15 -OH-lactone-pheophytin

Fig. 2.133. HPLC chromatogram of pigment extracts from table olives cv. Gordal (a) healthy fruits and (b) altered fruits. Peaks 1 = 15-glyoxilic acid pheophorbide-b 2 = 15-glyoxilic acid pheophorbide-a 3 = Cu-15-glyoxilic acid pheophorbide-a 4 = pheophorbide-b 5 = pheophorbide-a 6 = pyropheophorbide-a 7 = 15-glyoxilic acid pheophytin-b 8 = Cu-15-glyoxilic acid pheophytin-b 9 = 15-glyoxilic acid pheophytin-a 10 = Cu-15-glyoxilic acid pheophytin-a 11 = 15 -OH-lactone-pheophytin-b 12 = 15 -OH-lactone-pheophytin-a 13 = 15-formylpheophytin-b 14 = pheophytin-b 14 = pheophytin-b 15 = 15-formylpheophytin-a 16 = pheophytin-a 16 = pheophytin-a 17 = pyropheophytin-b 18 = Cu-pheophytin-a 19 = Cu-15-formylpheophytin-a 20 = pyropheophytin-a 21 = Cu-pyropheophytin-a. Reprinted with permission from B. Ganul-Rojas el al. [304].

The spectral changes caused by the inclusion of a lactone ring in the structure of pheophytin a can be observed in Figure 7.11. The spectrum of 15 -OH-lactone-pheophytin a shows a 10-nm hypsochromic displacement of the Soret band. In the case of phytol-purpurin 18 a, the most-striking displacement is that of the maximum of the red region, a bathochromic change of around 30 nm. 

FIGURE 7.11 Electronic absorption spectra of 15 -OH-lactone-pheophytin a (—) and phytol-puipurin 18 a (—). 

FIGURE 7.18 High-performance liquid chromatography (HPLC) separation of a mixture of standards of pheophytins and their oxidation products. Peaks 1,15-glyoxilic acid-pheophytin b 2, 15-gJyoxilic acid-pheophytin a 3, 15-OH-lactone-pheophytin b 4, 15-OH-lactone-pheophytin a 5, pheophytin b 5, pheophytin b C-13 epimer 6, pheophytin a, 6, pheophytin a C-13 epimer 7, phytol-purpurin 18 b ester 8, phytol-purpurin 18 a ester. 

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