LAWSONE: AN INTEGRATED REVIEW OF CHEMICAL RESEARCH, ANALYTICAL TECHNIQUES, AI APPLICATIONS, AND SAFETY

ABSTRACT Lawsone is a naturally occurring naphthoquinone mainly obtained from the leaves of Lawsonia inermis (henna). It is responsible for the characteristic orange-red colour of henna and has attracted interest because of its chemical reactivity, natural origin, analytical importance and biological properties. Chemically, lawsone is known as 2-hydroxy-1,4-naphthoquinone and contains a conjugated quinone system with hydroxyl and carbonyl functional groups. This review summarizes the botanical sources, chemical composition, synthesis, physicochemical properties and major analytical techniques used for lawsone. TLC, HPTLC, HPLC, UV-Visible spectroscopy, FT-IR, LC-MS/MS, GC-MS and NMR techniques are discussed for identification and quality assessment. The application of artificial intelligence and machine learning in chemical and analytical research is also highlighted. Safety aspects of lawsone and henna preparations are briefly discussed. Overall, lawsone remains an important natural quinone with applications in pharmaceutical, cosmetic, analytical and organic chemical research.