Pharmacological properties of edible mushrooms: their implications in cardiovascular protection

Abstract

Mushrooms are commonly consumed as food worldwide. Their nutritional values are known but their pharmacological activities have not been well investigated. The vascular effects of two edible mushrooms were studied recently. The first one is Pleurotus ostreatus (Oyster mushroom). In isolated rat basilar arteries, Pleurotus osteratus extract attenuated the reduction in acetylcholine-induced relaxation caused by pyrogallol, xanthine oxidase plus xanthine, or incubation in high glucose. Chronic treatment with the Pleurotus osteratus extract also improved the response to acetylcholine in arteries of rats with streptozotocin-induced diabetes. It is believed that the vasorelaxing effect of Pleurotus osteratus extract was due to the ingredient ergothioneine, which is a powerful antioxidant. Reverse-transcription polymerase chain reaction and Western blotting demonstrated transcription and translation of an ergothioneine transporter in brain microvascular endothelial cells. Cellular uptake of ergothioneine was reduced when expression of organic cation transporter novel type-1 was silenced by small interfering RNA. Reactive oxygen species production and cell death induced by pyrogallol, xanthine oxidase plus xanthine, and high glucose could be suppressed by both ergothioneine and Pleurotus osteratus extract. In addition, the expression of NADPH oxidase 1 was decreased, and those of glutathione reductase, catalase, and superoxide dismutase were enhanced by both ergothioneine and Pleurotus ostertus extract. The second mushroom of investigation is Schizophyllum commune, which is widely consumed by Chinese, especially in southern part of China. Our study showed that Schizophyllum commune extract induced a marked relaxation in rat aortic rings with or without endothelium. After the pretreatments of N(ω)-nitro-l-arginine methyl ester, indomethacin, RP-cAMP, and methylene blue, the Schizophyllum commune-induced relaxation was significantly decreased. In addition, the contraction due to calcium influx and intracellular calcium release was also inhibited by Schizophyllum commune. Furthermore, expression of endothelial nitric oxide synthase protein was significantly elevated in rat aortic endothelial cells after treatment of Schizophyllum commune. It is believed that Schizophyllum commune induces an endothelium-dependent and -independent relaxation in blood vessels. The vasorelaxing effect may involve the modulation of nitric oxide-cGMP-dependent pathways, prostacyclin-cAMP-depedent pathways, calcium influx through calcium channels and intracellular calcium release. We hope that these studies can advance our knowledge of the pharmacology of edible mushrooms. The findings may be useful for the development of cardiovascular protective agents.