Synthesis and assessment of gold nanoparticles conjugated with extracts, sterols and pure compounds derived from marine sponges from the Indian and Pacific Oceans.

Gold nanoparticles (AuNPs) exhibit different physical properties compared to small molecules, bulk materials and other nanoparticles. Their synthesis using plant extracts, particularly polyflavonoids as phytoreductants, for the conversion of Au(iii) into Au(0) has been reported. In this study, AuNPs were synthesized with extracts, sterols and pure compounds derived from marine sponges using gold(iii) chloride trihydrate.

Alkaloids and Styryl Lactones from and Their Biological Activities.

Phytochemical investigations of the twig and leaf extracts of resulted in the isolation and identification of two new alkaloids, goniotortiline () and goniotortilactam (), three new styryl lactone derivatives, goniotortilactone () and goniotortilols A () and B (), and 25 known compounds. Their structures were elucidated by spectroscopic methods and HRESITOFMS data. Compounds , , , , , and inhibited nitric oxide (NO) production with IC values ranging from 8.

Prephenate decarboxylase: An unexplored branchpoint to unusual natural products.

Prephenate decarboxylases are a small family of enzymes which initiate a specialized divergence from the shikimate pathway, where prephenate (2) is decarboxylated without aromatization. In addition to effecting a challenging chemical transformation, prephenate decarboxylases have been implicated in the production of rare specialized metabolites, sometimes directly constructing bioactive warheads. Many of the biosynthetic steps to natural products derived from prephenate decarboxylases remain elusive.

An anti-mitotic compound, (+)-6-tuliposide A, isolated from the Canadian glacier lily, Erythronium grandiflorum.

The Canadian prairie ecosystem is subjected to abiotic and biotic conditions that induce plants to produce secondary metabolites that affect mammalian physiology. Extracts prepared from certain plant species native to Canadian prairie and montane cordillera ecosystems have previously been shown to have anti-mitotic activity on human cancer cell lines. In this study, we investigated the glacier lily, Erythronium grandiflorum (Liliaceae), in which the species was the most phylogenetically distant from Asteraceae and had anti-mitotic activity.

Tetrahydroxanthene-1,3(2)-diones and Oxidized Hexadiene Derivatives from and Their Biological Activities.

The first phytochemical investigation of the twig extract of resulted in the isolation and identification of three new tetrahydroxanthene-1,3(2)-diones, uvarialeptones A-C, two new oxidized hexadiene derivatives, uvarialeptols A and B, together with ten known compounds. Their structures were elucidated by spectroscopic techniques and mass spectrometry. Uvarialeptones A and B were unprecedented tetrahydroxanthene-1,3(2)-dione dimers which exhibited a cyclobutane ring via [2 + 2] cycloaddition from uvarialeptone C and 9a--methyloxymitrone, respectively.

Highly oxygenated cyclohexenes from Uvaria dac Pierre ex Finet & Gagnep. and their α-glucosidase inhibitory activity.

Phytochemical investigations of the twig and leaf extracts of Uvaria dac Pierre ex Finet & Gagnep. resulted in the isolation and identification of five new highly oxygenated cyclohexenes, uvaridacols M - Q (1-3, 5, and 6), and six known compounds (4 and 7-11). All new structures were elucidated by spectroscopic methods and HRESITOFMS data.

Piperazate-Guided Isolation of Caveamides A and B, Cyclohexenylalanine-Containing Nonribosomal Peptides from a Cave Actinomycete.

Hybrid genome-mining/N-NMR was used to target compounds containing piperazate (Piz) residues, leading to the discovery of caveamides A () and B () from sp. strain BE230, isolated from New Rankin Cave (Missouri). Caveamides are highly dynamic molecules containing an unprecedented β-ketoamide polyketide fragment, two Piz residues, and a new -methyl-cyclohexenylalanine residue.

Styryl lactone derivatives and aristolactam alkaloids from Miq. and their α-glucosidase inhibitory activity.

