Introduction
The use of Aloe vera has a long history dating back to several millennia. Historically this plant has gained remarkable recognition for its medicinal and cosmetic values. The first documented human use of aloe vera comes from Sumerian hieroglyphics (a form of ancient writing wherein pictures and symbols were used to explain various concepts) dating back to 4000 years wherein it was recounted as a laxative. However, its medicinal value was first described in Papyrus Ebers, an Egyptian document. The De Materia medica, a five-volume work on medicinal plants written by Greek physician Dioscorides, describes its use for wound healing, hemorrhoids, hair loss and genital ulcers.
The popularity of aloe vera spanned across many civilizations including Egypt, Greece, Mexico, India and China. Aloe vera was referred as the ‘plant of immortality’ by ancient Egyptians. It is said that the ancient Egyptian queens Nefertiti and Cleopatra used aloe vera consistently for skin and beauty treatments. Also, it was used as a wound healing strategy for soldiers by Alexander the Great and Christopher Columbus. In traditional Indian medicine, aloe vera was used as a remedy for constipation, colic (severe abdominal pain), worm infestation, infections and skin diseases. On the other hand, in the Caribbean it was used to treat hypertension and the Mexican Americans used it in the treatment of type 2 diabetes. In Chinese medicine, it was used as a remedy against fungal infections.
Aloe vera made its entry into the Western world in 17th century. It was in the mid seventeenth century, aloe vera was translated in English for the first time from the book De Materia medica. In the centuries that followed, aloe vera found a foot hold in the western society, especially in United States wherein it was used as a laxative as well as a remedy for radiation dermatitis (also called radiation burn that occurs as a result of radiation therapy used for cancer). Later on, it became one of the conventional herbs in pharmaceutical, food and cosmetic industries not only in USA, but also in other parts of the world. With the passage of time, aloe vera has carved a niche in botanical industries worldwide.
The Aloe vera plant
Aloe vera is regarded as a perineal, succulent and xerophytic plant. Botanically speaking, a perineal plant is a type of plant that lives for several years. Succulents are special plants that have thick fleshy roots, leaves or stems for storing water, specially adapted for dry climates. A xerophyte is a plant variety that survives with very little or no water. The aloe vera plant comes under the genus (a level of classification) called Aloe which has over 650 types of succulent plants. Among them the most extensively known plant is Aloe vera or true aloe which is botanically called as Aloe barbadensis miller. Worldwide it is found in the dry regions of Africa, Asia, Europe and America. In India it is seen in the states of Rajasthan, Gujarat, Maharashtra, Andra Pradesh and Tamil Nadu.
The plant has elongated and pointed leaves that are joined at the base in a rosette pattern. The leaves of a fully grown adult plant measure about 30-50 cm long and 10 cm broad and are green or grey coloured. The leaf has four layers. The outer layer of the leaf is thick and is called as the skin or rind. The margins of the leaf have sharp spines or teeth. The second layer contains a bitter yellow liquid called the ‘aloe sap’. Beneath this layer constitutes the inner area of the leaf containing a slimy substance called as ‘mucilage’. The fourth layer encloses a clear, colourless mucinous gel which is 99% water. This pulp or gel constitutes the main volume of the leaf as well as the plant. The plant bears bell shaped pink and orange flowers and fruits that have innumerable seeds.
Chemical components
There are about 75 bioactive compounds that have been recognized in aloe vera. The term bioactive can be split into two words i.e., ‘bio’ meaning ‘life’ and ‘active’ meaning ‘energetic’ or relating to an’ activity’ which represents a life process or functioning of a system. So, these can be referred as special type of chemical compounds that are present in small quantities capable of communicating with the living tissue producing innumerable health benefits. The bioactive active compounds present in aloe vera are
Vitamins
Aloe vera contains vitamins A, C and E. It also contains B-complex group of vitamins including thiamine (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), cobalamins (B12) (given the fact that vitamin B12 is present mainly in foods of animal origin, the claims that aloe vera contains vitamin B12 is conflicting. While some sources justify aloe vera as a plant source of vitamin B12, others have put forth that consumption of aloe vera enhances the intestinal absorption of vitamin B12 taken from animal sources), folic acid and choline. The Vitamins A, C and E are regarded as the anti-oxidant vitamins, which means that they are capable of scavenging harmful molecules called free radicles from the body thus protecting against illnesses. The B group of vitamins support the normal functioning of the cells including those of the brain and the nervous system. Choline is an essential nutrient needed for the efficient functioning of the liver, muscle and brain.
