Protective effects of bilberry (Vaccinium myrtillus L.) extract on restraint stress-induced liver damage in mice

Our experiments showed that 18 h restraint stress could induce serious liver damage, with an increase in plasma alanine aminotransferase (ALT) level (107.68 +/- 3.19 U/L vs 18.08 +/- 1.46 U/L). Meanwhile, we observed increased malondialdehyde (MDA) levels and lowered oxygen radical absorbance capacity (ORAC) values in plasma and liver of restraint mice compared with starved mice. Bilberry extract (containing 42.04% anthocyanins) was oral administrated to mice at 50, 100, and 200 mg/(kg x day) for five days, which remarkably decreased plasma ALT level to 17.23 +/- 2.49 U/L at the dose of 200 mg/(kg x day) and thus alleviated stress-induced liver damage. In addition, bilberry extracts increased glutathione (GSH) and vitamin C levels and significantly decreased MDA and nitric oxide (NO) levels in the liver tissues. These results suggest that bilberry extract plays an important role in protecting against restraint stress-induced liver damage by both scavenging free radicals activity and lipid peroxidation inhibitory effect. This study showed the beneficial health effects of bilberry extract through its antioxidative action.     

Erythritol attenuates the diabetic oxidative stress through modulating glucose metabolism and lipid peroxidation in streptozotocin-induced diabetic rats

We investigated the effects of erythritol on rats with streptozotocin- (STZ-) induced diabetes mellitus. Oral administration of erythritol [100, 200, or 400 mg (kg body weight)(-1) day(-1) for 10 days] to rats with STZ-induced diabetes resulted in significant decreases in the glucose levels of serum, liver, and kidney. Erythritol also reduced the elevated serum 5-hydroxymethylfurfural level that is glycosylated with protein as an indicator of oxidative stress. In addition, thiobarbituric acid-reactive substance levels of serum and liver and kidney mitochondria were dose-dependently lower in the erythritol-treated groups than in the control diabetic group. Furthermore, the serum creatinine level was reduced by oral administration of erythritol in a dose-dependent manner. These results suggest that erythritol affects glucose metabolism and reduces lipid peroxidation, thereby improving the damage caused by oxidative stress involved in the pathogenesis of diabetes.     

Gentiana manshurica Kitagawa reverses acute alcohol-induced liver steatosis through blocking sterol regulatory element-binding protein-1 maturation

This study was undertaken to investigate the protective effects of Gentiana manshurica Kitagawa (GM) on acute alcohol-induced fatty liver. Mice were treated with ethanol (5 g/kg of body weight) by gavage every 12 h for a total of three doses to induce acute fatty liver. Methanol extract of GM (50, 100, or 200 mg/kg) or silymarin (100 mg/kg) was gavaged simultaneously with ethanol for three doses. GM administration significantly reduced the increases in serum ALT and AST levels, the serum and hepatic triglyceride levels, at 4 h after the last ethanol administration. GM was also found to prevent ethanol-induced hepatic steatosis and necrosis, as indicated by liver histopathological studies. Additionally, GM suppressed the elevation of malondialdehyde (MDA) levels, restored the glutathione (GSH) levels, and enhanced the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities. The concurrent administration of GM efficaciously abrogated cytochrome P450 2E1 (CYP2E1) induction. Moreover, GM significantly reduced the nuclear translocation of sterol regulatory element-binding protein-1 (nSREBP-1) in ethanol-treated mice. These data indicated that GM possessed the ability to prevent ethanol-induced acute liver steatosis, possibly through blocking CYP2E1-mediated free radical scavenging effects and SREBP-1-regulated fatty acid synthesis. Especially, GM may be developed as a potential therapeutic candidate for ethanol-induced oxidative damage in liver.     

