Phytochemical screening, phenolic determination and antibacterial activity of the extracts of Bridelia scleroneura Muell. Arg. (Euphorbiaceae) from Chad

Abstract

Bridelia scleroneura Müll. Arg. is traditionally used in the southern part of Chad to treat diabete, hypertension and anemia. This study reports the chemical composition of B. scleroneura leaves, barks twigs extracts and their polyphenols contents and also their antibacterial activity. Phytochemicals were assessed by phytochemical screening and spectrophotometry. The microdilution method was used to evaluate the antibacterial activity of extracts against Staphylococcus aureus (ATCC25923 /ATCC43300), Streptocococcus pneumonia (ATCC461916), Pseudomonas aeruginosa (HM801), Klebsiella pneumonia (clinical isolate), Salmonella typhi (clinical isolate) and Eschierichia coli (clinical isolate). The extracts showed the presence of alkaloids, saponins, terpenes, steroids, polyphenols, tannins, quinones and flavonoids. The flavonoid content is higher in the leaves, tannin and polyphenol contents are higher in the barks. The antibacterial tests indicated that the bark extract exhibited a significant activity on Staphylococcus aureus.

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

“…The optical density was obtained by a spectrophotometer (Thermo Scientific Evolution 300) at 760 nm against the blank (0.5 mL of Folin–Ciocalteu reagent and 0.5 mL of sodium carbonate). The test was carried out twice, and the outcome was represented as mg of gallic acid (Sigma-Aldrich) equivalents per 100 mg of extract (mg GAE/100 mg extract) [ 13 ].…”

“…The presence of flavonoids was established by the yellow stable coloring that corresponded to the production of a flavonoids-(Al 3+ ; 3Cl − ) complex in comparison to quercetin, which was quantified spectrophotometrically at 415 nm (Thermo Scientific Evolution 300). Based on a linear calibration curve made up with quercetin (Sigma-Aldrich) concentrations ranging from 0 to 100 mg/L, the total flavonoid levels in extracts were determined and expressed in mg quercetin equivalents (mg QE)/100 mg of dry extract [ 13 ].…”

“…After the hydrolyzed tube had cooled, a spectrophotometer was used to measure the optical density at 550 nm (Thermo Scientific Evolution 300). The optical densities were used to calculate the total tannin contents and expressing the results in g/L [ 13 ]. The following formula was used to calculate the total tannin content: C = 19.33 (Doh-Dot) where C is the content of total tannins expressed in g/L, Doh is the optical density of the hydrolyzed tube, and Dot is the optical density of the control tube.…”