Macroporous resin purification and characterization of flavonoids from Platycladus orientalis (L.) Franco and their effects on macrophage inflammatory response

The flavonoids (POFs) from the leaves of Platycladus orientalis (L.) Franco were purified using six different macroporous adsorption resins including polar resins NKA-9 and ADS-F8, semi-polar resins ADS-17 and AB-8, and non-polar resins D101 and ADS-5. Among semi-polar resins, AB-8 demonstrated the best adsorption and desorption capacities with an adsorption ratio of 86% and a desorption ratio of 52%. According to the Simultaneous Thermogravimetry-Differential Scanning Calorimetry (STA/TG-DSC) analysis, POFs showed three thermally decomposed temperatures (347.6 °C, 437.5 °C and 494.8 °C). The main flavonoids in POFs were identified as esculin, amentoflavone, glabridin, and afromosin. Meanwhile, POFs in the dosage range of 25 to 400 μg mL-1 showed a significant anti-inflammatory effect on lipopolysaccharide (LPS)-induced RAW 264.7 mouse macrophage cells, which could inhibit the secretion of NO, IL-6, and TNF-α through the inhibition of inflammatory-related gene expressions.

Effects of supplementation with grass carp protein versus peptide on swimming endurance in mice

OBJECTIVE

We investigated the effects of grass carp protein or peptide administration on swimming endurance in mice.

METHODS

Grass carp protein or peptide was intragastrically administered to male National Institutes of Health mice at low [1 mg/(g·d)] and high [5 mg/(g·d)] doses, continuously once per day before swimming exercise. After training for 28 d, fatigue-related biochemical parameters, including liver glycogen, gastrocnemius muscle glycogen, plasma glucose, serum lactic acid, blood urea nitrogen, superoxide dismutase (SOD), glutathione peroxidase, and catalase (CAT), were assayed.

RESULTS

Compared with the control group, all treatments applied significantly prolonged the exercise time, and high-dose peptide administration was the most effective (P<0.001). Liver glycogen was remarkably increased by seven times or more by protein or peptide ingestion compared with that of the control group. High-dose protein or peptide addition significantly elevated liver glycogen, muscle glycogen, glucose level, and the removal of metabolites, serum lactic acid, and blood urea nitrogen was greater after exercise. In terms of the comparison between protein versus peptide, high-dose peptide addition significantly enhanced CAT (P=0.016) and SOD (P=0.007), while no significant differences were observed for glutathione peroxidase, glucose, liver glycogen, or muscle glycogen between high-dose peptide and protein addition. The difference between low-dose protein and peptide supplementation was not significant.

CONCLUSION

Grass carp protein or peptide significantly improved the endurance capacity of mice. The superiority of peptide over protein was observed at high-dose supplementation, which was mainly attributed to the significant enhancement of antioxidant enzyme levels (CAT and SOD).

A polysaccharide isolated and purified from Platycladus orientalis (L.) Franco leaves, characterization, bioactivity and its regulation on macrophage polarization

The structure and bioactivity of a novel polysaccharide from Platycladus orientalis (L.) Franco leaves (POP2) were investigated in the present study. Structure characterization demonstrated that the average molecular weight of POP2 was 9.69 kDa and consisted of arabinose (14.39%), mannose (10.24%), glucose (63.95%) and galactose (11.42%). The main linkage types of POP2 consisted of (1→4)-linked α-d-Glc and (1→6)-linked α-d-Glc based on methylation and NMR analysis. Bioactivity evaluation showed that POP2 could effectively promote the secretion of inflammatory cytokines (IL-6 and TNF-α), as well as the anti-inflammatory cytokines (IL-10) in LPS-induced cells. Besides, the secretion of NO was significantly inhibited by POP2 in M1 model. POP2 could enhance the level of inflammatory cytokines (NO, IL-6 and TNF-α), while the secretion of the anti-inflammatory cytokine TGF-β was markedly suppressed in IL-4 induced cells. Our work attempted to elucidate the regulation of macrophage polarization and support the potential application of POP2 as bioactive ingredient for functional foods.

Purification, Characterization, and Bioactivities of Polyphenols from Platycladus orientalis (L.) Franco

The polyphenols (PF) from Platycladus Orientalis (L.) Franco leaves were purified by using 10 different macroporous adsorption resins. HPD-722 resin showed the best adsorption and desorption capacities. The static and dynamic adsorption and desorption of PF on HPD-722 resin were studied and the total polyphenols were separated into two fractions, PF-A and PF-B. PF-A and PF-B demonstrated similar scavenging activity of free radical (DPPH, ABTS, hydroxyl radical, superoxide anion). The scavenging activity of PF-A and PF-B on hydroxyl radical and superoxide anion radical reached the equal levels of vitamin C and gallic acid. The IC50 value of PF-A for hydroxyl radical scavenging activity and superoxide anion radical scavenging activity were 0.50 and 0.56 mg/mL, while those of PF-B were 0.61 and 0.64 mg/mL. PF-A and PF-B could reduce the overproduction of inflammatory cytokines (TNF-α, Pro-IL-1β, and IL-6) induced by lipopolysaccharide and their protein expression in THP-1 cells. PF-B exhibited better anti-inflammatory effect than PF-A in the dosage range of 1.0-4.0 µg/mL. Structural identification of PF-A and PF-B were conducted by HPLC-MS/MS. Ten polyphenol compounds were identified in PF-A and PF-B, respectively, by HPLC-MS/MS, including quercetin, apigenin, myricetin, and so on. Molecular docking studies indicated that apigenin, myricetin, luteolin, kaempferol, and quercetin effectively inhibit xanthine oxidase by forming hydrogen bonds with the amino acid residues and binding to the active site of the enzyme. The results might supply useful information for better understanding the chemical structure, antioxidant, and anti-inflammatory activities of Platycladuso (L.) Franco leaves polyphenols. PRACTICAL APPLICATION: This study demonstrated that polyphenols from P. orientalis (L.) Franco leaves have the potential applications as functional food ingredient for the prevention and treatment of gout and inflammation, hyperuricemia and gout.

Hepatoprotective peptides purified from Corbicula fluminea and its effect against ethanol‐induced LO2 cells injury

This study was focused on the purification, identification and mechanism of hepatoprotective peptides from Corbicula fluminea by using Sephadex G‐15 chromatography, UPLC–MS/MS, oxygen radical absorbance capacity (ORAC) assay, cell experiment and molecular docking. Six identified peptides were synthesised chemically and subjected to evaluate hepatoprotective effect. ORAC value and hepaprotective effect against ethanol‐induced LO2 cell injury in vitro were determined. The results showed that Tyr‐Phe‐Leu‐Pro (YP‐4) and Leu‐Val‐Tyr‐Pro (LP‐4) exhibited the strongest antioxidant activity and significantly increased the viability of ethanol‐injured LO2 cells. These two peptides significantly reduced ROS levels and efficiently inhibited the decrease of mitochondrial membrane potential in ethanol‐injured LO2 cells. Molecular docking revealed that YP‐4 and LP‐4 possess potential inhibitory activity on CYP2E1 and thus reduce ethanol‐induced oxidative stress. It is suggested that YP‐4 and LP‐4 have good hepatoprotective effect against alcoholic liver injury.