Chemical and Biological Properties of Lauric Acid : A Review

S Sandhya. Health, growth, immunity and development of infants depend on their breast milk consumption. Lauric acid is one important constituent among the various nutritional factors that complex together to form the breast milk. This medium chain triglyceride with 12-carbon atom chain component has many medicinal values. Lauric acid has been found to have present in 6.2% of human breast milk, 3.1% of goat milk and 2.9% in cow milk. Besides being present in milk its presence has been recognized in plant sources (mainly oil)-coconut, cohune and palm kernel oil in common. Coconut oil extracted from a single one contains approximately 50% of Lauric acid. The isolation of Lauric acid from plant sources hence is easier and convenient than animal sources with increase in the percentage of component extracted. Researchers conducted study on Lauric acid suggested, it to be a non-toxic, safe to handle component with long shelf-life. It is even easily absorbable and digestible by the body. This component has many therapeutic properties in human’s health as such – prevention from various skin diseases, decrease in the bad cholesterol level, body weight deduction. Even antioxidant, antibacterial, antifungal, antiviral and anticancer capabilities are present in this Lauric acid. But, till date the evidence is currently ambiguous as to whether Lauric acid supplementation has a significant effect on body.This article gives a review on the beneficial properties of Lauric acid with details of natural sources to isolate this specific component. Even the probable biological applications of it are given in this review which may ponder a path to future drug development process in various aspects.


S Sandhya.
Health, growth, immunity and development of infants depend on their breast milk consumption. Lauric acid is one important constituent among the various nutritional factors that complex together to form the breast milk. This medium chain triglyceride with 12-carbon atom chain component has many medicinal values. Lauric acid has been found to have present in 6.2% of human breast milk, 3.1% of goat milk and 2.9% in cow milk. Besides being present in milk its presence has been recognized in plant sources (mainly oil)-coconut, cohune and palm kernel oil in common. Coconut oil extracted from a single one contains approximately 50% of Lauric acid. The isolation of Lauric acid from plant sources hence is easier and convenient than animal sources with increase in the percentage of component extracted. Researchers conducted study on Lauric acid suggested, it to be a non-toxic, safe to handle component with long shelf-life. It is even easily absorbable and digestible by the body. This component has many therapeutic properties in human's health as suchprevention from various skin diseases, decrease in the bad cholesterol level, body weight deduction. Even antioxidant, antibacterial, antifungal, antiviral and anticancer capabilities are present in this Lauric acid. But, till date the evidence is currently ambiguous as to whether Lauric acid supplementation has a significant effect on body.This article gives a review on the beneficial properties of Lauric acid with details of natural sources to isolate this specific component. Even the probable biological applications of it are given in this review which may ponder a path to future drug development process in various aspects.

Introduction:-
Lauric acid (LA) (Fig. 1) -a medium-chain triglyceride (MCT) is widely acknowledged as a "healthier" saturated fat. MCT molecules can be rapidly absorbedby body because of their ability to hydrolyze completely into fatty acids and glycerol by pancreatic lipase. Hence being an MCT itself lauric acid's specific chemicalstructure also allows body to absorb them as whole which makes them more easily digestible 1 . Even when pancreatic juice secretion is reduced due to diseases,medium chain fatty acids have the ability to get easily digested and absorbed 2 . LA is also used as source of direct energy because body processes them as carbohydrates 1 . Found in abundance from natural resources it is inexpensive, has a long shelf-lifeis non-toxic and safe to handle. Like other fatty acids, LA is also said toincrease total serum cholesterol but it is mainly attributed to increase the "good" blood cholesterol i.e.high-density lipoprotein (HDL) which helps to decrease atherosclerotic risk in the body 3, 4 . This is because medium chain fatty acids are notreadily re-synthesized to triacylglycerol like long chain fatty acids. Instead these MCT are mostly bound with albumin as free fatty acids, transferred into portal blood, and transported to the liver, where they are transported to mitochondria and rapidly degraded through oxidation 2 . Although the net effects of LA, to decrease therisk of coronary artery disease till date remains uncertain 3 . The saturated fatty acid, LA consist of 12-carbon atom chain, also known as n-Dodecanoic acid, Dodecylic acid, Dodecoic acid, Laurostearic acid, Vulvic acid, 1-Undecanecarboxylic acid and Duodecylic acid. Fig. 1 shows the chemical structure of LA. It is a white, powdery solid with a faint odor of bay oil that is insoluble in water 5 . If a type of carboxylic acid donates hydrogen ions and a base is present to accept them it forms neutralization between acid and base that produces water plus a salt as byproducts. This neutralization process is mainly used for the production of soaps and cosmetics. LA when neutralized with sodium hydroxide produces sodium laurate, which is soap 6 . It is also used for molar mass identification ofunknown substances via the freezing-point depression method where LA mixes with unknown substance by melting and cooling process. And then the molar mass of the unknown substances may be determined by recording the temperature at which the mixture freezes. Lauric acid is thought to be convenient because its melting point when pure is relatively high (43.8 °C) 7 . Among the plant sources, many vegetables fats contain LA, particularly in coconut and palm kernel oils. The amount of LA found in foods is safe for health but there isn't enough information whether it can be used as medicine. Among animal resources LA is found in human breast milk, cow's milk and goat's milk 5 too. But the mechanism of extraction from plant resources is much efficient than that from animal resources. The mechanism by which LA is consumed by the body is -more amount of it gets converted into monolaurin (glyceryl laurate). Finally, this monolaurin gets converted into HDA (2-Hexadecynoic acid) version of cholesterol and prevent body from bacterial infection. Monolaurin is commonly used in deodorants 8 . Fig.2 depicts the chemical structure ofmonolaurin. This review of LA, studied by us is the very first of its kind besides it has depicting the numerous essential medicinal values. This paper also aims to bring researchers time and attention on chemical and biological properties along with identification of natural sources to isolate and applications of lauric acid for future drug development process.