Enzymes
Enzymes are naturally occurring chemical substances produced by all living organisms that are vital for sustaining life. Some of the enzymes present in aloe vera include aliiase, amylase, alkaline phosphatase, bradykinase, carboxypeptidase, catalase, cellulase, lipase and peroxidase. Each of these enzymes have specific functions. For instance, amylase helps in the breakdown of sugar and starch, bradykinase activates the immune system in addition to having analgesic and anti-inflammatory properties. It is said to reduce the skin inflammation when applied directly. On the other hand, catalase prevents the accumulation of excessive water in the body and cellulase and lipase aid in the digestion of cellulose and fats.
Minerals
Aloe vera contains calcium, copper, chromium, selenium, magnesium, manganese, potassium, sodium and zinc. Minerals like calcium, magnesium, potassium and sodium are considered as major minerals as they are needed in large amounts. On the other hand, copper, chromium, selenium, manganese and zinc are regarded as trace minerals as the body needs them in small amounts. Both these types of minerals are important as they carry out vital functions including mineralization of bones, proper functioning of the muscles and nerves and maintaining the fluid balance in the body. They also support the efficient functioning of the various enzymes and hormones in the body in addition to strengthening the immune system.
Carbohydrates
Aloe vera contains both monosaccharides as well as the polysaccharides. The polysaccharides that are present in the aloe vera are called mucopolysaccharides as they are sourced from the slimy ‘mucinous’ layer. The main monosaccharide that is present in aloe vera is called mannose-6-phosphate whereas the polysaccharides are termed as glucomannans. One of the most prominent glucomannan is called acemannan. Studies have reported the medicinal potential of this polysaccharide as a remedy against oral diseases, metabolic and cardiovascular diseases and has been recently extended to its application in dentistry and wound healing. Also, two more compounds called alprogen and C-glucosyl chromone possessing anti-allergic and anti-inflammatory properties have been isolated from aloe vera gel.
Anthraquinones
In aloe vera plant, anthraquinones are mostly concentrated in the ‘yellow sap’ layer of the leaf. Some of them include aloin, emodin, aloe-emodin, barbaloin, isobarbaloin and chrysophanic acid. These compounds have been demonstrated to possess antibacterial, antifungal, antiviral, analgesic (pain relief), laxative, diuretic, hepatoprotective (liver protection) and vasorelaxant (relieving the tension or relaxing the blood vessels) properties.
Fatty acids
On a general note, fatty acids are the major constituents of the lipids, a fatty, waxy and oily substance present in all living organisms. They not only constitute the ‘building blocks’ of cell membranes (a thin layer surrounding the cells), but also are a source of energy to the cells thus maintaining the efficient functioning of the cells and tissues. Plants constitute one of the main sources of essential fatty acids for humans and animals. The term plant sterol refers to the cholesterol like substances made by plants which confers certain health benefits when consumed. The main sterols present in aloe vera plant are cholesterol, campesterol, beta-sitosterol and lupeol. All these are regarded as having anti-inflammatory properties and in particular lupeol has been identified as an antiseptic and analgesic agent.
Hormones
Just like humans, plants also produce hormones that play an important role in the growth and development of the plant. Scientific evidence from recent studies have revealed the possible effects of the plant hormones in protecting against diseases such as cancer and diabetes. The main hormones present in aloe vera are called auxins and gibberellins. They have been recognised for their wound healing and anti-inflammatory properties.
Amino acids
Amino acids are the organic compounds that combine together to form proteins. They are not only needed for the synthesis of proteins, but also other compounds containing nitrogen such as creatine (a natural substance that gives energy to the muscle during action as well as helps in muscle growth and recovery), peptide hormones (these are hormones that are made up of amino acids, for example insulin) and neurotransmitters (chemical messengers that transmit signals between nerves or to the muscle or to other organs). Proteins, on the other hand are vital for the repair and healing of tissues. Hence amino acids and proteins are regarded as the building blocks of life.
Though hundreds of amino acids occur in nature, only 20 of them are needed to build the proteins. Among them, 9 are considered as essential as they have to be supplied from outside. The rest are non-essential as the body is capable of synthesizing them. Aloe vera contains most of the essential and non-essential amino acids.
