Acute and subacute toxicity of Schinus terebinthifolius bark extract

ETHNOPHARMACOLOGICAL RELEVANCE

Schinus terebinthifolius Raddi (Anacardiaceae) has long been used in traditional Brazilian medicine, especially to treat inflammatory and haemostatic diseases.

AIM OF THE STUDY

The objective of this study was to evaluate the acute and subacute toxicity (45 days) of Schinus terebinthifolius via the oral route in Wistar rats of both sexes.

MATERIALS AND METHODS

For the acute toxicity test, the dried extract of Schinus terebinthifolius bark was administered in doses from 0.625 to 5.0 g/kg (n=5/group/sex) and in the subacute toxicity test the following doses were used: 0.25, 0.625 and 1.5625 g/kg/day (n=13/group/sex), for 45 consecutive days.

RESULTS

In the acute toxicity test, Schinus terebinthifolius did not produce any toxic signs or deaths. The subacute treatment with Schinus terebinthifolius did not alter either the body weight gain or the food and water consumption. The hematological and biochemical analysis did not show significant differences in any of the parameters examined in female or male groups, except in two male groups, in which the treatment with Schinus terebinthifolius (0.25 and 0.625 g/kg) induced an increase of mean corpuscular volume values (2.9 and 2.6%, respectively). These variations are within the physiological limits described for the specie and does not have clinical relevance.

CONCLUSION

The acute and subacute administration of the dried extract of Schinus terebinthifolius bark did not produced toxic effects in Wistar rats.

Toxicological reproductive study of Cassia occidentalis L. in female Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Cassia occidentalis L. (Leguminosae) has long been used as natural medicine in rainforests and other tropical regions for the treatment of inflammation, fever, liver disorders, constipation, worms, fungal infections, ulcers, respiratory infections, snakebite and as a potent abortifacient.

AIM OF THE STUDY

This study has investigated the effects of oral sub-acute administration of Cassia occidentalis during pregnancy in female Wistar rats.

MATERIALS AND METHODS

Three groups of pregnant rats were treated orally from the 1st to the 6th day (pre-implantation period) and from the 7th to the 14th day (organogenic period) of pregnancy, with doses of 250 and 500 mg/kg. On the 20th day of pregnancy, the animals were euthanized and reproductive parameters evaluated.

RESULTS

The results revealed no statistically significant differences between the control and treated groups in terms of offspring/dam relationship; fetuses, placentae and ovaries weights; number of implantation and resorption sites; number of corpora lutea in the ovaries and pre- and post-implantation loss rates. However, the presence of dead fetuses was registered in both doses of 250 and 500 mg/kg of Cassia occidentalis.

CONCLUSIONS

Further studies should therefore be conducted to obtain more detailed characteristics of the toxic effects of this species, the use of which is not recommended during pregnancy.

Acute and subacute toxicity of the Carapa guianensis Aublet (Meliaceae) seed oil

Carapa guianensis (Meliaceae), known as Andiroba in Brazil, has been used by Amazon Rainforest indigenous communities for treatment of coughs, convulsions, skin diseases, arthritis, rheumatism, ear infections, to heal wounds and bruises and as an insect repellent. Carapa guianensis seed oil (SO) was evaluated for its acute and subacute toxicity (30 days) by the oral route in Wistar rats. In the acute toxicity test, SO (0.625-5.0g/kg, n=5/sex) did not produce any hazardous symptoms or deaths. The subacute treatment with SO (0.375, 0.75 and 1.5g/kg, n=10/group) failed to change body weight gain, food and water consumption. Hematological analysis showed no significant differences in any of the parameters examined. However, in the biochemical parameters, there was an increase in the alanine aminotransferase (ALT) serum level (29%) in the group SO 1.5g/kg. In addition, absolute and relative liver weights were increased at the doses of 0.75g/kg (23.4 and 19.1%) and 1.5g/kg (18.7 and 33.1%). In conclusion, acute and subacute administration of Carapa guianensis seed oil did not produce toxic effects in male Wistar rats. However, the increase in the ALT serum level and in both absolute and relative liver weights may indicate a possible hepatic toxicity.

Evidence for the participation of calcium in non-genomic relaxations induced by androgenic steroids in rat vas deferens

BACKGROUND AND PURPOSE

Androgens cause non-genomic relaxation in several smooth muscle preparations. However, such an effect has not been investigated in rat vas deferens yet. Our purpose was to study the effect of testosterone and derivatives in this tissue.

EXPERIMENTAL APPROACH

The influence of androgens was tested on contraction and translocation of intracellular Ca(2+) induced by KCl in rat vas deferens in vitro.

KEY RESULTS

The testosterone derivative 5alpha-dihydrotestosterone produced a rapid and reversible concentration-dependent relaxation of KCl-induced contractions. Other androgens were also effective, showing the following rank order of potency: androsterone >5beta-dihydrotestosterone >androstenedione >5alpha-dihydrotestosterone >testosterone. Calcium-induced contractions were also inhibited (about 45%) by 5alpha-dihydrotestosterone (30 microM). Moreover 5alpha-dihydrotestosterone blocked the increase of intracellular Ca(2+) induced by KCl, measured by the fluorescent dye fura-2. Relaxation to 5alpha-dihydrotestosterone was resistant to the K(+) channel antagonists glibenclamide, 4-aminopyridine and charybdotoxin. It was not affected by removal of epithelium or by L-NNA (300 microM), an inhibitor of nitric oxide biosynthesis, nor by selective inhibitors of soluble guanylate cyclase, ODQ or LY 83583, indicating that nitrergic or cGMP mediated mechanisms were not involved. The androgen-induced relaxation was also not blocked by the protein synthesis inhibitor cycloheximide (300 microM) or by the classical androgen receptor flutamide (up to 100 microM), corroborating that the effect is non-genomic.

CONCLUSIONS AND IMPLICATIONS

Testosterone derivatives caused relaxation of the rat vas deferens, that did not involve epithelial tissue, K(+) channels, or nitric oxide-dependent mechanisms, but was related to a partial blockade of Ca(2+) influx.

A toxicological evaluation of the effect of Carapa guianensis Aublet on pregnancy in Wistar rats

The effects of the administration of Carapa guianensis Aublet (Meliaceae) seed oil were investigated during pregnancy in female Wistar rats. Five groups of pregnant rats (n=5-9 per group) were treated orally from the 7th to the 14th day of pregnancy (organogenic period), at doses of: 0, 0.375, 0.75, 1.5 and 3.0gkg(-1). On the 20th day of pregnancy, the animals were sacrificed and laparotomized to evaluate reproductive parameters. The results showed that there was no difference between the control and treated groups in terms of the number of live and dead fetuses, the dam-offspring relationship, the weight of the fetus, the weight of the placentae and ovaries, the number of implantation sites, the number of resorption sites, the number of corpora lutea in the ovaries, and the pre- and post-implantation loss rates. It is therefore concluded that administration of Carapa guianensis seed oil did not bring about any toxic effect on pregnancy in Wistar rats.