Treatment with AAV1-Rheb(S16H) provides neuroprotection in a mouse model of photothrombosis-induced ischemic stroke.

We recently reported that upregulation of the constitutively active ras homolog enriched in brain [Rheb(S16H)], which induces the activation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway, can protect adult neurons, mediated by the induction of neurotrophic factors, such as brain-derived neurotrophic factor (BDNF), in animal models of neurodegenerative diseases. Here we show that neuronal transduction of Rheb(S16H) using adeno-associated virus serotype 1 provides neuroprotection in a mouse model of photothrombosis-induced ischemic stroke. Rheb(S16H)-expressing neurons exhibited neurotrophic effects, such as mTORC1 activation, increases in neuronal size, and BDNF production, in mouse cerebral cortex. Moreover, the upregulation of neuronal Rheb(S16H) significantly attenuated ischemic damage and behavioral impairments as compared to untreated mice, suggesting that Rheb(S16H) upregulation in cortical neurons may be a useful strategy to treat ischemic stroke.

No Synergistic Effect of Silibinin and Morin in a Kainic Acid-Induced Epileptic Mouse Model.

Temporal lobe epilepsy (TLE) is the most common form of localization-related epilepsy, with the highest prevalence rate in adulthood. Recently, we reported the beneficial effects of the individual treatment with flavonoids such as silibinin and morin in kainic acid (KA)-treated mouse model for TLE. In this study, we investigated whether there is a synergistic effect of co-treatment with silibinin and morin on the susceptibility to seizure, the frequency of spontaneous recurrent seizures (SRSs), and granule cell dispersion in the dentate gyrus, which could be partially controlled by treatment with each flavonoid in the animal model for TLE. Unfortunately, we did not observe any synergistic effect against the susceptibility of seizure and SRS induced by KA treatment. However, the combination of these flavonoids showed similar antiepileptic effects compared with treatment with each one individually. Therefore, although silibinin and morin are not suitable for combination therapy, our results still suggest that these flavonoids can be used as potent therapeutic compounds for preventing epileptic seizures.

Supplementation of the Flavonoid Myricitrin Attenuates the Adverse Metabolic Effects of Long-Term Consumption of a High-Fat Diet in Mice.

The flavonoid myricitrin exhibits various pharmacological and physiological effects. However, studies on the effects of myricitrin on obesity are limited. We hypothesized that dietary myricitrin would attenuate the adiposity and metabolic dysfunction that occur in obesity. To test this hypothesis, mice were randomly fed a high-fat diet (HFD) or HFD supplemented with myricitrin for 16 weeks. Myricitrin significantly reduced white adipose tissue (WAT) mass, adipocyte size, and plasma leptin levels, and also attenuated dyslipidemia. These changes appeared to result from increased energy expenditure and activation of the carnitine acyltransferase (CPT) and ß-oxidation in WAT. Expressions of the proinflammatory genes NF-κB, TLR2, MCP1, and TNF-α were also lower in the WAT of myricitrin-supplemented mice. Moreover, myricitrin markedly reduced hepatic triglyceride accumulation and plasma aspartate transaminase levels by increasing CPT activity and reducing fatty acid synthase activity in the liver. Myricitrin-supplemented mice also showed improved glucose tolerance, insulin sensitivity, and decreased hyperinsulinemia, along with decreased levels of circulating resistin. In conclusion, long-term consumption of a myricitrin-supplemented diet may effectively protect against HFD-induced obesity and related metabolic disorders.

Perspective: Therapeutic Potential of Flavonoids as Alternative Medicines in Epilepsy.