Bioavailability and tissue distribution of anthocyanins in bilberry (Vaccinium myrtillus L.) extract in rats

To clarify how structural diversity of anthocyanins relates to their in vivo function, bioavailability was precisely studied in rats using bilberry (Vaccinium myrtillus L.) extract (Bilberon 25) as an anthocyanin source that contains 15 different anthocyanins. The bilberry extract was orally or intravenously administered to rats, and the plasma levels of each anthocyanin were determined by high-performance liquid chromatography. As the result, all anthocyanins except peonidin 3-O-alpha-L-arabinoside were detectable in the blood plasma. The plasma concentration of anthocyanins as a whole reached the maximum level of 1.2 microM at 15 min after oral administration of 400 mg/kg bilberry extract (153.2 mg/kg as anthocyanins) and then decreased with time. Uptake and decay profiles of each anthocyanin in the plasma were almost the same for all anthocyanins except a few with their maximum after 30 min. Among the anthocyanins carrying the same aglycone, the plasma level after 15 min of oral administration was as follows: galactoside > glucoside > arabinoside. Plasma clearance of anthocyanins after intravenous administration clearly showed that arabinoside disappeared more rapidly than glucoside and galactoside. On the other hand, when anthocyanins carrying the same sugar moiety were compared, the half disappearance time of plasma anthocyanins was in the following order: delphinidin > cyanidin > petunidin = peonidin > malvidin. The bioavailability of anthocyanins was in the range of 0.61-1.82% and was 0.93% as the anthocyanin mixture. The bioavailability of anthocyanins carrying the same aglycone was in the following order: Galactoside showed the highest followed by glucoside and arabinoside for cyanidin and delphinidin, but arabinoside and galactoside showed a higher bioavailability than glucoside for petunidin and malvidin. Anthocyanins recovered in urine and bile during the first 4 h after intravenous administration were only 30.8 and 13.4%, respectively. Anthocyanin profiles in tissues were quite different from those in blood plasma. The major anthocyanins distributed in liver and kidney were the O-methyl anthocyanins such as peonidin, malvidin, and other O-methyl anthocyanins derived from delphinidin, cyanidin, and petunidin-glycosides.     

Protection by petaslignolide A, a major neuroprotective compound in the butanol extract of Petasites japonicus leaves, against oxidative damage in the brains of mice challenged with kainic acid

The neuroprotective effect of petaslignolide A (PA), a furfuran lignan isolated from butanol fraction of Petasites japonicus (Sieb. et Zucc.) Maxim. (Compositae) leaves, on the oxidative damage in the brain of mice challenged with kainic acid was examined using behavioral signs and biochemical parameters of oxidative stress. PA (40 mg/kg) was administered to ICR male mice through a gavage for 4 days consecutively, and on the final day, kainic acid (50 mg/kg) was administered intraperitoneally. During the 4-day treatment with PA, the body weight gain was not significantly different from that of vehicle-treated control animals. PA (40 mg/kg) alleviated the behavioral signs of kainic acid neurotoxicity and reduced the mortality (50%) by kainic acid to 12.5%. Moreover, the administration of PA restored the levels of glutathione and thiobarbituric acid-reactive substances as well as GSH-peroxidase activity in the brains of mice administered kainic acid to control levels (P < 0.05). In comparison, PA (40 mg/kg) was approximately comparable to the butanol fraction (200 mg/kg) of P. japonicus extract in reducing kainic acid neurotoxicity. On the basis of these results, PA is suggested to be a major neuroprotective agent primarily responsible for the protective action of the butanol fraction of P. japonicus extract against kainic acid-induced neurotoxicity in the brains of mice.     

Influence of green tea polyphenol in rats with arginine-induced renal failure

To determine whether green tea polyphenol ameliorates the pathological conditions induced by excessive dietary arginine, green tea polyphenol was administered to rats at a daily dose of 50 or 100 mg/kg body weight for 30 days with a 2% w/w arginine diet. In arginine-fed control rats, urinary and/or serum levels of guanidino compounds, nitric oxide (NO), urea, protein, and glucose increased significantly, while the renal activities of the oxygen species-scavenging enzymes superoxide dismutase (SOD) and catalase decreased, compared with casein-fed rats. However, rats given green tea polyphenol showed significant and dose-dependent decreases in serum levels of creatinine (Cr) and urea nitrogen and urinary excretion of Cr, and they exerted a slight reduction of nitrite plus nitrate, indicating that green tea polyphenol reduced the production of uremic toxins and NO. In addition, in arginine-fed rats the urinary urea, protein, and glucose level increases were reversed by the administration of green tea polyphenol. Moreover, in rats given green tea polyphenol the SOD and catalase activities suppressed by excessive arginine administration increased dose-dependently, implying the biological defense system was augmented as a result of free radical scavenging. These results suggest that green tea polyphenol would ameliorate renal failure induced by excessive dietary arginine by decreasing uremic toxin, and NO production and increasing radical-scavenging enzyme activity.     

