Identification and Quantification of Phenolic Compounds by HPLC-DAD and Bioactivity Assay of Acacia nilotica

Acacia nilotica, a versatile plant with diverse medicinal properties, has gained significant attention in recent years. This study focuses on the identification and quantification of phenolic compounds in various parts of A. nilotica, including leaves, stem, and roots, using a high-performance liquid chromatography with a diode-array detector (HPLC-DAD) method. The investigation reveals the presence of 10 bound phenolic compounds in different parts of A. nilotica, employing the base hydrolysis method, while seven free phenolic compounds are quantified using an ultrasonic-assisted extraction technique, i.e. sonication. Furthermore, the study explores the bioactivity of these phenolic compounds through DPPH radical scavenging assays, showcasing their antioxidant potential, with values ranging from 41.31 to 150.49 μmol/100g quercetin equivalents. Notably, the stem exhibits higher concentrations of absolute flavonoids (42.77 mg/g) and total tannins (33.61 mg/g) compared to other plant parts. Additionally, the antimicrobial properties of A. nilotica extracts are evaluated against two distinct microorganisms, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The results demonstrate significant antimicrobial activity against both types of bacteria. Among the plant’s components, the leaf extract exhibits the highest antimicrobial activity, with an inhibition zone of 2 mm at a concentration of 10 µg/mL. The selected samples are good sources of phenolic compounds as well as bioactive compounds with promising antioxidant and antimicrobial properties. These findings contribute to a deeper understanding of the therapeutic potential of A. nilotica and may pave the way for its utilization in various pharmaceutical and healthcare applications.