COCONUT OIL FRACTIONATION, LAURIC ACID CONTENT, AND TRANSDERMAL PERMEATION ENHANCEMENT: A NARRATIVE REVIEW

Coconut oil (Cocos nucifera L., Arecaceae), known classically as Narikela Taila, occupies a uniquely positioned chemical space among edible carrier oils. Its triglyceride matrix is dominated by medium-chain fatty acids (MCFAs), with lauric acid (C12:0) alone accounting for 45-52% of total fatty acids and the combined C8-C12 MCFA fraction reaching approximately 62%. This narrative review synthesises 46 published sources (42 peer-reviewed studies and 4 classical Ayurvedic primary texts) across phytochemistry, lauric acid biochemistry, fractionation chemistry, transdermal permeation, and dermatological applications, with the integrated aim of evaluating coconut oil as a periumbilical (Nabhi-route) carrier in Ayurvedic formulation. Phytochemical analysis highlights the compositional and processing-grade distinction between virgin coconut oil (VCO), which retains phenolic antioxidants (10-20 mg gallic acid equivalents / 100 g) and trace tocotrienols, and refined-bleached-deodorised (RBD) coconut oil, which retains the fatty-acid skeleton but loses ~85% of polar phytochemicals. Fractionation chemistry allows separation of the liquid medium-chain triglyceride (MCT) fraction-enriched in tricaprylin (C8) and tricaprin (C10)-from the higher-melting C12+ stearin fraction, yielding a pharmaceutical-grade carrier with a melting point below 5°C. Mechanistic review of lauric acid identifies four convergent bioactivities relevant to topical Ayurvedic formulation: (i) penetration enhancement via reversible disruption of stratum corneum lipid lamellae, with reported flux enhancement varying substantially by permeant and test conditions across published studies; (ii) in-situ monolaurin formation conferring antimicrobial activity against skin commensal organisms in published in-vitro studies; (iii) skin-emollient and barrier-reinforcing activity through squalene-mimetic lipid chemistry; and (iv) an exceptionally favourable general irritation–sensitisation profile; paediatric-specific topical safety data are addressed separately as a knowledge gap rather than assumed. Relevance to Nabhi-route application is supported by coconut oil's general skin-compatibility profile and its mechanistic basis in lauric acid biochemistry, with paediatric-specific topical application treated as an area requiring dedicated future evidence rather than assumed (Section 8.2). The review identifies five standardisation and evidence gaps and proposes a quality-control framework for coconut oil and its fractionated form in AYUSH-compliant medicated oil preparation.

• Persley G.J. (1992). Replanting the Tree of Life: Towards an International Agenda for Coconut Palm Research. CAB International, Wallingford, UK.
• Sharma P.V. (1996). Bhavaprakasha Nighantu of Sri Bhavamishra. Chaukhambha Orientalia, Varanasi (Taila Varga: Narikela Taila section).
• Marina A.M., Che Man Y.B., Nazimah S.A.H., Amin I. (2009). Chemical properties of virgin coconut oil. Journal of the American Oil Chemists' Society, 86(4): 301–307.
• Mansor T.S.T., Che Man Y.B., Shuhaimi M., Abdul Afiq M.J., Ku Nurul F.K.M. (2012). Physicochemical properties of virgin coconut oil extracted from different processing methods. International Food Research Journal, 19(3):         837–845.
• Krishnakumar V., Thampan P.K., Nair M.A. (Eds.). (2018). The Coconut Palm (Cocos nucifera L.) - Research and Development Perspectives. Springer Singapore.
• Marina A.M., Che Man Y.B., Amin I. (2009). Virgin coconut oil: emerging functional food oil. Trends in Food Science & Technology, 20(10): 481–487.
• Dayrit F.M. (2015). The properties of lauric acid and their significance in coconut oil. Journal of the American Oil Chemists' Society, 92(1): 1–15.
