Antioxidant Cymbopogon efficiency ratio (ACE) = (citronellal + citronellol)/(citral + geraniol) to determine the antioxidant capacity of the genus Cymbopogon.

BACKGROUND: The essential oil (EO) of species of the genus Cymbopogon contains molecules with antioxidant activity such as the monoterpenoids citronellal, citronellol citral, and geraniol, which have non-phenolic characteristics and act as termination-enhancing antioxidants. The objective is to evaluate the antioxidant efficiency of citronella (Cymbopogon winterianus-CEO), lemongrass (Cymbopogon flexuosus-LEO) and palmarosa (Cymbopogon martinii-PEO) EOs directly on an oxidisable substrate (vegetable oil). The chemical composition was determined by gas chromatography coupled with mass spectrometry, and their antioxidant activity was determined by free radical scavenging activity (FRSA) and total phenol content (TPC). 0.2% g kg-1 EO was applied to sunflower oil, and chemical and volatile oxidation indicators were measured. RESULTS: FRSA and TPC yielded values of 31.12%, 26.34% and 11.98% and 15.63, 11.74 and 13.29 mg g-1 for CEO, PEO and LEO, respectively. For the directly measured antioxidant activity, it was observed that the antioxidant efficiency was: CEO > PEO > LEO. The application of the antioxidant Cympobopong efficiency ratio (ACE) = (citronellal + citronellol)/(citral + geraniol) fits adequately with values of 2.922, 0.317 and 0.052, respectively. The ACE results correlate with data on chemical and volatile oxidation (Pearson correlation of -0.92, -1.00 and - 0.97 for slopes of regression of peroxide value, hexanal y 2-heptenal), demonstrating that a higher ACE value indicates greater antioxidant protection. CONCLUSION: ACE can be used for the selection of industrial crops of the genus Cymbopogon with higher antioxidant efficiency. © 2026 Society of Chemical Industry.