A novel 5-HT receptor ligand and related cytotoxic compounds from an acid mine waste extremophile

Chemical Constituents With Antiproliferative Activity From Pogostemon cablin (Blanco) Benth

Two new patchoulene sesquiterpenoid glycosides (1–2), a natural patchoulane-type sesquiterpenoid (3) and a natural cadinene-type sesquiterpenoid (4), were isolated from the aerial parts of Pogostemon cablin (Blanco) Benth., together with eleven known sesquiterpenoids (5–15) and eleven known flavonoids (16–26). Their chemical structures were elucidated on the basis of spectroscopic methods, including NMR, HRESIMS, IR, and CD spectroscopic data analysis, as well as chemical hydrolysis. The isolated compounds 1–13 and 15–26 were tested for inhibitory effects on the proliferation of HepG2 cancer cells. Among them, compounds 17 and 19 displayed anti-proliferative effects against HepG2 cells with IC₅₀ values of 25.59 and 2.30 μM, respectively. Furthermore, the flow cytometry analysis and Western blotting assays revealed that compound 19 significantly induced apoptosis of HepG2 cells by downregulating the ratio of Bcl-2/Bax and upregulating the expression of cleaved caspase-3 and cleaved caspase-9. Therefore, the potential pharmaceutical applications of P. cablin would be applied according to our study findings.

Hedycaryol - Central Intermediates in Sesquiterpene Biosynthesis, Part II

The known sesquiterpenes that arise biosynthetically from hedycaryol are summarised. Reasonings for the assignments of their absolute configurations are discussed. The analysis provided here suggests that reprotonations at the C1=C10 double bond of hedycaryol are directed toward C1 and generally lead to 6-6 bicyclic compounds, while reprotonations at the C4=C5 double bond occur at C4 and result in 5-7 bicyclic compounds. Read more in the Review by H. Xu and J. S. Dickschat (DOI: 10.1002/chem.202200405).

Assessing Microbial Metabolic and Biological Diversity to Inform Natural Product Library Assembly

The pressing need for novel chemical matter to support bioactive compound discovery has led natural product researchers to explore a wide range of source organisms and environments. One of the implicit guiding principles behind those efforts is the notion that sampling different environments is critical to accessing unique natural products. This idea was tested by comparing fungi from disparate biomes: aquatic sediments from Lake Michigan (USA) and terrestrial samples taken from the surrounding soils. Matched sets of Penicillium brevicompactum, Penicillium expansum, and Penicillium oxalicum from the two source environments were compared, revealing modest differences in physiological performance and chemical output. Analysis of LC-MS/MS-derived molecular feature data showed no source-dependent differences in chemical richness. High levels of scaffold homogeneity were also observed with 78-83% of scaffolds shared among the terrestrial and aquatic Penicillium spp. isolates. A comparison of the culturable fungi from the two biomes indicated that certain genera were more strongly associated with aquatic sediments (e.g., Trichoderma, Pseudeurotium, Cladosporium, and Preussia) versus the surrounding terrestrial environment (e.g., Fusarium, Pseudogymnoascus, Humicola, and Acremonium). Taken together, these results suggest that focusing efforts on sampling the microbial resources that are unique to an environment may have a more pronounced effect on enhancing the sought-after natural product diversity needed for chemical discovery and screening collections.

Germacrene A-A Central Intermediate in Sesquiterpene Biosynthesis

This review summarises known sesquiterpenes whose biosyntheses proceed through the intermediate germacrene A. First, the occurrence and biosynthesis of germacrene A in Nature and its peculiar chemistry will be highlighted, followed by a discussion of 6-6 and 5-7 bicyclic compounds and their more complex derivatives. For each compound the absolute configuration, if it is known, and the reasoning for its assignment is presented.

Sesquiterpenoids from the roots and rhizomes of Valeriana amurensis and their effects on NGF-induced neurite outgrowth in PC12 cells

Two new sesquiterpenoids, including a kessane-type sesquiterpenoid (1) and one bisabolane derivative (2), together with fourteen known sesquiterpenoids (3-16), were isolated from the roots and rhizomes of Valeriana amurensis. The structures of new compounds were established on the basis of extensive spectroscopic analysis. All isolates were evaluated for their effects on nerve growth factor (NGF)-mediated neurite outgrowth in pheochromocytoma (PC12) cells. As a results, four compounds including 10-12 and 15 showed potent promoting effects at the concentration of 10 µM on NGF-induced neurite outgrowth in PC12 cells with the differentiation rate of 11.84%, 12.21%, 13.77% and 12.16%, respectively.

Three new drimane sesquiterpenoids from cultures of the fungus Penicillium sp

Three new drimane sesquiterpenoids, 12-hydroxyalbrassitriol (1), drim-8(12)-en-6β,7α, 9α,11-tetraol (2), and drim-68(12)-dien-9α,11-diol (3), along with one known analog albrassitriol (4), were isolated from cultures of the tin mine tailings-associated fungus Penicillium sp. The new structures were determined on the basis of extensive spectroscopic analyses. All compounds were tested for their cytotoxicities against five human cancer cell lines.

