Biological quality and phytochemical profiling of olive fruits using gas chromatography–mass spectrometry (GCMS) analysis

Abstract

The quality of olive fruit (OF) is widely affected due to geographical variation, affecting OF's chemical composition and biological properties. It is a novel and first-time study to evaluate the quality variation of 42 olive samples from different geographical origins based on phytochemical profile and their biological activities. The study reports the presence of unique chemical markers responsible for the difference in quality and biological activity of the olive samples. Biological activity (cytotoxic and antimicrobial) with GCMS phytochemical profile was evaluated. GCMS analysis confirmed the presence of 111 volatile compounds from various chemical classes with range (%) and average (%): esters (21.61–60.49) and 44.62, alcohols (20.73–49.2) and 38.06, hydrocarbons (3–38.88) and 15.39, ketones (0.16–3.87) and 0.75, acids (0.07–2.62) and 0.27, and aldehydes (0.12–1.47) and 0.45. The predominant ester was 13-methyl-pentadecanoic acid methyl ester, a differentiation marker between these samples. Cytotoxicity assay showed a significant inhibitory effect against MCF7 (8–64%) and HCT116 (0.11–44%) cell lines, whereas the extracts with the highest cytotoxicity observed were O17 (52.00 ± 2.00) and O25 (64.00 ± 4.88). The antimicrobial activity exhibited a range of zones of inhibition (mm) against P. aeruginosa (0.00–17.00), E. coli (0.00–15.00), S. aureus (0.00–13), and resistant S. aureus, i.e., MRSA (0.00–12.00). The extracts with the highest antimicrobial activity, i.e., O8 and O39 had identical MIC and MBC of 12.5 and 25 µg/ml against P. aeruginosa. In contrast, an MIC (50 and 25) and MBC (100 and 50) against E. coli were determined for O39 and O8. The statistical PCA and K-mean cluster analysis (P < 0.05) confirmed the presence of a high number of esters, alcohols, and hydrocarbons in GCMS data. Moreover, O8, O23, O25, and O39 were suggested as comparatively better varieties than those OF samples (P = 0.001). The presence of distinct volatile markers in these 42 OF samples may be further studied as a potential source of antimicrobials, food preservatives and therapeutic purposes.Graphical abstract