Spectroscopy and Structure Determination

Cyclic tetrapyrrolic photosensitizers from Cladophora patentiramea (Cladophoraceae, Chlorophyta) and Turbinaria conoides (Sargassaceae, Phaeophyta) for photodynamic therapy

“…Typically, a pheophorbide-a compound exhibits a UV-Vis profile with a Soret band at λ max =408 nm while a pheophorbide-b compound exhibits a UV-Vis absorption profile with a Soret band λ max that is shifted to 432 nm. It is also noted that λ max of the Q y band of the pheophorbide-a compound is higher at 667 nm, and with stronger intensity compared to that of the pheophorbide-b compound which has a λ max of 654 nm (Kobayashi et al 2006).…”

“…The difference between the mean% cell viability in "Unirradiated" and "Irradiated" experiments is significant for most (P<0.001 or 0.05) but not significant (ns) for three samples Compound 4 has previously been synthesized by Wongsinkongman et al (2002) but this is the first description of its isolation as a naturally occurring compound. Compound 5 was identified as 15 1 -methoxypurpurin-7-lactone methyl diester by comparison of its UV-Vis and mass spectral data with the literature values of the closely related 15 1 -hydroxypurpurin-7-lactone ethyl methyl diester (Kobayashi et al 2006;Kim et al 2003;Chee et al 2005). Even though hydroxypurpurin lactones have been described, this is the first description of the methoxypurpurin lactone structure.…”

“…Compound 3 was identified as purpurin-18 methyl ester by comparison of its UV-Vis and mass spectral data with the literature spectral data of the same compound (Naylor and Keely 1998;Ocampo and Repeta 1999). Compound 4 was identified as 13 2 -methoxypheophorbide-a methyl ester by comparison of its UV-Vis and 1 H NMR spectral data with the literature spectral data of the same compound (Kobayashi et al 2006;Rho et al 2003 The mean values and SEMs from six replicates in two separate experiments are presented. The difference between the mean% cell viability in "Unirradiated" and "Irradiated" experiments is significant for most (P<0.001 or 0.05) but not significant (ns) for three samples Compound 4 has previously been synthesized by Wongsinkongman et al (2002) but this is the first description of its isolation as a naturally occurring compound.…”

“…Compound 2 was identified as 13 2 -hydroxypheophorbidea-methyl ester by comparison of its UV-Vis and 1 H NMR spectral data with the literature spectral data of the same compound (Kobayashi et al 2006;Ma and Dolphin 1996). Compound 3 was identified as purpurin-18 methyl ester by comparison of its UV-Vis and mass spectral data with the literature spectral data of the same compound (Naylor and Keely 1998;Ocampo and Repeta 1999).…”

“…Even though hydroxypurpurin lactones have been described, this is the first description of the methoxypurpurin lactone structure. Compound 6 and 7 were identified as S/R diastereomers of 13 2 -hydroxypheophorbide-b-methyl ester by comparison of their UV-Vis and 1 H NMR spectral data with the literature values of the ethyl ester derivative, 13 2 (S/R)-hydroxypheophorbide-b methyl ester (Kobayashi et al 2006;Chee et al 2005). Compound 8 was identified as 7-formyl-15 1 -methoxypurpurin-7-lactone methyl diester by comparison of its UV-Vis data with those typical of b-type chromophores (Kobayashi et al 2006) and its 1 H NMR spectral data with the literature values of the closely related 15 1 -hydroxypurpurin-7-lactone ethyl methyl diester Chee et al 2005).…”