Plant materials derived from the Aloe plant are used as cosmetic ingredients, including Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice, Aloe Barbadensis Leaf
Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract. These ingredients function primarily as skin-conditioning agents and are included in
cosmetics only at low concentrations. The Aloe leaf consists of the pericyclic cells, found just below the plant's skin, and the inner central area of the leaf, i.e., the gel, which is used for cosmetic products. The pericyclic cells produce a bitter, yellow
latex containing a number of
anthraquinones, phototoxic compounds that are also gastrointestinal irritants responsible for
cathartic effects. The gel contains
polysaccharides, which can be acetylated, partially acetylated, or not acetylated. An industry established limit for
anthraquinones in aloe-derived material for nonmedicinal use is 50 ppm or lower. Aloe-derived ingredients are used in a wide variety of cosmetic product types at concentrations of raw material that are 0.1% or less, although can be as high as 20%. The concentration of Aloe in the raw material also may vary from 100% to a low of 0.0005%.
Oral administration of various
anthraquinone components results in a rise in their blood concentrations, wide systemic distribution, accumulation in the liver and kidneys, and excretion in urine and feces;
polysaccharide components are distributed systemically and metabolized into smaller molecules. aloe-derived material has fungicidal, antimicrobial, and
antiviral activities, and has been effective in wound healing and
infection treatment in animals. Aloe barbadensis (also known as Aloe vera)-derived ingredients were not toxic in acute oral studies using mice and rats. In parenteral studies, the LD(50) using mice was > 200 mg/kg, rats was > 50 mg/kg, and using dogs was > 50 mg/kg. In intravenous studies the LD(50) using mice was > 80 mg/kg, rats was > 15 mg/kg, and dogs was > 10 mg/kg. The 14-day no observed effect level (NOEL) for the Aloe
polysaccharide,
acemannan, in the diet of Sprague-Dawley rats, was 50,000 ppm or 4.1 to 4.6 g/kg day(-1). In a 3-month study using mice, Aloe vera (extracted in
ethanol) given orally in
drinking water at 100 mg/kg produced reproductive toxicity,
inflammation, and mortality above that seen in control animals. Aloe vera extracted in
methanol and given to mice at 100 mg/kg in
drinking water for 3 months caused significant sperm damage compared to controls. Aloe barbadensis extracted with water and given to pregnant Charles Foster albino rats on gestational days (GDs) 0 through 9 was an abortifacient and produced skeletal abnormalities. Both negative and positive results were found in bacterial and mammalian cell genotoxicity assays using Aloe barbadensis-derived material, Aloe Ferox-derived material, and various
anthraquinones derived from Aloe.
Aloin (an
anthraquinone) did not produce
tumors when included in the feed of mice for 20 weeks, nor did
aloin increase the incidence of
colorectal tumors induced with
1,2-dimethylhydrazine.
Aloe-emodin (an
anthraquinone) given to mice in which
tumor cells had been injected inhibited growth of malignant
tumors. Other animal data also suggest that components of Aloe inhibit
tumor growth and improve survival. Various in vitro assays also demonstrated anticarcinogenic activity of
aloe-emodin.
Diarrhea was the only adverse effect of note with the use of Aloe-derived ingredients to treat
asthma,
ischemic heart disease, diabetes,
ulcers, skin disease, and
cancer. Case reports include acute
eczema, contact urticaria, and
dermatitis in individuals who applied Aloe-derived ingredients topically. The Cosmetic Ingredient Review Expert Panel concluded that
anthraquinone levels in the several Aloe Barbadensis extracts are well understood and can conform to the industry-established level of 50 ppm. Although the
phototoxicity anthraquinone components of Aloe plants have been demonstrated, several clinical studies of preparations derived from Aloe barbadensis plants demonstrated no
phototoxicity, confirming that the concentrations of
anthraquinones in such preparations are too low to induce
phototoxicity. The characterization of aloe-derived ingredients from other species is not clear. In the absence of well-characterized derivatives, biological studies of these materials are considered necessary. The studies needed are 28-day dermal toxicity studies on Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice (ingredients should be tested at current use concentrations). In Aloe-derived ingredients used in
cosmetics, regardless of species,
anthraquinone levels should not exceed 50 ppm. The Cosmetic Ingredient Review Expert Panel advised the industry that the total polychlorobiphenyl (PCB)/
pesticide contamination of any plant-derived cosmetic ingredient should be limited to not more than 40 ppm, with not more than 10 ppm for any specific residue and that limits were appropriate for the following impurities:
arsenic (3 mg/kg maximum),
heavy metals (20 mg/kg maximum), and lead (5 mg/kg maximum).