Hypocholesterolemic effects of phenolic extracts and purified hydroxytyrosol recovered from olive mill wastewater in rats fed a cholesterol-rich diet

In our previous studies, a phenolic-rich extract of olive mill wastewaters (OMW) was prepared under optimal conditions, using a continuous countercurrent extraction unit, and hydroxytyrosol was purified from the obtained OMW extract. The antioxidant activity of OMW extract and hydroxytyrosol was determined by a series of models in vitro. In this study, the hypocholesterolemic effects of hydroxytyrosol and OMW extract in rats fed a cholesterol-rich diet were tested. Wistar rats, fed a standard laboratory diet or a cholesterol-rich diet for 16 weeks, were used. Serum lipid levels, as well as thiobarbituric acid reactive substances (TBARS) and superoxide dismutase and catalase activities in liver were examined. Cholesterol-rich diet-induced hypercholesterolemia was manifested in the elevation of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Administration of a low-dose (2.5 mg/kg of body weight) of hydroxytyrosol and a high-dose (10 mg/kg of body weight) of OMW extract significantly lowered the serum levels of TC and LDL-C while increasing the serum levels of high-density lipoprotein cholesterol (HDL-C). Furthermore, the TBARS contents in liver, heart, kidney, and aorta decreased significantly after oral administration of hydroxytyrosol and OMW extract as compared with those of rats fed a cholesterol-rich diet. In addition, OMW phenolics increased CAT and SOD activities in liver. These results suggested that the hypocholesterolemic effect of hydroxytyrosol and OMW extract might be due to their abilities to lower serum TC and LDL-C levels as well as slowing the lipid peroxidation process and enhancing antioxidant enzyme activity.     

Gastroprotective effect of red pigments in black chokeberry fruit (Aronia melanocarpa Elliot) on acute gastric hemorrhagic lesions in rats

It has been reported that the fruits and leaves of berries such as the blackberry, raspberry, and strawberry contain a high level of scavenging activity for chemically generated active oxygen species. This study investigated the antioxidative activities of black chokeberry fruit (Aronia melanocarpa Elliot) both in vitro and in vivo using the DPPH stable radical and rats with ethanol-induced gastric injury, respectively. The red pigment fraction of the black chokeberry contained three main components, one of which was identified as cyanidin 3-O-beta-glucoside by HPLC analysis and (1)H NMR. The black chokeberry red pigment fraction scavenged >44% of DPPH radicals at a concentration of 25 microg/mL compared to the control solution. The black chokeberry extract and its hydrolysate administrated at 2 g/kg of body weight each had nearly the same protective effect as quercetin administrated at 100 mg/kg of body weight in suppressing the area of gastric mucosal damage caused by the subsequent application of ethanol to <30% compared to the control group. The black chokeberry red pigment fraction had a similarly significant protective effect on gastric mucosa in a dose-dependent manner when administered at 30-300 mg/kg of body weight, and the administration of 30 mg/kg of body weight could suppress ethanol-induced gastric mucosal damage by approximately 50% (ID(50) = 30 mg/kg of body weight).     

Buckwheat extract inhibits progression of renal failure

Rats subjected to partial resection of the parenchyma showed reduced radical-scavenging activity in the remaining kidney and increased severity of renal tissue lesions. However, in similarly nephrectomized rats given buckwheat extract, the state of oxidative stress improved by restoring the decreased activities of reactive oxygen species-scavenging enzymes such as superoxide dismutase and catalase. The degree of mesangial proliferation, severity of extratubular lesions such as crescents and adhesions, glomerulosclerosis index, and severity of tubular interstitial lesions also improved. In addition, nephrectomized rats given buckwheat extract showed improvement in renal function, as indicated by decreased serum level of creatinine, with a significant decrease in the level of methylguanidine, a uremic toxin produced from creatinine in the presence of hydroxyl radical.     