Two new styryl lactone derivatives, goniothapic acids A () and B (), and 18 known compounds, were isolated from the twig and leaf extracts of Miq. The structures of new compounds were characterised by spectroscopic methods and HRESITOFMS. Their absolute configuration was established by comparing the experimental and calculated ECD spectra.

Curcuphenol possesses an unusual histone deacetylase enhancing activity that counters immune escape in metastatic tumours.

Curcuphenol, a common component of the culinary spices, naturally found in marine invertebrates and plants, has been identified as a novel candidate for reversing immune escape by restoring expression of the antigen presentation machinery (APM) in invasive cancers, thereby resurrecting the immune recognition of metastatic tumours. Two synthetic curcuphenol analogues, were prepared by informed design that demonstrated consistent induction of APM expression in metastatic prostate and lung carcinoma cells. Both analogues were subsequently found to possess a previously undescribed histone deacetylase (HDAC)-enhancing activity.

New norclerodane diterpenoids from bulbils of L.

Investigation of extracts from bulbils of L. yielded two new norclerodane diterpenoids, diosbulbin N acetate () and -diosbulbin B (), together with eleven known compounds. Their structures were established based on spectroscopy.

Synthetic Analogs of the Sponge Sesterterpenoid Alotaketal C are Potent Inhibitors of SARS-CoV-2 Omicron BA.1 and BA.5 Infections of Human Lung Cells.

The protein kinase C-activating sponge natural product alotaketal C () potently inhibits the infection of human Calu-3 lung cells by SARS-CoV-2 Omicron BA.1 and BA.5 variants.

A novel cell-based screen identifies chemical entities that reverse the immune-escape phenotype of metastatic tumours.

Genetic and epigenetic events have been implicated in the downregulation of the cellular antigen processing and presentation machinery (APM), which in turn, has been associated with cancer evasion of the immune system. When these essential components are lacking, cancers develop the ability to subvert host immune surveillance allowing cancer cells to become invisible to the immune system and, in turn, promote cancer metastasis. Here we describe and validate the first high-throughput cell-based screening assay to identify chemical extracts and unique chemical entities that reverse the downregulation of APM components in cell lines derived from metastatic tumours.

Phaeanthuslucidines A-D, dimeric aporphine alkaloid derivatives from Phaeanthus lucidus Oliv.

The first phytochemical investigation of the twigs of Phaeanthus lucidus Oliv. resulted in the isolation and identification of four undescribed alkaloids, including two aporphine dimers, phaeanthuslucidines A and B, a hybrid of aristolactam-aporphine, phaeanthuslucidine C, and a C-N linked aporphine dimer, phaeanthuslucidine D, together with two known compounds. Their structures were determined by extensive analysis of spectroscopic data, and by comparison of their spectroscopic and physical data with previous reports.

Alkaloids and Styryl lactones from King and Their -Glucosidase Inhibitory Activity.

Gonioridleylactam (), a new compound, is a unique dimeric aristolactam isolated from the EtOAc extract of the twigs of King. The structure of gonioridleylactam () consists of two different aristolactams linked together with two methylenedioxy bridges at C-3/C-3' and C-4/C-4', generating a ten-membered ring of [1,3,6,8]tetraoxecine. A new natural product, gonioridleyindole (3-hydroxymethyl-1-methyl-1-benz[]indole-4,9-dione, ), together with eight known compounds () were also isolated from this plant.

Thorectidiol A Isolated from the Marine Sponge Disrupts Interactions of the SARS-CoV-2 Spike Receptor Binding Domain with the Host ACE2 Receptor.

Thorectidiols isolated from the marine sponge (family Thorectidae, order Dictyoceratida) collected in Papua New Guinea are a family of symmetrical and unsymmetrical dimeric biphenyl meroterpenoid stereoisomers presumed to be products of oxidative phenol coupling of a co-occurring racemic monomer, thorectidol (). One member of the family, thorectidiol A (), has been isolated in its natural form, and its structure has been elucidated by analysis of NMR, MS, and ECD data. Acetylation of the sponge extract facilitated isolation of additional thorectidiol diacetate stereoisomers and the isolation of the racemic monomer thorectidol acetate ().

