Inflammation
A study by Davis (1985) showed that when Cape Aloe was applied topically in a hydrophilic cream it reduced inflammation associated with arthritis (39%) and subsequent arthritis (45%). It has also been found that aloe has analgesic properties that can be ascribed to the presence of salicylates, which has an aspirin like effect (Shelton 1991)
Wound healing
Wounds treated with aloe showed rapid granulation and increased oxygen supply as a result of the increased blood flow (Davis 1989). The skin punch wounds healed more rapidly. The aloe gel reduced wound diameter, seemed to reduce scarring and inhibited acute inflammation. In another study, (Heggers 1996) stimulation of fibroblast activity and collagen proliferation was demonstrated. A recent study (Barrantes 2003) demonstrated aloe gel enriched with aloins (bitter) to inhibit collagenase and metalloproteases activity, which can degrade collagen connective tissue when unchecked. This activity supports the use of aloe in the treatment of chronic ulcers, burns and wounds.
Skin
The skin is composed of polypeptide chains that form aggregates of collagen fibrils, which influences the swelling and water uptake by the skin. The diffusion of water through the skin is limited and controlled by the stratum corneum (skin surface) that is in equilibrium with the atmosphere and underlying tissue. Since aloe is approximately 99% water it penetrates through the surface of the skin (stratum corneum) to the vascular dermal area thus hydrating the skin. Concurrently, the gel forms a cover to prevent the escape of moisture in the skin. Aloe gel increases the penetration of the skin by water hydration, occlusiveness (closes passage) and by increasing compound solubility. Subsequently, Davis (1991) has demonstrated that aloe gel enhanced the penetration of hydrocortisone and adds to its biological activity. Concomitantly, aloe gel increased oxygen supply as a result of increased blood flow (Davis 1989) and stimulates fibroblast activity and collagen proliferation (Thompson 1991) essential for skin tissue regeneration.
Gut health
The aloe juice has been used as a gastroinal tonic in a series of trials (Bland 1985) on human patients. It indicated a tonic effect on the intestinal tract with: a reduction in pH a reduction in bowel transit time intestinal bacterial flora benefited with a reduction in yeast bowel putrefaction was reduced and protein digestion and absorption was improved.The cathartic and laxative action of aloe bitter is well established. Its primary effect is caused by its influence on the motility of the colon (inhibition of stationary and stimulation of propulsive contractions). This results in an accelerated intestinal passage and a reduction in liquid absorption increasing water content in the faeces (Blumenthal 1998). In addition to the purgative effect the anthraquinone (bitter) substances stimulate the flow of gastric juices thus improving digestion. Soeda (1964) found that fractions from Cape Aloe gave a prophylactic (prevents infection) effect. While in a subsequent study, Soeda (1966) found the aloe juice to have inhibitory action against some bacteria and fungi.