Extraction, Optimization and Characterization of Aloe Vera Oil from Aloe vera leaf and Evaluate Antimicrobial Activity

Abstract

Aloe Barbadensis Miller, commonly known to as aloe Vera, is belonging to family Liliaceae of aloe, one of more than 400 species that originated in South Africa, but have been indigenous to dry subtropical and tropical climates, including the southern USA. The objective of this research work was extraction, optimization and characterization of aloe Vera oil as well as evaluation of antimicrobial effect. The extraction was carried out using Soxhlet extraction method and separated from solvents by using rotary evaporator. The proximate analysis of Aloe vera leaf was revealed that of moisture content 94.72±0.13%, proteins 10.86±0.06%, crude fiber 70.56±0.33% fat content 3.0±0.08%, and ash content 12.88± 0.04%. The minerals analysis were indicated that potassium is the dominant one then the sodium, magnesium, iron and zinc in aloe vera leaves. Response Surface Methodology with composite center design was employed to optimize the extraction temperature (A), aloe vera meal to solvent ratio (B) and extraction time(C) and 20 experimental runs were performed for aloe vera oil extraction. As a result, a polynomial regression model equation was fitted as follows: Yield = 20.0182 -1.025 * A + 0.85 * B + 0.825 * C -1.53125 * AB + 0.96875 *AC -5.92045 * A^2 -1.04545 * B^2 - 1.42045 * C^2. The optimal extraction temperature, aloe vera powder to solvent ratio and extraction time were found to be 74 ºC, 1:11.6mg/ml and 4.27 hours respectively. The maximum oil yield was found to be 20.413%. Physiochemical property of aloe vera extracted oil at optimum conditions was specific gravity, pH, kinematic viscosity, density, acid value and saponification value were analyzed by ASTM method. FT-IR analysis was used for the identification of the functional group of carbohydrate, carbonyl, alkene, aromatic, alkane, aliphatic amine, carbocyclic, alcohol and methyl ester. Gas chromatography-Mass spectroscopy analysis indicated the presence of major free fatty acids linoleic acid, oleic acid, palmitic acid and stearic acid. The aloe vera oil also have secondary metabolites of alkaloids, anthraquinones, flavonoid, saponins, phenolic compounds, tannins and Terpenoids existence were showed good antimicrobial activity against of gram positive bacteria of Staphylococcus aureus and Bacillus subtiles; gram negative bacteria of Pseudomonades aerginosa and Salmonella typhus; fungus of Aspergillus Niger and Candida albicans.