Vol. 10(11) pp. 327-332, November 2016 DOI: 10.5897/AJFS2016.1472 Article Number: F30F4C160711 ISSN 1996-0794 African Journal of Food Science Copyright © 2016 Author(s) retain the copyright of this article http://www.academicjournals.org/AJFS Full Length Research Paper Volatile compound analysis of the leaves and seeds of Piper guineense using gas chromatography-mass spectrometry (GC-MS) Ojinnaka, M. C.1*, Ubbor, S. C.1, Okudu, H. O.2 and Uga, U.1 1Department of Food Science and Technology, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. 2Department of Nutrition and Dietetics, Michael Okpara University of Agriculture, Umudike Abia State, Nigeria. Received 31 May, 2016; Accepted 5 August, 2016 The volatile compounds in the leaves and seeds of Piper guineense plant from South East Nigeria, were investigated using gas chromatography-mass spectrometry (GC-MS). The analysis was carried out to identify the compounds responsible for the characteristic flavor of the flavouring spices. A total of thirty-three volatile constituents were identified in the leaves and seeds of Piper guineense using GC- MS. The major compounds identified include acids, esters, alcohols, hydrocarbons and others. Acids were found to be the predominant constituent group followed by esters. The leaves and seeds of Piper guineense had acids in the values of 65.56 and 53.72%, respectively. The esters were also found to be more in the leaves (25.63%) than in the seeds (5.22%) of P. guineense. The hydrocarbons identified appeared more in the seeds (11.47%) of P. guineense. The monoterpene (beta-myrcene) and sesquiterpenes (aromadendrene, trans-alpha-bergamotene, copaene) hydrocarbons identified were also present in the seeds than in the leaves of the P. guineense. Gamma-elemene, a sesquiterpene were identified in both the leaves and seeds of P. guineense at the same retention time of 10.242 min but at different concentrations of 0.41 and 0.72%, respectively. Key words: Piper guineense, volatile compounds, leaves, seeds. INTRODUCTION P. guineense is a spice plant from the family, Piperaceae and are prolate-elliptically shaped. The seeds of the plant and from the genus piper. The genus Piper is made up of are commonly known in English-speaking countries as about 1050 species of tropical shrubs, lianas, and small “West African black pepper”, “uziza” in Igbo “iyeree” in trees, many of which are important as spices and Yoruba and “poivrie” in French. West African black flavoring agents and medicines (Owolabi et al., 2013; pepper (Piper guineense) is an important plant used in Mabberley, 2008). P. guineense is a climbing plant that traditional medicine and as spice. The fruits (the part of can grow up to 20 m in length. The seeds are smooth the plant traditionally used) are rich in a wide range of *Corresponding author. E-mail: [email protected]. Author(s) agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License 328 Afr. J. Food Sci. natural products including volatiles oils, lignans, amides, Table 1. Percent composition of the different volatile alkaloids, flavonoids and polyphenols (Rodolfo et al., compounds identified in the leaves and seeds of Piper 2013). The leaves and seeds are usually sold in Nigerian guineense (%). markets as an edible medicinal plant or additive in foods Samples (%) to offer aroma and flavor. S/N Compounds The seeds, leaves and sometimes the stems are used Uziza leaves Uziza seeds in preparing soup. It imparts “heat” and a spicy pungent 1 Acids 65.56 53.72 aroma to food. The medicinal properties of P. guineese 2 Esters 25.63 5.22 exert bacteriostatic and bacteriocidal effects on some 3 Alcohol - 1.90 bacteria.The leaves are considered aperitive, carminative 4 Hydrocarbons 6.96 11.47 and eupeptic. They are also used for the treatment of 5 Others 1.88 27.66 cough, bronchitis, intestinal disease and rheumatism (Okoye and Ebeledike, 2013; Sumathykutty et al., 1999).The leaves are also used for female infertility while, the fruits are used as an aphrodisiac (Echo et al., 2012). P. guineense has culinary, medicinal, cosmetic and Determination of volatile compounds using gas chromatographic-mass spectral analysis insecticidal uses (Nwinyi et al., 2013; Okwute, 1992). The powder obtained from the ground seeds is used for its GC-MS analysis was carried out on a GC Clarus 500 Perkin Elmer stimulating properties (Tchoumbougnang et al., 2009; system comprising of a AOC-20i auto- sampler and gas Sofowora, 1982). P. guineense is added to food meant chromatograph interfaced to a mass spectrometer (GC-MS) for pregnant and nursing mothers as a medicinal spice instrument employing the following conditions: column Elite-1 fused and among the post partum women, it is claimed that it silica capillary column (30 x 