Chemical Properties of lauric acid:-
Being a component of triglyceride, LA is the type of MCT component foundin human breast milk and helps boosting metabolism of the body. At normal roomtemperature, a MCT component looks colorless, transparent and low viscous "waterlike" liquid oil and odorless components 2 . With unique chemical and biochemicalproperties this fatty acid is used for neutralization and molar mass identification ofunknown substances via the freezing-point depression method. This dodecylic acidcontaining numerous medicinal values may cure many diseases with its unique abilityof being easily absorbed and digested by the body 1 . Table 1 represents the chemical properties of LA in tabular form.LA is an insoluble carboxylic acid that can donate hydrogen ions if a base ispresent to accept them. The reaction of LA with bases form neutralization, areaccompanied by the evolution of substantial amounts of heat. This neutralizationprocess is mainly used for the production of soaps and cosmetics. Lauric acid when neutralized with sodium hydroxide produces sodium laurate, which is soap 7 .In an aqueous solution, carboxylic acids may react with active metals to form gaseoushydrogen and a metal salt. This phenomenon alsogenerate flammable or toxic gases along with heat by reacting with sulfites, nitrites, thiosulfates (to give H 2 S and SO 3 ), dithionites (SO 2 ). They can even generate a harmless gas (carbon dioxide) but still heat when they react with carbonates and bicarbonates. Other chemical properties of carboxylic acids are they may initiate polymerization reactions and they often catalyze (increase the rate of) chemical reactions like other acids 14 . Solubility in methanol 12.7 g/100 g (0 °C),120 g/100 g (20 °C),2250 g/100 g (40 °C) 15

Biological properties of Lauric Acid:-
The LA may be used in the daily diet for appreciable amount to prevent many diseases. But the only way one could receive LA is from natural sources. Table 2illustrates the list of natural sources with approximate percentage of lauric acid in them. Because of its easily absorbable and digestible properties by body a new breakthrough in research may be found that a natural LA is very safe to consume. LA is mostly found in plant material such as vegetables, coconut oil, cohune oil, palm kernel oil etc. They can be easy natural sources for isolating the acid in huge amount to study its biological activity for the development of new drug in future. Now a day's medium chained fatty acid have attracted more attention as being part of a healthy diet, because they are absorbed directly into the portal vein, transported rapidly to the liver for β-oxidation, and thus increase diet-induced thermo genesis. By β-oxidation process LA is directly metabolized with successive removal of two carbon (acetyl) fragments from the carboxyl terminal end of the molecule 16 . This acid may also be metabolized by a route involving hydroxylation of its twelfth (ω) carbon atom by certain cytochrome P45023 4A isoforms, followed by the oxidation of ω hydroxyl group to a carboxylic acid by cytosolic alcohol and aldehyde dehydrogenases 17, 18, 19 . In the 1950s for the first time MCT was recommended as clinical dietary supplements of malnutrition syndromes, because of its rapid absorption and solubility. In the 1970s, started it's utilization as edible oil and currently used as additive for foods, base material of pigments, and mold and lubricating oil in food production 2 .

