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

Abstract

BACKGROUND: Aloe vera is a popular medicinal plant used widely by the cosmetic, pharmaceutical, and food industries. 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 aloin content, their antioxidant activity by 2,2 0-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS •+) and the 2,2-diphenyl-1-picrylhydrazyl radical (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 −1) of the EU legislation however, the unprocessed and unfiltered samples were found to contain more than 10 mg L −1. Antioxidant activity was estimated to vary from 1.64 to 9.21 ∼mol Trolox mL −1 for DPPH • and from 0.73 to 5.14 ∼mol Trolox mL −1 for ABTS •+. Toxicity values on A. fisheri, expressed as the concentration at 50% loss of initial luminescence, ranged from 0.03 to 0.09 mg mL −1. The cytotoxic study indicated that aloin A at low concentrations (1 and 10 ∼g mL −1) protects SH-SY5Y cells from toxicity induced by hydrogen peroxide. CONCLUSIONS: Consequently, the filtration process of A. vera leaf gels, either laboratory or industrial, resulted in aloin A content below the EU legislation detection limits.

Effects of Heteroatom Doping of Carbon Dots from Sugar on Optical Properties, Phenolic Content, Antioxidant Activity, Photostability, and Cytotoxicity

“…Therefore, antioxidants have been widely used in cancer patients or added in dietary supplements. In addition to pharmaceutical industries, antioxidants are also widely used in cosmetics [37–40] . Antioxidants in cosmetics can protect the skin from free radical damage.…”

“…In addition to pharmaceutical industries, antioxidants are also widely used in cosmetics. [37][38][39][40] Antioxidants in cosmetics can protect the skin from free radical damage. There are many types of antioxidants in cosmetics, such as L-ascorbic acid and coenzyme Q10.…”

Overview of Viral Pneumonia Associated With Influenza Virus, Respiratory Syncytial Virus, and Coronavirus, and Therapeutics Based on Natural Products of Medicinal Plants

“… Huang et al (2019) conducted a study to investigate the efficacy of aloin, which is contained in Aloe vera (L.) Burm.f., to reduce virus load in the lungs. Yet, it is worth noting that aloin was reported to be the most toxic in all the compounds of A. vera , and related institutions have introduced the safety usage guideline on recommending acceptable amounts of aloin in pharmaceuticals and food ( Kaparakou et al, 2021 ). Since 2002, the FDA has suggested that it should not exceed 10 mg L −1 aloin in A. vera products when used as food or as a dietary supplement.…”

Temperature and pH Stability of Anthraquinones from Native Aloe vera Gel, Spray-Dried and Freeze-Dried Aloe vera Powders during Storage

“…It was also found that aloe-emodin and emodin are highly prone to acidic and hydrolytic degradation, moderately prone to oxidative and thermal degradation (105 °C) and least prone to basic degradation [ 19 ]. Anthraquinone concentrations vary greatly depending upon climatic conditions, species, and even within various parts of the same plant [ 11 , 20 , 21 ]. Chang and colleagues [ 22 ] reported instability of polysaccharides and barbaloin upon heating and in various solvents, respectively, though exact mechanisms of hydrolysis remain unclear.…”