• Madhavi Y.D., Rajurkar M., Warty C. (2026). Sesame oil (Tila Taila) as the Ayurvedic gold-standard carrier: a narrative review of its phytochemical composition, oxidative stability, and topical skin compatibility. Manuscript in preparation by the present authors; not yet peer-reviewed or published - cited here for internal cross-reference only, not as an independently verified source. [Ved Sanjeevani Nabhi Series Paper YM-01/P1]
• Seneviratne K.N., Hapuarachchi C.D., Ekanayake S. (2009). Comparison of the phenolic-dependent antioxidant properties of coconut oil extracted under cold and hot conditions. Food Chemistry, 114(4): 1444–1449.
• Marina A.M., Che Man Y.B., Nazimah S.A.H., Amin I. (2009). Antioxidant capacity and phenolic acids of virgin coconut oil. International Journal of Food Sciences and Nutrition, 60(suppl 2): 114–123.
• Intahphuak S., Khonsung P., Panthong A. (2010). Anti-inflammatory, analgesic, and antipyretic activities of virgin coconut oil. Pharmaceutical Biology, 48(2): 151–157.
• Lieberman S., Enig M.G., Preuss H.G. (2006). A review of monolaurin and lauric acid: natural virucidal and bactericidal agents. Alternative & Complementary Therapies, 12(6): 310–314.
• Bach A.C., Babayan V.K. (1982). Medium-chain triglycerides: an update. American Journal of Clinical Nutrition, 36(5): 950–962.
• Marina A.M., Che Man Y.B., Nazimah S.A.H., Amin I. (2009). Monitoring the adulteration of virgin coconut oil by selected vegetable oils using differential scanning calorimetry. Journal of Food Lipids, 16(1): 50–61. NOTE: this reference concerns adulteration detection via DSC, not oxidative-stability (Rancimat/OSI) testing - the OSI values attributed to this reference elsewhere in the manuscript should be independently re-sourced before publication.
• Cevc G. (2004). Lipid vesicles and other colloids as drug carriers on the skin. Advanced Drug Delivery Reviews, 56(5): 675–711.
• Mack Correa M.C., Mao G., Saad P., Flach C.R., Mendelsohn R., Walters R.M. (2014). Molecular interactions of plant oil components with stratum corneum lipids correlate with clinical measures of skin barrier function. Experimental Dermatology, 23(1): 39–44.
• Kabara J.J., Swieczkowski D.M., Conley A.J., Truant J.P. (1972). Fatty acids and derivatives as antimicrobial agents. Antimicrobial Agents and Chemotherapy, 2(1): 23–28.
• Bergsson G., Arnfinnsson J., Steingrímsson Ó., Thormar H. (2001). In vitro killing of Candida albicans by fatty acids and monoglycerides. Antimicrobial Agents and Chemotherapy, 45(11): 3209–3212.
• Thormar H., Hilmarsson H. (2007). The role of microbicidal lipids in host defense against pathogens and their potential as therapeutic agents. Chemistry and Physics of Lipids, 150(1): 1–11.
• Aungst B.J., Rogers N.J., Shefter E. (1986). Enhancement of naloxone penetration through human skin in vitro using fatty acids, fatty alcohols, surfactants, sulfoxides and amides. International Journal of Pharmaceutics, 33(1–3): 225–234.
• Aungst B.J. (1989). Structure/effect studies of fatty acid isomers as skin penetration enhancers and skin irritants. Pharmaceutical Research, 6(3): 244–247.
• Kanikkannan N., Kandimalla K., Lamba S.S., Singh M. (2000). Structure-activity relationship of chemical penetration enhancers in transdermal drug delivery. Current Medicinal Chemistry, 7(6):           593–608.
• Williams A.C., Barry B.W. (2012). Penetration enhancers. Advanced Drug Delivery Reviews, 64(suppl): 128–137.
