Myristic acid: Description, Preparation method and Main application

Introduction

Myristic acid (CAS No. 544-63-8) is a fatty acid found widely distributed among plant and animal fats. Myristic acid (Figure. 1) is a 14-carbon, straight-chain saturated fatty acid. The substance exists at room temperature as white or yellowish glossy crystals with a faint, waxy-oily odor, detectable at 10 mg/kg; it may have a more acid–rancid smell in aged commercial material due to trace amounts of unsaturated contaminants. The taste is similarly waxy and bland. Additional descriptive characteristics and common synonyms are provided in Table 1[1].

Source and preparation method

Myristic acid is a solid organic acid usually obtained from coconut oil, nutmeg butter (Myristica fragrans Houtt), palm seed oils, and milk fats. Seed oils of the plant family, Myristaceae, contain the largest amounts of myristic acid (up to 80%), but small amounts have been measured in most animal fats and vegetable oils. According to the CTFA (now the Personal Care Products Council [the Council]), myristic acid is produced commercially by the saponification and fractionation of animal or vegetable fats and oils. The isolated acid fraction is hydrogenated to produce the saturated fatty acid [2]. The isolation of myristic acid from nutmeg was first reported in 1926. Its presence in significant quantities in sperm whale oil was reported in the mid-1940s. Earliest reports of its synthesis date to the late 1940s and early 1950s [3].

The following methods have been used in the preparation of myristic acid: isolation from tail-oil fatty acids, from 9-ketotetradecanoic acid; by electrolysis of a mixture of methyl hydrogen adipate and decanoic acid, by Maurer oxidation of myristanol; and from cetanol. The most common means of preparation is by fractional distillation of hydrolyzed coconut oil, palm kernel oil,or coconut acids [2].

Main application areas

Application in food and daily chemical products[1]

In the food industry, myristic acid is used as a multipurpose food additive and flavor adjuvant, as a defoaming agent, and as a coating on fresh citrus fruits. Myristic acid is approved for food uses by FDA, EC, FEMA, JECFA, and CoE. Food uses of myristic acid include that of a multipurpose food additive and flavor adjuvant, as a defoaming agent and as a coating on fresh citrus fruits. Its use is said to result in a waxy mouthfeel that can be synergistically pleasing in conjunction with other organoleptically active ingredients. The International Organisation of Flavor Industries has classified myristic acid as "flavor identical to natural flavor from aromatic raw materials or chemically identical synthesized materials". FEMA and National Association of Chewing Gum Manufacturers reported food uses of myristic acid. Myristic acid is safe to be consumed below 37.0 mg, daily.

It is also employed in the soap and cosmetics industries where it is used in the manufacture of the corresponding alkali salts, in the synthesis of perfume esters, as well as a simple "cutting" agent in various flower absolutes, essential oils, etc. Becker LC's report [2] had addresses the safety of the inorganic salts and esters of various fatty alcohols of myristic acid. Most of the esters are used as skin conditioning agents in many types of cosmetics in a range of concentrations. Myristate esters are readily hydrolyzed to the corresponding alcohols and acids, which are then further metabolized. Myristate salts readily dissociate in any likely cosmetic formulation. The Cosmetic Ingredient Review (CIR) Panel recognized that much of the data supporting the ingredients in this group were previously reviewed in safety assessments for related ingredients. Where specific data did not exist, the Panel considered structure activity relationships in determining the safety of these ingredients as used in cosmetics. The Panel determined that myristic acid and its salts and esters are safe as cosmetic ingredients in the current practices of use and concentration.

Application in Pharmaceutical field

Myristic acid is also approved by FDA for use as a pharmaceutical excipient [4]. Studies have shown that myristic acid features some pharmacological activities. A study has found that myristic acid exhibited higher antioxidant activity, compared to other saturated fatty acids, including lauric (C12:0), palmitic (C16:0), and stearic acids (C18:0) [5]. Thus, there is a possibility that MA could play a role as a better antioxidant among the saturated fatty acids. MA was also shown to facilitate the conversion of α-linolenic acid to docosahexaenoic acid (DHA), where both are types of polyunsaturated fatty acids (PUFA) [6]. Diabetes mellitus (DM) may lead to testicular-related infertility while myristic acid is beneficial to lower hyperglycaemia.Takato et al. [7] demonstrated that chronic oral administration of myristic acid was able to increase the glucose uptake in the myotubes of skeletal muscles, resulting in the attenuation of hyperglycaemia. In addition, myristic acid not only exhibits certain anti-inflammatory activity by upregulating the level of IL-10 in macrophages, but also it promote the proliferation and differentiation of neural stem cells in vitro, thereby improving cognitive decline caused by aging. These research findings suggest that myristic acid is likely involved in regulating the expression of inflammatory markers in macrophages associated with age-related diseases.The anti-inflammatory and anti-nociceptive actions of myristic acid have also been previously reported by Alonso-Castro AJ et al.[8]. The results suggest that myristic acid induced anti-inflammatory effects in LPS-stimulated macrophages through the participation of IL-10. The antinociceptive effects of MA are attributed to the participation of the nitrergic system. Previous studies have also shown that myristic acid can cause Ca²⁺imbalance in myocardial cells Ca²⁺oscillations and inflammatory pathways are involved in the formation of osteoclasts, which have a significant impact on the stability of the bone microenvironment [9].

Other applications: Myristic acid can also be used to prepare myristate esters and myristate salts, polyvinyl chloride heat stabilizers and plasticizers, as well as used as lubricants, pigment dispersants, printing ink additives, etc.

In summary, myristic acid is an important saturated fatty acid widely used in multiple fields.

References

[1] Burdock GA, Carabin IG. Safety assessment of myristic acid as a food ingredient. Food Chem Toxicol. 2007;45(4):517-529.

[2] Becker LC, Bergfeld WF, Belsito DV, et al. Final report of the amended safety assessment of myristic acid and its salts and esters as used in cosmetics. Int J Toxicol. 2010;29(4 Suppl):162S-86S.

[3] Stecher PG, Windholz M, L et al., Myristic acid. In: The Merck Index. An Encyclopedia of Chemicals and Drugs. Merck and Company, Rahway, NJ, 1968;709.

[4] FDA. Inactive ingredient guide. Myristic acid. Food and Drug Administration; Center for Drug Evaluation and Research; Office of Management, Rockville, MD, 1996; 84.

[5] Henry GE, Momin RA, Nair MG, Dewitt DL. Antioxidant and cyclooxygenase activities of fatty acids found in food. J Agric Food Chem. 2002;50(8):2231-2234.

[6] Legrand P, Rioux V. The complex and important cellular and metabolic functions of saturated fatty acids. Lipids. 2010;45(10):941-946.

[7] Takato T, Iwata K, Murakami C, Wada Y, Sakane F. Chronic administration of myristic acid improves hyperglycaemia in the Nagoya-Shibata-Yasuda mouse model of congenital type 2 diabetes. Diabetologia. 2017;60(10):2076-2083.

[8] Alonso-Castro AJ, Serrano-Vega R, Pérez Gutiérrez S, Isiordia-Espinoza MA, Solorio-Alvarado CR. Myristic acid reduces skin inflammation and nociception. J Food Biochem. 2022;46(1):14013.

[9] Cecatto C, Amaral AU, da Silva JC, et al. Metabolite accumulation in VLCAD deficiency markedly disrupts mitochondrial bioenergetics and Ca2+ homeostasis in the heart. FEBS J. 2018;285(8):1437-1455.

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