European Journal of Nutrition & Food Safety 12(5): 35-47, 2020; Article no.EJNFS.57298 ISSN: 2347-5641 Fatty Acids Composition, Variation and Distribution in Different Accessions of the West African Pear (Dacryodes edulis) and Potential Health Benefits Godwin Oju Igile1*, Henrietta Nkechi Ene-Obong1 and Godwin Eneji Egbung1 1Department of Biochemistry, Faculty of Basic Medical Sciences, University of Calabar, P.M.B 1115, Calabar, Nigeria. Authors’ contributions This work was carried out in collaboration among all authors. Author GOI conceptualized the research study, developed the methodology with GC-MS investigations, interpretation of GC-MS data, validation of data, preparation of final manuscript and visualization of general study outcome, Author HNEO developed study design, supervised the research work, reviewed and edited the draft manuscript. Author GEE carried out formal analysis and selection of statistical model, data curation; data validation and choice of software for preparation of manuscript. All authors read and approved the final manuscript. Article Information DOI: 10.9734/EJNFS/2020/v12i530226 Editor(s): (1) Dr. Kristina Mastanjevic, Josip Juraj Strossmayer University of Osijek, Croatia. Reviewers: (1) Lucian Ioniță, Romania. (2) Seema Rai, Guru Ghasidas Vishwavidyalaya, India. Complete Peer review History: http://www.sdiarticle4.com/review-history/57298 Received 20 March 2020 Accepted 25 May 2020 Original Research Article Published 06 June 2020 ABSTRACT The pulp of Dacryodes edulis is eaten raw, cooked or roasted by West and central Africans. The aim of this study was to determine the fatty acid composition, type, variation and distribution among different accessions of D. edulis purchased from different locations of Eastern Nigeria, using GC-MS data. The results showed that D.edulis is rich in ω-3,6,9 unsaturated fatty acids. Saturated fatty acids namely, pentadecanoic, tetradecanoic (myristic), tridecanoic, hexadecanoic (palmitic), undecanoic and octadecanoic (stearic) acids were common to all accessions. Unsaturated fatty acids identified in the four accessions included, Oleic, linoleic, linolenic, linoelaidic and several other polyunsaturated fatty acids including brassidic and vacennic acids, and 19,19-Dimethyl-Eicosa-8,11-dienoic acid (6.83±0.37%) a derivative of oleic acid which was found only in Nsukka samples. Two novel polyunsaturated fatty acids namely; Methyl,9,12- _____________________________________________________________________________________________________ *Corresponding author: Email: [email protected]; Igile et al.; EJNFS, 12(5): 35-47, 2020; Article no.EJNFS.57298 Heptadecadienoic acid and 2,6,10,14-Hexadecatetraenoic acid were identified in the present study. The ratio of saturation to unsaturation was calculated to be approximately 1:2. The concentration of TSFAs fell in the range of 27.07±1.75-39.87±1.72%, while TMUFAs was 3.14±0.22-10.77±0.55%, and TPUFAs was 46.81±1.22-58.71±2.33% respectively. We concluded that, the presence of polyunsaturated fatty acids in D. edulis may provide cardio-protective benefits in terms of human nutrition and could be substitutes for olive oil in healthy normo-cholesterolemic human diets. We further concluded that the differences in fatty acid composition, distribution, variation and concentration between the locations studied may be affected not only by their biogenetic origin but also by soil type and climatic conditions. Keywords: Dacryodes edulis; fatty acids; unsaturation; saturation; cardio-protection. 1. INTRODUCTION unsaturated fatty acids (with double bonds). Unsaturated fatty acids with double bonds form The West African Pear (Dacryodes edulis), is a what is nutritionally referred to as Omega-3, perennial and herbaceous plant that fruits Omega--6 and Omega-9 oils, which are known to seasonally especially in the rainy season. The be the best sources of cooking oils [5]. Omega plant grows also in Central African countries fatty acids have been variously reported to be including Cameroun, Angola, Congo, Gabon; and cardio-protective oils against all forms of heart some parts of East Africa. People in West Africa disease [5,6]. Unsaturated fatty acids, generally consume the fruit raw, boiled or roasted. The referred to as Omega oils are considered the pulp and the seed have been reported to contain best source of oils for human nutrition and health fatty acids and mineral elements [1]. The fatty [5,6]. acid concentration, its distribution and variation among different accessions, and the The West African pear oil has been reported by classification of the oil has not been reported. [4] and [7] to contain palmitic acid (9.06%), The oil has been evaluated as surface coating stearic acid (15.46%), oleic acid (26.63%) and driers in a recent study [2]. linoleic acid (30.85%). A previous report by [7] gave the fatty acid composition and ranges as palmitic acid 47.89% (35 – 65%), oleic acid 31.25% (16 – 35%) and linoleic acid 17.5% (14 – 27%) but did not