Other compounds
Aloe vera contains salicylic acid, an aspirin like compound possessing antibacterial, anti-inflammatory and analgesic properties. It has also been shown that the addition of a compound called lignin to the skin formulations enhances the penetration of medications into the skin. Saponins are soap like substances that have cleansing and antiseptic properties.
Medicinal properties
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Promotes wound healing
The term wound is referred as an injury to the body caused by a cut, blow of any form of impact resulting in break or damage to the tissues. While minor wounds can be managed by first aid, large wounds with extensive tissue damage needs medical care. The process of wound healing involves a well charted out series of events or phases that involve tissue repair and remodeling.
Aloe vera has been recognised as a natural healer since antiquity. Studies have found that the enhancement of wound healing by aloe vera is attributed to the presence of compounds such as glucomannan, a mucopolysaccharide and gibberellin, a plant hormone. The mucopolysaccharides present in the aloe vera gel together with amino acids and zinc contribute to the skin health. Also, the magnesium lactate present in the aloe vera gel has been said to suppress the release of a chemical called histamine, known to cause allergic reactions and itching. Scientific evidence points out to the fact that aloe vera gel improves the moisture and elasticity of the skin and this is attributed to its high water content.
Aloe vera gel has been shown to be an effective healer in first degree burns i.e., the burns involving mainly the outer layer of the skin. In addition to reducing inflammation and promoting cell growth, this remarkable gel has been shown to possess anti-bacterial, ani-viral, anti-fungal and antiseptic properties. These qualities of the gel promote healing of minor wounds like cuts and abrasions. It has been demonstrated that aloe vera enhances the blood circulation in the wound thus augmenting the oxygen supply, an important prerequisite for wound healing. This gel also clears off the dead tissues in the wound and increases the production of collagen. The effectiveness of aloe vera has also been demonstrated in treating psoriasis, mouth sores, ulcers, bedsores, herpes infection, lichen planes ( an inflammatory condition of the skin characterised by the presence of itchy rashes ) and gingivitis.
Radiation therapy is a part of the cancer treatment in many patients and most often is associated with side effects such as redness, itching and pain. The potential of aloe vera in preventing these side effects have been evaluated in studies. Though the outcomes from these studies have been conflicting, it was found that aloe vera had modest effectiveness against the radiation effects when used in combination with a mild soap.
Aloe vera has been incorporated in facial tissues as a moisturising agent in order to minimise the soreness of the skin around the nose in individuals with cold and hay fever (an allergic reaction to pollen resulting in sneezing and running nose).
Improves digestive health
Aloe vera in its various forms has been recommended as a remedy for a number of digestive disorders. The juice of aloe vera has been found to be beneficial in treating indigestion, colitis, heartburn, constipation, diarrhoea and irritable bowel syndrome (a condition which presents as abdominal pain or discomfort along with diarrhoea or constipation or both in the absence of any abnormalities). The flushing effect of aloe vera juice not only helps to alleviate the discomfort caused by these conditions, but also aids to remove the harmful substances that collects in the intestines from our diet.
The leaf and gel of aloe vera are used to relieve the symptoms due to gastrointestinal irritation. The irritation of the digestive tract occurs as a result of dietary changes, stress, allergies, medications, changes in the gut microbial balance and environmental pollutants. The symptoms include vomiting, diarrhoea, pain, development of ulcers etc.
The outcomes from the scientific studies that have tested the efficiency of aloe vera in digestive disorders is conflicting. The first clinical studies that were conducted on aloe vera gel about six decades back reported its effectiveness in patients with peptic ulcer. Though the studies conducted on patients with irritable bowel syndrome did not produce satisfactory results, some encouraging results were brought into light in patients with ulcerative colitis (a condition involving the colon and the rectum leading to the development of ulcers) treated with aloe vera gel.
Gastroesophagial reflux disease (GERD) refers to one of the disorders of the digestive system wherein there is back flow of the contents of the stomach into the oesophagus (food pipe) resulting in heartburn. Regarded as one of the most common symptom of GERD, heartburn is felt as a burning sensation in the chest spreading out towards the mouth. Several factors such as being overweight, food habits in particular the type and amount of food consumed in relation to the bedtime, presence of anxiety/depression, physical inactivity contribute to its development. Studies conducted on the effectiveness of aloe vera syrup at a dose of 10ml/day for four weeks have reported alleviation of symptoms without any side effects.
