Botany: Aloe species are perennial succulents native to Africa that later spread to other parts of world. Aloe vera is not a cactus and should not be confused with the American aloe or century plant (Agave). Aloe vera also called Curaçao aloe or Barbados aloe, is produced in the West Indies (Curaçao, Aruba, Bonaire). Aloe feroxis and its hybrids yield Cape aloe that is produced in South Africa.
History and/or Folklore: The Indians call the aloes “wand of heaven” because of their wonderful medicinal powers. According to legend it was the only plant that came directly from the Garden of Eden. Socotrine Aloe was said to be known to the Greeks as early as the 4th century B.C. Greek colonists were sent to the island Socotra by Alexandra the Great solely to preserve and cultivate the aloe plant.
Commercial products: Two major products are derived from aloe:
(1) the drug aloe comes from yellow bitter juice present in special cells beneath the thick epidermis. This is obtained by cutting the leaves at their base and letting the yellow bitter juice drain out. The water is evaporated from the juice by heat and the resulting light to dark mass is the drug of aloe.
(2) aloe gel comes from a mucilaginous gel in the parenchymatous tissue in the centre of the leaf. Aloe vera gel is prepared from the leaves by numerous methods, which essentially involve expression and/or solvent extraction often with harsh chemical and physical treatment. The resulting gel products vary considerably in properties and are not generally representative of the fresh gel.
Aloe vera extract
Anthraquinones present in aloe vera extract inhibit the activity of the tyrosinase enzyme, thereby preventing the conversion of the amino acid tyrosine via dihydroxyphenylalanine (DOPA) into melanin and consequently reducing the production of age spots that appear on the skin as a result of aging. So aloe vera is not only of therapeutic value but also has an effect of anti-aging on skin as it delivers moisture, eliminates wrinkles, increases collagen and elastin and reduces the formation of pigments.
Aloe vera gel
Contains a lot of mucilage but does not contain anthraquinones. Vitamins present in aloe vera gel are A, C, E, B (thiamine), B3 (niacin), B2 (riboflavine), which act as antioxidants, and choline, folic acid, and traces of vitamin B12.
The gel also contains many different types of biochemical catalysts, enzymes, such as amylase and lipase, which hydrolyse sugars and fats; and carboxypeptidase, which is an important enzyme that hydrolyses bradykinin, a peptide that is associated with the vasodilation blood vessels and the perception of pain; carboxypeptidase is responsible for a valuable soothing and anti-inflammatory effect.
Magnesium lactate inhibits histamine decarboxylase and thus prevents the formation of histamine from the amino acid histidine. Histamine is released in many allergic reactions and causes intense itching and pain. Aloe vera counteracts and soothes itching. Due to lignin the aloe vera gel extract can penetrate deeper into the skin. Aloe vera gel contains also saponins; soapy substances form a 3% gel and act as cleaners. The steroids found in aloe vera gel such as cholesterol, campesterol, ß-sitosterol and lupeol have an anti-inflammatory effect. Salicylic acid has anti-inflammatory and antibacterial properties, and has also a keratolytic effect which increases the rate of removal of dead tissue from wounds.
Aloe vera gel is as moisturizer, emollient, wound-healing agent (treatment of cuts, burns, ulcers, inflammatory skin diseases, radiation dermatitis, and roentgen dermatitis),
The gel can also be a good protection against the sun, since it blocks UV and initiates the process of skin renewal.
The gel possesses antibacterial, anti-inflammatory, antiviral, anti-fungi and anaesthetic effects. It is anti-inflammatory because it inhibits production of blood clotting agents, thromboxane and prostaglandin. The gel also stimulates the replication of fibroblast cells in the wound, resulting in more secreted collagen and fibrin, which helps the wound heal faster and the skin on the wound site to be more flexible and less scarred.
The fatty fractions of the aloe leaf is used in the cosmetic industry as pigment carrier.
In humans, aloe vera gel preparations containing anthraquinones (aloin) may cause allergic contact dermatitis, mild itching, and burning sensations. These effects have been mild, of rare occurrence and reversible when use was stopped.