The total concentration of phenolic compounds found in essential oil samples are presented in Table 1, and a decrease in phenolic content concentration in the following order was found: clove > thyme > tea tree > rosemary. Excepting the rosemary oil, all oils were found to have different phenolic levels, ranging from 0.034 to 1.136 mg·GAE/g·DW, which can play a vital role in the increase of food shelf-life. The clove oil has the highest content of phenolic compounds.