Cyclic tetrapyrrolic photosensitizers from Cladophora patentiramea (Cladophoraceae, Chlorophyta) and Turbinaria conoides (Sargassaceae, Phaeophyta) for photodynamic therapy
- 228 Downloads
In screening for novel photosensitizers for photodynamic therapy, 14 seaweed samples from Port Dickson in Malaysia were collected. Methanolic extracts of these samples were prepared and evaluated for phototoxicity using a short-term cell viability assay, where promyelocytic leukemia cells, HL60 were incubated with the extracts prior to irradiation with a broad spectrum light at 9.6 J cm−2 (equivalent to 10.5 mW cm−2 for 10 min). Four of the methanolic extracts demonstrated moderate to strong phototoxicity and bioassay-guided isolation of photosensitizers was carried out on two selected seaweeds to yield a total of eight cyclic tetrapyrrolic compounds which are derivatives of chlorophyll-a and -b. Seven of these compounds showed >50% phototoxicity at 5 μg mL−1 while exhibiting minimal cytotoxicity in the dark, which is an important characteristic of an ideal photosensitizer.
KeywordsPhotodynamic therapy Photosensitizer Seaweeds Cyclic tetrapyrroles Chlorophylls
The authors are grateful to the sponsors of Cancer Research Initiatives Foundation (CARIF) for supporting this work and the collaborators for their assistance in taxonomic identification and NMR experiments. The first author thanks the University of Malaya for the research grant (Vot PPP No. PS104/2007B; PS175/2008A) in support of this work.
- Cheng HH, Wang HK, Ito J, Bastow KF, Tachibana Y, Nakanishi Y, Xu Z, Luo TY, Lee KH (2001) Cytotoxic Pheophorbide-related compounds from Clerodendrum calamitosum and C. cyrtophyllum. J. Nat. Prod.: 915–919Google Scholar
- Chopin T, Sawhney M (2009) Seaweeds and their mariculture. In: Steele JH, Thorpe SA, Turekian KK (eds) The encyclopedia of ocean sciences. Elsevier, Oxford, pp 4477–4487Google Scholar
- Garido JL, Zapata M (2006) Chlorophyll cnalysis by new high performance liquid chromatography methods. In: Grimm B, Porra RJ, Rüdiger W, Scheer H (eds) Chlorophylls and bacteriochlorophylls: biochemistry, biophysics, functions and applications. Springer, The Netherlands, pp 109–119Google Scholar
- Hoober JK, Sery TW, Yamatomo N (1988) Photodynamic sensitizers from chlorophyll: purpurin-18 and chlorin p6. Photochem Photobiol 48:579–582Google Scholar
- Jeffrey SW (1976) The occurrence of chlorophyll c1 and c2 in algae. J Phycol 12:349–354Google Scholar
- Kobayashi M, Akiyama M, Kano H, Kise H (2006) Spectroscopy and structure determination. In: Grimm B, Porra RJ, Rüdiger W, Scheer H (eds) Chlorophylls and bacteriochlorophylls: biochemistry, biophysics, functions and applications. Springer, The Netherlands, pp 79–94Google Scholar
- Sreenivasan S, Ibrahim D, Mohd Kassim MJN (2007) Free radical scavenging activity and total phenolic compounds of Gracilaria changii. Int J Nat Eng Sci 1:115–117Google Scholar
- Vairappan CS, Goh PN, Ang MY (2007) Antibacterial activity of fine chemicals from Scenedesmus acuminatus (Scenedesmaceae, Chlorococcales, Chlorophyta). Malays J Sci 26:65–72Google Scholar