Epilepsy is a chronic neurological disorder that affects many people worldwide. Temporal lobe epilepsy is the most common and most studied type of epilepsy, but the pathological mechanisms underlying this condition are poorly understood. More than 20 antiepileptic drugs (AEDs) have been developed and used for the treatment of epilepsy; however, 30% of patients still experience uncontrolled epilepsy and associated comorbidities, which impair their quality of life. In addition, various side effects have been reported for AEDs, such as drowsiness, unsteadiness, dizziness, blurred or double vision, tremor (shakiness), greater risk of infections, bruising, and bleeding. Thus, critical medical needs remain unmet for patients with uncontrolled epilepsy. Flavonoids belong to a subclass of polyphenols that are widely present in fruits, vegetables, and certain beverages. Recently, many studies have reported that some flavonoids elicit various beneficial effects in patients with epilepsy without causing the side effects associated with conventional medical therapies. Moreover, flavonoids may have a property of regulating microRNA expression associated with inflammation and cell survival. These findings suggest that flavonoids, which are more effective but impose fewer adverse effects than conventional AEDs, could be used in the treatment of epilepsy.

Schizandrin A supplementation improves nonalcoholic fatty liver disease in mice fed a high-fat and high-cholesterol diet.

We hypothesized that schizandrin (SCH) A, a lignan found in the fruits of the Schisandra genus, would exert protective effects against high-fat and high-cholesterol (HFHC) diet-induced nonalcoholic fatty liver disease (NAFLD) via regulation of lipid metabolism and oxidative stress. To test our hypothesis, male C57BL/6J mice were fed an HFHC diet with or without SCH A for 15 weeks. There were no significant differences in food intake, body weight, fat mass, and plasma total cholesterol level between the 2 groups. However, supplementation of SCH A significantly decreased levels of plasma free fatty acid and triglyceride, whereas plasma high-density lipoprotein cholesterol level was increased in the SCH A-supplemented mice. Moreover, hepatic free fatty acid, triglyceride, and cholesterol content, as well as hepatic lipid droplet accumulation, were markedly lower in the SCH A group in contrast to the control group. Activity of hepatic enzymes involved in fatty acid and triglyceride synthesis was significantly decreased by SCH A supplementation, whereas SCH A markedly increased hepatic ß-oxidation and fatty acid oxidation-related gene expression as well as fecal excretion of free fatty acid and triglyceride. SCH A also significantly increased expression of genes involved in cholesterol homeostasis (biliary cholesterol excretion and cholesterol efflux to high-density lipoprotein) in the liver. Moreover, SCH A significantly decreased hepatic lipid peroxidation, which was accompanied by increased hepatic antioxidant enzymes activity. These results suggest that SCH A could alleviate HFHC diet-induced NAFLD by regulating hepatic lipid metabolism and oxidative stress as well as fecal lipid excretion.

Effects of Silibinin Against Prothrombin Kringle-2-Induced Neurotoxicity in the Nigrostriatal Dopaminergic System In Vivo.

Parkinson's disease (PD) and Alzheimer's disease exhibit common features of neurodegenerative diseases and can be caused by numerous factors. A common feature of these diseases is neurotoxic inflammation by activated microglia, indicating that regulation of microglial activation is a potential mechanism for preserving neurons in the adult brain. Recently, we reported that upregulation of prothrombin kringle-2 (pKr-2), one of the domains that make up prothrombin and which is cleaved and generated by active thrombin, induces nigral dopaminergic (DA) neuronal death through neurotoxic microglial activation in the adult brain. In this study, we show that silibinin, a flavonoid found in milk thistle, can suppress the production of inducible nitric oxide synthase and neurotoxic inflammatory cytokines, such as interleukin-1ß and tumor necrosis factor-α, after pKr-2 treatment by downregulating the extracellular signal-regulated kinase signaling pathway in the mouse substantia nigra. Moreover, as demonstrated by immunohistochemical staining, measurements of the dopamine and metabolite levels, and open-field behavioral tests, silibinin treatment protected the nigrostriatal DA system resulting from the occurrence of pKr-2-triggered neurotoxic inflammation in vivo. Thus, we conclude that silibinin may be beneficial as a natural compound with anti-inflammatory effects against pKr-2-triggered neurotoxicity to protect the nigrostriatal DA pathway and its properties, and thus, may be applicable for PD therapy.

