RESUMO
The Caribbean region is a hotspot of biodiversity (i.e., algae, sponges, corals, mollusks, microorganisms, cyanobacteria, and dinoflagellates) that produces secondary metabolites such as polyketides and polypropionates. Polyketides are a diverse class of natural products synthesized by organisms through a biosynthetic pathway catalyzed by polyketide synthase (PKS). This group of compounds is subdivided into fatty acids, aromatics, and polypropionates such as macrolides, and linear and cyclic polyethers. Researchers have studied the Caribbean region to find natural products and focused on isolation, purification, structural characterization, synthesis, and conducting biological assays against parasites, cancer, fungi, and bacteria. These studies have been summarized in this review, including research from 1981 to 2020. This review includes about 90 compounds isolated in the Caribbean that meet the structural properties of polyketides. Out of 90 compounds presented, 73 have the absolute stereochemical configuration, and 82 have shown biological activity. We expect to motivate the researchers to continue exploring the Caribbean region's marine environments to discover and investigate new polyketide and polypropionate natural products.
RESUMO
Serum transferrin (sTf) plays a pivotal role in regulating iron biodistribution and homeostasis within the body. The molecular details of sTf Fe(III) binding blood transport, and cellular delivery through transferrin receptor-mediated endocytosis are generally well-understood. Emerging interest exists in exploring sTf complexation of nonferric metals as it facilitates the therapeutic potential and toxicity of several of them. This review explores recent X-ray structural and physiologically relevant metal speciation studies to understand how sTf partakes in the bioactivity of key non-redox active hard Lewis acidic metals. It challenges preconceived notions of sTf structure function correlations that were based exclusively on the Fe(III) model by revealing distinct coordination modalities that nonferric metal ions can adopt and different modes of binding to metal-free and Fe(III)-bound sTf that can directly influence how they enter into cells and, ultimately, how they may impact human health. This knowledge informs on biomedical strategies to engineer sTf as a delivery vehicle for metal-based diagnostic and therapeutic agents in the cancer field. It is the intention of this work to open new avenues for characterizing the functionality and medical utility of nonferric-bound sTf and to expand the significance of this protein in the context of bioinorganic chemistry.