Protective effect of heat-processed American ginseng against diabetic renal damage in rats

We investigated the effects of American ginseng (AG) and heat-processed American ginseng (H-AG) on diabetic renal damage using streptozotocin (STZ)-induced diabetic rats in this study. The diabetic rats showed a loss of body weight gain, and increases in kidney weight, food intake, water intake, and urine volume, whereas the oral administration of H-AG at a dose of 100 mg/kg of body weight per day for 20 days attenuated these diabetes-induced physiological abnormalities. Among the renal function parameters, the elevated urinary protein levels in diabetic control rats were significantly decreased by the AG or H-AG administrations, and the decreased creatinine clearance level was significantly increased in H-AG-administered rats. In addition, the markedly high serum levels of glucose and glycosylated protein in diabetic control rats were significantly decreased by the administration of H-AG, implying that H-AG might prevent the pathogenesis of diabetic complications caused by impaired glucose metabolism and glycosylation of serum proteins. Although no significant ameliorations were shown in overexpressed protein expressions related to diabetic oxidative stress by the AG or H-AG administrations, the accumulation of N (epsilon)-(carboxymethyl)lysine and receptors for advanced glycation endproduct (AGE) expressions were significantly reduced by the administration of H-AG. On the basis of these results, we found that AG and H-AG inhibit AGE accumulation in diabetic rat kidney by their hypoglycemic and renal function ameliorating effects, and this effect was stronger in the H-AG-administered group than in the AG-administered group. These findings indicate that H-AG may have beneficial effect on pathological conditions associated with diabetic nephropathy.     

Amla (Emblica officinalis Gaertn.) attenuates age-related renal dysfunction by oxidative stress

To investigate the effects of amla on renal dysfunction involved in oxidative stress during the aging process, we employed young (2 months old) and aged (13 months old) male rats and administered SunAmla (Taiyo Kagaku Co., Ltd., Japan) or an ethyl acetate (EtOAc) extract of amla, a polyphenol-rich fraction, at a dose of 40 or 10 mg/kg body weight/day for 100 days. The administration of SunAmla or EtOAc extract of amla reduced the elevated levels of serum creatinine and urea nitrogen in the aged rats. In addition, the tail arterial blood pressure was markedly elevated in aged control rats as compared with young rats, while the systolic blood pressure was significantly decreased by the administration of SunAmla or EtOAc extract of amla. Furthermore, the oral administration of SunAmla or EtOAc extract of amla significantly reduced thiobarbituric acid-reactive substance levels of serum, renal homogenate, and mitochondria in aged rats, suggesting that amla would ameliorate oxidative stress under aging. The increases of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expression in the aorta of aging rats were also significantly suppressed by SunAmla extract or EtOAc extract of amla, respectively. Moreover, the elevated expression level of bax, a proapoptotic protein, was significantly decreased after oral administration of SunAmla or EtOAc extract of amla. However, the level of bcl-2, an antiapoptotic protein, did not show any difference among the groups. The expressions of renal nuclear factor-kappaB (NF-kappaB), inhibitory kappaB in cytoplasm, iNOS, and COX-2 protein levels were also increased with aging. However, SunAmla or EtOAc extract of amla reduced the iNOS and COX-2 expression levels by inhibiting NF-kappaB activation in the aged rats. These results indicate that amla would be a very useful antioxidant for the prevention of age-related renal disease.     

Induction of apoptosis in cancer cells by Bilberry (Vaccinium myrtillus) and the anthocyanins

Among ethanol extracts of 10 edible berries, bilberry extract was found to be the most effective at inhibiting the growth of HL60 human leukemia cells and HCT116 human colon carcinoma cells in vitro. Bilberry extract induced apoptotic cell bodies and nucleosomal DNA fragmentation in HL60 cells. The proportion of apoptotic cells induced by bilberry extract in HCT116 was much lower than that in HL60 cells, and DNA fragmentation was not induced in the former. Of the extracts tested, that from bilberry contained the largest amounts of phenolic compounds, including anthocyanins, and showed the greatest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Pure delphinidin and malvidin, like the glycosides isolated from the bilberry extract, induced apoptosis in HL60 cells. These results indicate that the bilberry extract and the anthocyanins, bearing delphinidin or malvidin as the aglycon, inhibit the growth of HL60 cells through the induction of apoptosis. Only pure delphinidin and the glycoside isolated from the bilberry extract, but not malvidin and the glycoside, inhibited the growth of HCT116 cells.     

