Evaluation of bioactive potential of an aloe vera sterol extract

We prepared a crude gel material from Aloe vera succulent leaf tissues. The ethanolic extract of lyophilized A. vera gel was used for the GC-MS analysis. Hexadecanoic acid (22.22%) was identified as major compound. Sitosterol and stigmasterol were found to be 2.89% and 2.1% in the extract. HPLC analysis was carried out to confirm the presence of stigmasterol. The concentration of sterol extract needed to scavenge DPPH free radical by 50% was calculated as 5.2 mg mL^-1. In the FRAP assay, the sterol extract showed significant hydroxyl radical scavenging in a dose-dependent manner (IC₅₀ value 1.17 μg mL^-1). Concentration of the sample required to reduce lipid peroxidation was found to be 4.18 μg mL^-1, and the extract also possessed acetylcholinesterase activity (IC₅₀ - 5.26 μg mL^-1). Catalase activity was 0.196 μM H₂O₂ decomposed min^-1 μg^-1 protein, whereas the peroxidase activity was 17.01 μM of pyragallol oxidized min^-1 μg ^-1 protein. The extract recorded higher activity against growth of S. greseus and C. albicans in the experiments carried out to determine antibacterial and antifungal activity, respectively.