Antioxidant activity of polysaccharides extracted from Lentinus edodes mycelia and their protective effects on INS-1 cells / Atividade antioxidante de polissacarídeos extraídos de Lentinus edodes micélio e seus efeitos protectores em células INS-1

The disruption of the delicate balance between the generation of reactive oxygen species (ROS) and antioxidant scavenging systems can lead to many health problems. Polysaccharides extracted from fungi fruit body and myceliums have several potential health benefits. In this study, the antioxidant capacity and cell protective effects of a polysaccharide isolated from Lentinus edodes mycelia (LMP) were investigated. The antioxidant properties of LMP were screened using radical scavenging (1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and superoxide anion), reducing power and inhibition of lipid peroxidation assays. Intracellular reactive oxygen species (ROS), in response to H2O2, was determined by the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. Rat insulinoma (INS-1) cells apoptosis was detected using flow cytometry analysis. The results showed that LMP exhibited significantly strong radical scavenging activity. At the concentration of 2.0 mg mL-1, DPPH radical, hydroxyl radical, and superoxide anion radical scavenging rates are 80.32 ± 2.58%, 92.56 ± 3.11% and 93.73 ± 2.82%, respectively. The reducing power and inhibition of lipid peroxidation activity of LMP were as strong as the positive control. LMP alleviated the intracellular reactive oxygen species level and inhibited islet cell apoptosis significantly. The results open perspectives for studies of LMP in the treatment of diabetes.

O estresse oxidativo tem uma função biológica importante em muitos organismos. A ruptura do equilíbrio delicado entre a geração de espécies reativas de oxigênio (ROS) e sistemas de eliminação de antioxidantes pode levar a muitos problemas de saúde. Polissacarídeos extraídos do corpo fungos frutas e micélio têm vários benefícios potenciais para a saúde. Neste estudo, foram investigados os efeitos celulares e capacidade de proteção antioxidante de um polissacarídeo isolado a partir de Lentinus edodes micélios (LMP). As propriedades antioxidantes da LMP foram rastreadas utilizando eliminação de radicais (1, 1-difenil-2-picrilhidrazil (DPPH), hidroxilo e anião superóxido), e a redução da potência de inibição de ensaios de peroxidação lipídica. Espécies reativas de oxigénio intracelulares (ROS), em resposta ao H2O2, foi determinada pelo ensaio de diacetato de dicloro-di-hidro-f luoresceina (DCFH-DA). INS-1 células a apoptose foi detectada utilizando análise de citometria de fluxo. Os resultados mostraram que LMP exibiu significativamente forte atividade de eliminação de radicais. Na concentração de 2 mg mL-1, DPPH radical, radical hidroxilo e anião superóxido velocidades de eliminação de radicais livres são 80,32 ± 2,58%, 92,56 ± 3,11% 93,73 ± 2,82%, respectivamente. O poder redutor e inibição da peroxidação lipídica de LMP foram tão forte quanto o controlo positivo. LMP aliviou a nível de espécies reativas de oxigênio intracelular e apoptose de células da ilhota inibiu significativamente. Sugere-se que LMP pode ser utilizado como um reagente complementar para a diabetes a prevenção e terapia.

Protective Effects of a Water-Soluble Extract from Culture Medium of Lentinus Edodes Mycelia against Neuronal Damage after Hypoxia-Ischemia in Mice / 日本補完代替医療学会誌

<b>Objective</b>: <i>Lentinus edodes</i> (Shiitake) is a very popular mushroom in Asian cuisine. The water-soluble extract from culture medium of <i>Lentinus edodes</i> mycelia (LEM), which is commercially available as a nutritional supplement, is prepared by hot-water treatment from a solid medium composed of bagasse and defatted-rice bran overgrown for about 4 months with its mycelia. LEM was previously reported to have antioxidant activity and to suppress various oxidative damages. In this study, the neuroprotective effects of 2-week intake of LEM on cerebral ischemic damage induced by hypoxia/ischemia (H/I) followed by reoxygenation in mice were examined.<br> <b>Method</b>: Male C57BL/6J mice were divided into three groups, fed for two weeks with the control laboratory powder chow, 0.5% LEM-contained chow, or 1% LEM-contained chow, respectively. Cerebral ischemic damage was induced in the mice by H/I (i.e., unilateral ligation of the carotid artery and exposure of 8%O₂ for 30 min). Twenty-four hours after H/I, total plasma oxidative stress, neurological deficits, cerebral infarction volume were evaluated in each group. Furthermore, the number of apoptotic cells in ischemic penumbra, the hippocampal CA1 and CA2, and the somatosensory area of the cortex, were analyzed by TUNEL staining and cleaved caspase-3 immunostaining.<br> <b>Results</b>: The infarct area assessed 24-h after H/I was extended to the corpus striatum and cortex in the control mice. Treatment of LEM dose dependently improved plasma oxidative stress, neurological deficits, and cerebral infarction volume. Moreover, LEM decreased the levels of dihydroethidium activity as an index of super oxide production and the number of apoptotic cells in ischemic penumbra.<br> <b>Conclusion</b>: These results show that chronic intake of LEM relieves the hypoxia-induced cerebral ischemic injury, which may be attributed to the antioxidant effects of LEM.<br>