Decoding the Bioactive Profile of Lawsonia inermis: Phytochemical and Spectroscopic Analysis with Antibacterial Implications

Introduction: Lawsonia inermis has long been recognized in traditional medicine for its bioactive compounds. The growing threat of antibiotic resistance necessitates the exploration of plant-based antibacterial agents as alternatives to conventional antibiotics. The present research focuses on investigating the antibacterial potential of Lawsonia inermis (henna) leaf extracts against various bacterial species, evaluating their phytochemical profile and chemical composition. Methods: Phytochemical screening of ethanolic and aqueous leaf extracts was conducted to detect the presence of bioactive compounds such as carbohydrates, steroids, quinones, flavonoids, tannins, and phenolic compounds. The antibacterial activity of the extracts was evaluated using the disc diffusion method against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. Advanced spectroscopic techniques, including XRF and UV-visible spectroscopy, were used to confirm the chemical composition and absorbance characteristics of the extracts. Results: The phytochemical analysis revealed higher concentrations of steroids and anthraquinones in the ethanolic extract. FTIR spectroscopy revealed the presence of key functional groups in Lawsonia inermis extracts, including hydroxyl, carbonyl, and aromatic compounds. These findings confirm the presence of bioactive constituents such as flavonoids, quinones, and terpenoids, which contribute to medicinal properties of the plant. The ethanolic extract exhibited superior antibacterial activity, with the largest zone of inhibition (9.1 ± 0.002 mm) recorded against Klebsiella pneumoniae. Spectroscopic analysis identified elements such as sulfur (S), carbon (C), calcium (Ca), and iron (Fe) in the bioactive compounds of the extracts. Discussion: These findings confirm the presence of bioactive constituents such as flavonoids, quinones, and terpenoids, contributing to the medicinal properties of the plant. Spectroscopic analysis has revealed that the hydroxyl and quinone groups are essential for antimicrobial and antioxidant effects. Conclusion: Lawsonia inermis demonstrates significant antibacterial potential, particularly in its ethanolic leaf extract, making it a promising source of natural antibacterial agents. The study highlights the need for further research to isolate and characterize specific bioactive compounds responsible for its antimicrobial effects. This underscores the role of plant-based treatments as an alternative strategy to combat the global challenge of antibiotic resistance.