INTRODUCTION The giant mudskipper (P. schlosseri) is an amphibious fish belongs to the Periophthalmin spp. within the family Gobiidae. The fish lives in brackish water near mangrove swamps and intertidal habitats which are found only in tropical and subtropical regions, including Malaysia, Indonesia, India, Australia and Africa 1 . The mudskipper is also a valuable source of protein in some countries throughout the Asian and African region, including Japan, Korea and India 2,3 . Besides protein, it contains a high amount of lipid substances, which act as the sources of fatty acids, including polyunsaturated fatty acids (PUFA). Most fish lipids contain PUFA categorized as ω-fatty acids including arachidonic acid (AA, C20:4 ω-6), eicosapentaenoic acid (EPA, C20:5 ω-3) and docosahexaenoic acid (DHA, C22:6 ω-3) 4,5,6 . These ω-fatty acids have been recognized to exhibit special physiological and Oriental Journal of Chemistry Vol. 26(3), 861-864 (2010) Study on ω-fatty acids from Malaysian giant mudskipper (Periophthalmodon schlosseri) fish oil MUHAMMAD NOR OMAR, C.O. SITI-FAIRUZ, M.T. HASAN, M.N. NOR-NAZUHA¹, M.N. NOR-DALILAH¹ and Y. KAMARUZZAMAN Kulliyyah of Science, International Islamic University Malaysia, Jalan Sultan Ahmad Shah, Bandar Indera Mahkota - 252 00 (Malaysia). ¹NikkyDylla Corporation, Bandar Bukit Mahkota, 43000 Kajang, Selangor (Malaysia). (Received: June 24, 2010; Accepted: July 16, 2010) ABSTRACT The main aim of the present study is to look into the composition of Malaysian giant mudskipper lipid which might be useful to human health by looking into the ratio of ω-fatty acids present in P. schlosseri oil. Lipid from the fish flesh was extracted using the Folch method and the fatty acid composition was analysed using GC and GC-MS. It was found that the major constituents of P. schlosseri lipid were palmitic acid (C16:0) (29.2%), oleic acid (C18:1 ω-9) (23.0%) and stearic acid (C18:0) (12.6%). Besides that, the essential ω-fatty acids eicosapentaenoic acid (EPA, C20:5, ω-3) and docosahexaenoic acid (DHA, C22:6, ω-3) contents were 3.3 and 4.3% respectively. The result shows that the total ω-fatty acid (ω-3 and ω-6) content of P. schlosseri was 15.4% and is nutritionally significant due to its ω- 3:ω-6 ratio of 1:1. Key words: Periophthalmodon schlosseri, giant mudskipper, ω-fatty acids. pharmacological effects on human health. Many studies have been carried out to determine the effect of ω-3 fatty acid on lipid profiles. Rivellese et al. 7 found that a significant decrease in LDL-cholesterol of healthy subjects when they are fed with ω-3 fish oil supplements. The results of an in vivo study by Eitsuka et al 8 conclude that ω-3 fatty acids inhibit proliferative colorectal cancer cell by downregulating the reversed transcriptase via protein kinase C inhibition. Meanwhile, a report by Helland et al 9 show that the intake of ω-3 fatty acid supplement during pregnancy has favorable effect in the cognitive development of the children. Besides pharmacological effects, ω fatty acids also play important roles in human nutrition. Since the human body cannot synthesize ω-fatty acids de novo, it can form 20- and 22-carbon PUFAs from the eighteen-carbon ω-fatty acid, such as α- linolenic acid. Both ω-3 α-linolenic acid and ω-6