Roman Popov

• PhD
• Researcher at G.B. Elyakova Pacific Institute of Bioorganic Chemistry

Marine alga-derived fungal strain КММ 4176 was identified as Aspergillus niveoglaucus based on ITS region BenA, CaM and RPB2 gene sequence analysis. The anthraquinone derivatives emodin anthrone (1) and 4-hydroxyemodin anthrone (2), chromone derivative aloesone (3), and indole diketopiperazine alkaloid neoechinulin B (4) were isolated from the ethy...

Background Marine sponges and sponge-associated fungi are rich sources of bioactive compounds with pharmacological potential. However, the secondary metabolites of Vietnamese marine sponge-derived fungi have been poorly studied. Objective The aim of this study was to investigate the low-molecular-weight compounds in the extract of Penicillium sp....

Background: During the cultivation of the marine fungus KMM 4668 on solid agar medium, the morphological instability of the strain was observed. As a result of the selection work, five intra-strain variants, named KMM 4711, KMM 4712, KMM 4713, KMM 4714, and KMM 4715, were obtained. Methods: The main objectives of this work were to compare the paren...

Five new non-holostane di- and trisulfated triterpene pentaosides, conicospermiumosides A3-1 (1), A3-2 (2), A3-3 (3), A7-1 (4), and A7-2 (5) were isolated from the Far Eastern sea cucumber Cucumaria conicospermium Levin et Stepanov (Cucumariidae, Dendrochirotida). Twelve known glycosides found earlier in other Cucumaria species were also obtained a...

Stonikacidin A (1), the first representative of a new class of 4-bromopyrrole alkaloids containing an aldonic acid core, was isolated from the marine sponge Lissodendoryx papillosa. The compound is named in honor of Prof. Valentin A. Stonik, who is one of the outstanding investigators in the field of marine natural chemistry. The structure of 1 was...

Ten new decalin polyketides, zosteropenilline M (1), 11-epi-8-hydroxyzosteropenilline M (2), zosteropenilline N (3), 8-hydroxyzosteropenilline G (4), zosteropenilline O (5), zosteropenilline P (6), zosteropenilline Q (7), 13-dehydroxypallidopenilline A (8), zosteropenilline R (9) and zosteropenilline S (10), together with known zosteropenillines G...

Three new monosulfated polyhydroxysteroid glycosides, spiculiferosides A (1), B (2), and C (3), along with new related unsulfated monoglycoside, spiculiferoside D (4), were isolated from an ethanolic extract of the starfish Henricia leviuscula spiculifera collected in the Sea of Okhotsk. Compounds 1–3 contain two carbohydrate moieties, one of which...

Eight sulfated triterpene glycosides, peronioside A (1) and psolusosides A (2), B (3), G (4), I (5), L (6), N (7) and P (8), were isolated from the sea cucumber Psolus peronii. Peronioside A (1) is a new glycoside, while compounds 2–8 were found previously in Psolus fabricii, indicating the phylogenetic and systematic closeness of these species of...

The marine holothurian-derived fungal strain KMM 4401 has been identified as Paragliomastix luzulae using 28S rDNA, ITS regions and the partial TEF1 gene sequences. The metabolite profile of the fungal culture was studied by UPLC-MS technique. The strain KMM 4401 is a source of various virescenoside-type isopimarane glycosides suggested as chemotax...

Four extracts of the marine-derived fungus Penicillium velutinum J.F.H. Beyma were obtained via metal ions stress conditions based on the OSMAC (One Strain Many Compounds) strategy. Using a combination of modern approaches such as LC/UV, LC/MS and bioactivity data analysis, as well as in silico calculations, influence metal stress factors to change...

Two new steroid 3β,21-disulfates (1, 2) and two new steroid 3β,22- and 3α,22-disulfates (3, 4), along with the previously known monoamine alkaloid tryptamine (5) were found in the ethanolic extract of the Far Eastern slime sea star Pteraster marsippus. Their structures were determined on the basis of detailed analysis of one-dimensional and two-dim...

Six previously unknown triterpene glycosides, pacificusosides L–Q (1–6), and two previously known triterpene glycosides, cucumariosides B1 (7) and A5 (8), were isolated from an alcoholic extract of Pacific sun star, Solaster pacificus. The structures of 1–6 were determined using 1D and 2D NMR, ESIMS, and chemical modifications. Compound 1 is a rare...

