Compositional features and bioactive properties of whole fraction from Aloe vera processing

Abstract

Aloe vera processing leaves generates a liquid and bagasse fraction. The resulting bagasse is mostly discarded as waste. Both the bagasse and liquid fraction can have interesting metabolites with biological activities for pharmaceutical and agro-food industries. The main objectives of the present work were: (1) to characterize the gel, liquid fraction and bagasse of A. vera; (2) to obtain extracts from bagasse (ethanolic extract, EE-B and aqueous extract, AE-B); and (3) to evaluate biological activity of gel, liquid and bagasse extracts in terms of the antifungal effect on phytopathogenic fungi and antioxidant activity by the DPPH radical scavenging method. The carbohydrates were the major component of A. vera fractions corresponding to 57.45, 40.09 and 58.47g of carbohydrates/100g of gel, liquid fraction, and bagasse respectively. Uronic acids and malic acid were hallmarks of gel (15.80% and 18.17%, respectively); whilst for bagasse the occurrence of lignin is to be highlighted. The total phenolic content of the liquid fraction was 43.30mgaloing⿿1 extract, whereas the value of IC50 was 7.66mgmL⿿1; the first was significantly higher and the second was lower when compared to the corresponding values for the gel (19.11mgaloing⿿1 and 17.01mgmL⿿1, respectively). EE-B presented a greater antioxidant activity, higher total phenolic content and better antifungal activity than AE-B. In all the treatments, the antifungal effect was concentration-dependent and varied according to the fungus genera used in the experiments. A. vera gel and liquid fraction as well as EE-B are interesting natural alternatives to control phytopathogenic fungi in industrial crops during pre- and postharvest stages.