Barbaloin inAloeSpecies

Abstract

Barbaloin levels in the exudates from the leaves of 68 species of ALOE in the Kew collection have been determined by light absorption at 375 nm following separation by HPLC. The exudates from most species contained between 10-20% although a few concentrations of around 30% were found. The level in the leaf was usually around 1% of thedry weight in plants grown in glasshouses at Kew although some species were found to contain up to 5%. The highest concentrations of barbaloin were found in exudates from young mature leaves just below the apex and the level decreased in older leaves towards the base of the plant. Species in the natural groupings of the genus, Section ANGUIALOE and Group 4, all had appreciable concentrations of barbaloin in the leaf exudates. Species containing barbaloinwere distributed throughout the large heterogeneous Sections EUALOE and PACHYDENDRON with no apparent taxonomic significance.

Inhibitory activity of Aloe vera gel on some clinically isolated cariogenic and periodontopathic bacteria

“…Aloin and aloe-emodin possess strong antibacterial and antiviral activities as well as laxative, hepatoprotective, and antineoplastic characteristics (32). Aloin and aloeemodin are the major anthraquinones in aloe plants, and their levels range between 0.1% and 25.5% dry weight in the leaf exudates of 68 Aloe species (33,34). Aloin and aloe-emodin have polyphenolic structures, which can inhibit protein synthesis by bacterial cells, thus explaining their antimicrobial activity.…”

Effects of heat treatments on the stabilities of polysaccharides substances and barbaloin in gel juice from Aloe vera Miller

“…Barbaloin (also named aloin), the C-glucoside of aloe emodin anthrone, localizes in the outer rind of the aloe plant, has been reported to constitute up to 30% of the aloe plantÕs dried leaf exudates (Groom & Reynolds, 1986) and proposed as a part of the defense mechanisms against herbivores (Gutterman & Chauser-Volfson, 2000). Orally administered barbaloin is poorly absorbed but is metabolized by intestinal microflora to aloe emodin, which is readily absorbed (Ishii, Tanizawa, & Takino, 1994).…”

Peripheral defence strategy: variation of barbaloin content in the succulent leaf parts of Aloe arborescens Miller (Liliaceae)

“…A relationship between deterrence and toxicity of plant secondary metabolites has been suggested for the generalist grasshopper Schistocmu umericuns (Bernays & Raubenheimer,199 1). Groom & Reynolds (1987) found differing amounts of barbaloin in Aloe urborescens and some other Aloe species. Differences were found in individual plants as well as between different leaves of the same plant, according to the leaf position on the plant.…”