0.25 mm ID x 1 μM df, composed of assists in the contraction of the uterus (Achinewhu et al., 100% dimethylpoly diloxane), operating in electron impact mode at 70 eV; helium (99.999%) was used as carrier gas at a constant flow 1995). Okoye and Ebeledike (2013) reported that the leaf of 1 mL/min and an injection volume of 0.5 μL was employed (split extracts of P. guineese have antimicrobial effect on some ratio of 10:1) injector temperature 250°C; ion-source temperature of test organisms. The leaf extracts exhibited antimicrobial 280°C. The oven temperature was programmed from 110°C effect activity due to the presence of tannins, saponins, (isothermal for 2 min), with an increase of 10°C/min, to 200°C, then flavonoids and alkaloids (Rabe and Vonstanden, 1987). 5 C/min to 280°C, ending with a 9 min isothermal at 280°C. Mass The essential oils of P. guineense from Cameroon spectra were taken at 70 eV; a scan interval of 0.5 s and Fragments from 40 to 450 Da. Total GC running time was 36 min. N/B: Before (Tchoumgougnang et al., 2009) and from Nigeria GC-MS analysis, the plant is subjected to cold extraction process (Oyedeji et al., 2005) have also been studied. using ethanol as the solvent. Monoterpenes,sesquiterpenes and benzenoids(e.g. dildillapiole and myristicin) have been identified as the main compounds in P. guineense. In addition to their Identification of components importance as a spice and for the flavoring of food products, this Piper species is also used in traditional Interpretation on mass spectrum GC-MS was conducted using the African medicine, because of its various pharmacological database of National Institute Standard and Technology (NIST) effects (e.g. antimicrobial, insecticidal, anticonvulsive, having more than 62,000 patterns. The spectrum of the unknown antihypertensive, sedative and tranquillizing activities component was compared with the spectrum of the known (Jirovetz et al., 2002). An investigation of the volatile components stored in the NIST library. The name, molecular weight compounds that contribute to the flavor characteristics of and structure of the components of the test materials were ascertained. P. guineense from South East Nigeria by means of GC- MS has not been performed previously.Therefore, the objective of this study was to identify the entire volatile RESULTS AND DISCUSSION compounds of the leaves and seeds of P. guineense responsible for the characteristic aroma of these natural flavourings and spices and to compare the volatile The volatile compounds of the leaves and seeds of P. constituents in the leaves and seeds of the P. guineense guineense analyses using GC-MS are shown in Tables 1 plant. and 2. The gas chromatogram showed the relative concentrations of various compounds getting eluted as a function of retention time (Figures 1 and 2). The heights MATERIALS AND METHODS of the peak indicate the relative concentrations of the compounds of the components present in the plant The seeds and leaves of P. guineense were purchased from extract (Negbenebor et al., 1999). A total of thirty-three Umuahia modern market, Urbani Ibeku Abia State, Nigeria. The volatile constituents were identified in the leaves and leaves and seeds of P. guineense were separated from the stem, sorted to remove debris. The leaves and seeds were washed seeds of P. guineense. The compounds which were separately and oven dried at 65°C for 4 h and milled into powder identified by GC-MS analysis were twenty-two for the before further analysis. leaves and twenty-five for the seeds of P. guineense. Ojinnaka et al. 329 Table 2. Concentrations of volatile compounds in the leaves and seeds of Piper guineense. Normalized Retention time Area S/N Compounds (%) (minute) Formula Uziza leaves Uziza seeds Acids 1. 11.858 Dodecanoic acid C12H24O2 - 2.48 2. 11.875 Dodecanoic acid C12H24O2 1.47 - 3. 14.258 Tetradecanoic acid C14H28O2 - 3.26 4. 14.267 Tetradecanoic acid C14H28O2 4.03 - 5. 17.942 n-Hexadecanoic acid C16H32O2 - 16.28 6. 17.958 n-Hexadecanoic acid C16H32O2 15.14 - 7. 20.783 Oleic Acid C18H34O2 33.37 - 8. 20.800 Oleic Acid C18H34O2 - 26.09 9. 21.033 Octadecanoic acid C18H36O2 8.22 - 10. 21.042 Octadecanoic acid C18H36O2 - 5.61 11. 23.292 Eicosanoic acid C20H40O2 3.33 - Esters 12. 13.592 Methyl tetradecanoate C15H30O2 1.19 - 13. 16.883 Pentadecanoic acid,14-methyl-,methyl ester C17H34O2 - 1.28 14. 16.892 Hexadecanoic acid,methyl ester C17H34O2 6.53 - 15. 19.900 9,12-Octadecadienoic acid, methyl ester (E,E) C19H34O2 - 0.74 16. 19.908 9,12-Octadecadienoic acid,methyl ester (E,E)- C19H34O2 3.42 - 17. 19.992 11-Octadecenoic acid, methyl ester C19H36O2 - 2.26 18. 20.008 11-Octadecenoic acid, methyl ester C19H36O2 9.64 - 19. 20.350 Octadecanoic acid methyl ester C19H38O2 3.49 0.94 20.