Antioxidant effects of isorhamnetin 3,7-di-O-beta-D-glucopyranoside isolated from mustard leaf (Brassica juncea) in rats with streptozotocin-induced diabetes

To investigate the effects of isorhamnetin 3,7-di-O-beta-D-glucopyranoside (isorhamnetin diglucoside), a major flavonoid compound of mustard leaf, on oxidative stress due to diabetes mellitus, in vivo and in vitro studies were carried out. Oral administration of isorhamnetin diglucoside (10 or 20 mg/kg of body weight/day for 10 days) to rats with streptozotocin-induced diabetes significantly reduced serum levels of glucose and 5-(hydroxymethyl)furfural (5-HMF), which is glycosylated with hemoglobin and is an indicator of oxidative stress. After intraperitoneal administration, isorhamnetin diglucoside did not show these activities. In addition, after oral administration, the thiobarbituric acid-reactive substance levels of serum, and liver and kidney mitochondria declined significantly compared with the control group in a dose-dependent manner, whereas after intraperitoneal administration these levels fell only slightly. On the basis of the oral and intraperitoneal results, it was hypothesized that isorhamnetin diglucoside was converted to its metabolite in vivo, and its conversion to its aglycone, isorhamnetin, by beta-glucosidase was confirmed; isorhamnetin acted as an antioxidant. Moreover, it was observed that isorhamnetin diglucoside had no effect on the 1,1-diphenyl-2-picrylhydrazyl radical, whereas isorhamnetin showed a potent antioxidant effect in vitro. In addition, intraperitoneal administration of isorhamnetin reduced serum glucose and 5-HMF levels. Furthermore, lipid peroxidation in blood, liver, and kidney associated with diabetes mellitus declined after the administration of isorhamnetin. These results suggest that isorhamnetin diglucoside is metabolized in vivo by intestinal bacteria to isorhamnetin and that isorhamnetin plays an important role as an antioxidant.     

Effect of curcumin on inflammation and oxidative stress in cisplatin-induced experimental nephrotoxicity

Nephrotoxicity is a major complication and a dose limiting factor for cisplatin therapy. Recent evidence suggests that inflammation and oxidative stress may contribute to the pathogenesis of cisplatin-induced acute renal failure. Curcumin is claimed to be a potent anti-inflammatory and antioxidant agent. The present study was performed to explore the effect of curcumin against cisplatin-induced experimental nephrotoxicity. Curcumin in the dosages of 15, 30, and 60 mg kg(-1) was administered 2 days before and 3 days after cisplatin administration. Renal injury was assessed by measuring serum creatinine, blood urea nitrogen, creatinine, urea clearance, and serum nitrite levels. Renal oxidative stress was assessed by determining renal malondialdehyde levels, reduced glutathione levels and enzymatic activities of superoxide dismutase and catalase. Systemic inflammation was assessed by tumor necrosis factor-alpha (TNF-alpha) levels. A single dose of cisplatin resulted in marked inflammation (486% rise in TNF-alpha level) and oxidative stress and significantly deranged renal functions as well as renal morphology. The serum TNF-alpha level was markedly reduced in curcumin-treated rats. Curcumin treatment significantly and dose-dependently restored renal function, reduced lipid peroxidation, and enhanced the levels of reduced glutathione and activities of superoxide dismutase and catalase. The present study demonstrates that curcumin has a protective effect on cisplatin-induced experimental nephrotoxicity, and this effect is attributed to its direct anti-inflammatory and strong antioxidant profile. Hence, curcumin has a strong potential to be used as a therapeutic adjuvant in cisplatin nephrotoxicity.     

Anthocyanin composition and antioxidant activity of the Crowberry (Empetrum nigrum) and other berries

The anthocyanin composition and antioxidant activity of the crowberry ( Empetrum nigrum) were studied. High-performance liquid chromatography (HPLC) combined with a diode array detector and electrospray ionization mass spectrometry were used for identification and quantification of individual anthocyanins. Freeze-dried crowberry powder was extracted with 80% methanol containing 0.5% acetic acid and subjected to HPLC. Thirteen kinds of anthocyanins were identified. The major anthocyanins were cyanidin-3-galactoside and delphinidin-3-galactoside, at 8.04 and 8.62 mg/g extract, respectively. The HPLC profile of crowberry extract was similar to bilberry and blueberry. The total content of anthocyanins in crowberry was 41.8 mg/g extract, higher than the other nine major berry species (2.5-38.8 mg/g extract). The antioxidant activity was also evaluated using the 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis(3-ethybenzothiazoline-6-sulfonic acid) radical quenching assays and the ferric reducing activity power assy. Crowberry extract exerted the strongest antioxidant activity. In conclusion, individual anthocyanins in crowberry were identified and then quantified in this study. Additionally, crowberry is suggested to be associated with a reduction in the risk of developing chronic diseases because of its strong antioxidant activity.     

