ABSTRACT
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.
ABSTRACT
Objective To assess the antioxidant and anti-inflammatory activities as well as to determine the flavonoids and phenolic acids content of active fractions. Methods Two medicinal plant samples were extracted successively in Soxhlet apparatus with n-hexane, dichloromethane, acetonitrile, ethyl acetate, methanol and n-butanol. Five methods were used to evaluate the antioxidant activity. Anti-inflammatory activity was done through the inhibition of the cyclooxygenase enzymes (COX-1 and COX-2). Polyphenolic compounds were analyzed by using a spectrophotometrical and high performance liquid chromatography-mass spectrometry (HPLC-MS) methods. Results The data showed that the stem leaves extracts of Commiphora africana and Loeseneriella africana possessed significant in vitro antioxidant and anti-inflammatory activities. Polar extracts had radical scavenging effects and they reduced iron (III). The prostaglandin production was significantly stopped by acetonitrile and methanol extracts. These biological activities were supported by some bioactive compounds quantified by using the HPLC-MS. p-Coumaric acid, ferulic acid, isoquercitrin, quercitrin, quercetin, rutin, kaempferol and apigenin were the most metabolites quantified. Conclusions The present study may explain the effectiveness of plants in traditional medicine of Burkina Faso, singularly Commiphora africana and Loeseneriella africana. The next investigation was to sub-fractionate the methanol fraction in order to isolate new antioxidant and/or anti-inflammatory compounds.