Aloe vera

Aloe vera, also known as the medicinal aloe, is a species of succulent plant that probably originated in Northern Africa. Aloe vera grows in arid climates and is widely distributed in Africa and other arid areas. The species is frequently cited as being used in herbal medicine. There have been many scientific studies of the use aloe vera, some of it conflicting.[1][2][3][4] Despite these limitations, there is some preliminary evidence that Aloe vera extracts may be useful in the treatment of diabetes and elevated blood lipids in humans. These positive effects are thought to be due to the presence of compounds such as polysaccharides, mannans, anthraquinones and lectins.
Medicinal uses
Scientific evidence for the cosmetic and therapeutic effectiveness of Aloe vera is limited and when present is typically contradictory. Despite this, the cosmetic and alternative medicine industries regularly make claims regarding the soothing, moisturising and healing properties of Aloe vera, especially via Internet advertising. Aloe vera gel is used as an ingredient in commercially available lotion, yogurt, beverages and some desserts.[42][43][44] Aloe vera juice is used for consumption and relief of digestive issues such as heartburn and irritable bowel syndrome. It is common practice for cosmetic companies to add sap or other derivatives from Aloe vera to products such as makeup, tissues, moisturizers, soaps, sunscreens, incense, razors and shampoos.[42] It has also been suggested that biofuels could be obtained from Aloe vera seeds.[45] Other uses for extracts of Aloe vera include the dilution of semen for the artificial fertilization of sheep,[46] use as fresh food preservative,[47] and use in water conservation in small farms.[48]
Aloe vera has a long association with herbal medicine, although it is not known when its medical applications were first discovered. Early records of Aloe vera use appear in the Ebers Papyrus from 16th century BCE,[15] in both Dioscorides' De Materia Medica and Pliny the Elder's Natural History written in the mid-first century CE[15] along with the Juliana Anicia Codex produced in 512 CE.[42] Aloe vera is non-toxic, with no known side effects, provided the aloin has been removed by processing. Taking Aloe vera that contains aloin in excess amounts has been associated with various side effects.[3][4][49] However, the species is used widely in the traditional herbal medicine of China, Japan, Russia, South Africa, the United States, Jamaica and India.[3]
Aloe vera is alleged to be effective in treatment of wounds.[4] Evidence on the effects of Aloe vera sap on wound healing, however, is limited and contradictory.[4] Some studies, for example, show that Aloe vera promotes the rates of healing,[50][51] while in contrast, other studies show that wounds to which Aloe vera gel was applied were significantly slower to heal.[52][53] A more recent review (2007) concludes that the cumulative evidence supports the use of Aloe vera for the healing of first to second degree burns.[54] In addition to topical use in wound or burn healing, internal intake of Aloe vera has been linked with improved blood glucose levels in diabetics,[55][56] and with lower blood lipids in hyperlipidaemic patients.[57] In other diseases, preliminary studies have suggested oral Aloe vera gel may reduce symptoms and inflammation in patients with ulcerative colitis.[58] Compounds extracted from Aloe vera have been used as an immunostimulant that aids in fighting cancers in cats and dogs;[5] however, this treatment has not been scientifically tested in humans. The injection of Aloe vera extracts to treat cancer has resulted in the deaths of several patients.[59]
Topical application of Aloe vera may be effective for genital herpes and psoriasis.[60] However, it is not effective for the prevention of radiation-induced injuries, nor does it offer protection from sunburn or suntan.[61] In a double-blind clinical trial the group using an Aloe vera containing dentifrice and the group using a fluoridated dentifrice both demonstrated a statistically significant reduction of gingivitis and plaque.[62]
Aloe vera extracts have antibacterial and antifungal activities. Aloe vera extracts have been shown to inhibit the growth of fungi that cause tinea,[63] however, evidence for control beneath human skin remains to be established. For bacteria, inner-leaf gel from Aloe vera was shown to inhibit growth of Streptococcus and Shigella species in vitro.[64] In contrast, Aloe vera extracts failed to show antibiotic properties against Xanthomonas species.[65]