Comparison of the fatty acid compositions of Six Centaurea species

Abstract

Fatty acids have very important biological functions, including as a source of energy and as components of biological membranes. The dietary intake of fatty acids is very important because many degenerative diseases such as cardiovascular diseases are associated with fatty acids. Centaurea belong to the family Asteraceae, and there are more than 500–600 species of this genus worldwide [1]. In Turkey, there are about 179 Centaurea species. Many species of the genus are endemic to Turkey, and the endemism ratio is 61%. [2]. Centaurea species have attractive flowers and have been used in important medicinal applications in many countries. For example, C. drabifolia, C. pulchella, C. depressa, and C. solsititialis are used to treat various ailments such as abscesses, hemorrhoids, and the common cold in Anatolian folk medicine. Previous studies have shown differences in the fatty acid compositions of some Centaurea species, such as C. carduiformis [3], C. patula and C. pulchella [4], C. kotschyi var. persica [5], C. amanicola [6], and C. depressa [7]. In the present study, the fatty acid compositions of six Centaurea species from the Central Anatolia region of Turkey were examined by gas chromatography. The results can be used to determine the usefulness of these plants as new sources of fatty acids. Twenty different fatty acids with chain lengths between C8 to C20 were identified in the total fatty acid content of the studied Centaurea oils (Table 1). Linoleic acid (18:2 6) was the major fatty acid in all the studied Centaurea oils. Among the Centaurea oils, the levels of this fatty acid ranged from 29.15% in C. virgata to 55.27% in C. kotschyi var. kotschyi. Generally, oleic (18:1 9), palmitic (16:0), and -linolenic acid (18:3 3) were the other predominant fatty acids in the studied species. Similar results have been obtained for some other Centaurea species, including C. balsamita and C. patula [3, 4]. PUFAs are beneficial for decreasing LDL levels and aiding brain development [8]. Therefore, the content of PUFAs is an important indicator of the nutritional value of an oil. PUFAs accounted for 43.90% of the total fatty acids in C. triumfettii and 60.52% in C. kotschyi var. kotschyi oils (Table 1). Among the PUFAs, linoleic and -linolenic acid are called essential fatty acids because they are not synthesized in the human body. The studied Centaurea species are a source of essential fatty acids, and their high essential fatty acids contents could make the Centaurea oils important for a variety of health applications. The -linolenic acid (18:3 3) content of C. pterocaula oil was 16.57%, and -linolenic acid (18:3 6) was found in small quantities in all the Centaurea species. The results of the present study agree with earlier studies in that linoleic and -linolenic acid were major PUFAs in Asteraceae or Centaurea species [3, 9]. Oleic acid is the main monounsaturated fatty acid (MUFA) in numerous plant oils, and because it is beneficial for decreasing LDL levels, it is a good fatty acid for consumption [10]. Oleic acid was identified as the major component of the MUFAs in all of the studied Centaurea species. The content of this fatty acid varied between 7.98% in C. solsititialis subsp. solsititialis and 28.47% in C. triumfettii. Other MUFAs present at high levels in the Centaurea oils were palmitoleic (16:1 7), myristoleic (14:1 5), pentadecenoic (15:1 6), heptadecenoic (17:1 8), and eicosenoic (20:1 9) acids. The fatty acid profiles obtained for the Centaurea oils in the present study agree with those from a previous study that found high levels of oleic acid [7]. SFAs are unhealthy because they increase the cholesterol level, and consumption of these fatty acids should be reduced for human health [11]. In the present study, SFAs accounted for 16.85% and 39.79% of the total fatty acids in the Centaurea oils. Palmitic acid was the major SFA, and its content varied from 11.89% in C. urvillei subsp. urvillei to 28.41% in C. virgata.