The use of medicinal plants in traditional medicine is a common practice in developing countries. However, this unregulated or poorly rational use may present a dose-dependent risk of toxicity to humans. This study aimed to explore the phytochemical and toxicological characteristics of ten (10) plant species used in the traditional treatment of infectious diarrhea in Benin. The acute toxicity of aqueous and hydroethanolic extracts of Khaya senegalensis, Daniellia oliveri, Rauvolfia vomitoria, Vernonia amygdalina, Manihot esculenta, Ocimum gratissimum, Senna italica, Diospyros mespiliformis, Pterocarpus erinaceus, and Anacardium occidentale was evaluated following the OECD 423 protocol at a single dose of 2000 mg/kg. This safety test was complemented by a larval cytotoxicity test. Hematological and biochemical examinations, as well as a histological study of the liver and kidneys, were performed. Larval cytotoxicity was assessed by the sensitivity of Artemia salina larvae to different concentrations of the plant extracts studied. Testing for chemical compounds was performed on the basis of differential staining and precipitation reactions. The mean lethal concentration (LC50) was determined by the probit method. The qualitative phytochemical screening of the plants studied revealed the presence of catechic tannins, gallic tannins, flavonoids, anthocyanins and sterol-terpenes, alkaloids, saponosides, and reducing compounds. This composition varied according to the plants studied. Acute toxicity data indicated that there was no mortality and no structural and functional alterations of the liver and kidneys of treated animals. Larval cytotoxicity data suggest that the plants studied are not cytotoxic (LC50 ≥ 0.1 mg/mL). These observations reflect the safety of these plants and justify their use in traditional medicine in the treatment of many diseases including diarrheal diseases.

Recent studies reported interesting ethnopharmacological, antibacterial, and phytochemical data on some medicinal plants used in the traditional treatment of salmonellosis in Benin. Unfortunately, very little data exists on the toxicity of these species. This study aims to evaluate chemical characteristic of six Benin pharmacopoeial plants used in the traditional treatment of salmonellosis in Benin. The acute toxicity of aqueous and ethanolic extracts ofPsidium guajava,Vernonia amygdalina,Cajanus cajan,Phyllanthus amarus,Uvaria chamae, andLantana camarawas evaluated according to OECD Guideline 423 at a single dose of 2000 mg/kg body weight on Wistar rats. Histological sections were performed on the liver and kidneys to confirm hematological and biochemical data. The content of aluminum, chromium, cadmium, copper, iron, lead, zinc, arsenic, selenium, and manganese was measured in 10 mg of each extract by the inductively coupled plasma optical emission spectroscopy (ICPOES) method. The results of our study generally show the absence of significant effect of the extracts on the hematological and biochemical parameters of the rats. However, with the exception of the aqueous and ethanolic extracts ofPsidium guajavaroot and the ethanolic extract ofPhyllanthus amarus(P>0.05), all the extracts have a significant effect on the aspartate aminotransferase (ASAT) level, with a variable threshold of significance (0.0001< P ≤ 0.05). No mortalities and no renal histological conditions were recorded in the treated rats. In general, the heavy metal contents of the extracts do not exceed the standards set by the WHO/FDA except for a few extracts. Arsenic was not detected in any extract, while aluminum and chromium were detected at levels above the WHO/FDA standards. On the basis of these data, it appears that the six plants studied do not show any toxicity. In view of the pharmacological and chemical data previously available, these plants are good candidates for the development of improved traditional medicines with antibacterial and particularly anti-Salmonellaproperties.

The rise in antimicrobial resistance increases researchers' interest in medicinal plants used for traditional treatment of infectious diseases. The study is based on ten (10) medicinal plants mostly cited in the treatment of diarrhea in West Africa: Khaya senegalensis, Anacardium ouest L., Cassia sieberiana DC., Pterocarpus erinaceus, Diospyros mespiliformis, Ocimum gratissimum, Manihot esculenta, Vernonia amygdalina Delile, Pseudocedrela kotschyi, Daniellia oliveri. The objective is to make a review on ethnopharmacological, pharmacological, toxicological and chemical data that enhance these medicinal plants in the fight against diarrheal infections. Specific keywords were used for bibliographic research in Google Scholar, Science Direct, PubMed Directory of Open Access Journals (DOAJ) and other databases. Generalities relating to diarrheal infections and scientific data on the ten selected plants in the fight against diarrheal infections were sought. From the results, it emerges that each of the ten plants has been listed as useful in the traditional treatment of diarrheal infections.