Beneficial Effects of Hesperetin in a Mouse Model of Temporal Lobe Epilepsy.

Abnormal reorganization of the dentate gyrus and neuroinflammation in the hippocampus represent characteristic phenotypes of patients suffering from temporal lobe epilepsy. Hesperetin, a flavanone abundant in citrus fruit, is known to have protective effects by preventing inflammation and oxidative stress in neuronal cultures and in the adult murine brain. However, the protective effects of hesperetin against epileptic seizures in vivo remain unclear, despite one study reporting anticonvulsant effects in vitro. In this study, we report that oral administration of hesperetin not only delays the onset of seizures triggered by kainic acid (KA) but also contributes to the attenuation of granule cell dispersion in the KA-treated hippocampus. Moreover, we observed that hesperetin administration inhibited the expression of pro-inflammatory molecules produced by activated microglia in the hippocampus. Thus, administration of hesperetin might be beneficial for preventing epileptic seizures.

Beneficial Effects of Flavonoids Against Parkinson's Disease.

Parkinson's disease (PD) is characterized by the progressive degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta and decreases in striatal dopamine levels. These changes led to several clinical symptoms: rigidity, resting tremor, and bradykinesia. Although the cause of PD remains unclear, it is widely accepted that oxidative stress, neuroinflammation, mitochondrial dysfunction, and insufficient support of neurotrophic factors are involved in the pathophysiology of the disease. However, novel regimens to prevent neurodegeneration and restore the degenerated nigrostriatal DA system are still required. In recent years, there has been a growing interest in naturally occurring phytochemicals, which are believed to reduce the risk of neurodegenerative diseases. This review provides an overview of the scientific literature concerning the preventive and protective roles of flavonoids, one of the largest families of phytochemicals, against PD. In addition to providing antioxidant and anti-inflammatory effects, flavonoids exhibit a neuroprotective effect by activating antiapoptotic pathways that target mitochondrial dysfunction and induce neurotrophic factors. This review suggests that flavonoids may be promising natural products for the prevention of PD and could potentially be utilized as therapeutic compounds against PD, even though there was no report showing that the treatment with flavonoids could restore the aberrant phenotypes of patients with PD.

Long-Term Dietary Supplementation with Yerba Mate Ameliorates Diet-Induced Obesity and Metabolic Disorders in Mice by Regulating Energy Expenditure and Lipid Metabolism.

This study evaluated whether long-term supplementation with dietary yerba mate has beneficial effects on adiposity and its related metabolic dysfunctions in diet-induced obese mice. C57BL/6J mice were randomly divided into two groups and fed their respective experimental diets for 16 weeks as follows: (1) control group fed with high-fat diet (HFD) and (2) mate group fed with HFD plus yerba mate. Dietary yerba mate increased energy expenditure and thermogenic gene mRNA expression in white adipose tissue (WAT) and decreased fatty acid synthase (FAS) mRNA expression in WAT, which may be linked to observed decreases in body weight, WAT weight, epididymal adipocyte size, and plasma leptin level. Yerba mate also decreased levels of plasma lipids (free fatty acids, triglycerides, and total cholesterol) and liver aminotransferase enzymes, as well as the accumulation of hepatic lipid droplets and lipid content by inhibiting the activities of hepatic lipogenic enzymes, such as FAS and phosphatidate phosphohydrolase, and increasing fecal lipid excretion. Moreover, yerba mate decreased the levels of plasma insulin as well as the homeostasis model assessment of insulin resistance, and improved glucose tolerance. Circulating levels of gastric inhibitory polypeptide and resistin were also decreased in the mate group. These findings suggest that long-term supplementation of dietary yerba mate may be beneficial for improving diet-induced adiposity, insulin resistance, dyslipidemia, and hepatic steatosis.

Omija fruit ethanol extract improves adiposity and related metabolic disturbances in mice fed a high-fat diet.