Four new mono- and trisulfated triterpene penta- and tetraosides, djakonoviosides C1 (1), D1 (2), E1 (3), and F1 (4) were isolated from the Far Eastern sea cucumber Cucumaria djakonovi (Cucumariidae, Dendrochirotida), along with six known glycosides found earlier in other Cucumaria species. The structures of unreported compounds were established on...

The content of a dangerous amnesic toxin, that is, domoic acid (DA), was determined in cultures of the diatom genus Pseudo-nitzschia and in bivalve samples collected in the Russian waters of the Sea of Japan and off the Pacific coast of Kamchatka. For the first time, the presence of DA has been confirmed in cultures of Pseudo-nitzschia pungens (Gru...

The marine-derived fungal strains KMM 4718 and KMM 4747 isolated from sea urchin Scaphechinus mirabilis as a natural fungal complex were identified as Penicillium sajarovii and Aspergillus protuberus based on Internal Transcribed Spacer (ITS), partial β-tubulin (BenA), and calmodulin (CaM) molecular markers as well as an ribosomal polymerase two, s...

Two new cyclopiane diterpenes and a new cladosporin precursor, together with four known related compounds, were isolated from the marine sediment-derived fungus Penicillium antarcticum KMM 4670, which was re-identified based on phylogenetic inference from ITS, BenA, CaM, and RPB2 gene regions. The absolute stereostructures of the isolated cyclopian...

An Aspergillus fumigatus KMM 4631 strain was previously isolated from a Pacific soft coral Sinularia sp. sample and was found to be a source of a number of bioactive secondary metabolites. The aims of this work are the confirmation of this strain’ identification based on ITS, BenA, CaM, and RPB2 regions/gene sequences and the investigation of secon...

Investigation of the Vietnamese marine sponge Rhabdastrella globostellata led to the isolation of two new polar isomalabaricanes: rhabdastrellosides A (1) and B (2). Their structures and stereochemistry were elucidated with the application of 1D and 2D NMR, HRESIMS, and HRESIMS/MS methods, as well as chemical modifications and GC–MS analysis. Metab...

Content of a dangerous amnesic toxin – domoic acid (DA) – was determined in cultures of the diatom genus Pseudo-nitzschia and in bivalve samples collected in the Russian waters of the Sea of Japan and off the Pacific coast of Kamchatka. For the first time, the presence of DA has been confirmed in cultures of Pseudo-nitzschia pungens (Grunow ex Clev...

Assimiloside A (1), an unprecedented marine glycolipid containing a γ-lactone of 4R,16,26R-trihydroxy C28 fatty acid as an aglycon and a trisaccharide carbohydrate moiety, was isolated from the marine sponge Hymeniacidon assimilis. Its structure was elucidated by NMR spectroscopy, mass spectrometry, chemical transformations, and ECD spectroscopy co...

New anthraquinone derivatives acruciquinones A–C (1–3), together with ten known metabolites, were isolated from the obligate marine fungus Asteromyces cruciatus KMM 4696. Acruciquinone C is the first member of anthraquinone derivatives with a 6/6/5 backbone. The structures of isolated compounds were established based on NMR and MS data. The absolut...

Seven new monosulfated triterpene glycosides, djakonoviosides A (1), A1 (2), A2 (3), and B1–B4 (4–7), along with three known glycosides found earlier in the other Cucumaria species, namely okhotoside A1-1, cucumarioside A0-1, and frondoside D, have been isolated from the far eastern sea cucumber Cucumaria djakonovi (Cucumariidae, Dendrochirotida)....

Sea cucumber triterpene glycosides are a class of secondary metabolites that possess distinctive chemical structures and exhibit a variety of biological and pharmacological activities. The application of MS-based approaches for the study of triterpene glycosides allows rapid evaluation of the structural diversity of metabolites in complex mixtures....

The metabolic profile of the Aspergillus sp. 1901NT-1.2.2 sponge-associated fungal strain was investigated using the HPLC MS technique, and more than 23 peaks in the HPLC MS chromatogram were detected. Only two minor peaks were identified as endocrocin and terpene derivative MS data from the GNPS database. The main compound was isolated and identif...

