Aloe Vera (Gel): family, products, uses, benefits, evidence, dosage, side effects, interactions

Aloe Vera (Gel): family, products, uses, benefits, evidence, dosage, side effects, interactions

What is Aloe Vera?

Aloe Vera is a perennial, succulent and shrubby plant with green leaves (color varies from bright green to gray) arranged in a rosette pattern at the stem. The leaves are triangular and fleshy with serrated edges consisting of a thick epidermis covered by cuticle surrounding the mesophyll. The leaves have a high capacity to retain water which enables the plant to survive in harsh circumstances, i.e., long periods of drought and warm dry climate.

Aloe plants have been used to treat wounds since ancient times and are mentioned in the Ebers papyrus, an important medical text of ancient Egypt, dating from 1550 BCE. Among various species of aloe, aloe vera is considered to be the most potent, commercially important and the most popular plant in the research field. Various parts of the plant contain approximately 75 nutrients, as well as 200 active compounds including amino acids, sugars, enzymes, vitamins, minerals, saponins, anthraquinones, lignin and salicylic acid.

Aloe vera is well known for its antioxidant, anti-inflammatory, antidiabetic, sunburn relief, immune boost, anti-ageing and anticancer properties. Owing to its unique composition various industrial applications of aloe vera have been initiated.

Aloe Vera family, other names, origin, and botanical drug used

Family: Xanthorrhoeaceae (Aloaceae); the genus Aloe has also been placed in the Liliaceae and Asphodelaceae

Other names: According to the International Rules of Botanical Nomenclature, the scientific name for
Aloe vera is Aloe barbadensis. Other names include: Aloe chinensis, Aloe elongate, Aloe indica, Aloe officinalis, Aloe perfoliata, Aloe rubescens, Aloe vulgaris Lam etc.

Origin:  Aloe is a large genus with 446 species that belongs to the Xanthorrhoeaceae. Aloe spp. grows wildly in the tropical climates around the world particularly South Africa, Madagascar, Arabia and the Canary Islands. They are cultivated mainly for medicinal and decorative purposes.

Botanical drug used: Gel extracted from the internal tissues of the succulent leaf.

Aloe Vera’s chemical composition and main compounds

Although many biological investigations have been performed to reveal the active constituents of Aloe spp., it is still not yet completely clear which compounds are responsible for the various observed pharmacological properties. However, polysaccharide and glycoprotein (lectin) fractions of Aloe spp. have been reported to possess considerable bioactivity. Several constituents from various phytochemical classes such as alkaloids, anthrones, chromones, flavonoids, glyocoproteins, naphthalenes and pyrones have been isolated from different Aloe spp. Aloin, aloesin, aloenin, aloeresin, aloe-emodin and chrysophanol are some examples of such bioactive compounds.

Main compounds:

  • Polysaccharides (e.g. acemannan in A. vera and aloemannan in A. arborescens);
  • glycoproteins (lectins) such as aloctin A and B
  • enzymes such as carboxypeptidases
  • hexadecanoic acid and sterols including sitosterol and stigmasterol
  • Traces of anthraquinones, such as aloin and aloe emodin
Aloe Vera's chemical composition and main compounds
Aloin structure

What is Aloe Vera gel?

Aloe gel which is derived from the succulent leaves of the plant. Aloe gel is widely used in cosmetics, medicinal products and food supplements, and polysaccharides are its major constituents. Linear chains of glucose and mannose molecules, ranging in size from a few to several thousands of residues, form the polysaccharides. Due to the predominance of mannose to glucose, these polysaccharides are referred to as polymannans. About 98.5% of the pulp and 99.5% of the gel or mucilage content is water, the remaining 0.5–1.0% ingredients include over 75 various compounds such as polysaccharides, anthraquinones/anthrones, carbohydrates, chromones, phenolic compounds, minerals, enzymes, water-soluble and fat-soluble vitamins, minerals, proteins and organic acids.