This study investigated the biological and molecular mechanisms underlying the antiobesity effect of omija fruit ethanol extract (OFE) in mice fed a high-fat diet (HFD). C57BL/6J mice were fed an HFD (20% fat, w/w) with or without OFE (500 mg/kg body weight) for 16 weeks. Dietary OFE significantly increased brown adipose tissue weight and energy expenditure while concomitantly decreasing white adipose tissue (WAT) weight and adipocyte size by up-regulating the expression of brown fat-selective genes in WAT. OFE also improved hepatic steatosis and dyslipidemia by enhancing hepatic fatty acid oxidation-related enzymes activity and fecal lipid excretion. In addition to steatosis, OFE decreased the expression of pro-inflammatory genes in the liver. Moreover, OFE improved glucose tolerance and lowered plasma glucose, insulin and homeostasis model assessment of insulin resistance, which may be linked to decreases in the activity of hepatic gluconeogenic enzymes and the circulating level of gastric inhibitory polypeptide. These findings suggest that OFE may protect against diet-induced adiposity and related metabolic disturbances by controlling brown-like transformation of WAT, fatty acid oxidation, inflammation in the liver and fecal lipid excretion. Improved insulin resistance may be also associated with its antiobesity effects.

Long-term dietary supplementation with low-dose nobiletin ameliorates hepatic steatosis, insulin resistance, and inflammation without altering fat mass in diet-induced obesity.

SCOPE: We evaluated the long-term effect of low-dose nobiletin (NOB), a polymethoxylated flavone, on diet-induced obesity and related metabolic disturbances. METHODS AND RESULTS: C57BL/6J mice were fed a high-fat diet (HFD, 45 kcal% fat) with or without NOB (0.02%, w/w) for 16 weeks. NOB did not alter food intake or body weight. Despite increases in fatty acid oxidation-related genes expression and enzymes activity in adipose tissue, NOB did not affect adipose tissue weight due to simultaneous increases in lipogenic genes expression and fatty acid synthase activity. However, NOB significantly decreased not only pro-inflammatory genes expression in adipose tissue but also proinflammatory cytokine levels in plasma. NOB-supplemented mice also showed improved glucose tolerance and insulin resistance, along with decreased levels of plasma insulin, free fatty acids, total cholesterol, non-HDL-cholesterol, and apolipoprotein B. In addition, NOB caused significant decreases in hepatic lipid droplet accumulation and triglyceride content by activating hepatic fatty acid oxidation-related enzymes. Hepatic proinflammatory TNF-α mRNA expression, collagen accumulation, and plasma levels of aminotransferases, liver damage indicators, were also significantly lower in NOB-supplemented mice. CONCLUSION: These findings suggest that long-term supplementation with low-dose NOB can protect against HFD-induced inflammation, insulin resistance, dyslipidemia, and nonalcoholic fatty liver disease, without ameliorating adiposity.

Naringenin ameliorates kainic acid-induced morphological alterations in the dentate gyrus in a mouse model of temporal lobe epilepsy.

Granule cell dispersion (GCD) in the dentate gyrus (DG) of the hippocampus is a morphological alteration characteristic of temporal lobe epilepsy. Recently, we reported that treatment with naringin, a flavonoid found in grapefruit and citrus fruits, reduced spontaneous recurrent seizures by inhibiting kainic acid (KA)-induced GCD and neuronal cell death in mouse hippocampus, suggesting that naringin might have beneficial effects for preventing epileptic events in the adult brain. However, it is still unclear whether the beneficial effects of naringin treatment are mediated by the metabolism of naringin into naringenin in the KA-treated hippocampus. To investigate this possibility, we evaluated whether intraperitoneal injections of naringenin could mimic naringin-induced effects against GCD caused by intrahippocampal KA injections in mice. Our results showed that treatment with naringenin delayed the onset of KA-induced seizures and attenuated KA-induced GCD by inhibiting activation of the mammalian target of rapamycin complex 1 in both neurons and reactive astrocytes in the DG. In addition, its administration attenuated the production of proinflammatory cytokines such as tumor necrosis tumor necrosis factor-α (TNFα) and interleukin-1ß (IL-1ß) from microglial activation in the DG following KA treatment. These results suggest that naringenin may be an active metabolite of naringin and help prevent the progression of epileptic insults in the hippocampus in vivo; therefore, naringenin may be a beneficial metabolite of naringin for the treatment of epilepsy.