The KMM 4639 strain was identified as Amphichorda sp. based on two molecular genetic markers: ITS and β-tubulin regions. Chemical investigation of co-culture marine-derived fungi Amphichorda sp. KMM 4639 and Aspergillus carneus KMM 4638 led to the identification of five new quinazolinone alkaloids felicarnezolines A–E (1–5), a new highly oxygenated...

A bromine-containing naphthoquinone-carbohydrate conjugate was obtained for the first time by intramolecular condensation of 3-acetylthioglucoside of 6-bromo-2-methoxy-1,4-naphthoquinone under sodium methoxide/ methanol treatment. It has been established that the heterocyclization reaction is accompanied by the substitution of the thioglucoside sub...

Changes in cultivation conditions, in particular salinity and temperature, affect the production of secondary fungal metabolites. In this work, the extracts of fungus previously described as Penicillium dimorphosporum cultivated in various salinity and temperature conditions were investigated using HPLC UV/MS techniques, and their DPPH radical scav...

Five new β-resorcylic acid derivatives, 14-hydroxyasperentin B (1), β-resoantarctines A-C (3, 5, 6) and 8-dehydro-β-resoantarctine A (4), together with known 14-hydroxyasperentin (5′-hydroxyasperentin) (2), were isolated from the ethyl acetate extract of the fungus Penicillium antarcticum KMM 4685 associated with the brown alga Sargassum miyabei. T...

Three new tetrasulfated triterpene glycosides, chilensosides E (1), F (2), and G (3), have been isolated from the Far-Eastern sea cucumber Paracaudina chilensis (Caudinidae, Molpadida). The structures were established based on extensive analysis of 1D and 2D NMR spectra and confirmed by HR-ESI-MS data. The compounds differ in their carbohydrate cha...

Renal excretions of the drug Histochrome contained echinochrome, the drug substance; 2(3)-methoxyechinochrome derivatives; and monoglucuronides of 2(3)-methoxy-, 2,3-dimethoxy-, 2,6-dimethoxy-, and 3,6-dimethoxyechinochrome derivatives according to HPLC-MS (high resolution) using a deuterated label.

Two new guanidine alkaloids, batzelladines O (1) and P (2), were isolated from the deep-water marine sponge Monanchora pulchra. The structures of these metabolites were determined by NMR spectroscopy, mass spectrometry, and ECD. The isolated compounds exhibited cytotoxic activity in human prostate cancer cells PC3, PC3-DR, and 22Rv1 at low micromol...

New meroterpenoids, meroantarctines A-C (1-3), with unique 6/5/6/6, 6/5/6/5/6, and 6/5/6/5 polycyclic systems were isolated from the alga-derived fungus Penicillium antarcticum KMM 4685. Their structures were elucidated by spectroscopic methods, X-ray diffraction, and quantum chemical calculations. A biogenetic pathway for 1-3 was proposed. Meroant...

Five new triterpene (4,4,14-trimethylsterol) di-, tri- and tetrasulfated pentaosides, chilensosides A (1), A1 (2), B (3), C (4), and D (5) were isolated from the Far-Eastern sea cucumber Paracaudina chilensis. The structures were established on the basis of extensive analysis of 1D and 2D NMR spectra and confirmed by HR-ESI-MS data. The structural...

Three new ceramides (1–3) and three new cerebrosides (4, 8, and 9), along with three previously known cerebrosides (ophidiocerebrosides C (5), D (6), and CE-3-2 (7)), were isolated from a deep-sea starfish species, the orange cookie starfish Ceramaster patagonicus. The structures of 1−4, 8, and 9 were determined by the NMR and ESIMS techniques and...

The nicotinic acetylcholine receptors (nAChRs) are prototypical ligand-gated ion channels, provide cholinergic signaling, and are modulated by various venom toxins and drugs in addition to neurotransmitters. Here, four APETx-like toxins, including two new toxins, named Hmg 1b-2 Metox and Hmg 1b-5, were isolated from the sea anemone Heteractis magni...

Chemical investigation of a coculture of the marine-derived fungi Beauveria felina KMM 4639 and Aspergillus carneus KMM 4638 led to the identification of three new drimane-type sesquiterpenes, asperflavinoids B, D and E (2, 4, 5), and nine previously reported related compounds. The structures of these compounds were established using spectroscopic...