Is aloe vera gel anti inflammatory?
Aloe vera gel

Aloe Vera juice production

Traditionally, for juice preparation, unwanted parts of the leaf (leaf base, leaf top, tapering point and spines at leaf margins) are removed and the fillet is washed. This material is added to the pulper where juice is extracted under refrigerated temperatures. The extracted juice is then stored at low temperature to prevent the loss of bioactivity of sensitive molecules. In an alternative method of juice preparation, the base and tip of the leaf are removed and ground to form slurry that produces a soup like consistency. It is then treated with cellulose enzyme to release cell constituents. The material is then passed through a series of coarse filters to remove impurities (e.g. rind particles). The resulting liquid is subjected to the removal of large pieces of pulp and rind (through de-pulping extractor) formed during grinding process. The material is finally passed through a series of filters to remove aloin, emodin, traces of leaves, sand and other particles. Juice prepared by this method contains three times more bioactive components compared to the juice prepared with the traditional method.

Aloe Vera indications and uses

  • Aloe vera gel is applied externally to treat skin irritation (such as from insect bites), burns, psoriasis, wounds, radiation dermatitis and frost-bite.
  • It is also frequently found in cosmetic preparations, usually at low doses.
  • Internally, aloe ‘juice’ is taken as a general tonic to enhance the immune system and to treat constipation.
  • Aloe has also reported antidiabetic, anticancer and antibiotic properties.

Aloe Vera evidence of eficacy

Most clinical uses are based on anecdotal data. Data from small trials suggests effectiveness in healing first- and second-degree burns and increased survival of frostbitten tissue. Aloe Vera has been demonstrated to lower blood glucose and lipid levels in diabetic patients with hyperlipidaemia and patients with metabolic syndrome.

There is a lack of evidence based on high quality clinical trials to support the topical use of aloe for treating acute or chronic wounds. Despite the paucity of evidence, data from a few other small trials suggest that topical Aloe vera may be effective in healing firstand second-degree burns, although these conclusions should be treated with caution. In vivo studies in animals have indicated that Aloe vera may accelerate wound healing and prevent progressive dermal ischaemia caused by burns, frostbite and electrical injury by inhibition of thromboxane A2. Topical application of aloe has been shown to significantly enhance survival of frost-bitten tissue in both rabbit ears and in a clinical trial in humans.

In two randomized double-blind placebo-controlled clinical trials, aloe leaf gel demonstrated significant lowering of blood glucose and cholesterol levels, including low-density lipoprotein cholesterol (LDL) levels in hyperlipidimic type 2 diabetic patients and patients with prediabetes/ metabolic syndrome. In another trial, oral aloe gel produced a beneficial clinical effect greater than placebo in patients with active ulcerative colitis.

Antipsoriatic effects have been demonstrated in mice and the polysaccharides and glycoproteins have in vitro and in vivo immunomodulating and anticancer effects hexadecanoic acid has antifungal effects.

Aloe Vera side effects

Taken internally in large doses, aloe preparations are known to cause nephritis. Two cases of acute renal failure have been reported following aloe administration. It may also precipitate allergic reactions and has been associated with gastrointestinal complications (colonic injury). Two acute cases of hepatitis have been associated with internal use of Aloe vera.

An in vivo study in mice demonstrated a weak enhancing effect of aloe gel and aloe whole leaf on the photocarcinogenicity of simulated sunlight. Other in vivo studies have indicated that A. vera whole leaf extract is a gastrointestinal irritant in mice and rats, and carcinogenic in the large intestine of rats.

Aloe Vera interactions

A report of an interaction suggests that taken internally, ‘aloe vera tablets’ may interact with the anaesthetic sevoflurane, increasing its antiplatelet effects. However, the composition of the preparation was not stated and no other interactions have been recorded.

