Aloe Vera (Aloe barbadensis), is a cactus plant that belongs to the Liliaceae family, a family that includes more than 300 species of this perennial succulent plant known as aloe, from which Aloe vera is the most accepted specie for various medical, cosmetic and neutraceutical purposes [5,6,7,8]. The ideal environment to grow this plant is tropical climate and low-rainfall areas [1,3]. In spite it will be difficult to talk about all the properties and health benefits of Aloe vera, in this article we will try to explain the scientific evidence behind all these claims in a comprehensive way.
In spite the properties and health benefits of Aloe vera were known since a very long time ago, in fact since a few thousand years ago, it hasn't been until recent years that cosmetic and medical companies profited from it to make Aloe vera gel and other Aloe vera cosmetic products from the mucilaginous tissue or Aloe gelpresent in the center of the Aloe vera leaf. Aloe vera plant is known to contain in all its parts many Phenolic compounds, a certain type of active constituent found in Aloe that is also found in some essential oils and plants that exert very strong antiseptic andantibacterial properties. Image left:Making Aloe Vera Dessert by Ton Rulkens under Creative Commons license (CC BY-SA 2.0).
The Aloe vera leaf consists of 2 different parts:
- The central mucilaginous part from which the Aloe gel is extracted and
- The peripheral bundle sheath cells in the form of green rind.
The parenchymal tissue makes up the inner portion of the aloe leaves and produces a clear, thin tasteless jelly-like material called Aloe vera gel[1,4]. Image left: Aloe sp. Ribaue - leaf margin by ER and Jenny under Creative Commons license (CC BY-SA 2.0).
Several studies have demonstrated that Aloe vera leaf skin possesses many pharmaceutical properties and health benefits, including:
- Purgative [5,10],
- Antibacterial [11,12],
- Anticancer [13-15],
- Anti-fungal  and
- Antioxidant [17-21] properties.
Aloe vera has been used medicinally since the last few thousand years. Aloe verahas been used for medicinal purposes in several cultures for millenniums: Greece,Egypt, India, Mexico, Japan and China. Egyptian queens Nefertiti and Cleopatra used it as part of their regular beauty regimes. Alexander the Great, and Christopher Columbus used it to treat soldiers’ wounds [22,23]. Wars have been fought, as by Hannibal, in order to obtain control over its growing area in North Africa around 1750 BC. Image right: Aloe sp. Ribaue by Ton Rulkens under Creative Commons license (CC BY-SA 2.0).
Mentioned in various books and Mesopotamian clay tabloids in
various countries like Egypt, Greece,[1,24] South Africa, India, China, Mexico, Japan[1,25] for various ailments like:
- Hair loss,
- Skin infections,
- Gastrointestinal pain
- Wound healer for bruises,
- X-ray burns 
- Insect bites; and
- Anti-arthritic 
In modern times the first reference to Aloe vera in English language was found in a translation by John Goodyew in A.D. 1655 of Dioscorides’ Medical treatise De Materia Medica [22,23]. Anyway, it wasn't until the early 1800s, that Aloe vera started to be used as a laxative in the United States, being in the mid-1930s, when its successful use to treat chronic and severe radiation dermatitis gave it the boost that brought Aloe vera to one of the first places if not the first as natural remedy for severe radiation dermatitis, position that it already keeps [22,23].
Aloe vera, have been identified as beneficial in the treatment of psoriasis and atopic dermatitis, respectively, due to their anti-inflammatory properties . Topical aloe vera (AV) has been used to treat various skin conditions, including psoriasis, with good results. In a study were Aloe vera was compared with 0.1% triamcinolone acetonide, it was concluded that Aloe vera cream may be more effective than 0.1% triamcinolone acetonide cream in reducing the clinical symptoms of psoriasis .
In a double-blind, placebo-controlled study to evaluate the clinical efficacy and tolerability of topical Aloe vera extract 0.5% in a cream to cure patients with psoriasis vulgaris, the findings suggested that topically applied Aloe vera extract 0.5% in a hydrophilic cream is more effective than placebo, not showing any toxic or other side-effects. Therefore, the regimen can be considered a safe and alternative treatment to cure patients suffering from psoriasis.
Periodontitis is an infectious inflammatory disease. Bacteria modulate the inflammatory response and alter the diversity of periodontal disease. In recent years, various host-response modulation therapies and local drug therapies have been developed to block the pathways responsible for periodontal tissue breakdown [1,2], among them, some natural herbal remedies including Aloe vera as one of them.
Several studies demonstrate how the subgingival administration of Aloe vera gel results in improvement of periodontal condition. Aloe vera gel can be used as a local drug delivery system in periodontal pockets [1,2].