Antioxidant activity of true aloe (Aloe vera) extract in model systems

Abstract

SummaryBackground. Aloe contains numerous bioactive compounds which are attributed to have health advantages. Widely used in the cosmetic and pharmaceutical industries, also found its application in the food industry. The antioxidant compounds in aloe may increase the stability and nutritional value of food. The aim of the paper was to evaluate the results of the antioxidant properties of aqueous extract of aloe in model systems. Material and methods. Analyses were conducted on true aloe (Aloe vera L.). Extraction was run using water at temperature 80-90°C. The level of phenolics was determined spectrophotometrically with the Folin-Ciocalteu reagent, using gallic acid as a standard. Antioxidant activity of extract was analysed in relation to linoleic acid, running incubation for 19 h, by scavenging of stable radical DPPH (2,2-diphenyl-1-picrylhydrazyl) and cation radical ABTS (2,2'-azino-bis[3--ethylbenzothiazoline-6-sulfonic acid]) and on the basis of metal chelating ability. Recorded results were compared with the activity of BHT (butylated hydroxytoluene). Results. The total phenolic content of water extract of aloe was 17.85 mg/g d.m. The extract exhibited concentration-dependent DPPH and ABTS radical scavenging activity. The ability was in the range of 4.32-8.87 and 0.58-0.87 mg of trolox per 1 g d.m., respectively. A lower chelating ability of the aloe extract was 1.23 mg EDTA per 1 g d.m. at 20 mg/ml concentration and the higher was 8.76 mg EDTA per 1 g d.m. at 10 mg/ml concentration. The aloe extract reduced levels of the conjugated dienes in the emulsion system. The samples with additions of 0.1-0.5 mg/ml extract contain over 90% less of dienes than control sample. The addition of 0.05 mg/ml and 0.06 mg/ml results in significantly lower (40% and 57%, respectively) activities of the aloe extract.Hęś, M., Dziedzic, K., Le Thanh-Blicharz, J., Kmiecik, D., Górecka, D. (2016). Antioxidant activity of true aloe (Aloe vera) extract in model systems. Nauka Przyr. Technol., 10, 4, #53. DOI: http://dx.doi.org/10.17306/J. NPT.2016.4.53 2 Conclusions. The extract of aloe showed different antioxidant properties in various model systems. The available literature on the antioxidant potential of aloe is still rather scarce. Due to the complex composition and broad activity of aloe, raw material should be further studied.

Dielectric barrier plasma effect on surface functionality and coating properties of ultrasonically coated cotton with ZnO nanoparticles and Aloe vera extraction

“…7b, the optical band gap was obtained by extrapolating a straight line to the Tauc plot. The optical band gap of ZnO nanoparticles was estimated about 3.47 eV, which is in good agreement with the published literature (Ibrahim et al 2017;Hęś et al 2016;Kasaai 2013;Zhu et al 2014). At room temperature, ZnO shows a band gap of 3.37 eV at an absorption peak of 375 nm.…”

“…Aloe Vera extract has greater antibacterial properties against bacteria (Ibrahim et al 2017). Aloe vera contains polyphonls, anthranoids and mineral components (chromium, calcium, iron, manganese, phosphorus, potassium and zinc) as well as vitamins (C, E, B1, B2, B3, B6, B12 and folic acid) (Hęś et al 2016;Kasaai 2013). Therefore, to impart excellent antibacterial properties and laundering durability, cotton fabric can be treated with DBD plasma and Aloe vera gel and coated with ZnO nanoparticles.…”

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

“…Sample 1 showed I % = 5.14 μmol Trolox mL −1 , sample 2 showed I % = 2.62 μmol Trolox mL −1 , sample 3 showed I % = 1.41 μmol Trolox mL −1 , sample 4 showed I % = 2.13 μmol Trolox mL −1 , and sample 5 showed I % = 0.73 μmol Trolox mL −1 . According to Hęś et al ., 31 aqueous A. vera leaf extracts antioxidant activity using the ABTS · + assay found I % varied from 0.58 to 0.87 mg Trolox mL −1 , indicating that the A. vera plant has low antioxidant capacity. As also mentioned previously, for the DPPH · assay the antioxidant capacity of A. vera is relatively low compared with plants such as oregano and sage, at I % = 1.73 μmol Trolox mL −1 and 0.62 μmol Trolox mL −1 respectively; 32 in contrast, goji berry, which is known for its high antioxidant activity, was found to reach I % = 8.35 μmol Trolox mL −1 33 …”

“…Sample 1 showed I% = 9.21 μmol Trolox mL −1 , sample 2 showed I% = 8.91 μmol Trolox mL −1 , sample 3 showed I % = 8.15 μmol Trolox mL −1 , sample 4 showed I% = 2.61 μmol Trolox mL −1 , and sample 5 showed I% = 1.64 μmol Trolox mL −1 . Hęś et al, 31 by applying the same assay, showed that A. vera leaf aqueous extracts had I% from 4.32 to 8.87 mg Trolox mL −1 , with the result that A. vera aqueous extract presents relatively low antioxidant capacity. Compared with other plants' antioxidant capacities, such as oregano and sage, which have I% = 1.62 μmol Trolox mL −1 and 0.42 μmol Trolox mL −1 respectively, 32 when estimated by the DPPH • assay, A. vera shows a relative lower antioxidant capacity; this compares with goji berry, which is known for its high antioxidant activity, for which I% = 10.62 μmol Trolox mL −1 .…”

ETHNO-MEDICINAL POTENTIALS AND PHYTOCHEMICAL PROPERTIES OF Aloe vera: A REVIEW

“…A. vera contains great numbers of antioxidant compounds which may help in increasing nutritional value and stability of food. It has been reported that the use of different model system showed different antioxidant properties of the extract of A. vera (Hęś et al, 2016). The cytotoxic and antioxidant activity were reported by López et al (2017).…”