Aloe Vera gel has potential to enhance the absorption of drugs with low bioavailability. Oral bioavailability of vitamin C and E was investigated with Aloe Vera gel and leaf extract. Absorption of vitamin C was found to decrease with both the gel and leaf extract. However, overall bioavailability of vitamin C and E was increased. The mechanism of action was proposed to be the protection against degradation as well as binding of polysaccharides resulting in slower absorption rates. In addition to enhancing absorption and bioavailability through the gut, Aloe Vera oil has also been found beneficial in accelerating the penetration rate of drugs through the transdermal route. In a recent study, the effect of Aloe Vera oil on skin penetration of losartan potassium (a drug used to treat hypertension) was investigated and compared with other essential oils such as tea tree oil, cumin oil and rose oil. Among these essential oils, only Aloe Vera oil could provide the target flux required to deliver the therapeutic transdermal dose of losartan potassium. The availability of such formulations provides an alternative and convenient route for drug administration as compared to the conventional oral route, which can result in poor patient compliance in case of long-term treatment.

Aloe Vera contraindications

Its contraindications include allergy to any of the constituents. While external use during pregnancy is not thought to be of concern, internal use of aloe vera gel and whole leaf aloe extracts should be avoided during pregnancy and breastfeeding, due to their gastrointestinal stimulant and genotoxic effects.

Aloe Vera dosage

For external use, it can be applied liberally; for internal use, manufacturers’ instructions should
be followed and large doses or long-term use should be avoided.

Aloe Vera and wound healing

Wound healing is the restoration of integrity of injured tissues. Amino acids that are essential in wound healing process are present in Aloe Vera. It also contains many inorganic electrolytes like iron, potassium, magnesium, chromium, copper, sodium, calcium and zinc which are vital part of wound healing process. It stimulates the body to produce antibodies and starts wound healing by releasing growth factors. Many studies have shown fast healing of wounds with Aloe Vera treatment. Aloe Vera prevents scar formation during skin injury by stimulating the cell production and promoting the regeneration process at the deepest layers of the skin.

Aloe Vera anti-ulcer effects

Aloe Vera gel has the potential to prevent and cure gastric ulcers through a number of mechanisms including anti-inflammatory properties, healing effects, mucus stimulation and regulation of gastric secretions. Mansour et al have reported that aloe and myrrh based gels were found effective in decreasing ulcer size, erythema and exudation. At concentrations of about 80%, Aloe Vera can be successfully used for treatment of skin ulcers including mouth ulcers, cold sores and leg ulcers.

Aloe Vera anti-inflammatory effects

Aloe Vera gel exhibits strong anti-inflammatory effects due to the presence of anthraquinones and chromone. An intake of oral aloe gel (2%) has been reported to be effective in decreasing the severity of pain and wound size in aphthous stomatitis patients. The anti-inflammatory effect of Aloe Vera is also helpful in relieving joint pain. The complex mechanisms of the body that cause painful inflammation involve the production of bradykinin in response to various types of injuries. Studies have shown that Aloe Vera possesses anti-bradykinin activity because it contains a bradykinase enzyme, which breaks down the bradykinin and reduces the inflammation. Aloe Vera gel is more effective against inflammation caused by prostaglandin synthesis as well as infiltration of leukocytes and is less effective against inflammation caused by allergenic agents.

Aloe Vera and anticancer activity

Glycoproteins and polysaccharides present in Aloe Vera make it a potent chemo-preventive agent that is useful against various types of cancers. These agents stimulate the immune system to fight against cancer. Barbaloin, aloe-emodin and aloesin extracted from Aloe Vera have shown cytotoxicity against acute myeloid leukemia (AML) and acute lymphocytes leukemia (ALL) cancerous cells. Administration of these active compounds have been reported to significantly extend the life span of tumor transplanted animals.