classify the oil type and the studies did not indicate variation and distribution between locations. This study aim to address these gaps. Fatty acids are required for cellular processes, and for the correction of metabolic and endocrine dysfunction, and the production of other necessary and essential omega-3 and omega-6 fatty acids in the body [6,8,9,10,11]. It has been established that humans cannot Fig. 1. Mature fruits of D. edulis synthesize linoleic acid (Omega-6 fatty acid) and α-linolenic acid (Omega-3 fatty acid). Thus these The variation in the nutrients and bioactive group of fatty acids are referred to as essential compounds of different accessions of the West fatty acids because they must be taken into the African pear, and implications for dietary intake body through the diet [9,11]. Omega-6 and assessment and health has recently been omega-3 fatty acids derived from linoleic and α- reported [3]. linolenic acids are needed conditionally by many mammals including humans [9]. They are formed Fatty acids occur generally in plant oils and in the body from their parent fatty acids but not animal fats. The commonly occurring and always at levels needed to maintain optimal dominant fatty acids in foods of plant and animal health or development [9,11]. Infants for instance origin include capric, caprylic, myristic, stearic, are thought to have a conditionally essential lauric, palmitic, arachidonic, oleic, linoleic and need for docosahexaenoic acid (DHA) which is linolenic acids [4]. Fatty acids are grouped into derived from α-linolenic acid, and perhaps from saturated (without double bonds) and arachidonic acid which is derived from linoleic 36 Igile et al.; EJNFS, 12(5): 35-47, 2020; Article no.EJNFS.57298 acid. This is because, the hydrocarbon endocarp was blended into powdered form using molecules of unsaturated fatty acids have two a manual blender and stored in air tight plastic carbons that share double or triple bonds and are containers until required. 200 g of each therefore not completely saturated with hydrogen accession was placed in a thimble, and its oil atoms. Unsaturated fatty acids molecules are not was extracted with petroleum ether (40-60°C) for stable at room temperature and therefore easily 3 h using a Soxhlet apparatus on an disintegrate. The molecules do not stick to the electrothermal mantle. The extract was walls of blood vessels or the body as is the case concentrated in vacuo at 40°C, using a rotary with saturated fatty acids [9,12]. evaporator to remove all alcohol and to afford 22 g, 21.4, 20.9 and 20.85 g of golden brown oil However, saturated fatty acids which do not respectively. The oil samples were stored under contain any double bond in their structure are refrigeration until required for GC-MS analysis. considered to be unhealthy source of edible oils. These include Palm oil (Palmitic acid) and 2.3 Fatty Acids Methyl Esters (FAMEs) refined palm kernel oil (Lauric acid) as well as Derivatization of the Oil Sample stearic acid [13,14]. A saturated fatty acid structure is fully hydrogenated as in palmitic, Twenty five (25) ng of oil sample was weighed lauric and stearic fatty acids. The molecule is into 10 mL micro-reaction vessel and 2 mL BCl3- said to be very stable (usually solid at room MeOH 12% w/w was added. This was followed temperature) and hard to break-up or by the addition of 1 mL 2, 2-dimethoxyproprane. disintegrate. This allows it to store and provide The mixture was mixed thoroughly and then more energy than carbohydrates and makes it heated for 5 minutes at 60°C. It was then cooled more likely to stick to the body as cholesterol to below 30°C and 1 mL distil water and 1 mL n- resulting in high arterial and plasma cholesterol, hexane was added and mixed thoroughly again, also known as hypercholesterolemia [13,14,15]. then allowed to stand for 10 minutes. The upper High arterial and plasma cholesterol predisposes (organic) layer was pipette into a sterile and hypertension. Studies have shown clearly clean vial and covered with a stopper and stored that hypercholesterolemia; hyperlipidemia, for GC-MS analysis. This was repeated for the 4 dyslipidemia and diabetes are some of the pre- accessions. disposing factors of cardiovascular disease (CVD), and indeed hypertension [13,14,16]. 2.4 GC-MS Analysis of FAMEs Samples for Fatty Acids Studies 2. MATERIALS AND METHODS The method reported by [16] was used to carry 2.1 Collection of Plant Material out the GC-MS analysis with a slight modification. Samples of FAMEs prepared from Fresh mature fruits of Dacryodes edulis (D. each sample oil extract, were injected manually edulis) were purchased from four local markets in through the injector pot of the GC. An Agilent the Eastern region of Nigeria namely: Akpabuyo 6890 GC coupled with a 5973i mass and Ikom in Cross River State; Ikot Ekpeya in spectrometer (Agilent Technologies, Palo Alto, Akwa Ibom State and Nsukka market in Enugu CA, USA) was used, with a ChemStation State respectively.