Influence of Phleum pratense pollen grains rupture on lipids extraction

Abstract

In this work, we completed the first identification and quantification of internal lipids for allergenic Phleum pratense pollen grains (PGs). We have extracted PGs with aqueous solvent under different extraction procedures and observed release of extra amount of unsaturated fatty acids (α-linolenic and linoleic acids) when PGs were broken during extraction. We showed that rupture of PGs is necessary for the release of higher quantity of bioactive compounds. Organic solvent extraction of crushed PGs confirmed the predominance of unsaturated fatty acids in the inner parts of PGs as well as a different distribution of external and internal lipids. The total mass of extractible matter by organic solvent was determined at 22 ± 1 mg g−1 for intact pollen and at 48 ± 1 mg g−1 for broken pollen. This finding brings new insight into the physical degradation of PGs by air pollutants during atmospheric transport. We hypothesize that the presence of bioactive lipids in pollen cytoplasm gives further importance to asthma triggered by cracked or broken allergenic PGs. The rupturing of PGs in the atmosphere may expose the population to the risk of inhaling micrometer-sized aerosols (cytoplasmic granules) containing not only allergens but also bioactive lipids.