Antioxidant Potential of Several Polypores Mushrooms from the South of France.

We selected polypore mushrooms growing in the Mediterranean area of France to screen their antioxidant activity: Ganoderma applanatum, G. lucidum, Inonotus cuticularis, I. hispidus, Trametes hirsuta, and T. versicolor. Our work also evaluated antioxidant capacity from wild and cultivated G. lucidum fruiting bodies to optimize this biological property on human health. Dried fungal materials were sequentially extracted using cyclohexane, dichloromethane, ethanol, and water. Folin-Ciocalteu assay, oxygen radical absorbance capacity using DPPH and ORAC tests of the polypore extracts were assessed and compared. Among the 28 mushroom extracts tested, four exhibited significant antioxidant activity as ethanol extracts of I. cuticularis, T. hirsuta and wild and cultivated G. lucidum. The ethanol extracts of I. cuticularis and T. hirsuta revealed the highest values for the ORAC test, while the highest values for the Folin-Ciocalteu and DPPH tests were found for the ethanol extracts of cultivated G. lucidum and I. cuticularis. Further studies are needed to identify potential bioactive compounds, especially from I. cuticularis and G. lucidum grown under selected conditions and explore their benefits in the pharmaceutical and food industries.

Effect of thymoquinone on 1,2-dimethyl-hydrazine-induced oxidative stress during initiation and promotion of colon carcinogenesis.

We evaluated pre- and post-thymoquinone (TQ) treatment on 1,2-dimethyl-hydrazine (DMH)-induced oxidative stress during initiation and promotion of colon carcinogenesis. Wistar rats were induced with DMH (20mg/kg) for 10 or 20 weeks, and treated with TQ (5mg/kg). Following sacrifice, the colons were analysed for tumour development, reactive oxygen species (ROS) generation, lipid peroxidation [conjugated diene (CD) and malondialdehyde (MDA)], antioxidants [glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD) and reduced glutathione (GSH)], and histological changes. Increased ROS levels and lipid peroxidation were seen during tumour initiation and promotion. All ROS-scavenging enzyme activities were increased upon shorter DMH treatment but not following longer treatment, while GSH amount was increased upon both treatments. Oxidative state perturbations were associated with moderate colon dysplasia and 30% tumour incidence at initiation and marked dysplasia and 100% tumour incidence at promotion. TQ pre-treatment restored completely DMH-induced oxidative stress at initiation and established histological changes and tumour development. It also abrogated oxidative status aggravation at promotion, and significantly reduced tumour incidence (67%). By comparison, TQ post-treatment corrected oxidative status and attenuated tumour development at initiation. It slightly reduced MDA and antioxidant level at promotion, with a slight reduction in tumour state and dysplasia degree. TQ is efficacious in protecting and curing DMH-induced initiation phase of colon cancer, while exerting a protective role at promotion. TQ effect seems to be related to its capacity in preventing DMH-induced oxidative stress. These in vivo results support the notion that TQ may be of value as a chemo-preventive alternative in colorectal cancer patients.

Thymoquinone, the Nigella sativa bioactive compound, prevents circulatory oxidative stress caused by 1,2-dimethylhydrazine in erythrocyte during colon postinitiation carcinogenesis.

We have performed this study to investigate the modulatory effect of thymoquinone (TQ), the Nigella sativa active compound, on erythrocyte lipid peroxidation and antioxidant status during 1,2-dimethylhydrazine- (DMH-) induced colon carcinogenesis after initiation in male Wistar rats. Rats exposed to DMH showed an increase of malondialdehyde and conjugated diene levels, and an augmentation of enzyme activities like catalase, glutathione peroxidase, and superoxide dismutase activities was also noted. The TQ pretreatment restored the parameters cited above to near-normal values. However, the posttreatment shows an activity similar as that presented by DMH. Therefore, our investigation revealed that TQ was a useful compound preventing DMH-induced erythrocyte damages.