James Odell, OMD, ND, L.Ac.
Aloe vera is a member of the Liliaceae (lily) family (or Asphodelaceae, Asparagales in APG system). According to the World Checklist of Selected Plant Families, there are currently about 580 species of Aloe. The genus is native to tropical and southern Africa, Madagascar, Jordan, the Arabian Peninsula, and various islands in the Indian Ocean (Mauritius, Réunion, Comoros, etc.). Aloe is a shrubby or arborescent, perennial, xerophytic, succulent, pea-green color plant found throughout the tropics and warmer regions worldwide. Because of this global naturalization, its true origin is unknown. The commercially significant aloes are perennials, with 15 to 30 fleshy leaves up to 1.5 feet long and 4 inches across the base. Saw-teeth mark the margins of the leaves.1
The Aloe vera plant has been known and used for centuries for its health, beauty, medicinal, and skincare properties. The name aloe vera derives from the Arabic word “Alloeh” meaning “shining bitter substance,” while “vera” in Latin means “true.” Belonging to the lily family and related to the onion, garlic, and asparagus, evidence supporting the early use of aloe was discovered on a Mesopotamian clay tablet dating from 2100 BC. 2000 years ago, Greek scholars regarded aloe as the universal panacea. The Egyptians called aloe “the plant of immortality.” Egyptian queens Nefertiti and Cleopatra used it as part of their regular beauty regimes.2
Today, Egyptians still hang an aloe plant over the door of a new house to provide a long and fruitful life for its occupants. According to the Roman scholar, Pliny, the plant was also used for embalming. In the first century C.E., the Greek physician Dioscorides used aloe for soothing sores and wounds. In the 10th century, aloe was used in England, and during the 17th-century records show that the East India Company frequently purchased aloe from the king of Socotra. Alexander the Great used it to treat soldiers’ wounds. One of the first references to aloe vera in English was a translation by John Goodyew in A.D. 1655 of Dioscorides’ Medical treatise De Materia Medica. By the early 1800s, aloe vera was in use as a laxative in the United States, but in the mid-1930s, a turning point occurred when it was successfully used to treat chronic and severe radiation dermatitis. Today, the aloe plant has a multi-purpose use, primarily in dermatology for burns and skin health, but also as a nutritious food and laxative.3
The plant produces two substances used for medicine: a gel that is obtained from the cells in the center of the leaf, and the latex, which is obtained from the cells just beneath the leaf’s skin. Aloe contains at least 75 known potentially active constituents: vitamins, enzymes, minerals, sugars, lignin, saponins, salicylic acids, and amino acids.4, 5, 6, 7
Vitamins: Aloe contains many vitamins such as A (beta-carotene), C and E, which are also antioxidants, and the B vitamins B1 (thiamine), B2 (riboflavin), B3 (niacin), B12 (cobalamins), choline, and B9 (folic acid).8
Enzymes: It contains 8 enzymes: aliiase, alkaline phosphatase, amylase, bradykinase, carboxypeptidase, catalase, cellulase, lipase, and peroxidase. Biochemical catalysts, such as amylase and lipase, can aid digestion by breaking down fats and sugars. Carboxypeptidase inactivates bradykinins and produces an anti-inflammatory effect. During the inflammatory process, bradykinin produces pain associated with vasodilation and, therefore, its hydrolysis reduces these two components and produces an analgesic effect.9, 10
Minerals: Aloe contains magnesium, calcium, chromium, copper, selenium, manganese, potassium, sodium, and zinc. These minerals are essential for the proper functioning of numerous critical enzyme systems in different metabolic pathways, and a few are antioxidants. Aloe juice contains high levels of magnesium, which is a vital nutrient for nerve and muscle use. Magnesium helps your body with more than 300 different enzyme reactions, including those that regulate your blood pressure. It also helps regulate heart rhythm. Magnesium also inhibits histidine decarboxylase and prevents the formation of histamine from the amino acid, histidine. Histamine is released in many allergic reactions and causes intense itching and pain. The prevention of its formation may explain the antipruritic or anti-itch effect of aloe. Zinc is also an important component in this beneficial plant — making it a great natural source for combating zinc deficiency.
Fatty acids: Aloe provides 4 plant steroids; cholesterol, campesterol, β-Sitosterol, and lupeol. All these have anti-inflammatory action and lupeol also possesses antiseptic and analgesic properties.
Sugars: Aloe contains monosaccharides (glucose and fructose) and polysaccharides: (glucomannans/polymannose). Sugars are derived from the mucilage layer of the plant under the rind, surrounding the inner parenchyma or gel. They form 25 percent of the solid fraction and comprise both mono- and polysaccharides. The most important are the long-chain polysaccharides, comprising glucose and mannose, known as glucomannans. The polysaccharides are absorbed complete and appear in the bloodstream unchanged hence they act as immunomodulators.11, 12, 13, 14, 15, 16
Hormones: Aloe contains auxins and gibberellins that help in wound healing and have an anti-inflammatory action.
Anthraquinones: The bitter aloes consist of free anthraquinones and their derivatives - barbaloin, aloe-emodin-9-anthrone, isobarbaloin, anthrone-C-glycosides, and chromones. In large amounts, these compounds exert a powerful laxative effect, but when smaller they appear to aid absorption from the gut, are potent antimicrobial agents and possess powerful analgesic effects.17, 18 They also reduce the formation of melanin and any tendency to hyperpigmentation.19, 20 Lignin with their penetrative ability to carry other active ingredients deep into the skin to nourish the dermis. Aloin and emodin act as analgesics, antibacterials, and antivirals.
Other medicinal components: Aloe also contains 20 of the 22-human required amino acids and 7 of the 8 essential amino acids. It also contains salicylic acid that possesses anti-inflammatory and antibacterial property. Lignin, an inert substance, when included in topical preparations, enhances the penetrative effect of the other ingredients into the skin. Saponins that are soapy substances form about 3% of the gel and have cleansing and antiseptic properties.
Mechanism of Actions