Improved production and properties of β-glucosidase influenced by 2-deoxy-d-glucose in the culture medium of Termitomyces clypeatus

Capillary electrophoresis-based online immobilized enzyme reactor for beta-glucosidase kinetics assays and inhibitors screening

A capillary electrophoresis (CE)-based beta-glucosidase (beta-Glu) immobilized enzyme microreactor (IMER) was constructed for enzyme kinetics study and inhibitor screening with the aid of polydopamine coating. The enzyme kinetic and inhibition studies of beta-Glu were comprehensively evaluated using p-nitrophenyl beta-d-glucopyranoside as a model substrate and castanospermine as a model inhibitor. The Michaelis-Menten constant value of the immobilized beta-Glu in the developed IMER was calculated to be 2.79 mmol/L. The half-maximal inhibitory concentration and inhibition constant of castanospermine were 13.22 μg/mL and 1.54 μg/mL, respectively. In addition, after 50 consecutive runs, the IMER activity was remained at 89.5% of the initial immobilized beta-Glu activity, which showed that the constructed IMER has good stability and repeatability. Finally, the developed method was successfully applied to screen beta-Glu inhibitors from twelve flavonoids. Four flavonoids include genistein, baicalein, epicatechin gallate and epigallocatechin gallate had significant inhibitory effect on beta-Glu, and their binding mode with enzyme was further verified via the molecular docking analysis. In summary, the developed CE based beta-Glu-IMER is a reliable method for screening beta-Glu inhibitors from natural products.

Evaluation of in vitro antioxidant, anticancer and in vivo antitumour activity of Termitomyces clypeatus MTCC 5091

CONTEXT

Termitomyces clypeatus (Lyophyllaceae) is a filamentous edible mushroom, having ethnomedicinal uses. However, information about the antioxidant, anticancer and antitumour properties of this mushroom remains to be elucidated.

OBJECTIVE

The study examines the in vitro antioxidant, anticancer and in vivo antitumour activity of T. clypeatus.

MATERIALS AND METHODS

Antioxidant activity was evaluated with seven in vitro assays. Cytotoxicity of T. clypeatus was tested against a panel of cancer cells lines including U373MG, MDA-MB-468, HepG2, HL-60, A549, U937, OAW-42 and Y-79 using MTT assay. The antitumour activity of aqueous extract was evaluated against Ehrlich ascites carcinoma (EAC) tumour model in Swiss albino mice.

RESULTS

HPLC analysis of aqueous extract revealed the presence of sugar entities. Termitomyces clypeatus showed excellent in vitro antioxidant activity. Termitomyces clypeatus was found cytotoxic against all cancer cells, among which it showed higher activity against U937 (IC₅₀ 25 ± 1.02 μg/mL). Treatment of EAC-bearing mice with varied doses of aqueous extract significantly (p < 0.01) reduced tumour volume, viable tumour cell count and improved haemoglobin content, RBC count, mean survival time, tumour inhibition and % increase life span. The enhanced antioxidant status in treated animals was evident from the decline in the levels of lipid peroxidation, increased levels of glutathione, catalase and superoxide dismutase.

DISCUSSION

The analyzed data indicate that the aqueous extract of T. clypeatus exhibits significant antitumour activity, which might be due to the antioxidant effects on EAC bearing hosts.

CONCLUSION

Termitomyces clypeatus possesses anticancer activity, valuable for application in food and drug products.