<b>Phytochemical Screening, Antibacterial and Toxicological Activities of <i>Acacia Nilotica</i> Extracts</b>

Abstract

The phytochemical screening, antibacterial and toxicological activities of extracts of the leaves, stem bark and roots of Acacia nilotica were investigated. The phytochemical analyses according to standard screening tests using conventional protocols revealed the presence of tannins and sterols in the leaves stem barks and roots of the plant. Alkaloids were detected only in the leaves. Glycosides, saponins, resins and flavonoids were not detected in the plant. In-vitro agar-diffusion sensitivity tests of crude extract fractions of the plant extracts using ethanol, chloroform, methanol, petroleum ether, water and ethyl acetate were investigated on nine bacterial isolates. The extract fractions generally exhibited marked antibacterial activities on Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris, Salmonella typhi, Shigella dysenteriae Staphylococcus aureus and Escherichia coli except on Streptococcus pneumoniae and Streptococcus pyogenes. All the leaves extract fractions of the plant exhibited weak or no antibacterial activity on the bacterial isolates tested but the stem bark and root extracts generally exhibited strong antibacterial activities on them. The minimum inhibitory concentration and minimum bactericidal concentration studies revealed that some bacterial isolates were inhibited at concentrations of about 12.5mg/ml and 50mg/ml and killed at concentrations of about 100mg/ml and 400mg/ml. Toxicity studies of the ethanol extracts revealed that they exhibited no significant toxicity (LD 50 of 123.86µg/ml and312.55µg/ml) against Artemia salina . These results suggest that the plant may not be toxic to man and could be a potential source of novel antibacterial compound.

Antibacterial Activities and Possible Modes of Action of Acacia nilotica (L.) Del. against Multidrug-Resistant Escherichia coli and Salmonella

“…This indicated a strong antibacterial potential of A. nilotica against the antibiotic-resistant pathogens tested here, arguably with a novel mechanism of action than other tested antibiotics. The antibacterial results of the current study are in accordance with literature, where extracts of A. nilotica were effective against clinical bacterial isolates of E. coli and Salmonella [ 20 , 21 ].…”

“…The MIC values of acacia leaves and bark extracts against multidrug-resistant E. coli were lower in the current study than previously reported for E. coli , causing otitis infection [ 22 ]. The leaves and bark extracts in the current study also showed lower MIC value against Salmonella typhimurium than previously reported for Salmonella typhi [ 21 ]. The reported differences might be due to different strains of E. coli and Salmonella , and/or different experimental protocols.…”

Inhibitory Effects of Pod Extract of Acacia Nilotica Against Some Pathogenic Bacteria

“…The zones of inhibition exhibited by the crude extract against the test isolates ranged between 10 mm and 18 mm. The results support previous reports on the antibacterial activity of this plant (Banso, 2009;Okoro et al, 2014;Abdulhamid et al, 2019). Thus, the pod extract of Acacia nilotica appears to be a potential source of antibacterial compounds that could be relevant in the treatment of infections caused by these organisms.…”

Seed oil composition of Acacia nilotica (L.) Delile from Iran

“…The use of oil from the seeds is of potential economic benefit to the poor native population of the areas where it is cultivated. Despite that previous studies reported that the different parts of the plant were not toxic to human [12], the seed oil of A. nilotica could be a new source of edible vegetable oil after the future toxicological studies. The 26-ethylcholesta-5,25(Z)-dien-3.β-ol structure was elucidated just by mass spectra and the most possible and inexhaustible structure was determined for this phytosterol.…”