Modulation of antipyrine clearance by polysaccharide peptide (PSP) isolated from Coriolus versicolor in the rat

Antioxidant and antimicrobial properties of an extract rich in proteins obtained from Trametes versicolor

Introduction

Bioactive proteins and peptides generated from fruit, vegetables, meat or fish have great potential as functional food or substitutes for antibiotics. In recent years it has also been demonstrated that the fungus kingdom could be a source of these compounds. The study investigated the bioactivity of an extract of the lignicolous fungus Trametes versicolor and its hydrolysate.

Material and Methods

The fungus was collected in a mixed forest in October, extracted and hydrolysed. To inspect the protein and peptide profiles before and after hydrolysis, matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometric analysis was performed. To evaluate the antioxidant properties of the preparations, 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS•+) radical scavenging assays were used. The activity of the fungus extract and hydrolysate against Aeromonas veronii, Bacillus cereus, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella Typhimurium, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis was determined by the minimum inhibitory concentration and minimum bactericidal concentration values.

Results

The extract and its hydrolysate showed almost 100% ABTS•+ and DPPH• radical scavenging with a low half maximal inhibitory concentration. The water extract and hydrolysate of T. versicolor exhibited antimicrobial activity against two S. aureus strains, E. coli, P. aeruginosa and Salmonella Typhimurium.

Conclusion

These results provide compelling evidence that the analysed fungus extract and its hydrolysate hold promise with their antibacterial and antioxidant properties.

Polysaccharide peptides from Coriolus versicolor competitively inhibit model cytochrome P450 enzyme probe substrates metabolism in human liver microsomes

Polysaccharide peptide (PSP), isolated from COV-1 strain of Coriolus versicolor, is commonly used as an adjunct in cancer chemotherapy or health supplement in China. Previous studies have shown that PSP decreased antipyrine clearance and inhibited rat CYP2C11-mediated tolbutamide 4-hydroxylation and in human CYP2C9. In this study, the effects of the water extractable fraction of PSP on the metabolism of model CYP1A2, CYP2D6, CYP2E1 and CYP3A4 probe substrates were investigated in pooled human liver microsomes. PSP (1.25-20μM) dose-dependently decreased CYP1A2-mediated metabolism of phenacetin to paracetamol (IC(50) 19.7μM) and CYP3A4-mediated metabolism of testosterone to 6β-hydroxytestosterone (IC(20) 7.06μM). Enzyme kinetics studies showed the inhibition of CYP1A2 activity was competitive and concentration-dependent (K(i)=18.4μM). Inhibition of testosterone to 6β-hydroxytestosterone was also competitive and concentration-dependent (K(i)=31.8μM). Metabolism of dextromethorphan to dextrorphan (CYP2D6-mediated) and chlorzoxazone to 6-hydroxychlorzoxazone (CYP2E1-mediated) was only minimally inhibited by PSP, with IC(20) values at 15.6μM and 11.9μM, respectively. This study demonstrated that PSP competitively inhibited the CYP1A2- and CYP3A4-mediated metabolism of model probe substrates in human liver microsomes in vitro. The relatively high K(i) values for CYP1A2 and CYP3A4 would suggest a low potential for PSP to cause herb-drug interaction related to these CYP isoforms.

Polysaccharide peptides from Coriolus versicolor competitively inhibit tolbutamide 4-hydroxylation in specific human CYP2C9 isoform and pooled human liver microsomes

Polysaccharide peptide (PSP), isolated from COV-1 strain of Coriolus versicolor, is commonly used as an adjunct in cancer chemotherapy in China. Previous studies have shown that PSP decreased antipyrine clearance and inhibited CYP2C11-mediated tolbutamide 4-hydroxylation in the rat both in vitro and in vivo. In this study, the effects of water extractable fraction of PSP on tolbutamide 4-hydroxylation was investigated in pooled human liver microsomes and in specific human CYP2C9 isoform. PSP (2.5-20μM) dose-dependently decreased the biotransformation of tolbutamide to 4-hydroxy-tolbutamide. Enzyme kinetics studies showed inhibition of tolbutamide 4-hydroxylase activity was competitive and concentration-dependent. In pooled human liver microsomes, PSP had a K(i) value of 14.2μM compared to sulfaphenazole, a human CYP2C9 inhibitor, showed a K(i) value of 0.32μM. In human CYP2C9 isoform, the K(i) value of PSP was 29.5μM and the K(i) value of sulfaphenazole was 0.04μM. This study demonstrated that PSP can competitively inhibit tolbutamide 4-hydroxylation in both pooled human liver microsomes and specific human CYP2C9 in vitro. This study compliments previous findings in the rat that PSP can inhibit human tolbutamide 4-hydroxylase, but the relatively high K(i) values in human CYP2C9 would suggest a low potential for PSP to cause herb-drug interaction.

