PC12 cells were used to examine the in vitro antioxidative and anti-inflammatory effects of oleanolic acid (OA) and ursolic acid (UA). PC12 cells were pretreated with OA or UA at 20 and 40 microM and followed by exposure of hydrogen peroxide (H(2)O(2)) or 1-methyl-4-phenylpyridinium ion (MPP(+)) to induce cell injury. Results showed that H(2)O(2)- or MPP(+)-treatment significantly decreased cell viability and increased lactate dehydrogenase (LDH) release (P < 0.05). The pretreatment from OA or UA significantly and concentration-dependently reduced subsequent H(2)O(2)- or MPP(+)-induced cell death and LDH release (P < 0.05). Either H(2)O(2)- or MPP(+)-treatment significantly increased malonyldialdehyde (MDA) formation, decreased glutathione (GSH) content, and diminished glutathione peroxidase (GPX), catalase, and superoxide dismutase (SOD) activities (P < 0.05). The pretreatment from OA or UA significantly retained GSH, and reversed H(2)O(2)- and MPP(+)-induced impairment in catalase and SOD activities (P < 0.05), and decreased MDA formation (P < 0.05). Either H(2)O(2)- or MPP(+)-treatment significantly elevated interleukin-6 (IL-6) and tumor necrosis factor (TNF)-alpha levels (P < 0.05). The pretreatments from OA or UA significantly attenuated subsequent H(2)O(2)- or MPP(+)-induced release of IL-6 and TNF-alpha (P < 0.05). Based on the observed antioxidative and anti-inflammatory activities from OA and UA, these 2 compounds were potent agents against neurodegenerative disorder.

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Renal protective effects of naringenin at 0.5, 1, and 2% of the diet in diabetic mice were examined. Naringenin supplemented at 1 and 2% increased its deposit in liver and kidney of diabetic mice. Compared with the diabetic control group, naringenin treatments at 1 and 2% lowered plasma levels of glucose and blood urea nitrogen, as well as increased insulin level and creatinine clearance (P < 0.05). Naringenin treatments dose-dependently reduced renal tumor necrosis factor-α level and expression (P < 0.05) but only at 1 and 2% significantly decreased production and expression of interleukin (IL)-1β, IL-6, and monocyte chemoattractant protein-1 (P < 0.05). Naringenin intake at 2% decreased renal formation and expression of type IV collagen, fibronectin, and transforming growth factor-β1 (P < 0.05). This compound at 1 and 2% lowered protein kinase C activity and suppressed nuclear factor κB (NF-κB) p65 activity, mRNA expression, and protein production in kidney. However, this agent only at 2% diminished NF-κB p50 activity, mRNA expression, and protein production (P < 0.05). These results indicate that naringenin could attenuate diabetic nephropathy via its anti-inflammatory and antifibrotic activities.

Mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were used to examine the neuroprotective effects of carnosine. Carnosine at 0.5, 1, and 2 g/L was directly added to the drinking water for 4 weeks. MPTP treatment significantly depleted striatal glutathione content, reduced the activity of glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase, increased malondialdehyde and reactive oxygen species levels, and elevated interleukin-6, nitrite, and tumor necrosis factor-α production as well as enhanced inducible nitric oxide synthase (iNOS) activity in the striatum (P < 0.05). The preintake of carnosine significantly attenuated MPTP-induced glutathione loss, retained the activity of GPX and SOD, diminished oxidative stress, and lowered inflammatory cytokines and nitrite levels as well as suppressed iNOS activity (P < 0.05). MPTP treatment significantly suppressed GPX mRNA expression and enhanced iNOS mRNA expression (P < 0.05). Carnosine preintake significantly elevated GPX mRNA expression and declined iNOS mRNA expression (P < 0.05). Preintake of carnosine also significantly improved MPTP-induced dopamine depletion and maintained 3,4-dihydroxyphenylacetic acid and homovanillic acid levels (P < 0.05). These results suggest that carnosine could provide antioxidative and anti-inflammatory protection for the striatum against the development of Parkinson's disease.