Spongian diterpenes are a group of marine natural compounds possessing various biological activities. However, their anticancer activity is still poorly studied and understood. We isolated six spongian diterpenes from the marine sponge Spongionella sp., including one new spongionellol A and five previously known molecules. The structures were eluci...

The bacterium Streptomyces sp. KMM 9044 from a sample of marine sediment collected in the northwestern part of the Sea of Japan produces highly chlorinated depsiheptapeptides streptocinnamides A (1) and B (2), representatives of a new structural group of antibiotics. The structures of 1 and 2 were determined using nuclear magnetic resonance and mas...

Five new triterpene di-, tri- and tetrasulfated hexaosides (chitonoidosides I (1), J (2), K (3), K1 (4) and L (5)) were isolated from the Far-Eastern sea cucumber Psolus chitonoides, collected near Bering Island (Commander Islands) from a depth of 100–150 m. The structural variability of the glycosides concerned both the aglycones (with 7(8)- or 9(...

Today, marine natural products are considered one of the main sources of compounds for drug development. Starfish and sea cucumbers are potential sources of natural products of pharmaceutical interest. Among their metabolites, polar steroids, triterpene glycosides, and polar lipids have attracted a great deal of attention; however, studying these c...

Six new polyketides acrucipentyns A–F (1–6) were isolated from the alga-derived fungus Asteromyces cruciatus KMM 4696. Their structures were established based on spectroscopic methods. The absolute configurations of acrucipentyn A was assigned by the modified Mosher’s method and ROESY data analysis. Acrucipentyns A–E were identified to be the very...

Toporosides A-D (1-4), new ω-glycosylated fatty acid amides, were isolated from the sponge Stelodoryx toporoki. The structures of these compounds, including absolute configurations of stereogenic centers, were established using analysis of 1D and 2D NMR, ECD, and HR mass spectra as well as chemical transformations. Toporosides A (1) and B (2) are t...

Nucleophilic substitution of the chlorine atom in 4,5-dichloro-1,2-dithiol-3-one using 1-thio-β-d-glucopyranose and its 2,3,4,6-tetra-O-acetyl derivative in acetonitrile resulted in two new 5-thioglucoside conjugates of 4-chloro-1,2-dithiol-3-one. The obtained thioglucosides showed cancer-preventive properties in a model of mouse epidermal JB6Cl41...

New steroidal 3β,21-disulfates (2–4), steroidal 3β,22-disulfate (5), and the previously known related steroidal 3β,21-disulfate (1) were isolated from the ethanolic extract of the Far Eastern starfish Pteraster marsippus, collected off Urup Island in the Sea of Okhotsk. The structures of these compounds were determined by intensive NMR and HRESIMS...

Three new tripeptide derivatives asterripeptides A–C (1–3) were isolated from Vietnamese mangrove-derived fungus Aspergillus terreus LM.5.2. Structures of isolated compounds were determined by a combination of NMR and ESIMS techniques. The absolute configurations of all stereocenters were determined using the Murfey’s method. The isolated compounds...

Four new triterpene disulfated glycosides, chitonoidosides E1 (1), F (2), G (3), and H (4), were isolated from the Far-Eastern sea cucumber Psolus chitonoides and collected near Bering Island (Commander Islands) at depths of 100–150 m. Among them there are two hexaosides (1 and 3), differing from each other by the terminal (sixth) sugar residue, on...

The peculiarities of the survival and adaptation of deep-sea organisms raise interest in the study of their metabolites as promising drugs. In this work, the hemolytic, cytotoxic, antimicrobial, and enzyme-inhibitory activities of tentacle extracts from five species of sea anemones (Cnidaria, orders Actiniaria and Corallimorpharia) collected near t...

Six new triterpene tetra-, penta- and hexaosides, chitonoidosides A (1), A1 (2), B (3), C (4), D (5), and E (6), containing one or two sulfate groups, have been isolated from the Far-Eastern sea cucumber Psolus chitonoides, collected near Bering Island (Commander Islands) from the depth of 100–150 m. Three of the isolated compounds (1, 3 and 6) are...

