Generation of isoprenoid compounds, notably prist-1-ene, via photo- and autoxidative degradation of vitamin E

Photo- and Free Radical-Mediated Oxidation of Lipid Components During the Senescence of Phototrophic Organisms

“…In order to check this hypothesis, we searched for the presence of 5a-methoxytocopherol (30) after methanolysis of NaBH 4 -reduced and non-reduced lipid extracts obtained from cells of Emiliania huxleyi s t r a i n T W P 1 a n d Chrysotila lamellosa strain HAP17. The detection of significant amounts of this methanolysis product of trimers (Yamauchi et al, 1988) in these extracts (Nassiry et al, 2009) well supported the presence of such trimeric oxidation products of vitamin E in these algae.…”

“…12) (Yamauchi et al, 1988). ESI-TOF MS analyses of oxidation products were also carried out in order to confirm the presence of high proportions of trimers (Nassiry et al, 2009). …”

Formation of pristane from α-tocopherol under simulated anoxic sedimentary conditions: A combination of biotic and abiotic degradative processes

“…On the basis of the ratio trimers/4,8,12,16-tetramethylheptad- Table 1 Production of pristane observed after incubation of intact and oxidized a-tocopherol in anaerobic sediment slurries under conditions promoting or limiting nitrate reduction. ecan-4-olide (ranging from 28 to 85) previously obtained after photo-and autoxidation of a-tocopherol (Nassiry et al, 2009), a production of significant amounts of trimers during the incubations could be expected. The detection of 5a-methoxytocopherol after methanolysis of the lipid extracts (Fig.…”

“…doi:10.1016/j.gca.2009.09.028 (Goossens et al, 1984). However, the very high efficiency of autoxidation (Liebler et al, 1990;Rosenau et al, 2007;Rontani et al, 2007), photooxidation (Grams et al, 1972;Krol et al, 2001;Nassiry et al, 2009) and aerobic biodegradation processes (Rontani et al, 2008) towards a-tocopherol suggests that only a small part of intact tocopherols should enter the sedimentary record. These compounds could thus be a likely source of pristane only in environments with high primary production or where sediments are buried under strongly reducing conditions.…”

“…These compounds could thus be a likely source of pristane only in environments with high primary production or where sediments are buried under strongly reducing conditions. In contrast, whatever the conditions of sedimentation significant amounts of trimeric oxidation products of a-tocopherol (Krol et al, 2001;Yamauchi et al, 1988) may be produced in surface in senescent phytoplanktonic cells (Nassiry et al, 2009). On the basis of their increased ability to produce prist-1-ene during pyrolysis compared with intact a-tocopherol, these oxidation products were recently proposed as likely additional sources of pristane in sediments (Nassiry et al, 2009).…”