The Chemical Ecology and Drug Discovery Potential of the Antarctic Red Alga Plocamium cartilagineum and the Antarctic Sponge Dendrilla membranosa

• Main Author: Shilling, Andrew Jason
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: Digital Commons @ University of South Florida 2019
• Subjects: anverenes; dendrillins; membranoids; metabolomics; natural products; Chemistry; Antarctic; Anvers; Anvers Island; Palmer Station; Palmer-Station; The Antarctic; Antarc*; Antarctica
• Online Access: https://digitalcommons.usf.edu/etd/8684; https://digitalcommons.usf.edu/context/etd/article/9881/viewcontent/Shilling_usf_0206D_15759.pdf

Chemical ecology is the study of chemical interactions between organisms and their environment mediated by small molecules involved in nonessential physiological functions, known as secondary metabolites. These compounds can be crucial to survival of the organism, and have also provided the field of medicine with some of history’s most influential drugs, referred to in that context as natural products. Antarctica is a dynamic and understudied environment, which affords the opportunity to examine the chemical ecology of unique organisms while simultaneously evaluating their novel chemistry for potential therapeutic properties as natural products. Plocamium cartilagineum is a red macroalgal species found in the shallow waters of Antarctica known to produce many cytotoxic polyhalogenated monoterpenes thought to serve as feeding deterrents to sympatric algal consumers. Individuals around Palmer Station on Anvers Island can be classified into two distinct genotypes, both shown to produce varying combinations of these chemical defenses linked with site specificity, suggesting each alga is able to tailor its defenses to better suit its unique set of environmental conditions. Metabolomic data linked with genomic analysis from newer and larger field collections during the 2016-2018 field seasons show an even greater diversity of chemical phenotypes than previously found, and that both genotype and depth seem to play a role determining the constituency of the chemical feeding deterrents produced. In an attempt to further evaluate this diversity, the major components of several of the most common chemogroups at our collection sites were determined using GC/MS and NMR guided fractionation. In the process, a small library of anverene-like (2.22) polyhalogenated monoterpenes was generated, containing several known compounds and four previously undescribed natural products, referred to as anverenes B-E (2.29-2.31, 2.34). This collection of molecules was screened for cytotoxicity towards human cervical cancer cells, and ...