The content of secondary phenol metabolites in pruned leaves of Aloe arborescens, a comparison between two methods: leaf exudates and leaf water extract

Abstract

Aloe arborescens plants, originating from the deserts of South Africa, are grown in the Introduction Garden at Sede Boker in the Negev Desert of Israel. In previous studies, we developed agro-technical methods to raise the content of secondary phenol metabolites (SPhMs) in the Aloe leaves. Plants that are subjected to repeated leaf pruning respond by increasing the content of their SPhMs. The SPhMs found in Aloe arborescens include barbaloin, aloenin and derivatives of aloeresin. Such compounds are used for many purposes, including human skin protection from sun and fire burns and high radiation, as products of the pharmaceutics and cosmetics industries, and as food supplements for treating stomach ulcers and diabetes. In the current study, the SPhMs were separated from pruned leaves of the same A. arborescens plants at the same time by two methods: (1) exudation by squeezing the tissues of the leaves, (2) immersion of the leaves' pruned cut bottom in water and collection of the extract. The exudates and extract were frozen, freeze-dried to a powder and the SPhMs were then separated by chromatography. The yield of powder from water extraction from pruned leaves was much lower than the yield from the exudates. However, higher percentages of the powder from the water extraction contained SPhMs (between 80 and 92.7%). The content of powder in leaf exudates from pruned leaves was much higher because the SPhMs were squeezed out from the cells and tissues. However, the percentages of SPhMs in this powder were much lower (between 39 and 62%).

Mass Spectrometry-Based Metabolite Profiling and Antioxidant Activity of Aloe vera (Aloe barbadensis Miller) in Different Growth Stages

“…1 A. vera gel and its products are commercially used for creams, yogurts, beverages, and desserts. 2,3 Studies on biological activities such as antioxidant, 4 antidiabetic, 5 and antimicrobial effects 6 of A. vera extracts have been widely reported. Even the pharmacological functions for a wide range of human diseases, including cancer, AIDS, and ulcerative colitis, have been discussed.…”

Candelabra Aloe (Aloe arborescens) in the therapy and prophylaxis of upper respiratory tract infections: traditional use and recent research results

“…The following compounds/classes have been described for A. arborescens in the literature [1][2][3][4][5][6]:…”

Barbaloin: A concise report of its pharmacological and analytical aspects

“…The SPhMs found in Aloe include barbaloin, aloenin and derivatives of aloeresin. Such compounds are used for many purposes, including human skin protection from sun and fire burns and high radiation, as products of the pharmaceutics and cosmetics industries, and as food supplements for treating stomach ulcers and diabetes [18] . A field study was conducted in Aloe vera with an objective to determine the effect of various levels of synthetic fertilizers on chemical constituents at the inflorescence stage of the plant.…”