Antioxidant and antimicrobial activity of essential oil from round kumquat (Fortunella japonica) peel using supercritical CO2 extraction

In this study, the highest oil yield of kumquat peel essential extraction 3.89±0.03% was achieved under supercritical carbon dioxide (SC-CO2) condition including 250 bars, 50°C, fluid rate 20 g/min and 120 min extraction. Limonene comprising 39.25% main component oil. It showed 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical (ABTS•+) scavenging activity ferric reducing antioxidant power (FRAP) value 25.29±0.17mM Trolox equivalent (mM TE)/g dry weight 6.25±0.15 mM TE/g weight, 4565 4623 folds lower than those vitamin C, respectively. Inhibition zone diameter (IZD) pure equaled to that (i) 9.2 µg/mL Ampicillin solution against Bacillus subtilis, (ii) 23.4 Staphylococcus aureus, (iii) 7.2 Streptomycin Klebsiella pneumoniae, (iv) 35.1 Amikacin Pseudomonas aeruginosa, (v) 37.7 Proteus mirabilis. Meanwhile, minimal inhibitory concentration (MIC) 5 mg/mL for B. subtilis 10 rest bacteria.