Integrated Phytochemical, Antioxidant, and Chemometric Evaluation of Clinically Relevant Ocimum tenuiflorum Extracts from Diverse Geo-Climatic Regions

Background/Objectives: Ocimum tenuiflorum (OT) exhibits diverse therapeutic effects linked to its antioxidant activity. Studies integrating phytochemical variability, functional antioxidant localization, and chemometric evaluation of Pharmacopeia-Relevant Extracts (PREs) remain limited. This study investigated phytochemical variability and antioxidant-associated profiling among PREs of OT from geo-climatic regions and commercial sources. Methods: PREs were investigated through High-Performance Thin-Layer Chromatography (HPTLC) fingerprinting, HPTLC-2,2-diphenyl-1-picrylhydrazyl (DPPH) bioautography, HPTLC quantification, Total Phenolic and Flavonoid Content (TPC and TFC), DPPH-IC50 and Ferric Reducing Antioxidant Power (FRAP) assays, correlation statistics, and chemometric analyses. Results: Rosmarinic acid (RA) and ursolic acid (UA) were detected across all PREs; eugenol was not detected but detected in non-polar extracts. HPTLC-DPPH bioautography exhibited antioxidant-associated localization for RA but not UA. RA concentration, TPC, TFC, DPPH-IC50, and FRAP showed substantial variability among PREs. RA correlated more strongly than TPC with antioxidant endpoints: positively with FRAP and inversely with DPPH-IC50; TFC correlated non-significantly with the dataset. Geo-climatic variability was linked to differences in RA, TPC, IC50, and FRAP, with TFC not reaching significance, and varietal differences remained non-significant. Chemometric analyses demonstrated distinguishable clustering among PREs. Conclusions: This study highlights observational trends in geo-climatic phytochemical variation, identifying RA as a major antioxidant-associated marker under the present conditions.