Radiation proctitis is a condition caused as a result of radiation treatment for cancers involving the organs present in the pelvic area which include the rectum, prostate and the reproductive organs. Acute radiation proctitis occurs shortly after starting the radiation treatment and presents with cramps, diarrhoea, nausea, bleeding, urgency and pain while passing stools. Evidence from the studies conducted on the application of 3% aloe vera ointment have revealed its beneficial effects in relieving the symptoms such as diarrhoea and urgency as well as its protective effect against the symptoms of radiation proctitis.
The application of aloe vera cream thrice a day for six weeks has been shown to be effective in relieving the pain, bleeding and healing of anal fissures.
Strengthens immune system
The immune system is regarded as the first line of defense against the external invaders such as microbes (bacteria, fungi, parasites), environmental toxins and viruses. The complex interaction between the cells, organs and the chemicals that constitute the immune system have one simple task to achieve i.e., protect the body against illness. The cells that make up the immune system are the different types of white blood cells performing specific functions. While the cells such as neutrophils, macrophages and monocytes are known for their phagocytic action (capable of engulfing and digesting the foreign body), eosinophils, basophils and mast cells protect against parasitic invasions and development of allergies. On the other hand, lymphocytes control the activities of other white blood cells and produce specific antibodies so as to prevent recurrent infections.
The two categories of the immune system include innate and adaptive immunity. The innate immunity is present since birth and includes the skin, mucus membranes (a specialised protective layer that lines the body cavities and the organs) immune cells and chemicals. The adaptive immunity, as the name suggests develops after birth as a consequence of exposure to the external invaders. Here specialised cells called lymphocytes produce antibodies in response to the external agents. The interesting fact about adaptive immunity is that it continuously evolves to the changing external environment and keeps a good memory of all the exposures encountered, thus offering protection.
A strong immune system is vital to keep the harmful infections and illnesses at bay. Among the healthy lifestyle practices that have been advocated to strengthen the immune system, aloe vera stands as one of the strategies. It has been shown that aloe vera is capable of conditioning the cells of the immune system and enhance their activity. Studies have reported the ability of aloe vera to activate the macrophages thus increasing their scavenging activity. The immune enhancing activity of aloe vera has been attributed to the presence of acemannan, a polysaccharide present in aloe vera gel. In addition to strengthening the systemic immunity, this polysaccharide present in aloe vera gel has been shown to improve the activity of macrophages present in the intestines thus upgrading the intestinal immunity against microbes and harmful substances that are ingested through food.
Alleviates arthritis
The term arthritis describes the inflammatory disease concerning the joints, presenting with a range of symptoms including pain, stiffness, reduced movement and joint deformities. The potential of aloe vera in easing the arthritis symptoms have been explored in scientific studies. Aloe vera has been shown to lessen the joint and muscle pain in arthritis. The oral administration of aloe vera has the potential to reduce the chronic pain associated with osteoarthritis. The application of aloe vera gel over the swollen joints eases the pain, swelling and stiffness and this effect is attributed to its anti-inflammatory properties. Aloe vera has been incorporated in nimesulide emugel (nimesulide is a medication used for the relief of pain and inflammation) preparations as an effective remedy for arthritis.
Anticancer activity
It is a well known fact that aloe vera contains about 75 bioactive compounds and these are potentially attributed to the anticancer effects. However, the scientific evidence behind the anticancer activity of aloe vera is limited to studies on animal models and cell cultures. Aloe vera extracts have been found to cause cell death in breast and cervical cancer cell cultures. The anthraquinone aloe emodin present in aloe vera has been shown to be effective against oesophageal, gastric (stomach), colon, colorectal, lung, prostate, bladder, liver, pancreas, bone cancer, leukemia (cancer of the blood cells), lymphoma (cancer involving the lymphocytes) and melanoma (skin cancer).
Aloesin, an active compound in aloe vera has been demonstrated to protect against ovarian cancer. The polysaccharides present in aloe vera have the potential to suppress the pancreatic cancer cells. Aloe mannan, a polysaccharide has been found to be effective in preventing the growth of sarcoma (general term used to describe cancers that originate in the bones and soft tissues) in animal studies.
The reports that have emerged from the recently conducted clinical studies have proposed the effectiveness of aloe vera eye drops in reducing the growth of cancer involving the outer layer of the eyes i.e., conjunctiva and cornea. These studies have also demonstrated the ability of the aloe polysaccharide to protect against the harmful effects of tobacco such as cancer.
