Authors: Olwen M Grace, Sven Buerki, Matthew RE Symonds, Félix Forest, Abraham E van Wyk, Gideon F Smith, Ronell R Klopper, Charlotte S Bjorå, Sophie Neale, Sebsebe Demissew, Monique SJ Simmonds and Nina Rønsted
Source: BMC Evolutionary Biology 15: 29, 2015
Brief summary of the paper: Aloe vera is one of the world’s most important plant commodities as a treatment for skin conditions and dietary problems. It’s popularity is evident in that there is an annual global market in excess of $16 billion Australia dollars for this plant.
It is, though, part of a enormous genus of aloes, many of which have also got medicinal properties, but have not been so commercially exploited. So, why has Aloe vera specifically become so popular, and what explains the evolution of medicinal properties in the genus Aloe as a whole?
We carried out a phylogenetic analysis of almost 200 species of aloes, to try and answer these questions from an evolutionary perspective. We found that medicinal use and leaf succulence in the genus is ‘clustered’ on the phylogenetic tree (indicating that these traits tend to be found in certain clades rather than others) and further that the two traits are evolutionarily correlated.
Species of aloes which appear to have ‘lost’ medicinal utility are those that have lost leaf succulence. Interestingly Aloe vera itself comes from an Arabian clade where medicinal use is less common.
Our analysis suggests that the particular reason why Aloe vera is so popular as a health-care product is due to a fortuitous combination of having been abundant in Arabia and the Middle East at about the time when this was one of the main trade-hubs of the world, and having been relatively unusual compared to other aloe species in the region.