Effect of Hypericum perforatum CO2 extract on the motivational properties of ethanol in alcohol-preferring rats

Hypericum perforatum L. prevents the acquisition of and promotes resilience against stress-induced reinstatement of the conditioned place preference induced by cocaine

Cocaine use disorder is a serious problem worldwide, and there are no approved medications for its treatment. A novel approach to the treatment of drug addiction is the use of natural products, and, in this context, preclinical evidence suggests that Hypericum perforatum L. (Hypericum) is effective against alcohol and other substance use disorders. We hypothesised that Hypericum could also be useful as a treatment for cocaine use disorder, and so we set out to test its effectiveness in a mice model of cocaine addiction. In the first experiment we evaluated its effects on the acquisition of cocaine-induced conditioned place preference (CPP). Adult male mice were conditioned with cocaine (25 mg/kg), cocaine with Hypericum (75, 150 or 300 mg/kg) or the plant extract alone (300 mg/kg). In the second experiment, we tested the effects of Hypericum on stress-induced reinstatement of cocaine CPP. All the mice were conditioned with cocaine (25 mg/kg) and, after extinction of CPP, the reinstating effects of social defeat (alone or with 75, 150 or 300 mg/kg of Hypericum) were evaluated. All the doses of Hypericum prevented the acquisition of cocaine-induced CPP. Furthermore, the plant extract dose-dependently reduced the reinstating effects of social defeat. Therefore, Hypericum is effective in reducing the rewarding effects of cocaine and prevents the stress-induced reinstatement of cocaine CPP in mice. The mechanisms underlying these positive effects of Hypericum perforatum L. need to be determined by future research. Our results endorse Hypericum as a natural treatment for cocaine dependence.

Genetically selected alcohol-preferring msP rats to study alcohol use disorder: Anything lost in translation?

For several decades, genetically selected alcohol-preferring rats have been successfully used to mimic and study alcohol use disorders (AUD). These rat lines have been instrumental in advancing our understanding of the neurobiology of alcoholism and enabling pharmacological studies to evaluate drug efficacy on alcohol drinking and relapse. Moreover, the results of these studies have identified genetic variables that are linked to AUD vulnerability. This is an up-to-date review that focuses on genetically selected Marchigian Sardinian alcohol-preferring (msP) rats. To support the translational relevance of the findings that are obtained from msP rats and highlight important similarities to AUD patients, we also discuss the results of recent brain imaging studies. Finally, to demonstrate the importance of studying sex differences in animal models of AUD, we present original data that highlight behavioral differences in the response to alcohol in male and female rats. Female msP rats exhibited higher alcohol consumption compared with males. Furthermore, msP rats of both sexes exhibit higher anxiety- and depressive-like behaviors in the elevated plus maze and forced swim test, respectively, compared with unselected Wistar controls. Notably, voluntary alcohol drinking decreases foot-shock stress and depressive-like behavior in both sexes, whereas anxiety-like behavior in the elevated plus maze is attenuated only in males. These findings suggest that male and female msP rats both drink high amounts of alcohol to self-medicate negative affective symptoms. For females, this behavior may be driven by an attempt to treat stress and depressive-like conditions. For males, generalized anxiety appears to be an important additional factor in the motivation to drink alcohol. This article is part of the special issue on 'Vulnerabilities to Substance Abuse.'

Plants with Anti-Addictive Potential

Drug addiction is prevalent among individuals of modern society, being a major cause of disability and premature loss of life. Although the drug addiction have profound social, economical and health impact in the world population, its management remains a challenge as available pharmacological treatments remains ineffective for most people. The limited efficacy and adverse effects have led to a search for alternative therapies to treat drug addiction. In this context, natural products are an important source for new chemical substances with a potential therapeutic applicability. Therefore, this chapter will present data obtained after an extensive literature search regarding the use of medicinal plants as a pharmacological alternative for drug addiction treatment.