Antibacterial activity:-
Laurostearic acid's use may prevent skin diseases becauseit has the ability to fight against various types of bacterial infections. As par example, from many decades'people have been using coconut oil as a cure for fungal and bacterial infections on skin. This LA is one of the main ingredients of coconut oil (approx~50%) but study on use of pure LA directly to cure skin diseases is less evidenced. Recently TeruakiNakatsujiet al. (2009) reported that LA shows the inhibitory effect on the growth of skin bacteria such as Propionibacteriumacnesisolated from the most common disorder of human skin i.e. acne vulgaris that affects up to 80% of individuals in their lives 20 . Atopic Dermatitis (AD) is again a chronic skin disease where the skin turns dry and is readily infected and colonized by Staphylococcus species with an increased penetration of allergens. This is characterized by defects in the epidermal barrier function and cutaneous inflammation. In this phenomenon there is an increased transepidermal water loss where the ability of the stratum corneum to hold water is impaired thus causing decreased skin capacitance and hydration 21, 22, 23 . However, researches have reported that Virgin Coconut Oil [(VCO) containing ~50%of LA] shows effect on AD compared to mineral oil and virgin olive oils 21, 22 .Thus, the excellent antimicrobial properties of LA may increase the demand of it in the pharmaceutical industries. Moreover monolaurin, the monoglyceride derivative of LA have even more potent antimicrobial properties against lipid-coated RNA and DNA viruses, numerous pathogenic gram-positive bacteria, and various pathogenic protozoa reported by Paul May (2012) 8 .In addition, James and Rahman (2005) 24 reported that coconut oil can be used as a skin moisturizer, as engine lubricant and even transformer oil. Even the acids derived from coconut oil may be used as an herbicide was also reported 24 .

Antifungal activity:-
In a recent study, Ogbolu DO et al.(2007) 25 reported that coconut oil had also shownantifungal activity against Candida species at 100% concentration isolated from clinical specimen compared to fluconazole. Coconut oil hence should also be used in the treatment of fungal infections in view of emerging drug-  32 reportedthat Lauric acid induced apoptosis in Caco-2 (p < 0.05) and IEC-6 cells (p < 0.05) bymodifying glutathione (GSH) levels. This occurred when LA modifiedthe phases ofcell cycle in Caco-2 and IEC-6 intestinal cell lines and generated reactive oxygenspecies (ROS) compared to butyrate, a short chain fatty acids.

Decreases Total Cholesterol level and Cardiovascular Disease:-
Saturated fats have the ability to increase cholesterol level in our body and soconsumption of it in daily life should be avoided. In the recent world, hence all thepeople are suggested by doctors to avoid consummation of saturated fats as much aspossible in food staff for living healthy life. However, MCT saturated fats have thepower to increase good cholesterol i.e. high-density lipoprotein (HDL) in blood. Thusconsumption of MCT products by people who are sensitive to cholesterol maydecrease the risk of coronary artery disease in them and even may actually help todecrease level of total blood cholesterol 1 , in contrast to long chain triglyceridesaturated fat that enhances blood bad cholesterols i.e. low-density lipoprotein (LDL)and increase the level of triglycerides in blood serum. Some studies also suggestedthat VCO shows the potential beneficiary effect in lowering lipid levels in serum andtissues and LDL oxidation by physiological oxidants 33 .

Decreases Body weight:-
Although many recent studied reported that use of coconut oil as dieteticsupplementation does not cause dyslipidemia and seems to promote a reduction inabdominal obesity of women presenting waist circumferences (WC) >88 cm(abdominal obesity). However LA directly used as dietetic supplement decreases thebody weight 1,

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.An article form nutrition review suggested that MCTs have fewercalories per serving, roughly 8.3 calories per gram rather than the standard 9 caloriesper gram compared to long-chain triglycerides, the type of other saturated fats 1 .Many researchers also suggested that a diet rich in MCTs may potentially help todecrease body weight as a result of choosing to consume fewer calories, as well as areduction in waist circumference compared to a diet rich in long chain triglycerides 1 .

Conclusion:-
Lauric acid (LA) being one of the major components of coconut oil and a MCTcomponent which may be having the ability to decrease cholesterol level and decreasebody weight. Even LA may be effective against many microorganisms and can be takenon a daily basis, given that evidence suggests it does not create antiviral orantibacterial resistance like coconut oil because approximately 50% of total fat ofcoconut oil consist of LA. The main point of this review is that LA is very commonsource of food, inexpensive, non-toxic, safe to handle and easily found from naturalsource. To isolate in huge amount can be very cost efficient and may be used as drugas active agent against various disease in future. But more clinical studies are neededto approve LA as supplement for human health.