Though these findings are in the experimental stage, they provide insights about the anticancer effects of aloe vera for future research.
Antidiabetic activity
Diabetes is one of the most common metabolic disorders encountered globally causing a major public health burden. The hallmark of diabetes is the elevated blood glucose levels occurring as a result of insulin resistance or inadequate production of insulin or both. The use of herbs in the management of diabetes has been known since ages and still continue their foothold as a therapeutic strategy. Aloe vera is one such herb that has been investigated for its antidiabetic effects.
Emerging reports from the studies have supported the role of aloe vera in reducing the blood glucose levels. The bioactive compounds present in aloe vera have been said to have hypoglycemic potential though more clarity is needed to ascertain this. However, some studies have put forth the effectiveness of the sterols present in aloe vera in reducing the fasting blood glucose levels. Also the administration of aloe vera has been demonstrated to bring down the blood cholesterol and triglyceride levels in addition to the blood glucose levels. Animal studies have acknowledged the blood glucose lowering effect of aloe vera juice. The intake of aloe vera along with diabetic medications has been shown to enhance their action. In addition to diabetes, the ability of aloe vera to reduce the fasting blood glucose levels has been demonstrated in pre-diabetes as well.
The fact that oxidative stress contributes to the development and progression of diabetic complications has been supported by several studies. Oxidative stress occurs as a result of accumulation of harmful substances called free radicals in the body. These highly unstable molecules are removed time to time by the chemicals called anti-oxidants. When there is imbalance between their production and elimination, excessive amounts pile up in the body causing cell damage. Experimental studies conducted on aloe vera have shown its effectiveness in protecting against diabetic nephropathy (kidney disease).
Though more research is needed to ascertain the above findings, they provide some understanding about the antidiabetic potential of aloe vera. In order to put these findings into clinical practice, a hardcore evidence base is warranted.
Protects the liver
On a global note, liver diseases contribute to 2 million deaths annually posing a significant public health burden. The factors that mainly contribute to the death from liver diseases include, the complications occurring from cirrhosis, liver cancer and acute hepatitis. Liver cirrhosis is a condition associated with scarring of the liver leading to permanent damage. Some of the common causes of cirrhosis are viral infections, alcohol and non-alcoholic fatty liver disease (build up of excessive fat in the liver). Acute hepatitis, which is the sudden derangement of liver function occurs as a result of viral infections notably hepatitis A,B,C,D and E. Also, the intake of certain medications (antibiotics, painkillers etc.) and exposure to chemicals can also lead to acute hepatitis.
The reports emerging from some studies have demonstrated the potential of aloe vera to protect the liver against damage on exposure to certain agents. It is a well known fact that exposure to carbon tetrachloride (owing to its toxic effects its use has been banned by many industries though it is still used on a limited scale in some industries)causes liver damage and studies have revealed that aloe vera protects against such damage. The protective effect of aloe vera leaf extract on lindane (an insecticide that is used to treat lice and scabies. Although banned by many countries, it is still available in some countries) has produced promising results. One of the significant outcome from the recent studies is the ability of aloe vera extract in offering protection against liver damage caused by paracetamol and azathioprine (a medicine used in the treatment of rheumatoid arthritis and also to prevent kidney transplant rejection).
The term ischemia/reperfusion (I/R) injury refers to the injury which an organ encounters after restoration of the blood supply (reperfusion) especially when preceded by a lack of blood supply (ischaemia). This type of injury can occur during organ transplants, coronary bypass and in conditions such as stroke and heart attacks. The consequence of this injury is organ damage resulting in failure. Recent studies have revealed the potential of aloe vera to prevent such an injury to the liver. However, further research is needed to ascertain its application in liver transplantation.
Protects against gastric ulcer
A gastric ulcer can be described as an open sore that develops in the inner protective layer of the stomach. It is a well known fact that stomach has an acidic environment owing to the presence of hydrochloric acid. The stomach is protected by a thick mucosal layer on the inner side which naturally protects the stomach against the harmful effects of the acid. Any damage that occurs to the mucosal lining exposes the stomach to the acid leading to the development of ulcers. Some of the common causes of gastric ulcer are bacterial infection with Helicobacter pylori, smoking, medications and alcohol intake.