Effect of Hypericum perforatum Extract in an Experimental Model of Binge Eating in Female Rats

Purpose. The present study evaluated the effect of Hypericum perforatum dry extract in an experimental model of binge eating (BE). Methods. BE for highly palatable food (HPF) was evoked in female rats by three 8-day cycles of food restriction/re-feeding and acute stress on the test day (day 25). Stress was induced by preventing access to HPF for 15 min, while rats were able to see and smell it. Hypericum perforatum dry extract was given by gavage. Results. Only rats exposed to both food restrictions and stress exhibited BE. The doses of 250 and 500 mg/kg of Hypericum perforatum extract significantly reduced the BE episode, while 125 mg/kg was ineffective. The same doses did not affect HPF intake in the absence of BE. The dose of 250 mg/kg did not significantly modify stress-induced increase in serum corticosterone levels, suggesting that the effect on BE is not due to suppression of the stress response The combined administration of 125 mg/kg of Hypericum perforatum together with Salidroside, active principle of Rhodiola rosea, produced a synergic effect on BE. Conclusions. The present results indicate for the first time that Hypericum perforatum extracts may have therapeutic properties in bingeing-related eating disorders.

Phytotherapeutic approach to alcohol dependence: new old way?

Alcohol abuse and dependence represent a worldwide problem from both medical and social points of view. In Italy it is estimated that there are about one million alcohol-dependent subjects. The pharmacological treatment of patients with alcohol dependence plays a key role in order to achieve alcohol abstinence and prevent relapse. At present, the possible utility of the complementary medicines in the treatment of alcohol dependence is controversial. In the last years, pre-clinical and clinical data from traditional medicines suggest that novel pharmacological approaches for treatment of alcoholism and alcohol abuse may stem from natural substances. The present review summarizes the findings of the effects of phytotherapy in alcohol addiction.

Wound-healing activity of St. John's Wort (Hypericum perforatum L.) on chicken embryonic fibroblasts

Wound-healing effect of St. John's Wort (Hypericum perforatum L.) extract was evaluated by comparing with dexpanthenol and titrated extract of Centella asiatica (TECA) on cultured chicken embryonic fibroblasts. Chicken embryonic fibroblasts from fertilized eggs were incubated with the plant extract, dexpanthenol and TECA. Using microscopical methods by staining cells, mitotic ability, morphologic changes and collagen production in the cultured fibroblasts were evaluated as parameters to approach its mechanism of action in wound repair. Findings obtained in the present study indicated that Hypericum perforatum extract exhibited a wound-healing activity whose mechanism of action is similar to that of TECA. Wound-healing activity of Hypericum perforatum extract seems to be mainly due to the increase in the stimulation of fibroblast collagen production and the activation of fibroblast cells in polygonal shape, which plays a role in wound repair by closing damaged area. The findings demonstrated the wound-healing activity of Hypericum perforatum, which has previously been based on ethnomedical data.

Attenuation of ethanol withdrawal syndrome by extract of Hypericum perforatum in Wistar rats

The effects of Hypericum perforatum (St John's wort) on ethanol withdrawal syndrome have been investigated in ethanol-dependent rats. Adult male Wistar rats were subjects. Ethanol (7.2% v/v) was given to rats by a liquid diet for 15 days. Hypericum perforatum extract (HPE) (25-200 mg/kg) and saline were injected to rats intraperitoneally just before ethanol withdrawal. After second, fourth and sixth hour of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs that included locomotor hyperactivity, stereotyped behavior and tremors were recorded or rated. A second series of injections was given at 6 h after the first one, and subjects were then tested for audiogenic seizures. HPE (25-200 mg/kg) produced some dose-dependent and significant inhibitory effects on locomotor hyperactivity at second and sixth hour of ethanol withdrawal. In addition, it significantly reduced the number of stereotyped behaviors at the same dose range. HPE (50 and 100 mg/kg) produced some significant inhibitory effects on tremor and audiogenic seizures during withdrawal period. These results suggest that HPE has some beneficial effects on ethanol withdrawal syndrome in rats.