Total synthesis of orientalol F via gold-catalyzed cycloisomerization of alkynediol

The total synthesis of orientalol F was accomplished in 13 steps using gold-catalyzed tandem cycloisomerization of alkynediol as a key step.

Fragrant volatile sesquiterpenoids isolated from the essential oil of Laggera pterodonta by using olfactory-guided fractionation

Chemical composition of the essential oil from Laggera pterodonta (Compositae) was inverstigated. GC/MS Analyses led to the identification of 68 components, representing more than 96% of the total oil. By focusing on the woody note fraction of the essential oil, one new bisabolane-type sesquiterpenoid, bisabola-2,7(14),11-trien-10-ol (1), together with ten known compounds, bisabolol oxide B (2), ylangenol (3), copaborneol (4), guai-11-en-10-ol (5), spathulenol (6), aromadendran-10-ol (7), caryophyllenol (8), 5α,7α-eudesm-11(13)-en-4α-ol (9), γ-costic acid (10), and eudesma-4(15),11(13)-diene-12,5β-olide (11), were isolated by using olfactory-guided fractionation. The structures of the eleven compounds were determined by NMR and MS analyses. All the volatile compounds reported here were isolated for the first time from this plant. On the basis of preliminary odor assessment, the odor of the woody-note fractions of the essential oil was assumed to be due to these isolated sesquiterpenoids.

Bioactive Secondary Metabolites from Acid Mine Waste Extremophiles

The extremophilic microbes of the Berkeley Pit Lake are a valuable source of new and interesting secondary metabolites. It is of particular interest that these acidophilic microbes produce small molecule inhibitors of pathways associated with low pH and high Eh. These same small molecules also inhibit molecular pathways induced by reactive oxygen species (ROS) and inflammation in mammalian cells. Low pH is a hallmark of inflammation and high Eh is one of ROS, so the suitability of this collection as a source of bioactive metabolites is actually quite biorational. Compound isolation was guided by inhibition of caspase-1 and matrix metalloproteinase-3, and active compounds were sent to the National Cancer Institute-Developmental Therapeutics Program and Memorial Sloan Kettering Cancer center for evaluation as either antiproliferative or cytotoxic agents.

Spirobacillenes A and B, unusual spiro-cyclopentenones from Lysinibacillus fusiformis KMC003

Two previously unreported spiro-cyclopentenones, spirobacillenes A (1) and B (2), were isolated from the 24 h broth culture of Lysinibacillus fusiformis KMC003 derived from acidic coal-mine drainage. The structures of 1 and 2 were elucidated by analyses of the NMR, HRFABMS, single-crystal X-ray diffraction crystallography, and circular dichroism (CD) spectral data. Compound 1 possessed moderate inhibitory activity against the production of nitric oxide (NO) and reactive oxygen species (ROS).

Caspase-1 inhibitors from an extremophilic fungus that target specific leukemia cell lines

Berkeley Pit Lake, Butte, Montana, is a 540 m deep abandoned open-pit copper mine filled with over 140 billion liters of acidic, metal-sulfate-contaminated water. This harsh environment has yielded several microorganisms that produce interesting biologically active compounds. Several polyketide metabolites including the new berkazaphilones A (1) and B (2) and octadienoic acid derivatives berkedienoic acid (13) and berkedienolactone (15), as well as previously reported azaphilone 4, vermistatin (6), dihydrovermistatin (7), penisimplicissin (8), aldehyde 9, and methylparaconic acid (11), were isolated from a culture broth of Penicillium rubrum taken from a depth of 270 m. The structures of these compounds were deduced by interpretation of spectroscopic data. The compounds were isolated either for their inhibition of the signal transduction enzyme caspase-1 or because of their structural similarity to these inhibitors. Selected compounds were further evaluated for their ability to inhibit interleukin-1β production by inflammasomes in induced THP-1 cells. Berkazaphilones B (2) and C (4) and vermistatin analogue penisimplicissin (8) exhibited selective activity against leukemia cancer cell lines in the National Cancer Institute 60 human cell line assay.

Caspase-1 and -3 inhibiting drimane sesquiterpenoids from the extremophilic fungus Penicillium solitum

Two new drimane sesquiterpene lactones and one new tricarboxylic acid derivative were isolated from the Berkeley Pit extremophilic fungus Penicillium solitum. The structures of these compounds were deduced by spectroscopic analysis. Berkedrimanes A and B inhibited the signal transduction enzymes caspase-1 and caspase-3 and mitigated the production of interleukin 1-β in the induced THP-1 (pro-monocytic leukemia cell line) assay.

