Profiling Prokaryotic Communities and Aaptamines of Sponge Aaptos suberitoides from Tulamben, Bali

Sponges (Porifera) harbor a diversity of microorganisms that contribute largely to the production a vast array of bioactive compounds. The microorganisms associated with sponge have an important impact on the chemical diversity of the natural products. Herein, our study focuses on an Aaptos suberitoides commonly found in Indonesia. The objective of this study was to investigate the profile of prokaryotic community and the presence of aaptamine metabolites in sponge Aaptos suberitoides. Sponges were collected from two site locations (Liberty Wreck and Drop Off) in Tulamben, Bali. The sponges were identified by barcoding DNA cytochrome oxidase subunit I (COI) gene. The profile of prokaryotic composition was investigated by amplifying the 16S rRNA gene using primers 515f and 806r to target the V4 region. The metabolites were analyzed using LC-MS, and dereplication was done to identify the aaptamines and its derivates. The barcoding DNA of the sponges confirmed the identity of samples as Aaptos suberitoides. The prokaryotic communities of samples A. suberitoides were enriched and dominated by taxa Proteobacteria, Chloroflexi, Actinobacteria, and Acidobacteria. The chemical analysis showed that all sponges produce aaptamine and isoaaptamine except A. suberitoides S2421 produce analog of aaptamines. This is the first report on the profile of prokaryotic community and the aaptamine of tropical marine sponges, A. suberitoides, from Tulamben, Bali.

Marine natural products

Covering: 2020This review covers the literature published in 2020 for marine natural products (MNPs), with 757 citations (747 for the period January to December 2020) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1407 in 420 papers for 2020), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. A meta analysis of bioactivity data relating to new MNPs reported over the last five years is also presented.

Marine Terpenic Endoperoxides

Organic extracts of marine invertebrates, mainly sponges, from seas all over the world are well known for their high in vitro anticancer and antibiotic activities which make them promising sources of compounds with potential use as pharmaceutical leads. Most of the structures discovered so far have a peculiar structural feature in common: a 1,2-dioxane ring. This is a highly reactive heterocycle that can be considered as an endoperoxide function. Together with other structural features, this group could be responsible for the strong biological activities of the substances present in the extracts. Numerous research programs have focused on their structural elucidation and total synthesis since the seventies. As a consequence, the number of established chiral centres and the similarity between different naturally occurring substances is increasingly higher. Most of these compounds have a terpenoid nature, mainly diterpene and sesterterpene, with several peculiar structural features, such as the loss of one carbon atom. Although there are many reviews dealing with the occurrence of marine peroxides, their activities, or potential pharmaceutical uses, no one has focused on those having a terpene origin and the endoperoxide function. We present here a comprehensive review of these compounds paying special attention to their structural features and their biological activity.

Biological Activity of Naturally Derived Naphthyridines

Marine and terrestrial environments are rich sources of various bioactive substances, which have been used by humans since prehistoric times. Nowadays, due to advances in chemical sciences, new substances are still discovered, and their chemical structures and biological properties are constantly explored. Drugs obtained from natural sources are used commonly in medicine, particularly in cancer and infectious diseases treatment. Naphthyridines, isolated mainly from marine organisms and terrestrial plants, represent prominent examples of naturally derived agents. They are a class of heterocyclic compounds containing a fused system of two pyridine rings, possessing six isomers depending on the nitrogen atom's location. In this review, biological activity of naphthyridines obtained from various natural sources was summarized. According to previous studies, the naphthyridine alkaloids displayed multiple activities, i.a., antiinfectious, anticancer, neurological, psychotropic, affecting cardiovascular system, and immune response. Their wide range of activity makes them a fascinating object of research with prospects for use in therapeutic purposes.

Four new aaptamine alkaloids from marine sponge Aaptos aaptos

Four new aaptamine alkaloids, named as 9-methoxy-N-demethylaaptanone (1), 3,5-dicarbomethoxy-1,​6-​naphthyridine (2), aaptosvanphongs A and B (3 and 4), and three known aaptamine alkaloids as 2-methoxy-3-oxoaaptamine (5), 8,9,9-trimethoxy-9H-benzo[de][1,6]-naphthyridine (6), and demethyl(oxy)aaptamine (7) were isolated from the sponge Aaptos by various chromatographic methods. Their structures were established by extensive spectroscopic analyses (HR-ESI-MS, 1 D and 2 D NMR) and by comparison of the spectral data with those reported in the literature. Compounds 1-7 significantly showed cytotoxic effects against SK-LU-1, MCF-7, HepG2, and SK-Mel-2 cell lines with IC₅₀ values in range from 7.7 ± 0.8 to 51.4 ± 1.8 µM. Among them, compound 7 exhibited the most cytotoxic activity with corresponding IC₅₀ values of 9.2 ± 1.0, 7.8 ± 0.6, 8.4 ± 0.8, and 7.7 ± 0.8 µM.

Bioactive Compounds from Marine Sponges: Fundamentals and Applications

Marine sponges are sessile invertebrates that can be found in temperate, polar and tropical regions. They are known to be major contributors of bioactive compounds, which are discovered in and extracted from the marine environment. The compounds extracted from these sponges are known to exhibit various bioactivities, such as antimicrobial, antitumor and general cytotoxicity. For example, various compounds isolated from Theonella swinhoei have showcased various bioactivities, such as those that are antibacterial, antiviral and antifungal. In this review, we discuss bioactive compounds that have been identified from marine sponges that showcase the ability to act as antibacterial, antiviral, anti-malarial and antifungal agents against human pathogens and fish pathogens in the aquaculture industry. Moreover, the application of such compounds as antimicrobial agents in other veterinary commodities, such as poultry, cattle farming and domesticated cats, is discussed, along with a brief discussion regarding the mode of action of these compounds on the targeted sites in various pathogens. The bioactivity of the compounds discussed in this review is focused mainly on compounds that have been identified between 2000 and 2020 and includes the novel compounds discovered from 2018 to 2021.