Aloe Vera antidiabetic effects

Aloe Vera gel is an effective antihyperglycemic agent against type 2 diabetes. It lowers the blood glucose level without disturbing the normal blood lipid level and liver/kidney function It has been proposed that blood glucose level is lowered due to its increased metabolism. Devaraj et al have reported reduced body weight and reduced insulin resistance in diabetic patients treated with Aloe Vera gel complex. The antidiabetic activity of Aloe Vera gel through reduced oxidative stress and improved antioxidant status has been also reported. Yongchaiyudha et al reported a 44 % reduction in blood glucose level in diabetic patients administered with Aloe Vera gel. Similar results were also observed when Aloe Vera gel was administered in combination with glibenclamide.

Aloe Vera antioxidant effects

A number of antioxidants such as α-tocopherol, carotenoids, ascorbic acid, flavonoids, tannins vitamin C and E are present in Aloe Vera. Antioxidant potential of the extracts of Aloe Vera (leaf and flower) have been reported. Aloe Vera has a dose dependent antioxidant effect, which is helpful in treatment of various diseases. Investigations of the antioxidant potential of a polysaccharide isolated from Aloe Vera gel showed that it had a protective effect against dihydrochloride induced oxidative stress and cell death in kidney epithelial cells.

Aloe Vera antihyperlipidemic activity

Aloe Vera gel is claimed to have antihyperlipidemic activity. When administered to patients not responding to dietary interventions, it effectively reduced the blood cholesterol level (15.4%), triglycerides (25.2%) and LDL cholesterol (18.9 %). One investigation also showed that Aloe Vera gel in combination with probiotic Lactobacillus rhamnosus can improve the lipid profiles in hypercholesteremic rats together with enhanced cholesterol production and absorption resulting in reduced risk of cardiovascular diseases.

Aloe Vera use in dentistry

Teeth and gum protection Aloe Vera is widely used in the field of dentistry to treat a variety of dental complications, such as to relieve pain and accelerate healing after periodontal flap surgery. Gum diseases like gingivitis and periodontitis are treated by using Aloe Vera to reduce bleeding, control inflammation and stop the swelling of the gums

Aloe Vera laxative effects

Aloe Vera gel is one of the most potent laxative compounds and is used traditionally to treat constipation. When taken in doses of 0.25mg, laxative effects start within 6 to 12 hours resulting in loose bowel movements. It is safe for nursing mothers, as no laxative effects are found in their infants.

Aloe Vera use for genital herpes

Genital herpes (caused by Herpes Simplex Virus) is one of the most common sexually transmitted diseases. Treatment of this disease involves medication for faster healing of sores and lesions so that outbreaks can be reduced or prevented. Aloe Vera extract (0.5%) in the form of a hydrophilic cream has shown effectively to treat genital herpes in men through a more rapid healing process.

Aloe Vera use for asthma

Storage of Aloe Vera extract in the dark for a period of 3-10 days produces some active compounds (prostanoids) in the glycoprotein and polysaccharide fractions. These active compounds have shown effectiveness against chronic bronchial asthmatics. However, the activity against asthma becomes ineffective if the patient has been previously administered with steroid drugs.

Aloe Vera use for treating HIV infection

Polysaccharides and acemannans present in Aloe Vera have proved to be effective against HIV. More studies are needed.

Aloe Vera top 5 selling products

According to the amazon.com, following five Aloe Vera products are listed as top selling:

  • Nature Republic New Soothing & Moisture Aloe Vera 92% Gel
  • George’s Aloe Vera Supplement, 128 Fluid Ounce
  • Lily of the Desert Inner Fillet Aloe Vera Juice
  • Herbalife Herbal Aloe Drink (Concentrate)16 oz
  • NOW Aloe Vera Gels, 10000mg,100 Softgels

 

 

benefits of aloe vera on face overnight
Nature Republic New Soothing & Moisture Aloe Vera 92% Gel

 

Is acai berry good for your skin?

About Miljan Krcobic 363 Articles
Miljan Krčobić. has bachelor degree in Pharmacy.