The protective effect of aloe vera in the prevention and treatment of gastric ulcers has been supported by studies. The administration of aloe vera extract has been shown to promote healing of gastric ulcers. Also, aloe vera given in combination with gastric ulcer medications has been shown to produce enhanced response in terms of decrease in inflammation as well as the size of the ulcer. The above effects of aloe vera have been attributed to its components such as polysaccharides and anthraquinones.
Protects the heart
Cardiovascular diseases are one of the leading causes of death and disability worldwide. As per the estimates put forth by the WHO, they contribute to 31% of deaths on a global scale every year. Some of the commonly encountered cardiovascular diseases include coronary heart disease (a condition that occurs as a result of the accumulation of fatty substance called plaques inside the blood vessels of the heart), myocardial infarction (commonly called ‘heart attack’, this occurs when there is lack of or complete blockage of blood flow to the heart muscle), peripheral vascular disease (a disease commonly involving the blood vessels of the feet and legs) and hypertension (commonly called as ‘high blood pressure’). An array of risk factors such as high blood cholesterol, diabetes, hypertension, obesity, smoking and unhealthy dietary habits are associated with the development of heart diseases.
It is a well known fact that the management of cardiovascular diseases has undergone drastic developments in the last few decades owing to the advancement in scientific research. However, the herbal medicines have been considered as a potential approach owing to their better tolerability. But their long term safety, effectiveness and possibility of them interacting with the medications should be taken into consideration.
Emerging reports from various studies have revealed the effectiveness of aloe vera in combating the risk factors that lead to the development of cardiovascular diseases such as hypertension, high blood sugar and cholesterol, atherosclerosis and obesity. Preliminary reports emerging from the studies have pointed to the protective effects of aloe vera gel on the heart owing to its ability to fight oxidative stress and inflammation. Emerging reports have revealed the potential ability of aloe vera to balance the blood glucose levels in diabetics. In addition to this, the blood lipid lowering effect of aloe vera, especially reductions in the triglycerides, cholesterol, low density lipoprotein (LDL- bad cholesterol) and very low density lipoprotein (VLDL) have been reported. Studies also support the potential of aloe vera to fight against obesity, atherosclerosis and high blood pressure.
Though the above mentioned effects have been attributed to the various bioactive compounds present in aloe vera, research conducted on barbaloin and aloe-emodin have revealed their ability to prevent the formation of atherosclerotic plaques and reduce the cholesterol levels. However, more extensive research is needed to ascertain the heart protecting activities of aloe vera in order to apply in clinical practice.
Laxative effect
A laxative is a medication that assists in the passing of stools in the presence constipation. The use of aloe vera as a laxative has been known since the ancient times. The laxative effect of aloe vera is due to the presence of anthraquinones, which are considered to be natural laxatives. They have been shown to increase the water content of the intestines in addition to enhancing the mucus production. These effects are said to stimulate the intestinal movements thus relieving constipation.
Protects the skin
It is a well known fact that the natural products derived from plants have a multitude of beneficial effects on the skin. The bioactive compounds present in aloe vera have been attributed to their skin protecting effects. The mucopolysaccharides present in aloe vera keep the skin hydrated. Aloe vera also enhances the activity of specialized cells called fibroblasts to produce collagen and elastin, thus maintaining the elasticity of the skin. It protects the skin from flaking/peeling thus keeping it soft. The amino acids and zinc present in aloe vera also contribute to the softness by conditioning the hardened skin cells, in addition to tightening the skin pores.
The moisturizing ability of aloe vera has been investigated in the management of dry skin related to occupational exposure. It was found that the use of aloe vera gloves brought about significant improvement in skin health in terms of reductions in the redness and wrinkling.
Studies exploring the effectiveness of aloe vera gel in treating mild/moderate acne have revealed its ability to combat acne when used in combination with tretinoin cream. Also, the comparative analysis of creams containing a combination of propolis, tea tree oil, aloe vera as well as mangosteen rinds, aloe vera and green tea extracts have revealed their efficiency over conventional acne medications.
Promotes hair health
The role of aloe vera in promoting the hair as well as the scalp health has been known since ancient times. However, the scientific studies conducted in the last few decades have attempted to decode the beneficial effects of aloe vera in specific hair conditions. The research conducted on a herbal preparation for hair loss due to dandruff, with aloe vera as one of the important ingredients, has revealed significant improvements in the symptoms such as itching, irritation and dryness. Also, considerable reduction in the hair loss with enhanced hair strength was noted. Although the herbal preparation was a mixed formulation, considering the fact that aloe vera was one of the main ingredients, it can be said that this herb has the potential to improve the symptoms associated with dandruff.
