Fatty acid composition of the monogalactosyldiacylglycerol fraction obtained from Rosa sp. and Litozin®

Abstract

The aim of this study was to determine and compare the fatty acid (FA) composition of the monogalactosyldiacylglycerol (MGDG) fraction, obtained from rose pericarps and seeds, as well as Litozin® powder. In this work two Rosa species, growing wild in Poland, namely Rosa canina and Rosa rugosa, were investigated. MGDG was eluted from the lipid extract using different solvents: (CHCl 3 , (CH 3 ) 2 CO, CH 3 OH) and its presence was observed only in the acetone-soluble fraction. MGDG was isolated and purified by means of medium-pressure liquid chromatography (MPLC) and preparative TLC. It is worth noting that the MPLC method was used for the first time to fractionate and isolate the MGDG fraction from the lipid extract. The carbohydrate part of MGDG was determined after acidic hydrolysis on a TLC plate. Only the spot with R f value corresponding to galactose (R f 0.33) was observed. The FA composition of MGDG from the rose seeds, rose pericarps, and Litozin® was determined by gas-liquid chromatography (GLC). The results are presented in Table 1. The FA composition of MGDG found in pericarps was similar for both rose species. Comparison of the FA composition of MGDG from the seeds of both species has also revealed no significant differences. However, there were some differences in the FA composition of MGDG between pericarps and seeds of the analyzed species. We have identified 13 FA in the pericarps and 10 FA in the seeds of both analyzed species. The FA composition of MGDG of the pericarps consisted mostly of fatty acids with chain length from 10 to 18 carbons. It is interesting that long-chain FA (24:0 and 24:1) have been observed only in the seeds of both species. Our investigation has revealed that unsaturated FA were dominant in the pericarps of both species (93.745–94.856%). The major unsaturated FA of MGDG from the pericarps of Rosa canina and Rosa rugosa were those with chain length of 18 C (93.886% and 92.795%, respectively), while the content of unsaturated FA with chain length of 16 and 17C was less than 1%. The dominant FA of MGDG from the pericarps of both species was linolenic acid (18:3 n-3), and the percentage of the compound was 74.486% of MGDG FA from R. canina and 86.057% of MGDG FA from R. rugosa. The analysis has also revealed high amounts of 18:2 n-6 FA, especially in MGDG from R. canina pericarps (17.330%).