Development of microemulsion based on garlic oil (Allium sativum L.) and evaluation of its antioxidant action

Garlic oil is commonly used as an antimicrobial agent, antioxidant, as a blood pressure controller, and diabetes besides its use as food seasoning. Its use in natura is quite normal for many purposes, although, its typical smell, and the lack of the garlic oil made with technologies that can make it viable the best use of this product, make it even harder the frequent use of this bioactive compound. The scented garlic oil was bought at Mundo dos Óleos in Brasilia, and the surfactant Tween 80 (tense active) bought at Dinâmica. The micro emulsion was formulated according to the research made by Ragavan (2017) and is composed by two stages, the emulsion’s preparation through mixing the oil and the surfactant (Tween 80) in different proportions (3:1:6, 2:1:7, 1:2:7) followed by the addition of deionized water , using magnetic blender at 754, 812 and 870 rpm respectively for 10 minutes at 25°C. Right after that it was emulsified with a sonicator at 25 kHz, every 30 minutes with maximum power of 750 W immerged in cold water (from 4,3 to 3,8°C). Micelles were found in an analysis made with a microscope, CG/MS and infrared readings made with the pure oil were done in order that it was possible to identify and quantify the active structures from the bio compound, as well as the antioxidant activity was made by DPPH. The statistical analysis will be done by varianic analysis (ANOVA), followed by Bouferroni’s test from STATA program. The data obtained by CG/MS showed the most plentiful compounds in garlic oil, which were identified within 4,3 minutes in the retention time, that is the compound named 3-Vinyl-1,2-dithiacyclohex-5-ene. The second peak shown in the 8 minute retention time chromatogram is 3-Vinyl-1,2-dithiacyclohex-4-ene. The results obtained through the statistical analysis showed that samples 1 (92.1 ± 1.8s) and 2 (55.2 ± 1.3s) obtained a better antioxidant result of mean and standard deviation compared to sample 3 (43 .1 ± 2.6s), until the 5th minute of the analysis the samples showed more than 50% of efficiency, however in the sample 3 it is possible to verify an expressive antioxidant activity but it significantly decays after 5 minutes of analysis. After reading the absorbance of the pure oil to evaluate its antioxidant capacity, it is possible to notice a reduction of more than 30% in its antioxidant function if we compare it with the micro emulsified samples according to the mean data and standard deviation 33.1 ± 1.1s identified in the statistical analysis. The results obtained in infra-red showed peaks that indicate sorbate-based components according to the equipment library, this component is characteristic of the surfactant, the absence of identification of organic compounds by infra-red shows that the micellar walls formed protect the compound and preserve the antioxidant activity. Therefore, based on the data obtained so far and after evaluating the comparison of the results, there was a substantial improvement in the antioxidant function when compared to the compound in its pure form.