Seborrheic dermatitis refers to an inflammatory skin condition that resembles dandruff. It presents as large itchy white or yellowish patches in the scalp, face and the trunk. One of the studies exploring the effectiveness of skin lotion containing aloe vera as the main ingredient in individuals with seborrheic dermatitis has revealed significant reduction in the symptoms.
The research conducted on the beneficial effects of adding aloe vera to skin and the hair products have revealed the potential of aloe vera to protect against bacterial infections of the scalp as well as from the UV rays of the sun.
Aloe vera can be used for the hair and the scalp in the form of gel or juice. However, the evidence behind drinking aloe vera juice in order to specifically improve the hair health is sparse. Though the application of aloe vera is a simple and practical remedy, it may leave behind residues on the hair. For direct effect on the hair follicles, it is recommended to get a precise natural hair product containing aloe vera. It also serves as a natural moisturizer and conditioner for the hair and the scalp. Aloe vera juice when combined with water and sprayed on to the hairs serves as a leave-in conditioner which dose not require washing.
Fights infection
Infection occurs when harmful germs get into the body and start to grow. The harmful germs in question may be either bacteria, viruses, fungi and parasites. The infections get transmitted either by coming into direct contact with another infected person, through animals and insects, consuming contaminated food and water and from the environment. However, it should be remembered that not all infections lead to disease. The disease process occurs when the cells of the body get affected leading to the development of signs and symptoms of illness.
The anti-infective properties of aloe vera have been explored in different studies. However, the majority of them have focused on their anti-bacterial effects. The two bacteria that have dominated the scientific studies are Staphylococcus aureus and Pseudomonas aeruginosa. Talking about the infections caused by these bacteria, Staphylococcus aureus is one of the most frequent bacterial infections encountered. It is connected to infections involving the skin and soft tissues, bones, lungs, heart, digestive system and urinary system. On the other hand, Pseudomonas aeruginosa infections pose special challenges due to their tendency to cause severe infections especially in individuals with low immunity. Aloe vera extracts and gel have been shown to prevent the growth of these two bacteria that are difficult to treat due to the development of drug resistance. In addition to this, aloe vera has been shown to offer protection against other bacteria such as Helicobacter pylori (causes stomach infection and ulceration), Escherichia coli (Though considered as a friendly bacteria residing in the intestine, some members of this group cause illness like diarrhoea, dysentery, urinary infections, pneumonia and abdominal infections), Enterococcus fecalis (associated with dental infections) and Mycobacterium tuberculosis (causes TB).
Recent studies exploring the antifungal effects of aloe vera against the fungus Candida albicans have produced encouraging results. Though this fungus is normally present in the digestive system and other parts, excessive growth of the same can lead to infections affecting the urinary tract, genital tract, oral cavity and the skin. Aloe vera gel extracts have been shown for their potential to prevent or treat oral fungal infections. On the other hand, aloe vera tooth paste has been shown to enhance the oral hygiene and protect against fungal infections. However, more extensive studies are needed to ascertain the antifungal effects of aloe vera for clinical application.
The antiviral activity of aloe vera has been studied for herpes simplex type 1 (causes oral herpes or cold sores which are small groups of painful blisters) and H1N1 subtype influenza virus (causes respiratory infection). The outcome has shown encouraging results wherein aloe vera was found to prevent the growth and multiplication of these viruses. The antiviral potential of aloe vera has been extended to covid-19. However, more extensive studies are warranted.
It is a well known fact that malaria is a parasitic infection transmitted by the bite of female Anopheles mosquito. The parasite that is responsible for causing malaria is Plasmodium. Among the species that are capable of infecting humans, it is known that Plasmodium falciparum malaria carries the highest risk with regards to the complications and survival. One of the studies that explored the potential of aloe vera extracts obtained from the aloe vera plants from six separate climatic regions in India revealed that the aloe vera from the colder climates was more effective against the malarial parasite.
Prebiotic effects
The human intestine harbours thousands of bacterial colonies that play an important role in maintaining the overall health and well being of an individual. Prebiotics are regarded as a type of plant fiber that encourages the growth of beneficial bacteria in the intestine. The acemannan present in aloe vera has the potential to enhance the digestive health by bringing about an increase in the population of beneficial bacteria involved in the production of short chain fatty acids. These are produced by the fermentation of dietary fibers in the large intestine and are highly regarded for their innumerable health benefits. Also the acemannan and fructans have been found to increase the population of Bifidobacterium, an important member of the gut microbial ecosystem.
