Dioscin is a natural steroid saponin derived from several plants, showing potent anti-cancer effect against a variety of tumor cell lines. In the present study, we investigated the anti-cancer activity of dioscin against human LNCaP cells, and evaluated the possible mechanism involved in its antineoplastic action. It was found that dioscin（1, 2 and 4 μmol/L） could significantly inhibit the viability of LNCaP cells in a time- and concentration-dependent manner. Flow cytometry revealed that the apoptosis rate was increased after treatment of LNCaP cells with dioscin for 24 h, indicating that apoptosis was an important mechanism by which dioscin inhibited cancer. Western blotting was employed to detect the expression of caspase-3, Bcl-2 and Bax in LNCaP cells. The expression of cleaved caspase-3 was significantly increased, and meanwhile procaspase-3 was markedly decreased. The expression of anti-apoptotic protein Bcl-2 was down-regulated, whereas the pro-apoptotic protein Bax was up-regulated. Moreover, the Bcl-2/Bax ratio was drastically decreased. These results suggested that dioscin possessed potential anti-tumor activity in human LNCaP cells through the apoptosis pathway, which might be associated with caspase-3 and Bcl-2 protein family.
Alzheimer＇s disease（AD） is one of the major neurodegenerative disorders of the elderly, which is characterized by the accumulation and deposition of amyloid-beta（Aβ） peptide in human brains. Oxidative stress and neuroinflammation induced by Aβ in brain are increasingly considered to be responsible for the pathogenesis of AD. The present study aimed to determine the protective effects of walnut peptides against the neurotoxicity induced by Aβ25-35 in vivo. Briefly, the AD model was induced by injecting Aβ25-35 into bilateral hippocampi of mice. The animals were treated with distilled water or walnut peptides（200, 400 and 800 mg/kg, p.o.） for five consecutive weeks. Spatial learning and memory abilities of mice were investigated by Morris water maze test and step-down avoidance test. To further explore the underlying mechanisms of the neuroprotectivity of walnut peptides, the activities of superoxide dismutase（SOD）, glutathione（GSH）, acetylcholine esterase（ACh E）, and the content of malondialdehyde（MDA） as well as the level of nitric oxide（NO） in the hippocampus of mice were measured by spectrophotometric method. In addition, the levels of 8-hydroxy-2＇-deoxyguanosine（8-OHd G）, tumor necrosis factor-α（TNF-α）, interleukin 1β（IL-1β） and IL-6 in the samples were determined using ELISA. The hippocampal expressions of inducible nitric oxide synthase（i NOS） and nuclear factor κB（NF-κB） were evaluated by Western blot analysis. The results showed that walnut peptides supplementation effectively ameliorated the cognitive deficits and memory impairment of mice. Meanwhile, our study also revealed effective restoration of levels of antioxidant enzymes as well as inflammatory mediators with supplementation of walnut peptides（400 or 800 mg/kg）. All the above findings suggested that walnut peptides may have a protective effect on AD by reducing inflammatory responses and modulating antioxidant system.
This study investigated the effect of diosgenin,a natural sapogenin possessing various pharmacological activities,on benign prostatic hyperplasia（BPH） in rats and the possible mechanisms.BPH was established in the castrated rats by subcutaneous injection of testosterone propionate.Animals were randomly divided into four groups（n=10 each）：model group（0.5% sodium carboxymethyl cellulose）;positive control group（3 mg/kg finasteride）;two diosgenin groups（50 and 100 mg/kg）.The drugs were intragastricaly given in each group for consecutive 3 weeks.Another 10 rats with no testicles cut off served as negative controls and they were subcutaneously injected with 0.1 m L olive oil per day and then treated with 0.5% sodium carboxymethylcellulose.After 3-week administration,the prostate index and serum PSA level were determined,and histopathological examination was carried out.The levels of MDA,SOD and GPx in prostates were also measured.Additionally,the expression of Bcl-2,Bax and p53 was examined using Western blotting.The results showed that the prostate index and serum PSA level were significantly decreased,and the pathological changes of the prostate gland were greatly improved in diosgenin groups as compared with the model group.Elevated activities of SOD and GPx,and reduced MDA level were also observed in diosgenin-treated rats.In addition,the expression of Bcl-2 in prostates was down-regulated,whereas that of Bax and p53 was up-regulated in diosgenin-treated rats.These results indicated that diosgenin was effective in inhibiting testosterone propionate-induced prostate enlargement and may be a candidate agent for the treatment of BPH.
