences were found on the content of sugar, uronic acid and protein after the ultrasonic treatment, but difference appeared in the ratio of monosaccharide composition of CP (1.0:4.6:3.5:4.5) and UCP (1.0:5.9:3.9:4.4), and the antioxidant activities of CP were promoted after ultrasonic treatment.

•MAE technology was firstly used for flavonoids extraction from C. paliurus.•Extraction conditions of flavonoids in C. paliurus have been optimised by RSM.•C. paliurus flavonoids showed good antioxidant activity in in vitro.•Five flavonoids have been identified by LC–MS.Microwave-assisted extraction of flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja leaves, its chemical composition and antioxidant activity were investigated in this study. The influences of parameters including temperature, extraction time, ratio of material to solvent and solvents on the yield of flavonoids were studied. The optimal conditions were determined and the quadratic response surfaces were drawn from the mathematical models. The maximum extraction yield of 15.64 mg/g was achieved at temperature of 76.8 °C, extraction time of 15 min, alcohol concentration of 63.2% and ratio of solvent to material of 21.4:1. Five main constituents in the extract including quercetin-3-O-β-d-glucuronide, quercetin, kaempferol-3-O-β-d-glucuronide, kaempferol-7-O-α-l-rhamnoside and kaempferol were identified by LC–MS. In vitro antioxidant assays showed that the extract exhibited a strong DPPH radical-scavenging ability with IC50 value of 0.146 mg/mL. Results indicated that MAE was a suitable approach for the selective extraction of flavonoids from C. paliurus (Batal.) Iljinskaja leaves.

The contents of 18 kinds of mineral elements in Cyclocarya paliurus polysaccharide samples were determined by ICP-AES. The limits of detection (LOD) of the method for 18 elements were in the range of 0.01–3.80 mg/kg. The average recoveries obtained by the standard addition method were found between 94.34% and 105.69% (RSD, 1.01–4.23%). The results showed that C. paliurus polysaccharides were abundant in major and trace elements which are healthy for human body. The contents of Ca, Al, Mg, K, Fe, Mn and P were very high, ranging from 274.5 ± 10.3 to 5980.0 ± 102.7 mg/kg, while the contents of Zn, Na, Se, Cr, Pb, Cu and As ranged from 0.9 ± 0.1 to 37.1 ± 4.2 mg/kg. Finally, the levels of Ni, Cd, V and Co were not detected in the samples. ICP-AES is a simple, precise and efficient method for the determination of many mineral elements in polysaccharide samples simultaneously.Highlights► ICP-AES for mineral elements determination in polysaccharide was proposed. ► Good values of LOD, repeatability, reproducibility and recoveries are achieved. ► ICP-AES is a rapid and simple method to determine mineral elements in polysaccharide.

Recently, renewed interest has grown in the use of ultrasonic-assisted extraction as an alternative approach to the traditional extraction methods. In this study, this novel extraction method was used to isolate polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja, and response surface methodology (RSM) was employed to optimize the extraction conditions. The optimal conditions for the extraction of polysaccharides were determined to be the ratio of liquid to solid of 8, extraction time of 59 min and extraction temperature of 58 °C. Under these optimal conditions, the yield of polysaccharides obtained was 4.91 ± 0.11%, which was well matched with the value predicted by the model. In vitro antioxidant assays showed that the polysaccharides exhibited strong DPPH radicals (92.09% at 0.25 mg/ml) and self-oxidation of 1,2,3-phentriol (37.22% at 1 mg/ml) scavenging activities, moderate hydroxyl radicals (43.18% at 1 mg/ml) scavenging activity and lipid peroxidation inhibitory effect (31.66% at 1 mg/ml). In addition, the polysaccharides showed moderate antimicrobial activity.Highlights► Ultrasonic technology was used for polysaccharides extraction from C. paliurus. ► C. paliurus polysaccharide showed good antioxidant properties in vitro assays. ► C. paliurus polysaccharide demonstrated potent antimicrobial activity in vitro. ► C. paliurus polysaccharide can be explored as a novel natural antioxidant.

•MCP administered could significantly reduce the blood glucose level.•MCP possessed significantly hypoglycemic effects on the alloxan-induced diabetic mice.•It confirmed the ethnobotanical data of Momordica charantia L. for treatment diabetes.•MCP could be a potential oral hypoglycemic agents or functional food.A water-soluble polysaccharide (MCP) was isolated from the fruits of Momordica charantia L., and the hypoglycemic effects of MCP were investigated in both normal healthy and alloxan-induced diabetic mice. MCP was orally administered once a day after 3 days of alloxan-induction at 100, 200 and 300 mg/kg body weight for 28 day. Results showed that fasting blood glucose level (BGL) was significantly decreased, whereas the glucose tolerance was marked improvement in alloxan-induced diabetic mice, and loss in body weight was also prevented in diabetic mice compared to the diabetic control group. The dosage of 300 mg/kg body weight exhibited the best effects. In addition, MCP did not exhibit any toxic symptoms in the limited toxicity evaluation in mice. The results suggest that MCP possess significantly dose-dependent anti-diabetic activity on alloxan-induced diabetic mice. Hence, MCP can be incorporated as a supplement in health-care food, drugs and/or combined with other hypoglycemic drugs.