Genetically selected Marchigian Sardinian alcohol-preferring (msP) rats: an animal model to study the neurobiology of alcoholism

The present article provides an up-to-date review summarizing almost 18 years of research in genetically selected Marchigian Sardinian alcohol-preferring (msP) rats. The results of this work demonstrate that msP rats have natural preference for ethanol characterized by a spontaneous binge-type of drinking that leads to pharmacologically significant blood ethanol levels. This rat line is highly vulnerable to relapse and presentation of stimuli predictive of alcohol availability or foot-shock stress can reinstate extinguished drug-seeking up to 8 months from the last alcohol experience. The msP rat is highly sensitive to stress, shows an anxious phenotype and has depressive-like symptoms that recover following ethanol drinking. Interestingly, these animals have an up-regulated corticotrophin releasing factor (CRF) receptor 1 system. Clinical studies have shown that alcoholic patients often drink ethanol in the attempt to self-medicate from negative affective states and to search for anxiety relief. We propose that msP rats represent an animal model that largely mimics the human alcoholic population that due to poor ability to engage in stress-coping strategies drink ethanol as a tension relief strategy and for self-medication purposes.

NMDA receptor-antagonistic properties of hyperforin, a constituent of St. John's Wort

Extracts of the medicinal plant St. John's wort (Hypericum perforatum) are widely used for the treatment of affective disorders. Hyperforin, a constituent of St. John's wort, is known to modulate the release and re-uptake of various neurotransmitters, an action that likely underlies its antidepressive activity. We now report that hyperforin also has N-methyl-D-aspartate (NMDA)-antagonistic effects. Hyperforin (10 microM) was found to inhibit the NMDA-induced calcium influx into cortical neurons. In rat hippocampal slices, hyperforin inhibited the NMDA-receptor-mediated release of choline from phospholipids. Hyperforin also antagonized the increase of water content in freshly isolated hippocampal slices, and it counteracted, at 3 and 10 microM, the increase of water content induced by NMDA. Hyperforin was inactive, however, in two in vivo models of brain edema formation, middle cerebral artery occlusion and water intoxication in mice. In conclusion, hyperforin has NMDA-receptor-antagonistic and potential neuroprotective effects in vitro. This effect may contribute to the therapeutic effectiveness of St. John's wort extracts in some situations, for example, for relapse prevention in alcoholism.

Identification of Miltirone as Active Ingredient of Salvia miltiorrhiza Responsible for the Reducing Effect of Root Extracts on Alcohol Intake in Rats

BACKGROUND

Previous work found that extracts from the roots of Salvia miltiorrhiza, a Chinese medicinal herb, reduced alcohol intake in selectively bred Sardinian alcohol-preferring (sP) rats. The present study was designed to evaluate whether miltirone, one of the possible active constituents of S. miltiorrhiza, might be responsible for the reducing effect of the extracts on alcohol intake.

METHODS

An initial experiment assessed the effect of 100 mg/kg (intragastric, i.g.) of 4 extracts of S. miltiorrhiza, differing in miltirone content (0, 2, 3, and 7%, respectively), on alcohol intake in alcohol-experienced sP rats exposed to the 2-bottle "alcohol (10%, volume in volume) versus water" choice regimen. Subsequently, the effect of pure miltirone (2.5-10 mg/kg, i.g., i.e., a dose range comparable to its content in the effective doses of the active extracts) on acquisition and maintenance of alcohol-drinking behavior was evaluated in alcohol-naive and alcohol-experienced sP rats exposed to the 2-bottle choice regimen. The effect of miltirone (10 mg/kg, i.g.) on blood alcohol levels was assessed after the i.g. and intraperitoneal (i.p.) administration of alcohol. Finally, the effect of miltirone (30-100 mg/kg, i.g.) on the severity of alcohol withdrawal syndrome was evaluated in Wistar rats made physically dependent on alcohol by the repeated administration of intoxicating doses of alcohol.

RESULTS

The reducing effect of 4 different extracts of S. miltiorrhiza on alcohol intake was positively and significantly correlated with their miltirone content. Pure miltirone reduced alcohol intake in alcohol-experienced rats and delayed acquisition of alcohol-drinking behavior in alcohol-naive rats. Similar to S. miltiorrhiza extracts, miltirone markedly reduced blood alcohol levels when alcohol was administered i.g. but not i.p., suggesting that miltirone hampered alcohol absorption from the gastrointestinal system. Finally, miltirone failed to affect the severity of alcohol withdrawal syndrome in alcohol-dependent rats.

CONCLUSIONS

The results of the present study suggest that miltirone is the likely active constituent of S. miltiorrhiza responsible for the reducing effect of its extracts on alcohol intake in different experimental models of excessive alcohol consumption.