Nine new mono-, di-, and trisulfated triterpene penta- and hexaosides, kurilosides A3 (1), D1 (2), G (3), H (4), I (5), I1 (6), J (7), K (8), and K1 (9) and two desulfated derivatives, DS-kuriloside L (10), having a trisaccharide branched chain, and DS-kuriloside M (11), having hexa-nor-lanostane aglycone with a 7(8)-double bond, have been isolated...

Nucleophilic substitution of a chlorine atom in 4,5 dichloro-1,2-dithiole-3-thione with per-O-acetyl-1-mercaptho derivatives of d-glucose, d-galactose, d-mannose, d-xylose, l-arabinose, and d-maltose gave six new acetylthioglycoside conjugates of 4-chloro-1,2-dithiole-3-thione. These thioglycosides were shown to possess cancer preventive activity o...

In continuation of our studies on a Vietnamese collection of a Stelletta sp., sponge we have isolated two new isomalabaricane triterpenoids, stellettins Q and R (1 and 2), and four new isomalabaricane-derived nor-terpenoids, stellettins S-V 3–6, along with previously known globostelletin N. Among them, compound 3 contains an acetylenic fragment, un...

Seven new deoxyisoaustamide derivatives (1–7) together with known compounds (8–10) were isolated from the coral-derived fungus Penicillium dimorphosporum KMM 4689. Their structures were established using spectroscopic methods, X-ray diffraction analysis and by comparison with related known compounds. The absolute configurations of some alkaloids we...

Low molecular weight secondary metabolites of marine fungi Aspergillus flocculosus, Aspergillus terreus and Penicillium sp. from Van Phong and Nha Trang Bays (Vietnam) were studied and a number of polyketides, bis-indole quinones and terpenoids were isolated. The structures of the isolated compounds were determined by 1D and 2D NMR and HR-ESI-MS te...

Six new monosulfated triterpene tetra-, penta- and hexaosides, namely, the kurilosides A1 (1), A2 (2), C1 (3), D (4), E (5) and F (6), as well as the known earlier kuriloside A (7), having unusual non-holostane aglycones without lactone, have been isolated from the sea cucumber Thyonidium (= Duasmodactyla) kurilensis (Levin) (Cucumariidae, Dendroch...

Two new natural compounds, sulfated polyhydroxysteroid, microdiscusol G (1), and polyhydroxysteroid bioside, microdiscusoside A (2), along with eight previously known polar steroid substances 3–10, were isolated from the Arctic starfish Asterias microdiscus. The structures of 1 and 2 have been elucidated by extensive 1D and 2D NMR spectroscopy and...

Seven new polyoxygenated steroids belonging to a new structural group of sponge steroids, gracilosulfates A–G (1–7), possessing 3β-O-sulfonato, 5β,6β epoxy (or 5(6)-dehydro), and 4β,23-dihydroxy substitution patterns as a common structural motif, were isolated from the marine sponge Haliclona gracilis. Their structures were determined by NMR and MS...

A series of new tetracyclic oxathiine-fused quinone-thioglycoside conjugates based on biologically active 1,4-naphthoquinones and 1-mercapto derivatives of per-O-acetyl d-glucose, d-galactose, d-xylose, and l-arabinose have been synthesized, characterized, and evaluated for their cytotoxic and antimicrobial activities. Six tetracyclic conjugates be...

Thirteen new mono-, di-, and trisulfated triterpene glycosides, quadrangularisosides A–D4 (1−13) have been isolated from the sea cucumber Colochirus quadrangularis, which was collected in Vietnamese waters. The structures of these glycosides were established by 2D NMR spectroscopy and HR-ESI (High Resolution Electrospray Ionization) mass spectromet...

New bicyclic guanidine alkaloid, urupocidin C (Ur-C) along with the previously known urupocidin A (Ur-A) were isolated from the rare deep-sea marine sponge Monanchora pulchra, harvested in Northwestern Pacific waters. The unique structure of Ur-C was elucidated using 1D and 2D NMR spectroscopy as well as mass spectra. We discovered a promising sele...

Leptogorgins A–C (1–3), new humulane sesquiterpenoids, and leptogorgoid A (4), a new dihydroxyketosteroid, were isolated from the gorgonian Leptogorgia sp. collected from the South China Sea. The structures were established using MS and NMR data. The absolute configuration of 1 was confirmed by a modification of Mosher’s method. Configurations of d...

