Hypericum perforatum subspecies angustifolium shows a protective activity on the consequences of unavoidable stress exposure at lower doses than Hypericum perforatum perforatum.

Clinical studies have demonstrated that the antidepressant efficacy of Hypericum perforatum extract is comparable to that of classic antidepressants, such as imipramine. The role played by its components, particularly hypericin and hyperforin, has been examined in different experimental models of depression. The present study was carried out in order to verify the hypothesis that hyperforin is the main active antidepressant component. For this purpose we evaluated the activity of a dry extract from a subspecies of H. perforatum, H. perforatum spp. angustifolium, which has a higher hyperforin content than H. perforatum perforatum, in a series of experimental models of depression. The models used are based on the development of hyporeactivity to aversive stimuli induced by unavoidable stress exposure in rats. The extract of H. perforatum angustifolium presented an efficacy that was similar to that obtained with a treatment with imipramine or H. perforatum perforatum. Furthermore, in the models used the H. perforatum angustifolium extract was active at doses eight times lower than those necessary to produce a comparable activity with H. perforatum extract.

A study of the antidepressant activity of Hypericum perforatum on animal models.

The treatment of non-selected depressed patients with a hydro-alcoholic extract of Hypericum perforatum has been reported to have an efficacy similar to that of classical antidepressants. The effects of H. perforatum on three animal depression models have been studied: (a) an acute form of escape deficit (ED) induced by unavoidable stress; (b) a chronic model of ED, which can be maintained by the administration of mild stressors on alternate days; (c) a model of anhedonia based on the finding that repeated stressors prevent the development of appetitive behavior induced by vanilla sugar in satiated rats fed ad libitum. H. perforatum: (i) acutely protects animals from the sequelae of unavoidable stress; (ii) reverts the chronic escape deficit state maintained by repeated stressors and (iii) preserves the animal's capacity to acquire motivated appetitive behavior. Exposure to chronic stress not only induces escape deficit, but also decreases extraneuronal levels of dopamine in the nucleus accumbens shell; both behavioral and neurochemical effects are reverted by long-term treatment with antidepressants. Three-week treatment with H. perforatum reverted the chronic stress effect on extraneuronal dopamine in the nucleus accumbens. A consistent body of data in the literature suggests that, among the components of H. perforatum extract, hyperforin is the compound (or one of the compounds) responsible for the antidepressant activity. We compared the efficacy of the total extract with the efficacy of hyperforin after p.o. administration. In the acute-escape deficit model, hyperforin showed a potency of about ten times that of the total extract in protecting rats from the sequelae of unavoidable stress. Thus, hyperforin appears to be the most likely active component responsible for the antidepressant activity of H. perforatum.

Efficacy of an Hypericum perforatum (St. John's wort) extract in preventing and reverting a condition of escape deficit in rats.

The treatment of unselected depressed patients with an hydro-alcoholic extract of Hypericum perforatum has been reported to have an efficacy similar to that of classical antidepressants. In the present report, the effects of H. perforatum were studied on three animal models of depression: (i) an acute form of escape deficit (ED) induced by an unavoidable stress; (ii) a chronic model of ED, which can be maintained by the administration of mild stressors on alternate days; (iii) a model of anhedonia based on the finding that repeated stressors prevent the development of an appetitive behavior induced by vanilla sugar in satiated rats fed ad libitum. H. perforatum acutely protected animals from the sequelae of unavoidable stress; such an effect was partially prevented by the administration of SCH 23390 or (-)-pindolol. Moreover, H. perforatum reverted the ED maintained by repeated stressors and preserved the animal's capacity to learn to operate for earning a positive reinforcer. It was concluded that H. perforatum contains some active principle(s) endowed with antidepressant activity.

Correlation between male fertility and acrosin-like protease activity in rats treated with Spartium junceum.

Intraperitoneal injections of extracts of Spartium junceum in adult male rats were shown to reduce the rate of fertility and acrosin enzyme activity. For the latter the drug effects could be divided into two phases: in the first stage a significant increase in proteolytic activity was observed in all experimental animals examined; and in the second stage, there was a general decrease of up to 50% in enzyme hydrolytic properties. There is a notable difficulty in correlating the acrosin activity and the data obtained from mating tests. The effect of drugs on the activity of another acrosomal protease, benzamidine-resistant protease, was assayed. A significant decrease in this enzyme was noted though the modality was different from that of acrosin. Extrapolating the data of the two co-extracted acrosomal proteases, the ratio of acrosin-like protease [E] and benzamidine-resistant protease [E]x, it was possible to correlate the value expressed to the rate of pregnancy. The implications of this finding is discussed although the exact molecular basis of the phenomenon is uncertain.

Evaluation of the antifertility activity of the broom Spartium junceum in the mammalian male.

Male adult rabbits and rats treated with Spartium junceum showed a significant decrease in fertility, demonstrated by a lower number of pregnancies. The target of the drug seems to be the acrosomal protease system, the activity of which appears greatly reduced, while the morphology of testicular cells and epididymal spermatozoa is only partially affected. The antifertility effect is completely reversible.

Effects of Smilax macrophylla Vers. in normal or hyperuricemic and hyperuricosuric rats.

Smilax macrophylla Vers., administered per os at the doses of 1 or 2 g/kg in normal rats or in rats made hyperuricemic and hyperuricosuric by potassium oxonate (250 mg/Kg p.o.) or fructose (4 g/Kg p.o.) does not modify diuresis, but increases the excretion of uric acid and allantoin in normal rats and in those pretreated with fructose, whereas it is inactive in oxonate pretreated rats. Allantoinemia is not modified by fructose or oxonate, whereas uricemia is modified.