title: Marine benthic diatoms contain compounds able to induce leukemia cell death and modulate blood platelet activity.
abstract: In spite of the high abundance and species diversity of diatoms, only a few bioactive compounds from them have been described. The present study reveals a high number of mammalian cell death inducing substances in biofilm-associated diatoms sampled from the intertidal zone. Extracts from the genera Melosira, Amphora, Phaeodactylum and Nitzschia were all found to induce leukemia cell death, with either classical apoptotic or autophagic features. Several extracts also contained inhibitors of thrombin-induced blood platelet activation. Some of this activity was caused by a high content of adenosine in the diatoms, ranging from 0.07 to 0.31 microg/mg dry weight. However, most of the bioactivity was adenosine deaminase-resistant. An adenosine deaminase-resistant active fraction from one of the extracts was partially purified and shown to induce apoptosis with a distinct phenotype. The results show that benthic diatoms typically found in the intertidal zone may represent a richer source of interesting bioactive compounds than hitherto recognized.
authors.affiliation: Department of Biology, University of Bergen, Jahnebakken 5, Bergen, Norway. siv.prestegard@bio.uib.no
authors.forename: Siv Kristin
authors.initials: SK
authors.lastname: Prestegard
authors.forename: Linn
authors.initials: L
authors.lastname: Oftedal
authors.forename: Rosie Theresa
authors.initials: RT
authors.lastname: Coyne
authors.forename: Gyrid
authors.initials: G
authors.lastname: Nygaard
authors.forename: Kaja Helvik
authors.initials: KH
authors.lastname: Skjaerven
authors.forename: Gjert
authors.initials: G
authors.lastname: Knutsen
authors.forename: Stein Ove
authors.initials: SO
authors.lastname: Døskeland
authors.forename: Lars
authors.initials: L
authors.lastname: Herfindal
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D018441:Biofilms; D001685:Biological Factors / Q000494:pharmacology*; D045744:Cell Line, Tumor; D017377:Diatoms / Q000378:metabolism*; D004354:Drug Screening Assays, Antitumor; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007938:Leukemia; D008297:Male; D008969:Molecular Sequence Data; D015539:Platelet Activation / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000970:Antineoplastic Agents; D001685:Biological Factors; D000241:Adenosine