Toxicological studies of stem bark extract from Schefflera barteri Harms (Araliaceae).

BACKGROUND: The use of herbal medicines as complements or alternatives to orthodox medicines has been on the increase. There has been the erroneous belief that these medicines are free from adverse effects. Schefflera barteri is popularly used in the West region of Cameroon for the treatment of various diseases such as diarrhea, spasm, pneumonia and animals bite. Considering the ethnopharmacological relevance of this plant, this study was designed to investigate the possible toxic effects of the stem bark extract of S. barteri. METHODS: The extract was prepared by maceration of stem bark dry powder in methylene chloride/methanol mixture. Phytochemical analysis was performed by chemical reaction method. Oral acute toxicity study was carried out by administering single geometric increasing doses (2 to 16 g/kg body weight) of plant extract to Swiss albino mice. For sub-acute toxicity study, repeated doses (100, 200, 400 and 800 mg/kg bw) of plant extract were given to Wistar albino rats for 28 consecutive days by oral route. At the end of the treatment period, hematological and biochemical parameters were assessed, as well as histopathological studies. RESULTS: Phytochemical analysis of stem bark extract of S. barteri revealed the presence of anthocyanins, anthraquinons and saponins. Acute toxicity results showed that the LD50 was greater than 16000 mg/kg. Sub-acute treatment significantly (P < 0.05) increased the level of serum transaminase, proteins and HDL cholesterol. On the other hand, the extract significantly (P < 0.05) reduced the level of leucocytes as well as neutrophils, basophils and monocytes in female. No significant variation of serum creatinine, LDL cholesterol, serum triglycerides as well as liver, spleen, testicles and ovaries proteins was noted. Histopathological analysis of organs showed vascular congestion, inflammation of peri-portal and vacuolization of hepatocytes at the level of the liver. Leucocytes infiltration of peri-portal veins were noticed on lungs and liver cells as well as inflammatory peri-bronchial and basal membranes seminar tube merely joined on lungs and testis respectively. CONCLUSION: The results suggest that acute administration of the stem bark extract of S. barteri is associated with signs of toxicity, administration over a long duration provokes hepatotoxicity, testes and lungs toxicities.

Substituted 2-aminothiophenes: antifungal activities and effect on Microsporum gypseum protein profile.

The increasing recognition and importance of fungal infections, the difficulties encountered in their treatment and the increase in resistance to antifungal agents have stimulated the search for therapeutic alternatives. The objective of this study was to evaluate the antifungal activities of three substituted 2-aminothiophenes (1, 2 and 3) against some fungal species. The synthesis of substituted 2-aminothiophenes was carried out through the most versatile synthetic method developed by Gewald et al. The antifungal activity was performed against yeast, dermatophytes and Aspergillus species using the broth microdilution method. The effect of these aminothiophenes was examined on the protein content and profile. Compound 2 was the most active (MIC varying from 2.00 to 128 µg ml(-1) ). All the three substituted 2-aminothiophenes had a relatively important dose-dependent effect on Microsporum gypseum protein profile and content. These compounds affected the structure and dye fixation of macroconidia of this fungus. The overall results indicate that the tested substituted 2-aminothiophenes can be used as precursors for new antifungal drugs development.