Gas Chromatography‑Mass Spectrometric Determination of Components of Leaves of Aegle marmelos and Psidium guajava and Seeds of Nigella sativa and Correlation with In vitro Antioxidant Activity

Objective: The aim of this study is to analyze the volatile components of the leaves of Aegle marmelos, Psidium guajava, and seeds of Nigella sativa, using gas chromatography‑mass spectrometric (GC‑MS) and correlate with their in vitro antioxidant activity. Materials and Methods: Plant material was analyzed for heavy metal content (HMC), pesticide residue (PR), and the presence of microbes/ fungi. Following hydrodistillation, the volatile components (AM, PG, and NS) were subjected to GC‑MS analysis and in vitro antioxidant assay (2,2‑diphenyl‑1‑picrylhydrazyl). Results: The plant material passed the test for HMC, PR, microbial, and fungal contamination. Using GC‑MS, the number of compounds identified in AM, PG, and NS were 62, 46, and 58, respectively. The antioxidant activity of AM, PG, and NS was 98.538%, 98.955%, and 97.755%, respectively. Conclusion: GC‑MS‑based methods can be successfully utilized for phytochemical profiling and standardization of plant material.