Control of Granule Cell Dispersion by Natural Materials Such as Eugenol and Naringin: A Potential Therapeutic Strategy Against Temporal Lobe Epilepsy.

The hippocampus is an important brain area where abnormal morphological characteristics are often observed in patients with temporal lobe epilepsy (TLE), typically showing the loss of the principal neurons in the CA1 and CA3 areas of the hippocampus. TLE is frequently associated with widening of the granule cell layer of the dentate gyrus (DG), termed granule cell dispersion (GCD), in the hippocampus, suggesting that the control of GCD with protection of hippocampal neurons may be useful for preventing and inhibiting epileptic seizures. We previously reported that eugenol (EUG), which is an essential component of medicinal herbs and has anticonvulsant activity, is beneficial for treating epilepsy through its ability to inhibit GCD via suppression of mammalian target of rapamycin complex 1 (mTORC1) activation in the hippocampal DG in a kainic acid (KA)-treated mouse model of epilepsy in vivo. In addition, we reported that naringin, a bioflavonoid in citrus fruits, could exert beneficial effects, such as antiautophagic stress and antineuroinflammation, in the KA mouse model of epilepsy, even though it was unclear whether naringin might also attenuate the seizure-induced morphological changes of GCD in the DG. Similar to the effects of EUG, we recently observed that naringin treatment significantly reduced KA-induced GCD and mTORC1 activation, which are both involved in epileptic seizures, in the hippocampus of mouse brain. Therefore, these observations suggest that the utilization of natural materials, which have beneficial properties such as inhibition of GCD formation and protection of hippocampal neurons, may be useful in developing a novel therapeutic agent against TLE.

Myricitrin Ameliorates 6-Hydroxydopamine-Induced Dopaminergic Neuronal Loss in the Substantia Nigra of Mouse Brain.

Parkinson's disease (PD) is a chronic and progressive movement disorder, resulting from the degeneration of the nigrostriatal dopaminergic (DA) pathway. The cause of DA neuronal loss in PD is still unclear; however, accumulating evidence suggests that treatment with certain flavonoids can induce neuroprotective properties, such as activation of mammalian target of rapamycin complex 1 (mTORC1) and anti-inflammatory activities in animal models of PD. The bioflavonoid myricitrin is well known for its anti-inflammatory and antioxidant properties. However, it is unclear whether systemic treatment with myricitrin can protect neurons against neurotoxin-induced DA degeneration in vivo via the preservation of tyrosine hydroxylase (TH) activity and the induction of mTORC1 activation. Our results found no significant neuroprotective effect of 30 mg/kg myricitrin on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in the substantia nigra (SN) of mice. However, myricitrin treatment with 60 mg/kg protected DA neurons against 6-OHDA-induced neurotoxicity. Moreover, myricitrin treatment preserved TH enzyme activity and mTORC1 activation in nigral DA neurons in the SN of 6-OHDA-treated mice, and its treatment suppressed an increase in tumor necrosis factor-α expression in activated microglia. These results suggest that myricitrin may have neuroprotective properties linked to mTORC1 activation, preservation of TH enzyme activity, and anti-neuroinflammation for preventing DA neuronal degeneration in vivo.

Naringin treatment induces neuroprotective effects in a mouse model of Parkinson's disease in vivo, but not enough to restore the lesioned dopaminergic system.