Direct in vivo evidence of protective effects of grape seed procyanidin fractions and other antioxidants against ethanol-induced oxidative DNA damage in mouse brain cells

Ethanol is a principle ingredient of alcoholic beverages with potential neurotoxicity and carcinogenicity, and the ethanol-associated oxidative DNA damage in the central nervous system is well documented. The present work studied the possible protective effects of grape seed oligomer and polymer procyanidin fractions against ethanol-induced toxicity and compared these with resveratrol and other well-known antioxidants (ascorbic acid and vitamin E). By using the single cell gel electrophoresis (comet assay), a simple and sensitive technique for genotoxicity studies, the potential genotoxicity of acute and chronic ethanol administration in the different brain regions was investigated. Acute ethanol administration, at the dose of 2.5 or 5.0 g kg(-1) i.p., could induce significant DNA damage in cerebellum and hippocampus. Chronic administration of ethanol at the dose of 2.5 or 5.0 g kg-1 p.o. for 30 days could induce significant DNA damage in cerebellum, hippocampus, hypothalamus, and cortex, which could be auto-repaired at least 3 days after ethanol withdrawal. Oral administration of grape seed oligomer and polymer procyanidins and resveratrol (25, 50, and 100 mg kg(-1)) for 3 days before acute ethanol (5.0 g kg(-1), i.p.) or repeated administration of these substances together with ethanol (5.0 g kg(-1), p.o.) for 30 consecutive days could significantly inhibit DNA damage in brain cells induced by ethanol. As compared, ascorbic acid (50, 100, and 200 mg kg(-1)) and vitamin E (100, 200, and 400 mg kg(-1)) could also present protective effects on ethanol-induced DNA damage. Furthermore, the concentrations of ethanol and acetaldehyde in brain regions of the mice were detected by gas chromatography after administration of ethanol plus antioxidants. All of the results indicated that ethanol could induce region-specific oxidative DNA damage in which the cerebellum and hippocampus were more vulnerable, but intake of grape seed procyanidins or other natural antioxidants could protect the brain against ethanol-induced genotoxicity.     

Evaluation of the hypolipemic property of Camellia sinensisVar. ptilophylla on postprandial hypertriglyceridemia

A naturally decaffeinated tea, Camellia sinensis var. ptilophylla (cocoa tea), has long been popular in southern China as a healthy beverage. Our experiments indicate that a single oral administration of 500 mg/kg of cocoa tea extract suppresses increases in plasma triacylgycerol (TG) levels when fed with 5 mL/kg of olive or lard oil in mice and that the inhibition rates are 22.9% and 31.5%, respectively, compared with controls. Under the same condition, cocoa tea extract did not affect the level of plasma free fatty acid. Likewise, the extract reduced the lymphatic absorption of lipids at 250 and 500 mg/kg. Also, cocoa tea extract and polyphenols isolated from cocoa tea inhibit pancreatic lipase. These findings suggest that cocoa tea has hypolipemic activity, which may be due to the suppression of digestive lipase activity by the polyphenols contained within the tea.     

Neuroprotective effects of resveratrol on cerebral ischemia-induced neuron loss mediated by free radical scavenging and cerebral blood flow elevation

