Recent Advances in the Isolation, Synthesis and Biological Activity of Marine Guanidine Alkaloids

Abstract

Marine organisms are prolific resources of guanidine-containing natural products with intriguing structures and promising biological activities. These molecules have therefore attracted the attention of chemists and biologists for their further studies towards potential drug leads. This review focused on the guanidine alkaloids derived from marine sources and discussed the recent progress on their isolation, synthesis and biological activities, covering the literature from the year 2010 to the present.

<p>In vitro Antibacterial Activity of Isopropoxy Benzene Guanidine Against Multidrug-Resistant <em>Enterococci</em></p>

“…14 Substituted benzene guanidine compounds belonging to amino-guanidine compound class have been used in the treatment of a broad range of diseases and emerged as candidates for further structural modification for new promising drugs. [15][16][17] For example, robenidine was synthesized as an anticoccidial agent widely used to prevent coccidian infections since the early 1970s. 18 Recently, robenidine analogues have been shown as Gram-positive antibacterial agents, including Staphylococcus aureus and vancomycin-resistant Enterococci.…”

Synthetic Approaches to a Challenging and Unusual Structure—An Amino-Pyrrolidine Guanine Core

“…For that purpose, the reaction mixture attained (Table 4, entry 10) was analysed by HPLC-ESI-MS (Supplementary Figure S5). With a retention time of 4.1 min, it was possible to identify compound 9 by the peak at m/z 130 that correspond to the [M + H] + and the pyrrolidone (10) The LC-MS indicates the presence of other compounds which shows the lability of the intermediates involved and indicates that, even prior to the formation of our product, the outcome of our reaction is being affected by a variety of divergent pathways. This factor, combined with the instability of the products, may explain the low to moderate yields obtained in this approach.…”

“…About one-third of all approved drugs classified as "small molecules" in this period are natural products, derived from natural or synthetic products but with a natural pharmacophore. Guanidine derivatives can be found in several natural products from diverse origin [9,10] and this structural unit is present as a building block in various pharmaceuticals such as rosuvastatin a cholesterol biosynthesis inhibitor, [11] guanabenz used clinically as an antihypertensive agent, [12] imatinib a tyrosine kinase inhibitor [13] used as an anticancer drug and the blockbuster drug used to treat peptic ulcers and cimetidine a histamine H2 receptor antagonist that inhibits stomach acid production [14]. Considered to be one of the strongest organic bases (pK HA = 13.6) guanidine has the capacity to bind to carboxylates, phosphates and metals with the guanidinium cation engaging special interactions between ligand/receptor or enzyme/substrate [15].…”

Marine sponges of the genus Stelletta as promising drug sources: chemical and biological aspects

“…To date, a variety of marine alkaloids and new derivatives have been isolated and characterized from marine sponges 40 . Some of these interesting bioactive marine alkaloids, represented by marine guanidines, may be the most promising for future medicinal applications 41. , 42.…”