We recently reported that treatment with naringin, a major flavonoid found in grapefruit and citrus fruits, attenuated neurodegeneration in a rat model of Parkinson's disease (PD) in vivo. In order to investigate whether its effects are universally applied to a different model of PD and whether its treatment induces restorative effects on the lesioned nigrostriatal dopaminergic (DA) projection, we observed the effects of pre-treatment or post-treatment with naringin in a mouse model of PD. For neuroprotective effects, 6-hydroxydopamine (6-OHDA) was unilaterally injected into the striatum of mouse brains for a neurotoxin model of PD in the presence or absence of naringin by daily intraperitoneal injection. Our results showed that naringin protected the nigrostriatal DA projection from 6-OHDA-induced neurotoxicity. Moreover, similar to the effects in rat brains, this treatment induced the activation of mammalian target of rapamycin complex 1 (mTORC1), which is well known as an important survival factor for DA neurons, and inhibited microglial activation in the substantia nigra (SN) of mouse brains treated with 6-OHDA. However, there was no significant change of DA phenotypes in the SN and striatum post-treated with naringin compared with 6-OHDA-lesioned mice, despite the treatment being continued for 12 weeks. These results suggest that post-treatment with naringin alone may not be enough to restore the nigrostriatal DA projection in a mouse model of PD. However, our results apparently suggest that naringin is a beneficial natural product to prevent DA degeneration, which is involved in PD.

Effects of eugenol on granule cell dispersion in a mouse model of temporal lobe epilepsy.

Granule cell dispersion (GCD), a structural abnormality, is characteristic of temporal lobe epilepsy (TLE). Eugenol (EUG) is an essential component of medicinal herbs and is suggested to exert anticonvulsant activity. However, it is unclear whether EUG ameliorates the abnormal morphological changes in granule cells induced by epileptic insults. In the present study, we examined whether intraperitoneal injection of EUG attenuated increased seizure activity and GCD following intrahippocampal injection of kainic acid (KA). Our results showed that EUG significantly increased the seizure threshold, resulting in delayed seizure onset, and reduced GCD in KA-induced epilepsy. Moreover, EUG treatment significantly attenuated KA-induced activation of mammalian target of rapamycin complex 1 (mTORC1), which is involved in GCD development, in the dentate gyrus (DG). These results suggest that EUG may have beneficial effects in the treatment of epilepsy through its ability to inhibit GCD via suppression of KA-induced mTORC1 activation in the hippocampal DG in vivo.

Naringin Attenuates Autophagic Stress and Neuroinflammation in Kainic Acid-Treated Hippocampus In Vivo.

Kainic acid (KA) is well known as a chemical compound to study epileptic seizures and neuronal excitotoxicity. KA-induced excitotoxicity causes neuronal death by induction of autophagic stress and microglia-derived neuroinflammation, suggesting that the control of KA-induced effects may be important to inhibit epileptic seizures with neuroprotection. Naringin, a flavonoid in grapefruit and citrus fruits, has anti-inflammatory and antioxidative activities, resulting in neuroprotection in animal models from neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. In the present study, we examined its beneficial effects involved in antiautophagic stress and antineuroinflammation in the KA-treated hippocampus. Our results showed that naringin treatment delayed the onset of KA-induced seizures and decreased the occurrence of chronic spontaneous recurrent seizures (SRS) in KA-treated mice. Moreover, naringin treatment protected hippocampal CA1 neurons in the KA-treated hippocampus, ameliorated KA-induced autophagic stress, confirmed by the expression of microtubule-associated protein light chain 3 (LC3), and attenuated an increase in tumor necrosis factor-α (TNFα) in activated microglia. These results suggest that naringin may have beneficial effects of preventing epileptic events and neuronal death through antiautophagic stress and antineuroinflammation in the hippocampus in vivo.

Nobiletin protects dopaminergic neurons in the 1-methyl-4-phenylpyridinium-treated rat model of Parkinson's disease.