Culturability and secondary metabolite diversity of extreme microbes: expanding contribution of deep sea and deep-sea vent microbes to natural product discovery

Microbes from extreme environments do not necessarily require extreme culture conditions. Perhaps the most extreme environments known, deep-sea hydrothermal vent sites, support an incredible array of archaea, bacteria, and fungi, many of which have now been cultured. Microbes cultured from extreme environments have not disappointed in the natural products arena; diverse bioactive secondary metabolites have been isolated from cultured extreme-tolerant microbes, extremophiles, and deep-sea microbes. The contribution of vent microbes to our arsenal of natural products will likely grow, given the culturability of vent microbes; their metabolic, physiologic, and phylogenetic diversity; numerous reports of bioactive natural products from microbes inhabiting high acid, high temperature, or high pressure environments; and the recent isolation of new chroman derivatives and siderophores from deep-sea hydrothermal vent bacteria.

Stachylines A-D from the sponge-derived fungus Stachylidium sp

The marine-derived fungus Stachylidium sp. was isolated from the sponge Callyspongia cf. C. flammea. Four new, putatively tyrosine-derived and O-prenylated natural products, stachylines A-D (1-4), were obtained from the fungal extract. The structures of 1-4 were elucidated on the basis of extensive spectroscopic analyses. The absolute configuration of compound 2 was established by Mosher's method. Stachyline A (1) possesses a rare terminal oxime group and occurs as an interchangeable mixture of E/Z-isomers.

Molecules derived from the extremes of life

In order to survive extremes of pH, temperature, salinity and pressure, organisms have been found to develop unique defences against their environment, leading to the biosynthesis of novel molecules ranging from simple osmolytes and lipids to complex secondary metabolites. This review highlights novel molecules isolated from microorganisms that either tolerate or favour extreme growth conditions.

Englerin A, a selective inhibitor of renal cancer cell growth, from Phyllanthus engleri

An extract from Phyllanthus engleri was identified in a bioinformatic analysis of NCI 60-cell natural product extract screening data that selectively inhibited the growth of renal cancer cell lines. Bioassay-guided fractionation yielded two new guaiane sesquiterpenes, englerins A (1) and B (2). Englerin A showed 1000-fold selectivity against six of eight renal cancer cell lines with GI(50) values ranging from 1-87 nM. The structures of 1 and 2 and their relative stereochemistry were established by spectroscopic methods.

Guaiane Sesquiterpenoids from Jatropha curcas

Two new guaiane sesquiterpenoids named jatrophaols A and B (1, 2), along with three known analogues, were isolated from the roots of Jatropha curcas. Their structures were determined by spectroscopic methods, including 1D and 2D NMR spectroscopy, HR-EI-MS, HR-ESI-MS, and X-ray diffraction, as well as by comparison of their spectral data with those of related compounds.

The berkeleyamides, amides from the acid lake fungus Penicillum rubrum

We previously reported several novel bioactive hybrid polyketide-terpenoid metabolites from a deep water Penicillium rubrum isolated from Berkeley Pit Lake, Butte, Montana. In this paper we report the structures of four new amides, berkeleyamides A-D (1, 4, 5, 7), isolated from extracts of this fungus. The structures of these compounds were deduced by analysis of NMR data, chemical derivatization, and comparison of their spectroscopic data to those of known compounds.

The berkeleyacetals, three meroterpenes from a deep water acid mine waste Penicillium

Berkeley Pit Lake is a 1500 ft deep abandoned open-pit copper mine filled with over 1140 billion liters of acidic, metal-sulfate-contaminated water. This harsh environment is proving to be a source of unusual microorganisms that produce novel bioactive compounds. We recently reported the structures of berkeleydione (1) and berkeleytrione (2), two novel hybrid polyketide-terpenoid metabolites isolated from a deep water Penicillium sp. growing in Berkeley Pit Lake. In this paper we report the structures of three new compounds, berkeleyacetals A-C ( 3-5) isolated from extracts of this fungus. The structures of these compounds were deduced by comparison of mass spectral and NMR data to that of berkeleydione (1).

Berkelic acid, a novel spiroketal with selective anticancer activity from an acid mine waste fungal extremophile

Berkeley Pit Lake is an abandoned open-pit copper mine filled with 30 billion gallons of acidic, metal-contaminated water. This harsh environment is proving to be a source of unusual microorganisms that produce novel bioactive metabolites. Bioassay-guided fractionation using signal transduction enzyme assays led to the isolation of the novel spiroketal, berkelic acid 1, and of the known gamma-pyrone, spiciferone A 4. Berkelic acid has shown selective, nanomolar activity against OVCAR-3, an ovarian cancer cell line in the National Cancer Institute cell line screen. The isolation and characterization of these compounds are reported here.

Novel sesquiterpenoid matrix metalloproteinase-3 inhibitors from an acid mine waste extremophile

Berkeley Pit Lake is a 1500 ft deep abandoned open-pit copper mine filled with 30 billion gallons of acidic, metal-contaminated water. This harsh environment is proving to be a source of unusual, biologically active microorganisms. Bioassay-guided fractionation using signal transduction enzyme assays led to the isolation of three novel bisabolane sesquiterpenes and a novel coumarin. The isolation and characterization of these compounds are reported here.