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The effect of an ethanolic extract from the stem bark of Bursera fagaroides on ornithine decarboxylase (ODC) activity in vitro and on the growth of Entamoeba histolytica was evaluated. For this purpose, increasing concentrations of the extract, up to 8.0 mg/mL, were added to amoeba cultures or ODC reaction mixtures, which were incubated at 37 °C. Metronidazole and G418 were added as controls. After 1.5 and 72 h, the ODC activity in vitro and growth, respectively, were determined. Results revealed a strong inhibition of growth with IC50 values on the order of 0.05 mg/mL. ODC activity, on the other hand, was inhibited by 12% and 50% at concentrations of 4.0 and 8.0 mg/mL, respectively.

We evaluated the immune response of healthy control and stressed Wistar rats submitted to hypothalamic-pituitary-adrenal (HPA) axis activation. Rats were treated with Ginkgo biloba extract (EGb 761) orally (100 mg/kg per day for 7 days). EGb 761 stimulated the digestion index of peritoneal and alveolar macrophages (PM and AM) of stressed rats. Likewise, the cellular immune response measured using the delayed-type hypersensitivity response to sheep red blood cells (SRBC) and the humoral immune response (measured through an anti-SRBC response), were also restored in stressed rats. Thus, this G. biloba extract possesses immunostimulatory activity in addition to its broad spectrum of pharmacological effects.

Natural aqueous crude extracts (NACE) of several Crassulaceae family plants have been applied as a vaginal contraceptive by the populace. The aim of this work was to evaluate the inhibition of fertility in male Wistar rats and some physiological and biochemical changes in spermatozoa and epididymal plasma induced by NACE from Kalanchoe gastonis bonnieri (K. g. b.) (Crassulaceae). The NACE was obtained by mechanic pressure on grinding fresh plant leaves. Sublethal doses (150-300 mg/kg body weight) of NACE were orally administered to adult and fertile male rats daily for 30 days in a search for a contraceptive effect, and physiological and biochemical modifications on sperm cells and cauda epididymal plasma. The toxicity studies revealed that the lethal dose (LD(50)) calculated was 11 g/kg body weight. Sublethal doses induced 50%-100% fertility inhibition, with 100% recovery of fertility 30 days after stopping the treatment. The sperm motility, viability and spermatic density were also significantly decreased (p < 0.001). The outstanding biochemical change observed in the cauda epididymal plasma was a decrease of carnitine concentration. The NACE of K. gastonis contains one substance active on fertility by affecting spermatozoa motility, viability and sperm density with a significantly decreased carnitine and sialic acid (p < 0.001) in the caudal epididymal plasma.

We evaluated the effects of Ginkgo biloba extract (EGb 761) on the cellular immune response of rats with immunosuppression induced by activation of the hypothalamic-pituitary-adrenal (HPA) axis. Groups of five rats were subjected to chronic stress by the application of daily electric shocks (ES) over 7 days. This stress produced a significant decrement in the delayed-type hypersensitivity response (DTH) to dinitrofluorobenzene (DNFB), and a decrease in the proliferation index of splenocytes. Treatment with oral doses of the phytopharmaceutical EGb 761 (100 mg/kg per day over 7 days) restored both the DTH response to DNFB and the proliferation index. EGb 761 has stress-alleviating properties through its moderation of corticosterone levels. It also possesses antioxidant activity that may contribute to its effects on the immune response. Our observations indicate that the phytopharmaceutical EGb 761 possesses immunostimulatory properties.

The endothelial nitric oxide synthase (eNOS) gene plays an important role in several biological functions. Polymorphisms of the eNOS gene have been associated with cancer. It has been suggested that the VNTR 4 a/b polymorphism may affect the expression of eNOS and contributes to tumor promotion in the mammary gland. We examined the role of the eNOS4 a/b polymorphism by comparing the genotypes of 281 healthy Mexican women with the genotypes of 429 Mexican women with breast cancer (BC). The observed genotype frequencies for control and BC patients were 0.6% and 0.7% for a/a (polymorphic); 87% and 77% for a/a (wild type); and 12% and 22% for a/b respectively. We found that the odds ratio (OR) was 1.9, with a 95% confidence interval (95%CI) of 1.29-2.95, P = 0.001 for genotypes a/a-a/b, b/c. The association was also evident when comparing the distribution of the a/a-a/b genotypes in patients with high levels of glutamate-oxaloacetate transaminase (SGOT) (OR, 1.93; 95% CI, 1.14-3.28; P = 0.015); undergoing menopause with high levels of SGOT (OR, 2.0; 95% CI, 1.1-3.84); and with high levels of glutamic-pyruvic transaminase (SGPT) (OR, 3.5; 95% CI, 1.56-8.22). The genotypes a/a-a/b are associated with BC susceptibility in the analyzed samples from the Mexican population.