Four new conjugates, esters of polyhydroxysteroids with long-chain fatty acids (1–4), were isolated from the deep-water Far Eastern starfish Ceramaster patagonicus. The structures of 1–4 were established by NMR and ESIMS techniques as well as chemical transformations. Unusual compounds 1–4 contain the same 5α-cholestane-3β,6β,15α,16β,26-pentahydrox...

Four new polyhydroxylated steroids 1–4 were isolated along with two previously known related steroids 5 and 6 from the methanolic extract of the starfish Anthenoides laevigatus collected off the coastal waters of Vietnam. Structures of new compounds were substantially elucidated by one-dimensional (1D) and two-dimensional (2D) NMR spectroscopy and...

One new dihydrobenzofuran derivative (1), known depsipeptide emericellamide A (2), three known drimanes (3–5) and two artifact drimane derivatives (6, 7) were isolated from the marine-derived fungus Aspergillus ustus KMM 4664. Their structures were determined by detailed analysis of spectroscopic data and by comparison with related known compounds....

Ten new di-, tri- and tetrasulfated triterpene glycosides, psolusosides B1 (1), B2 (2), J (3), K (4), L (5), M (6), N (7), O (8), P (9), and Q (10), were isolated from the sea cucumber Psolus fabricii collected in the Sea of Okhotsk near the Kurile Islands. Structures of these glycosides were established by two-dimensional (2D) NMR spectroscopy and...

Ten new diterpene glycosides virescenosides Z9-Z18 (1–10) together with three known analogues (11–13) and aglycon of virescenoside A (14) were isolated from the marine-derived fungus Acremonium striatisporum KMM 4401. These compounds were obtained by cultivating fungus on wort agar medium with the addition of potassium bromide. Structures of the is...

Two novel C19 terpenoids (1, 2) with an unprecedented carbon skeleton (A) were isolated from a Stelletta sp. sponge collected from Vietnamese waters. Their structures and absolute configurations were established by extensive NMR, MS, and ECD analyses together with quantum chemical modeling and biogenetic considerations. The probable pathways of bio...

Four new compounds were isolated from the Vietnamese marine sediment-derived fungus Aspergillus flocculosus, one aspyrone-related polyketide aspilactonol G (2), one meroterpenoid 12-epi-aspertetranone D (4), two drimane derivatives (7,9), together with five known metabolites (1,3,5,6,8,10). The structures of compounds 1–10 were established by NMR a...

Glycoconjugated and other polar steroids of starfish have unique chemical structures and show a broad spectrum of biological activities. However, their biological functions remain not well established. Possible biological roles of these metabolites might be indicated by the studies on their distribution in the organism–producer. In order to investi...

Seven new unusual polysulfated steroids—topsentiasterol sulfate G (1), topsentiasterol sulfate I (2), topsentiasterol sulfate H (3), bromotopsentiasterol sulfate D (4), dichlorotopsentiasterol sulfate D (8), bromochlorotopsentiasterol sulfate D (9), and 4β-hydroxyhalistanol sulfate C (10), as well as three previously described—topsentiasterol sulfa...

Five new triterpene glycosides, psolusosides C 3 (1), D 2 (2), D 3 (3), D 4 (4), and D 5 (5), have been isolated from the sea cucumber Psolus fabricii. The structures of these glycosides were elucidated by 2-dimensional nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. All the compounds contain hexasaccharide carbohydra...

Six new polyhydroxylated steroids conjugated with taurine, microdiscusols A-F, were isolated from the alcoholic extract of the Arctic starfish Asterias microdiscus. Three of them have been found to have additional sulfate groups in tetracyclic cores. The structures of new compounds were established by 1D and 2D NMR and HRESIMS techniques. The found...

Nine naphto-γ-pyrones rubrofusarine B (1), TMC 256 A1 (2), fansecinones A (3) and B (4), aurasperones A (5), B (6) and F (7), dianhydro-aurasperone C (8) and asperpyrone B (9) were isolated from the marine-derived fungus Aspergillus foetidus KMM 4694. Their structures were established based on spectroscopic methods. The effect of the substances on...