Previous work stated that Khaya senegalensis, Anacardium ouest L., Pterocarpus erinaceus, Diospyros mespiliformis, Ocimum gratissimum, Manihot esculenta, Vernonia amygdalina Delile, and Daniellia oliveri have a great potential for the fight against infectious diarrhea. However, data on their antibacterial activity on strains of bacteria responsible for infectious diarrhea are not available. This study is aimed at elucidating the mechanism of action of the antibacterial effect of these plants on some bacterial strains responsible for diarrheal infections. The design of the study included first evaluating the degree of sensitivity of Salmonella typhimurium 14028, Escherichia coli ATCC 25922, Shigella spp., and Salmonella spp. strains to aqueous and hydroethanolic extracts of each plant, followed by the determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibiotic power (Pa). This screening was completed with the evaluation of the possible mode of action of the extracts by testing the membrane permeability of these bacterial strains. The data collected indicate that the bacterial strains tested were sensitive to the extracts to varying degrees, except Cassia sieberiana DC and Pseudocedrela kotschyi extracts. For the active extracts, inhibition diameters ranged from 18.33 mm to 7 mm. With the exception of Escherichia coli, all strains were sensitive to the aqueous and hydroethanolic extracts of Anacardium occidentale. MICs vary between 3.37 and 25 mg/ml. Membrane permeability test data show that all active extracts affect the bacterial strains tested by attacking the stability of their outer membrane. For all active extracts, the high percentage of membrane destabilization of the bacteria is significantly ( p < 0.05 ) better than that of cefixime used as a reference. Thus, it appears that these extracts can destroy Gram-negative bacteria and increase the fluidity and permeability of their cytoplasmic membrane. The knowledge of the mechanism of action of these extracts is an interesting contribution to the fundamental knowledge on the alternative that medicinal plants represent to antibiotics. These extracts can be used in the management of infectious diarrhea.

The search for new bioactive molecules with antifungal properties to combat resistance to classical antifungals represents a great challenge. This study aimed to explore the virulence factors and resistance profile of Candida species isolated from urine samples in Benin and the in vitro efficacy of organic extracts of Cyanthillium cinereum (L.) H.Rob., Lippia multiflora Moldenke and Khaya senegalensis (Desv.) A.Juss. on the growth of these Candida spp. The study focused on Candida strains isolated from urine samples collected from patients admitted to the bacteriological analysis laboratories of hospitals in Southern Benin. The sensitivity of these strains to classical antifungal agents was determined by the simple diffusion method. Their pathogenicity was investigated via several virulence factors (gelatinase, hemolysin, hydrophobicity, adhesin, biofilm and lecithinase). The in vitro efficacy of the aqueous, ethanolic and hydro-ethanolic extracts of the plants on Candida albicans ATCC 90028 and on six clinical strains was evaluated by the method of determination of the inhibition diameters. The results obtained showed that 51 different Candida strains were isolated from the collected urine samples with a respective predominance of Candida albicans (52.94%) and Candida glabrata (17.64%) species. All identified species were sensitive to amphotericin B and nystatin but 20% are resistant to fluconazole and present 15 different resistance profiles. Six different virulence factors were identified with a high frequency of hydrophobicity (96.08%) and adhesin (94.12%). Antifungal tests revealed that at 100 mg/mL the plant extracts were active on the tested strains with better activity for Cyanthilium cinereum and Khaya senegalensis. Cyanthilium cinereum, Khaya senegalensis and Lippia multiflora showed antifungal activity on virulent Candida strains suggesting the possibility to explore them further for the discovery of new antifungal molecules.