Anti-oxidation activity of the crude polysaccharides isolated from Polygonum cillinerve (Nakai) Ohwi in immunosuppressed mice

AIM OF THE STUDY

Polygonum cillinerve (Nakai) Ohwi is commonly used in China for over 2000 years. Previous research has shown that the crude polysaccharides extracted from Polygonum cillinerve (Nakai) Ohwi (PCCP) have the scavenging free radicals and anti-tumor activities in vitro. In present study, PCCP were further approached the perspective of their anti-oxidation in immunosuppressed mice.

METHODS AND MATERIALS

ICR mice were treated firstly with cyclophosphamide (CY, 150 mg/kg), 1 day later, treated with different dosages of PCCP or saline solution once daily for 21 days. Twenty-four hours later for the last drug administration, the animals were weighed, and then killed by decapitation. The liver, spleen, and thymus indices were investigated, and the biochemical parameters were evaluated for various tissues (liver, heart, and kidney).

RESULTS

The administration of PCCP with gavage was able to overcome the cyclophosphamide-induced immunosuppression, and significantly to raise the TOC, CAT, SOD, and GSH-Px level. It also raised the liver, spleen, and thymus indices, and decreased the MDA level in mice.

CONCLUSIONS

PCCP possess the pronounced free radical-scavenging and antioxidant activities, and could play an important role in the prevention of oxidative damage in immunological system.

Effects of polysaccharide peptides from COV-1 strain of Coriolus versicolor on glutathione and glutathione-related enzymes in the mouse

The effects of polysaccharide peptide (PSP), an immunomodulator isolated from Coriolus versicolor COV-1, on glutathione (GSH) and GSH-related enzymes was investigated in C57 mouse. Administration of PSP (1-4 micromole/kg, i.p.) produced a transient, dose-dependent depletion (10-37%) of hepatic GSH, with no effect on serum glutamic-pyruvic transaminase (SGPT) activity. Blood GSH was depleted (6-25%) at 3 h, followed by a rebound increase above the control GSH level (20%) at 18 h. The GSSG/GSH ratio, a measure of oxidative stress, was increased 3 h after PSP treatment but returned to normal levels at 24 h. Sub-chronic treatment of PSP (1-4 micromole/kg/day, i.p.) for seven days did not produce any significant changes in hepatic GSH levels and the GSSG/GSH ratio when measured 24 h after the final dose of PSP. PSP had little effect on glutathione transferase (GST), glutathione reductase (GSSG reductase) and glutathione peroxidase (GPX) activities in the liver. However, a dose-dependent increase in blood GPX activity (30-48%) was observed at 3h, which coincided with the increase in the GSSG/GSH ratio. The increase in blood GPX activity may be a responsive measure to deal with the transient oxidative stress induced by PSP treatment. The results showed that PSP only caused a transient perturbation on hepatic glutathione without affecting the GSH-related enzymes such as GST, GSSG reductase and GPX. The observed changes in blood GSH simply reflected the intra-organ translocation of glutathione, as the glutathione-related enzymes were not significantly affected by PSP treatment.

Polysaccharide peptides from COV-1 strain of Coriolus versicolor inhibit tolbutamide 4-hydroxylation in the rat in vitro and in vivo

Polysaccharide peptide (PSP), isolated from COV-1 strain of Coriolus versicolor, is commonly used as an adjunct in cancer chemotherapy in China. In this study, the effects of whole PSP extract and water extract of PSP on 4-hydroxylation of tolbutamide were investigated in rat liver microsomes in vitro and in vivo in the rat. Both the whole PSP extract and the water soluble fraction (0.5-20 microM) decreased the metabolism of tolbutamide to 4-hydroxytolbutamide in vitro. Enzyme kinetics studies showed that PSP inhibited tolbutamide 4-hydroxylase activity in a competitive, concentration-dependent manner. The whole PSP extract had a Ki value of 12.6 microM and IC50 at 18.4 microM, while the water extract had a Ki value of 6.9 microM and IC50 at 9.8 microM. Sulphaphenazole, a specific human CYP2C9 inhibitor, showed a Ki value of 30.8 microM and IC50 at 44.0 microM in the test system. In the pharmacokinetic studies in vivo, acute PSP (4 micromol/kg, i.p.) treatment did not produce significant changes in tolbutamide clearance, but produced a decrease in the Cinitial (7.4%) and an increase in the Vd (7.4%). Sub-chronic pre-treatment of PSP (1-2 micromol/kg/day, i.p.) for three days did not affect the clearance and AUC of tolbutamide, but the Cinitial was decreased, together with increases in the T1/2, and Vd. The formation of 4-hydroxytolbutamide in vivo was decreased in both acute and sub-chronic studies. Taken together, this study demonstrated the PSP can inhibit tolbutamide 4-hydroxylation both in vitro and in vivo. Despite the fact that CYP isoforms that metabolise tolbutamide are different between rat and human liver due to different catalytic characteristics, and rat studies may not be directly extrapolatable to man, the concomitant use of PSP with other CYP2C substrates should be carefully monitored.