Hormesis: induction by Aloe vera extracts and individual constituents

Aloe vera has an extensive history in traditional folk medicine. There is a robust scientific literature on Aloe vera extracts and several prominent chemical constituents, covering chemical characterization, biological/chemoprotective effects, and mechanisms. This paper provides the first integrative assessment of Aloe vera-induced hormetic dose responses. Aloe vera extract-induced hormetic responses acted as an immunostimulant in multiple fish species, enhancing development/growth and reducing adverse effects from environmental stressors. Aloe vera extract-induced hormetic effects are prominent in dermatological studies, improving keratinocyte- and fibroblast-related wound-healing processes. Aloe vera extracts induced hormetic-based neuroprotective endpoints for epileptic seizures, pain, in Alzheimer's disease models, and for lifespan. This analysis includes the hormetic effects of specific chemical constituents of Aloe vera extracts (acemannan/aloin) on stem cells, cardiomyocytes, bone cells, and other cell types, and their mechanisms. These findings show that a complex range of Aloe vera extract mixtures/specific constituents induce hormetic dose responses. These findings also indicate that hormetic dose responses play a prominent role in mediating many biomedical and chemopreventive effects of Aloe vera extracts and their major chemical constituents. Recognition of these findings should assist in creating optimized hormetic-based study designs and improving biologically/mechanistically based interpretations of their dose-response findings with their clinical implications.