Safety of aloe vera products
Aloe vera whole leaf extract
This is also called whole leaf aloe vera juice or non-decolorized whole leaf extract. As per the name, this extract has all the layers of the leaf including the gel as well as the sap (latex). Application or oral intake of aloe vera can give rise to skin irritation, rashes, abdominal pain and diarrhoea in individuals who are allergic to the plants that belong to the same family as aloe vera, for example onion. Though there are no clinical studies regarding the toxic effects of aloe vera, isolated case reports of toxic reactions such as massive bleeding and renal failure have been reported. On the other hand, acute hepatitis (inflammation or injury to the liver causing deranged liver enzyme levels) has been more frequently reported from many parts of the world.
Aloe vera latex
The latex of aloe vera is a yellowish-brown coloured substance that is located between the outer layer of the leaf and gel. The latex has a long history as a remedy for constipation. Many countries have incorporated the aloe latex as a component of the herbal laxative formulations. Studies have reported a significant number of side effects with aloe latex. While potentially it is safe for short term use, prolonged use of the latex has been linked to abdominal pain, vomiting, diarrhoea, electrolyte imbalance and enlargement of the colon. Also, the aloe latex should not be consumed by pregnant and lactating woman due to the risk of miscarriage or premature labor and the likelihood of diarrhoea in infants.
Aloe vera decolorized whole leaf extract
This is prepared by the activated carbon treatment of aloe vera whole leaf extract and is also called as ‘ whole leaf aloe vera gel’. Here the latex part of the plant which has the laxative effect is removed. Despite the presumption to give less side effects compared to the whole leaf extract, the main drawback is the significant changes in the chemical composition affecting the health promoting components following treatment with activated carbon.
Aloe vera gel
This is a transparent jelly like substance obtained from the pulp of the leaf by mechanical extraction. Aloe gel has been used since many decades safely for the treatment of wounds and various skin conditions. Apart from minor side effects such as pain, discomfort and rashes, no other serious adverse effects were observed. However, there have been isolated cases of severe skin reactions in response to the usage of aloe vera gel.
Though these adverse effects need in-depth clinical analysis backed by extensive scientific studies, it is worth remembering the beneficial effects of aloe vera keeping in mind their potential toxic effects.
Summary
*Aloe vera had the reputation of a medicinal and cosmetic herb since ancient times.
*The botanical name of aloe vera is Aloe barbadensis miller, also called ‘true aloe’.
*The pulp or the gel constitutes the main volume of the plant and the leaf.
*About 75 bioactive compounds linked to health benefits have been recognised in aloe vera.
*The multifaceted role played by aloe vera in human health have been brought into light by scientific studies.
*The wound healing properties of aloe vera has been known since ancient times with modern research demonstrating its effectiveness towards many types of wounds.
*The effectiveness of various forms of aloe vera as a remedy for digestive disorders is supported by scientific evidence.
*Aloe vera has been shown to strengthen the immune system especially the activity of macrophages.
*Aloe vera reduces the pain and stiffness associated with arthritis.
*Though aloe vera has been demonstrated to have anticancer potential, the evidence behind this is limited to animal studies.
*The ability of aloe vera to reduce the blood glucose levels in diabetes and prediabetes warrants more research.
*Emerging evidence supports the effectiveness of aloe vera in protecting against liver damage on exposure to specific agents.
*Aloe vera extract has been shown to alleviate the inflammation and promote healing of gastric ulcers.
*Preliminary reports have supported the heart protecting effects of aloe vera in terms of prevention of atherosclerotic plaque formation and cholesterol reduction.
*The laxative effect of aloe vera is known since antiquity and is attributed to the presence of anthraquinones.
*Aloe vera has established a strong foothold in the cosmetic industry owing to its amazing benefits in promoting the skin health.
*In addition to serving as an excellent hair conditioner, aloe vera has been found to be effective against dandruff and seborrheic dermatitis.
*Studies have demonstrated the potential of aloe vera to fight and protect against infections involving bacteria, viruses, fungi and parasites.
*The acemannan and fructans present in aloe vera have been found to promote the colonisation of healthy gut bacteria.
*Though adverse effects have been reported with the use of aloe vera products, more extensive studies are needed to ascertain the same.
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