In Vitro Anti-Shigella, Antioxidant Activities, and Oral Acute Toxicity of Organics Extracts from the Root Bark of Detarium microcarpum Guill. and Perr.

Detarium microcarpum (Fabaceae) is a medicinal plant from the traditional pharmacopeia of Niger used against gastrointestinal disorders and dysentery. This study was designed to assess the in vitro anti-shigella, antioxidant activities, and oral acute toxicity of extract root barks of Detarium microcarpum. The crude extracts were prepared by maceration using methanol, ethanol, dichloromethane, water-ethanol (30/70 v/v), and methanol-dichloromethane (1/1 v/v). The anti-shigella activity was performed using the microdilution method coupled with the resazurin-based assay. The antioxidant activity was evaluated by the DPPH· (2, 2-diphényl-1-picrylhydrazyl), ABTS 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), and H2O2 assays. The oral acute toxicity was assessed following the Organization for Economic Cooperation and Development (OECD) guidelines. The extracts displayed activity against the Shigella boydii with Minimum Inhibitory Concentrations (MICs) from 500 to 1000 µg/mL. The methanolic crude extract of D. microcarpum shows good antioxidant activity with the radicals DPPH· and ABTS with inhibitory concentration 50 (IC50) at 228 and 191 µg/mL, respectively. The lethal dose 50 (LD50) of extract was up to 2000 mg/kg of body weight, and no signs of toxicity were observed. These findings supported the use of Detarium microcarpum in the traditional treatment of gastrointestinal disorders.

Antibacterial Activity of Eight Medicinal Plants from the Traditional Pharmacopoeia of Niger.

The emergence of multidrug bacterial resistance poses a great public health problem and requires a constant search for new antibacterial agents. However, Niger's flora possesses several medicinal plants used in traditional medicine to cure infectious diseases and can be used as sources of bioactive ingredients. This current study was designed to evaluate the antibacterial activity of eight plants used in the traditional pharmacopeia of Niger. The extracts were prepared by maceration using ethanol, methanol, and distilled water. The obtained extracts were screened against Salmonella spp., Shigella spp., and Escherichia coli using the microdilution method coupled with a resazurin-based assay. Phytochemical screening was performed using colorimetry, while the quantification of total polyphenols, total flavonoids, and total tannins was determined by spectrophotometry. Out of the eight plants obtained, five named Cassia italica, Limeum pterocarpum, Phyllanthus pentandrus, Strychnos innocua, and Ximenia americanum exhibited antibacterial activity with MICs ranging from 500 µg/mL to 2000 µg/mL. Phytochemical screening showed the presence of alkaloids, saponosides, tannins, flavonoids, terpenes/sterols, quinones, and polyphenols. The ethanolic and methanolic extracts of X. americana contained important quantities of total polyphenols, with 43.59 ± 0.15 and 41.97 ± 0.02 mg EAG/100 mg of extract, respectively. These extracts showed the highest contents of total tannins at 46.49 g/L and 45.52 g/L, respectively. For total flavonoids, the highest content was obtained with the methanolic extract of P. pentandrus, with 3.12 ± 0.01 mg QE/100 mg of extract. These findings justify the uses of these plants in traditional medicine for the treatment of infectious diseases such as diarrhea and can be used as starting points for the development of phytodrugs against infectious diarrhea.