• Cosmetic Ingredient Review Expert Panel (Bergfeld W.F., ed.). (2011). Final report on the safety assessment of Cocos nucifera (coconut) oil, hydrogenated coconut oil, hydrogenated coconut acid, hydrogenated coconut alcohols, and coconut acid. International Journal of Toxicology, 30(3 Suppl.): 5S–16S.
• Salvador S., Hentges C.R., Mostowski H., et al. (2016). Use of medium chain triglyceride emulsion in preterm infants on parenteral nutrition: a review. Journal of Pediatric Gastroenterology and Nutrition, 63(4): 433–438.
• Murthy K.R.S. (Trans.). (2017). Sharangadhara Samhita: A Treatise on Ayurveda. Chaukhambha Orientalia, Varanasi.
• Nevin K.G., Rajamohan T. (2006). Virgin coconut oil supplemented diet increases the antioxidant status in rats. Food Chemistry, 99(2): 260–266.
• Nakatsuji T., Kao M.C., Fang J.Y., Zouboulis C.C., Zhang L., Gallo R.L., Huang C.M. (2009). Antimicrobial property of lauric acid against Propionibacterium acnes: its therapeutic potential for inflammatory acne vulgaris. Journal of Investigative Dermatology, 129(10): 2480–2488.
• Schlüpen E.M., Friedl M., Cevc G., Fesq H. (2002). Pharmacokinetics of various dermal drug carrier systems containing diclofenac. Pharmaceutical Research, 19(2): 1591–1597.
• Bouwstra J.A., Honeywell-Nguyen P.L., Gooris G.S., Ponec M. (2003). Structure of the skin barrier and its modulation by vesicular formulations. Progress in Lipid Research, 42(1): 1–36.
• Hadgraft J., Lane M.E. (2011). Skin permeation: the years of enlightenment. International Journal of Pharmaceutics, 408(1–2): 1–4.
• Roberts M.S., Cross S.E., Pellett M.A. (2002). Skin transport. In: Dermatological and Transdermal Formulations (Walters K.A., ed.), Marcel Dekker, New York, 89–195.
• Indian Pharmacopoeia Commission. (2018). Indian Pharmacopoeia 2018, 8th edn. Ghaziabad, India. Coconut Oil monograph; Virgin Coconut Oil monograph.
• United States Pharmacopeial Convention. (2024). USP-NF: Medium-Chain Triglycerides excipient monograph. USP-NF Online, Rockville, MD.
• European Directorate for the Quality of Medicines. (2024). European Pharmacopoeia 11.0: Triglycerida saturata media (Medium-Chain Triglycerides) monograph 01/2024:0868. Strasbourg, France.
• DebMandal M., Mandal S. (2011). Coconut (Cocos nucifera L.: Arecaceae): in health promotion and disease prevention. Asian Pacific Journal of Tropical Medicine, 4(3): 241–247.
• Carandang E.V. (2005). Health benefits of virgin coconut oil. Philippine Journal of Coconut Studies, 30(2): 8–12.
• Babu A.S., Veluswamy S.K., Arena R., Guazzi M., Lavie C.J. (2014). Virgin coconut oil and its potential cardioprotective effects. Postgraduate Medicine, 126(7): 76–83.
• Codex Alimentarius Commission. (2019). Codex Standard for Named Vegetable Oils, CODEX-STAN 210-1999. FAO/WHO, Rome. Coconut Oil specifications.
• Sharma R.K., Dash B. (Trans.). (2003). Charaka Samhita, Vol I–VII. Chowkhamba Sanskrit Series Office, Varanasi (Sutrasthana ch. 27: classification of oils, including Narikela Taila).
• Anonymous. (2008). The Ayurvedic Pharmacopoeia of India, Part I, Vol. V. Government of India, Ministry of Health and Family Welfare, Department of AYUSH. Narikela Taila monograph.
• ICH Harmonised Tripartite Guideline. (2003). Stability Testing of New Drug Substances and Products Q1A(R2). International Council for Harmonisation, Geneva.