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Article
Isolation and Determination of Omega-9 Fatty Acids from
Telfairia Occidentalis
H.M. Inuwaa, I.A. Aimolaa*, A. Muhammada, N. Habilaa, P. Okibeb, M. Latayob and Z. Ahmeda a. Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria
b. National Research Institute for Chemical Technology, Zaria, Nigeria.
* Author to whom correspondence should be addressed; E-Mail: idowuaimola@gmail.com Article history: Received 19 January 2012, Accepted 6 February 2012, Published 8 February 2012.
Abstract: Long chain n-3 unsaturated fatty acids were isolated from Telfairia occidentalis using an arginated silica gel column. Telfairia occidentalis revealed a high percentage of long chain fatty acids (16.62%) of the dry weight of the leaves. Determination of the type of long chain n-3 unsaturated fatty acid present in Telfairia occidentalis using gas chromatography mass spectroscopy (GC-MS) revealed palmitoleic acid (16.62%) and elaidic acid (0.85%) as the predominant omega 9 fatty acid present in Telfairia occidentalis. The findings suggest a nutritional advantage with clinical significance.
Keywords: omega-9 fatty acids, Telfairia occidentalis
1. Introduction
Telfairia occidentalis is one of the commonly consumed leafy vegetables in Nigeria. It is generally cultivated and consumed for its inherent health benefits (Gbile, 1986). Studies have also revealed that the leaf extract possess hypolipideamic effects in rats fed high cholesterol diet (Adaramoye et al.,2007), and also the leaf extracts have been shown to increase the PCV of male albino rats (Salman et al. 2008). Long chain n-3 unsaturated fatty acids belong to a class of fatty acids known as essential fatty acids, and have been shown severally to contribute to human health in several ways; Omega-9 fatty acids from plants have been shown to lower the risk of atherosclerosis and the risk of sudden death (Adaramoye et al., 2007; Albert et al., 2002).
Telfaria occidentalis is a plant consumed for its nutritional and health benefits (Gbile 1986; Akubue et al., 1980) most studies carried out have focused on the proximate composition of the leaf and literature on its long chain fatty acid content is scanty hence the thrust to explore the long chain
n-2. Methods and Materials
2.1. Plant Samples
Leaves of Telfairia occidentalis were collected in Zaria, Kaduna state Nigeria at a latitude of 11° 4' 0" N and a longitude of 7° 42' 0" E. The collected leaves were identified at the herbarium of Biological Sciences Department, Ahmadu Bello University, Zaria, Nigeria.
2.2. Extraction of Lipids from Plant Samples This was done following the Folch method (Folch et al., 1957) with slight modifications as described by Bligh et al., (1959). The plant samples were dried in an oven and pulverized. 50g of dried sample extracted with 10 volumes of chloroform and methanol (2:1) for 12 hours and the extracts were concentrated at 45OC (Bligh et al., 1959).
2.3. Isolation of Long Chain n-3 Polyunsaturated Fatty Acid
An 8cm 0.5mm diameter column was packed with Argentated silica gel as previously described (Kepler et al., 1966). The column was washed with n-hexane prior to loading of lipids, 1g concentrated lipids was reconstituted in 10ml n-hexane and applied to the column and allowed for maximum binding with column, polyunsaturated fatty acids were eluted with n-hexane as previously described (Ockner et al., 1982).
2.4. GCMS of Long Chain n-3 Polyunsaturated Fatty Acid
The isolates were applied on a GC column after dissolving in methanol and separated at 60OC at a flow rate of 1.61ml/min 100.2Kpa pressure for 3.85min. Eluted fatty acids were then bombarded with a stream of protons from a mass spectra (MS) and analyzed using the following parameters:
Analysis time: 45 minutes
Analysis mode: scan
3. Results and Discussion
3.1. Percentage Yield of Long Chain n-3 Fatty Acids
The percentage yield of long chain n-3 fatty acid was calculated as percentage weight and was found to be 16.62% of the dry weight of Telfaria occidentalis leaves as shown on Table 1. This reveals that Telfaria occidentalis has a high quantity of long chain n-3 fatty acids.
Table 1: Percentage Yield of Total Lipids from Telfaira occidentalis Telfaira occidentalis(g)
Weight of leaves 10
Weight of PUFA 1.62
Percentage yield 16.62
3.2. Long Chain n-3 Fatty Acid Composition of Telfaria occidentalis
GC analysis of the long chain fatty acid isolates from Telfaria occidentalis revealed several peaks as shown in Figure 1. Further analysis of the peaks using MS and comparing with NISTO5s mass spectral library 2002 revealed peak 14 as palmitoleic acid (an omega-9 fatty acid). Similarity index of this peak with palmitoleic acid in the NISTO5s, 2002 mass spectral library was 98%. The chromatogram also revealed the presence of elaidic acid with a similarity index of 95% as peak 16 in Figure1.
Fig.1: Gas chromatogram of long chain fatty acid eluate of Telfaira occidentalis. Peaks 14 and 16 were identified on the mass spectra as palmitoleic acid and elaidic acid respectively as indicated with red circles
Fig.2a: Mass spectra of peak 14, which revealed 96% similarity with palmitoleic acid when compared with the NISTO5s mass spectral library
Fig.2b: Mass spectra of peak 16, which revealed 94% similarity with elaidic acid when compared with the NISTO5s mass spectral library
The chromatogram above in Figure 1 revealed several peaks of which peak 14 corresponds to palmitoleic acid (16.62%) with a retention time of 15.806min. Elaidic acid (0.85%) can also be seen at peak 16 with a retention time of 17.015 min.
Figure 2a and figure 2b show the mass spectra of peaks 14 and 16 respectively which when matched with the NISTO5s mass spectral library 2002 revealed palmitoleic acid and elaidic acid at 95% and 91% similarities respectively.
3.3 Discussion
Several long chain fatty acids were successfully isolated from the leaves of Telfairia occidentalis with palmitoleic acid and elaidic acids the major omega fatty acids detected in Telfairia occidentalis leaves. Palmitoleic acid was found in significantly high quantities (16.67%) comparable to other documented sources of omega fatty acids (Simopoulos, 2006). Palmitoleic acid an omega-9 fatty acid is a partially essential fatty acid as humans have a limited capacity to synthesize palmitoleic acid in the presence of the other essential fatty acids omega-3 and omega-6 fatty acids (Simopoulos, 2006) this could underscore some of the nutritional and clinical benefits of Telfaria occidentalis (Akubue, 1980). Several other studies have shown that the major omega fatty acids found in green leafy vegetables is alpha linoleic acid (ALA) (Simopoulos, 2006) although no ALA was found in the leaves of as a part of the long chain fatty acid isolates. The presence of palmitoleic acid in Telfaria occidentalis could account for some of the medicinal properties of the leaf as previously reported
(Engler, 1992; Krey et al., 1997; Adaramoye et al., 2007). Studies have also revealed several beneficial effects of omega-9 fatty acids (Krey et al., 1997) thus this study reveals that Telfaria occidentalis is potentially beneficial in other ways which would require further studies.
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