A depsipeptide is a peptide in which one or more of its amide, -C(O)NHR-, groups are replaced by the corresponding ester, -C(O)OR-. Many depsipeptides have both peptide and ester linkages. Elimination of the N–H group in a peptide structure results in a decrease of H-bonding capability, which is responsible for secondary structure and folding patterns of peptides, thus inducing structural deformation of the helix and β-sheet structures. Because of decreased resonance delocalization in esters relative to amides, depsipeptides have lower rotational barriers for cis-trans isomerization and therefore they have more flexible structures than their native analogs. They are mainly found in marine and microbial natural products.
Cryptophycins are a family of macrolide molecules that are potent cytotoxins and have been studied for potential antiproliferative properties useful in developing chemotherapy. They are members of the depsipeptide family.
A depside is a type of polyphenolic compound composed of two or more monocyclic aromatic units linked by an ester group. Depsides are most often found in lichens, but have also been isolated from higher plants, including species of the Ericaceae, Lamiaceae, Papaveraceae and Myrtaceae.
Halicylindramides are a group of antifungal peptides. The first compounds of this type, designated halicylindramides A through E, were isolated from sea sponges of the genus Halichondria. More compounds in the family, designated F, G and H, were found in sponges of the genus Petrosia. Halicylindramide A has been synthesized by chemists.
Eudistomins are β-carboline derivatives, isolated from ascidians, like Ritterella sigillinoides, Lissoclinum fragile, or Pseudodistoma aureum.
Agosterol A is a bio-active sterol which may have applications in removing multi-drug resistance in various cancers. It was first isolated from marine sponge but has also been produced synthetically.
Aplyzanzine A is a bio-active isolate of marine sponge.
Aplysamine-2 is a bio-active isolate of marine sponge.
Oroidin is a bromopyrrole alkaloid, originally isolated from marine sponges in the genus Agelas. Its complex structure leads to wide biological activities, which makes Oroidin a potential drug candidate for various diseases. It also serves as chemical defense in marine sponges.
Phakellistatin 13 is a cytotoxic cycloheptapeptide isolated from marine sponge.
14-Norpseurotin A is an alkaloid and a bio-active metabolite of Aspergillus, featuring an oxa-spiro-lactam core.
Xestoquinone is a bio-active isolate of the marine sponge Xestospongia.
Salinispora is a genus of obligately aerobic, gram-positive, non-acid-fast bacteria belonging to the family of Micromonosporaceae. They are heterotrophic, non-motile, and obligately grow under high osmotic/ionic-strength conditions. They are the first identified genus of gram-positive bacteria which has a high osmotic/ionic-strength requirement for survival. They are widely abundant in tropical marine sediments and were first identified in 2002. This genus of bacteria has potential biotechnological significance due to their production of novel secondary metabolites which can be used pharmaceutically.
Fungal isolates have been researched for decades. Because fungi often exist in thin mycelial monolayers, with no protective shell, immune system, and limited mobility, they have developed the ability to synthesize a variety of unusual compounds for survival. Researchers have discovered fungal isolates with anticancer, antimicrobial, immunomodulatory, and other bio-active properties. The first statins, β-Lactam antibiotics, as well as a few important antifungals, were discovered in fungi.
Streptomyces isolates have yielded the majority of human, animal, and agricultural antibiotics, as well as a number of fundamental chemotherapy medicines. Streptomyces is the largest antibiotic-producing genus of Actinomycetota, producing chemotherapy, antibacterial, antifungal, antiparasitic drugs, and immunosuppressants. Streptomyces isolates are typically initiated with the aerial hyphal formation from the mycelium.
Onnamide A is a bioactive natural product found in Theonella swinhoei, a species of marine sponge whose genus is well known for yielding a diverse set of biologically active natural products, including the swinholides and polytheonamides. It bears structural similarities to the pederins, a family of compounds known to inhibit protein synthesis in eukaryotic cells. Onnamide A and its analogues have attracted academic interest due to their cytotoxicity and potential for combating the growth and proliferation of cancer cells.
Dysidea arenaria is a species of marine sponge (poriferan) found in the Pacific Ocean. It is a member of the order Dictyoceratida, one of two sponge orders that make up the keratose or "horny" sponges in which a mineral skeleton is absent and a skeleton of organic fibers is present instead.
Mycale adhaerens, the purple scallop sponge, is a species of marine demosponge in the family Mycalidae. Mycale is a large genus and this species is placed in the subgenus Aegogropila making its full name, Mycale (Aegogropila) adhaerens. It grows symbiotically on the valves of scallop shells and is native to the west coast of North America.
Tanshinones are a class of chemical compounds. Examples include dihydrotanshinone, tanshinone I, or tanshinone IIA. These compounds are all naturally occurring and can all be isolated from Salvia miltiorrhiza.
Pseudoceratina is a genus of sponge within the family Pseudoceratinidae. They are characterized by possession of a dendritic fiber skeleton lacking laminar bark but containing pith. They have been found in a variety of habitats including the Great Barrier reef, the Red Sea, and Jamaica. Sponges of this genus have a microbiome known to produce a variety of chemicals that are used in pharmaceutical and anti-fouling activities. Notably, a species in this genus produces a chemical that is effective in inhibiting the migration of metastatic breast cancer cells.