Dimeric aporphine alkaloids from the twigs of Trivalvaria costata (Hook.f. & Thomson) I.M.Turner.

A phytochemical investigation of the twig extract of Trivalvaria costata (Hook.f. & Thomson) I.

Metabolomics Reveals a 26-Membered Macrolactone Produced by Endophytic spp. from Alcatrazes Island, Brazil.

Comparative metabolomics analysis of nonphytotoxic endophytic spp. isolated from endemic to Alcatrazes island (Brazil) and phytopathogenic spp. isolated from the mainland of Brazil revealed significant differences in chemical composition.

Discovery of lead natural products for developing pan-SARS-CoV-2 therapeutics.

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global public health crisis. The reduced efficacy of therapeutic monoclonal antibodies against emerging SARS-CoV-2 variants of concern (VOCs), such as omicron BA.5 subvariants, has underlined the need to explore a novel spectrum of antivirals that are effective against existing and evolving SARS-CoV-2 VOCs.

Rotenoids and isoflavones from the leaf and pod extracts of Millettia brandisiana Kurz.

Phytochemical investigations of the leaf and pod extracts of Millettia brandisiana Kurz led to the isolation and identification of four previously undescribed rotenoids, (-)-(6aS,12aS)-millettiabrandisins A-C and (-)-(6aS,12aS)-6-deoxyclitoriacetal, two previously undescribed isoflavones, millettiabrandisins D and E, and 20 known compounds. The structures of previously undescribed compounds were determined on the basis of NMR and MS data. The absolute configurations of (-)-(6aS,12aS)-millettiabrandisins A-C were determined from the comparison of their experimental and calculated ECD spectra.

Antidiabetic and Cytotoxic Activities of Rotenoids and Isoflavonoids Isolated from Benth.

A phytochemical investigation of the root and leaf extracts of Benth resulted in the isolation and identification of 16 compounds, including six rotenoids (-) and 10 prenylated isoflavonoids (-). Compound was isolated as a scalemic mixture, which was resolved by chiral HPLC to afford (-)-(6a,12a)-12a-hydroxy-α-toxicarol () and (+)-(6a,12a)-12a-hydroxy-α-toxicarol (). (+)-(6a,12a)-Millettiapachycarpin () and (-)-(6a,12a)-12a-hydroxy-α-toxicarol () were isolated as new compounds.

Free Piperazic Acid as a Precursor to Nonribosomal Peptides.

Piperazic acid (Piz) is a nonproteinogenic amino acid possessing a rare nitrogen-nitrogen bond. However, little is known about how Piz is incorporated into nonribosomal peptides, including whether adenylation domains specific to Piz exist. In this study, we show that free piperazic acid is directly adenylated and then incorporated into the incarnatapeptin nonribosomal peptides through isotopic incorporation studies.

Natural Products Produced in Culture by Biosynthetically Talented Strains Isolated from Northeastern and South Pacific Marine Sediments.

Laboratory cultures of two 'biosynthetically talented' bacterial strains harvested from tropical and temperate Pacific Ocean sediment habitats were examined for the production of new natural products. Cultures of the tropical strain RJA3005, harvested from a PNG marine sediment, produced salinorcinol () and salinacetamide (), which had previously been reported as products of engineered and mutated strains of , but had not been found before as natural products. An .

Ansellone J, a Potent and HIV-1 Latency Reversal Agent Isolated from a sp. Marine Sponge.

Five new minor sesterterpenoids, ansellones H (), I (), J (), and K () and phorone C (), have been isolated from a sp. marine sponge collected in British Columbia. Their structures have been elucidated by detailed analysis of NMR and MS data.