Biochemical composition of Phleum pratense pollen grains: A review

The Poaceae family is composed of 12,000 plant species. Some these species produce highly allergenic anemophilous pollen grains (PGs). Phleum pratense (PPPGs) emerged as a model for studies related to grass allergy. biochemical composition PGs has not yet been fully described despite potential health effects PG constituents other than proteins. This review brings together the information available in literature aiming at creating comprehensive picture current knowledge about chemical from timothy grass. PPPGs have an average diameter between 30–35 μm and mass single was reported 11 26 ng. cytoplasm filled with two types cytoplasmic granules (PCGs): starch polysaccharide particles (p-particles). Starch size 0.6–2.5 1.1 (estimated number 1000 per PG) while p-particles ranging around 0.3 0.4 61,000–230,000 PG). rupture induces release PCGs dispersion allergens inhalable fraction atmospheric aerosol. are sporopollenin, sugars, polysaccharides, starch, glycoproteins (including allergens), amino-acids, lipids, flavonoids isorhamnetin), various elements (the more abundant being Si, Mg Ca), phenolic compounds, phytoprostanoids, carotenoids (pigments) metals adsorbed pollutants. PPPG contains hundred different proteins molecular masses 10 94 kDa, isoelectric points 3.5–10.6. Among proteins, classified eleven groups 1 13 5 major contributors Phl p Major allergen quantified by several concentration 2.7 3.5 μg.mg−1 unpolluted environment. Values scarce literature; only one quantitative assessment exists 1, 2 4. extractible lipid estimated 1.7–2.2% total mass. main families lipids are: alkanes, alkenes, alcohols, saturated unsaturated fatty acids, di- tri-hydroxylated aldehydes sterols. Several compounds adjuvant on allergy specifically PPPGs: E2-like prostaglandin (PGE2), B4-like leukotriene (LTB4), acids (linoleic linolenic their hydroxylated derivatives), adenosine, vitamins compounds. characteristics such NAD(P)H oxidase, protease activity microbiome were literature. bioaccessibility physiological conditions most biochemicals transported PPPGs. There also considerable lack allergens. variability remains largely unknown its importance reproduction environment characterized pollution, climate change loss biodiversity.