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  • Author: Malika Barkat x
  • Geosciences x
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Abstract

The main objectives of this work are to optimize the extraction parameters, to test the antioxidant activity of Aloe Vera extract and to study the impact of this extract on deteriorating molds of Algerian variety of wheat (CIRTA). The extraction was optimized by central composite design. Determination of the polyphenols, flavonoids, and proanthocyanidins was performed by using colorimetric assays. Identification and quantification of phenolic compounds were performed by RPHPLC-UV method. The antioxidant activity was tested by three methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,20-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and CUPRAC (Cupric reducing antioxidant capacity), the antifungal activity of Aloe Vera extract on isolated strains from durum wheat were tested by dilution in a solid medium method. The optimum of total phenolic got was1,044 x 104 µg GAE/g of dry extract. The extract is rich in polyphenols, flavonoids, and proanthocyanidins. The analysis of phenolic compounds of Aloe Vera by RP-HPLC-UV revealed seven phenolic compounds. Strong antioxidant activity was obtained for Aloe Vera extract. Purification and microscopic study of isolated strains gave the possibility of identifying four strains: Alternaria spp1, Alternaria spp2, Penicillium spp, and Aspergillus spp. the antifungal potential of Aloe Veravaries according to the fungal genera and the concentrations of extract used.

Abstract

The objective of this study is to evaluate the antioxidant activities of six medicinal plants growing in Algerian Aurès Mountains. Total phenolic and flavonoids contents were measured using colorimetric methods, and the antioxidant capacities were evaluated using the DPPH radical scavenging and β-carotene bleaching tests. Juniperus phoenica L. had significantly the higher total phenolic compounds (53.6±3.86 mg GAE.g−1 DM) (p<0.05); followed by Romarinus officinalis L. (26.1±3.15 mg GAE.g−1 DM) and Artemisia campestris L. (20.5±1.99 mg GAE.g−1 DM). Artemisia campestris L. had significantly the higher flavonoid contents (11.1±0.56 mg QE.g−1 DM) than other studied plants (p<0.05). The best antiradical activity was observed in Thymus algeriensis extracts (EC50=11.1±0.33 µg.ml−1) and Romarinus officinalis L. (EC50=15.3±0.9 µg.ml−1). β-carotene bleaching test showed that the herbs’ phenolic compounds Antioxidant Activity (AA%) value was found in the range of 64-84%, whereas that of the standard antioxidant ascorbic acid was 51±2.4%. The present results indicate that medicinal plants from the Algerian Aurès mountains could be explored in food and pharmaceutical industries for development of natural’s antioxidant agents.

Abstract

The aim of this work is to study the effect of digestion on the total polyphenol content, flavonoids and the antioxidant activity of Aloe vera. Total polyphenol contents and flavonoid spectrophotometric methods: The evaluation of the antioxidant activity was carried out by three methods, DPPH, ABTS and CUPRAC. To confirm the results obtained we carried out an analysis by ATR-FTIR. The total phenol content found in the Aloe vera extract studied was 1.3638 mg EAG/100 g, while the content of flavonoids found in the Aloe vera extract studied was 0.690 mg EQ/100 g. The values of total polyphenols and flavonoids decreased under the effect of gastrointestinal digestion. The spectra obtained during the ATR-FTIR analysis show that Aloe vera is rich in phenolic compounds and flavonoids. Intense bands corresponding to O–H bonds, C=C bond, C–H, CO, CH3 and CH2 confirm the presence of these bioactive compounds. For both the DPPH and CUPRAC methods, Aloe vera extract reveals a strong antioxidant activity, which gradually decreases during the oral and gastric phase and then increases after the intestinal digestion. For the ABTS method, the antioxidant activity decreases during the oral phase, increases during the gastric phase and then decreases again during the intestinal phase.