This study investigated the effect of nobiletin, a flavonoid found in citrus fruits, on the degeneration of dopaminergic (DA) neurons in a neurotoxin model of Parkinson's disease (PD). 1-Methyl-4-phenylpyridinium (MPP(+)) was unilaterally injected into the median forebrain bundle of rat brains (to generate a neurotoxin model of PD) with or without daily intraperitoneal injection of nobiletin. Our results showed that nobiletin treatment at 10 mg/kg bw, but not at 1 or 20 mg/kg bw, significantly protected DA neurons in the substantia nigra (SN) of MPP(+)-treated rats. In parallel to the neuroprotection, nobiletin treatment at 10 mg/kg inhibited microglial activation and preserved the expression of the glial cell line-derived neurotrophic factor, which is a therapeutic agent against PD, in the SN. These results suggest that the proper supplementation with nobiletin may protect against the neurodegeneration involved in PD.

The beneficial effect of soybean (Glycine max (L.) Merr.) leaf extracts in adults with prediabetes: a randomized placebo controlled trial.

The present study investigated the effects of soybean leaf extracts (SLEs) on blood glucose, insulin resistance, body fat and dyslipidemia in prediabetes subjects, and compared them with the effects of banaba extracts (BE) which is known to ameliorate diabetes in several animals and clinical studies. Overweight subjects with mild hyperglycemia (fasting blood glucose level of 100-125 mg dL(-1)) were randomly assigned to three groups and administered four capsules containing starch (2 g per day, Placebo), BE (300 mg per day, 0.3% corosolic acid) or SLE (2 g per day) during regular meals for 12 weeks. The SLE as well as BE significantly decreased the baseline-adjusted final blood glucose, HbA1c, HOMA-IR and transaminase levels compared to the placebo group. The body weight, BMI and WHR were not different between the groups, but the baseline-adjusted final body fat content and waist circumference were lower in the BE and SLE groups than in the placebo group. Furthermore, the baseline-adjusted final plasma triglyceride concentration was lower in the BE and SLE groups compared to the placebo group. There were no significant differences in plasma total cholesterol and LDL-cholesterol concentrations between the groups. However, the SLE, but not the BE, significantly increased the plasma HDL-cholesterol concentration and the ratio of HDL-cholesterol to total cholesterol after 12 weeks of supplementation compared to the placebo group, while the atherogenic index was decreased. Taken together, these data suggest that SLE may play an important role in improving blood glucose, insulin resistance, adiposity, and dyslipidemia in prediabetes subjects consuming their habitual diet, similar to or better than BE.

Silibinin attenuates MPP⁺-induced neurotoxicity in the substantia nigra in vivo.

Parkinson's disease (PD) is characterized by degeneration of the nigrostriatal dopaminergic (DA) pathway. The cause of neuronal death in PD is largely unknown, but it is becoming clear that inflammation plays a significant role in the pathophysiology of PD. Silibinin is a major flavonoid in milk thistle which has an anti-inflammatory activity. We investigated whether silibinin could have neuroprotective effects on DA neurons in the 1-methyl-4-phenylpyridinium ion (MPP(+))-treated animal model of PD in vivo. To address this question, animals received intraperitoneal (i.p.) injections 10, 50, or 100 mg/kg of silibinin, starting 1 day before MPP(+) injection and continued daily until 6 days post-lesion for tyrosine hydroxylase (TH) staining, or until 1 hour prior to the MPP(+) injection to examine the expression levels of inflammatory proteins. Finally, their brains were harvested at the indicated time points for the analyses. Silibinin treatment with 10 mg/kg had no significantly neuroprotective effects in the substantia nigra (SN). However, 50 and 100 mg/kg of silibinin ameliorated the MPP(+)-induced neurotoxicity in the SN in a dose-dependent manner, and the increased levels of inflammatory molecules such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1ß) and inducible nitric oxide synthase (iNOS) by MPP(+) treatment were attenuated by treatment with 100 mg/kg of silibinin. These results indicate that silibinin could be a useful and beneficial natural product offering promise for the prevention of DA neuronal degeneration involved in PD.