Phytochemical Profiling and Spectroscopic Elucidation of a Terpenoid from Nigella sativa Seeds

The present study focuses on the extraction, isolation, and structural characterization of bioactive constituents from the ethyl acetate extract of Nigella sativa (black seed). Using Soxhlet extraction and silica gel column chromatography, ten fractions (A–J) were obtained, with fraction F showing significant similarity to the standard terpenoid (carvacrol) based on thin-layer chromatography (TLC) with an Rf value of 0.64. UV-Visible spectroscopy of fraction F revealed a λmax at 292 nm, indicating aromatic characteristics. FTIR analysis confirmed the presence of phenolic terpenoids. 1H NMR spectra indicated the presence of methyl, isopropyl, and aromatic protons, while mass spectrometry confirmed the molecular ion peak at m/z 150.2000, corresponding to the compound 2-methyl-5-(propan-2-yl)phenol (C₁₀H₁₄O). This study validates the presence of pharmacologically relevant terpenoids in N. sativa and supports its traditional medicinal applications. The identified compound can serve as a potential lead for future drug development due to its reported antioxidant and antimicrobial properties.