Aloe is used in asian medicine for therapy of fungal and other infections, infestations, tumors, and other skin diseases. The aloe substance released from comminuted leaves contains mucopolysaccharides, glucommamman including beta-mannan, allantoin, anthracenes such as aloin and emodin, alkylchromone including aletinic acid, and choline salicylate, flavonoids, amino acids, hydroxyquinine glycosides, carboxy – peptidases, and minerals (3). The hydroxyanthraquinone emodin inhibits neuroectodermal tumors such as Merkel cell carcinoma (18). Acetylated mannans and lectins appear to have immunomodulatory effects. Aloe is antibacterial to Staphylococcus aureus, Helicobacter pylori, and dermatophyte fungus. It is viricidal to herpes simplex and varicella zoster and is clinically effective in treating genital herpes. This herb inhibits thromboxane vasconstriction. Aloe inhibits photoimmunosuppression of UVB and inhibits cyclooxygenase for anti-inflammatory effects. It also increases collagen biosynthesis and degradation in granulation tissue (3). The antineoplasia effect is improved with melatonin and ascorbic acid. Aloe vera applied topically is accepted therapy for radiation and stasis dermatitis and ulcers, frostbite, burns, fungal and bacterial infections, cold sores, pruritis, pain, psoriasis, and contact irritant dermatitis. The latter two were documented in blinded studies (19,20).
No photoaging clinical studies using topical aloe vera have been published despite its use as one of the two most common extracts in skin care formulations. The health risks of aloe are cutaneous eruptions and mutagenicity. It is contraindicted in pregnancy and lactation (3,18).