Albusamides A-G: Hydroxylated Fatty Amine Derivatives from the Deep-Sea-Derived Actinomycete 228DD-066 and Their Cytotoxic Activity.

A series of new hydroxylated fatty amine derivatives, albusamides A-G (-), along with four known compounds (-), which are reported for the first time from a natural source, were isolated from the culture broth of 228DD-066 derived from a deep-sea sediment sample gathered off the coast of Dokdo Island, Republic of Korea. Their structures were elucidated through the comprehensive analysis of 1D and 2D NMR spectra and HRESIMS, and absolute configurations were determined using the modified Mosher's method. Biological evaluations against solid and blood cancer cell lines revealed that these new metabolites have moderate to strong cytotoxic activity.

Labdane-Type Diterpenoids from and Their Antimicrobial and Cytotoxic Activities.

Chemical investigation of the ethyl acetate (EtOAc) extract from a marine-derived actinomycete, , resulted in the discovery of five new labdane-type diterpenoids: chlorolabdans A-C (-), epoxylabdans A and B ( and ), along with one known analog (). The structures of the new compounds were determined by spectroscopic analysis (HR-ESIMS, 1D, and 2D NMR) and by comparing their experimental data with those in the literature. The new compounds were evaluated for their antimicrobial activity, and displayed significant activity against Gram-positive bacteria, with minimum inhibitory concentration (MIC) values ranging from 4 to 8 µg/mL.

Meirols A-C: Bioactive Catecholic Compounds from the Marine-Derived Fungus sp. 1210CH-42.

Three new catecholic compounds, named meirols A-C (-), and one known analog, argovin (), were isolated from the marine-derived fungus sp. 1210CH-42. Their structures were determined by extensive analysis of 1D, 2D NMR, and HR-ESIMS spectroscopic data.

Streptinone, a New Indanone Derivative from a Marine-Derived Inhibits Particulate Matter-Induced Inflammation.

Inflammatory diseases caused by air pollution, especially from particulate matter (PM) exposure, have increased daily. Accordingly, attention to treatment or prevention for these inflammatory diseases has grown. Natural products have been recognized as promising sources of cures and prevention for not only inflammatory but also diverse illnesses.

Rifamycin-Related Polyketides from a Marine-Derived Bacterium and Their Cytotoxic Activity.

Eight rifamycin-related polyketides were isolated from the culture broth of a marine-derived bacterium , including five known (- and ) and three new derivatives (, , and ). The structures of the new compounds were determined by means of spectroscopic methods (HRESIMS and 1D, 2D NMR) and a comparison of their experimental data with those previously reported in the literature. The isolated compounds were evaluated for their cytotoxicity against one normal, six solid, and seven blood cancer cell lines and showed moderate activity against all the tested cell lines with GI values ranging from 2.

Sesquiterpenes from and Their Cytotoxic Activity.

Nine sesquiterpenes, including eight pentalenenes (-) and one bolinane derivative (), were isolated from the culture broth of a marine-derived actinobacterium 213DD-006. Among them, , , , and were new compounds. Their planar structures were determined by spectroscopic methods (HRMS, 1D, and 2D NMR), and the absolute configuration was established by biosynthesis consideration and electronic-circular-dichroism (ECD) calculations.

Thiolactones and Δ-Pregnene Steroids from the Marine-Derived Fungus sp. 1210CH-42 and Their -Glucosidase Inhibitory Activity.

The fungal genus was first reported in 2003 and has mostly been found on land. This is the first report of second metabolites from the marine-derived yeast-like fungus sp. One new thiolactone (), along with one revised thiolactone (), two new Δ-steroids (, ), and one known Δ-steroid (), were isolated from the sp.

Pyrrole-Containing Alkaloids from a Marine-Derived Actinobacterium and Their Antimicrobial and Cytotoxic Activities.

Two new alkaloids, streptopyrroles B and C ( and ), were discovered through a chemical investigation of the ethyl acetate (EtOAc) extract from a marine-derived actinomycete, , along with four known analogs (-). The structures of the new compounds were elucidated by spectroscopic analysis (HR-ESIMS, 1D, and 2D NMR) and a comparison of their experimental data with literature values. The new compounds were evaluated for their antimicrobial activity by standard broth dilution assay, and the tested compounds showed significant activity against Gram-positive bacteria with minimum inhibitory concentration (MIC) values ranging from 0.

New Angucycline Glycosides from a Marine-Derived Bacterium .

Chemical investigation of the ethyl acetate extract from the culture broth of the marine-derived actinobacterium 156VN-095 led to the isolation of three hitherto undescribed angucycline glycosides, including urdamycins W and X ( and ) and grincamycin U (), as well as their seven known congeners. The structures of the new compounds were elucidated by means of spectroscopic methods (HRESIMS, 1D and 2 D NMR) and comparison of their experimental data with literature values. Compounds - and were evaluated for their anti-Gram-positive bacterial effect and cytotoxicity against six cancer cell lines.

Aspersterols A-D, Ergostane-Type Sterols with an Unusual Unsaturated Side Chain from the Deep-Sea-Derived Fungus .

Four previously undescribed ergostane-type sterols, aspersterols A-D (-), were isolated from a deep-sea-derived fungus, IV17-109. The structures of the new compounds were determined by extensive analyses of their spectroscopic data, pyridine-induced deshielding effect, Mosher's method, and electronic circular dichroism calculations. The key feature of these sterols is the presence of a rare unsaturated side chain with conjugated double bonds at Δ and Δ.

New Glycosylated Secondary Metabolites from Marine-Derived Bacteria.

Three new glycosylated secondary metabolites, including a new indole alkaloid, pityriacitrin D (), and two new trehalose lipids ( and ), together with three known compounds (-) were isolated from two marine-derived bacterial strains, 168CLC-66.1 and IV19-045. The structures of - were determined by extensive analysis and comparison of their spectroscopic data with literature values.

Antibacterial and Cytotoxic Phenolic Polyketides from Two Marine-Derived Fungal Strains of .

A chemical investigation on the EtOAc extracts from two marine-derived fungal strains of resulted in the isolation of three previously undescribed phenolic polyketides including unguidepside C (), aspersidone B (), and agonodepside C (), and their 14 known congeners. The structures of the new compounds were determined based on detailed analysis and comparison of their spectroscopic data with literature values, as well as Snatzke's method. The new compounds (, , and ) displayed a significant anti-Gram-positive bacterial activity, with MIC values ranging from 5.

Polyketides and Meroterpenes from the Marine-Derived Fungi 158SC-067 and 01NT-1.1.5 and Their Cytotoxic and Antioxidant Activities.

Ten secondary metabolites, including a new grifolin analog, grifolin B (); a new homovalencic acid derivative, 12-hydroxyhomovalencic acid (); and a compound isolated from a natural source for the first time (), along with seven known compounds, grifolin (), averantin (), 7-chloroaverantin (), 1'--methylaverantin (), 7-hydroxy-2-(2-hydroxypropyl)-5-pentylchromone (), homovalencic acid (), and bekeleylactone E (), were isolated from two fungal strains. The structures of - were identified by detailed analysis and comparison of their spectroscopic data with literature values. Compounds and showed moderate cytotoxic activity against a panel of cancer cell lines (PC-3, HCT-15, MDA-MB-231, ACHN, NCI-H23, NUGC-3), with the GI values ranging from 1.

Reisolation and Structure Revision of Asperspiropene A.

Asperspiropene A was originally reported to have a unique 1,8-dioxaspiro[4.5]decane skeleton. During the course of our ongoing research for novel marine natural products, we isolated compound , which has identical 1D and 2D NMR data to asperspiropene A.