Quantitative determination of aloin, antioxidant activity and toxicity of Aloe vera leaf gel products from Greece

Background: Aloe vera is a popular medicinal plant used widely by the cosmetic, pharmaceutical and food industry. The A. vera leaf gel which is used mostly for its positive effects on human health contains over 75 different bioactive compounds including aloin. Aloin is a toxic compound and its content in A. vera leaf gel products depends on the different cultivation conditions and especially on leaf processing.

Results: In this study A. vera leaf gel products, varied in terms of leaf processing, were analyzed using liquid chromatography for their content in aloin, their antioxidant activity by ABTS^•+ and DPPH^• antioxidant activity assays and their toxicity against Aliivibrio fisheri and SH-SY5Y cells. In the samples processed with industrial methods and in those filtered in the lab, the content of aloin was found below the limit (0.1 mg/L) of the European Union legislation however, the unprocessed and unfiltered samples were found to contain more than 10 mg/L. Antioxidant activity was estimated to vary from 1.64 to 9.21 μmol Trolox/mL for DPPH^• and from 0.73 to 5.14 μmol Trolox/mL for ABTS^•+ . Toxicity values on Aliivibrio fisheri expressed as EC₅₀ ranged from 0.03 to 0.09 mg/mL. The cytotoxic study indicated that aloin A at low concentrations (1 μg/mL and 10 μg/mL) protects SH-SY5Y cells from hydrogen peroxide-induced toxicity.

Conclusions: Consequently, the filtration process of Aloe vera leaf gels either laboratory or industrial resulted in content of aloin A below the European union legislation detection limits. This article is protected by copyright. All rights reserved.

Keywords: Aloe vera; Aloin; Antioxidant activity; Toxicity.