Phytochemical Profiling and Bioactivity Evaluation of Lawsonia inermis Leaf Extract Against Antibiotic-Resistant Bacteria and Antioxidant Activity

Lawsonia inermis (henna), a medicinal plant rich in bioactive secondary metabolites, has long been used in traditional medicine for its antimicrobial and antioxidant properties. The present study aimed to evaluate the phytochemical composition, antioxidant efficacy, and antibacterial activity of L. inermis leaf extracts against clinically relevant antibiotic-resistant bacteria. Leaves were extracted successively using diethyl ether, methanol, and hexane, followed by qualitative phytochemical screening. Among the extracts, the methanolic fraction exhibited the richest profile of bioactive constituents such as phenols, tannins, flavonoids, saponins anthocyanin, coumarins, terpenoids, steroids, quinones and was therefore subjected to GC–MS analysis, antibacterial efficacy, and antioxidant evaluation. GC–MS profiling of the methanolic extract revealed the presence of major compounds such as methyl-α-D-galactopyranoside, 1,6-anhydro-β-D-glucopyranose, phytol, N-hexadecanoic acid, and polyunsaturated fatty acids, many of which are associated with antimicrobial and antioxidant activities. Antibacterial activity, assessed by disc diffusion assay, demonstrated a concentration-dependent inhibitory effect against Staphylococcus aureus, Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae, with the strongest activity observed against S. aureus. S. aureus showed susceptibility, exhibiting a 3 mm inhibition zone at 20 µg/ml, followed by 4mm at 40 µg/ml, and 5mm at 80 µg/ml. Antioxidant potential, evaluated using the DPPH radical scavenging assay, showed significant free radical scavenging activity, in some cases exceeding that of the standard antioxidant L-ascorbic acid. At the highest concentration of 80 μg/ml, the scavenging activity was 34.21 ± 1.61, whereas it was 23.05 ± 0.31in L-ascorbic acid. Overall, the findings indicate that the methanolic extract of L. inermis possesses notable antioxidant and moderate antibacterial activities, attributable to its rich phytochemical composition. This study supports the potential of L. inermis as a natural source of bioactive compounds for developing alternative antimicrobial and antioxidant agents, particularly in the context of rising antibiotic resistance.