Resveratrol is a natural phytoestrogen and possesses many biological functions such as anti-inflammatory activity and protection against atherosclerosis and myocardial infraction. The present study was carried out to elucidate the neuroprotective effect and possible mechanism of resveratrol on cerebral ischemia-induced hippocampus neuron loss. Sixty adult male rats underwent general anesthesia (urethane, 1.4 g/kg, i.p.) and were divided into three groups: sham operation, ischemia treatment, and ischemia combined with resveratrol administration (20 mg/kg, i.v.). The carotid artery was bilaterally ligated to induce cerebral ischemia. Microdialysis and high-performance liquid chromatography were used to analyze dihydroxybenzoic acid (DHBA) that reflected the hippocampal hydroxyl radical level. Hippocampal nitric oxide was assayed among different groups. During cerebral ischemia, the hydroxyl radical levels were elevated in rats and animals displayed severe neuronal loss. A single dose of resveratrol significantly increased the nitric oxide level and decreased the hydroxyl radical level. The reduction of cerebral blood flow and neuronal loss were also attenuated by resveratrol treatment. The results demonstrated that a single infusion of resveratrol could elicit neuroprotective effects on cerebral ischemia-induced neuron damage through free radical scavenging and cerebral blood elevation due to NO release.     

Oral administration of Trapa taiwanensis Nakai fruit skin extracts conferring hepatoprotection from CCl4-caused injury

As a folk medicine, the hot-water infusion of water caltrop fruits has been used to protect the liver. In this study, the outer skins of mature water caltrop fruits ( Trapa taiwanensis Nakai) were removed, forced-air-dried, pulverized, and subjected to extraction with hot water, and the infusion was lyophilized and pulverized to prepare a hot water extract of T. taiwanensis (HWETT). HWETT was subjected to assays of α,α-diphenyl-β-picrylhydrazyl scavenging activity, reducing power, Trolox equivalent antioxidant capacity, and antioxidative potency, and all determinations showed HWETT to be a potent antioxidant. As further analyzed with LC-MS, two major HPLC-detected components were elucidated as gallic acid and ellagic acid. Hepatoprotective activity of HWETT was assessed with Sprague-Dawley male rats by oral administration. Six groups of rats (n = 8 for each) were respectively treated, namely, control, CCl(4) (20% CCl(4)/olive oil by 2.0 mL/kg bw), CCl(4) and Silymarin (200 mg/kg bw), CCl(4) and low HWETT dose (12.5 mg/kg bw), CCl(4) and medium HWETT dose (25 mg/kg bw), and CCl(4) and high HWETT dose (125 mg/kg bw). After 8 weeks, all animals were fasted for an additional day and sacrificed to collect blood, liver, and kidney for analyses. Histopathological examinations showed that oral administrations with Silymarin and HWETT were effective in protecting the liver from CCl(4)-caused fatty change. Oral administration of HWETT at 125 mg/kg bw was more effective than was Silymarin at 200 mg/kg bw. On biochemical analyses, oral administrations with HWETT at medium and high doses were effective (p < 0.05) in lowering CCl(4)-caused increases of alanine aminotransferase and aspartate aminotransferase activities. It is of merit to demonstrate HWETT as a potent source of antioxidants and hepatoprotective agents.     

Antioxidative and hepatoprotective effects of Antrodia camphorata extract

Antrodia camphorata (A. camphorata) is well-known in Taiwan as a traditional Chinese medicine. The purpose of this study was to evaluate the ability of A. camphorata extracts to protect against oxidative stress in vitro and against carbon tetrachloride (CCl(4))-induced hepatic injury in vivo. An extract of A. camphorata inhibited nonenzymatic iron-induced lipid peroxidation in rat brain homogenates with an IC(50) value about 3.1 mg/mL. It also scavenged the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). The dose of the A. camphorata extract resulting in a decrease of 0.20 in the absorbance of DPPH was about 31 +/- 0.7 microg/mL. Furthermore, an A. camphorata extract dose-dependently (250-1250 mg/kg) ameliorated the increase in plasma aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) levels caused by chronic repeated CCl(4) intoxication in mice. Moreover, A. camphorata extract significantly improved the CCl(4)-induced increase in hepatic glutathione peroxidase, reductase, and CCl(4)-induced decrease in superoxide dismutase activities. It also restored the decrement in the glutathione content and catalase activity of hepatic tissues in CCl(4)-intoxicated mice. Furthermore, it also dose-dependently inhibited the formation of lipid peroxidative products during CCl(4) treatment. Histopathological changes of hepatic lesions induced by CCl(4) were significantly ameliorated by treatment with an A. camphorata extract in a dose-dependent manner. These results suggest that A. camphorata extract exerts effective protection against chronic chemical-induced hepatic injury in vivo, by mediating antioxidative and free radical scavenging activities.