The fungus, Alternaria sonchi is considered to be a potential agent for the biocontrol of perennial sowthistle (Sonchus arvensis). A new chlorinated xanthone, methyl 8-hydroxy-3-methyl-4-chloro-9-oxo-9H-xanthene-1-carboxylate (1) and a new benzophenone derivative, 5-chloromoniliphenone (2), were isolated together with eleven structurally related compounds (3–13) from the solid culture of the fungus, which is used for the production of bioherbicidal inoculum of A. sonchi. Their structures were determined by spectroscopic (mostly by NMR and MS) methods. Alternethanoxins A and B, which were reported in A. sonchi earlier, were re-identified as moniliphenone and pinselin, respectively. The isolated compounds were tested for phytotoxic, antimicrobial, insecticidal, cytotoxic and esterase-inhibition activities. They did not demonstrate high phytotoxicity (lesions up to 2.5 mm in diameter/length at a concentration of 2 mg/mL) when tested on leaf disks/segments of perennial sowthistle (Sonchus arvensis) and couch grass (Elytrigia repens). They did not possess acute toxicity to Paramecium caudatum, and showed moderate to low cytotoxicity (IC₅₀ > 25 µg/mL) for U937 and K562 tumor cell lines. However, chloromonilicin and methyl 3,8-dihydroxy-6-methyl-4-chloro-9-oxo-9H-xanthene-1-carboxylate (4) were shown to have antimicrobial properties with MIC 0.5–5 µg/disc. Compound 4 and chloromonilinic acid B were found to have contact insecticidal activity to wheat aphid (Schizaphis graminum) at 1 mg/mL. Compounds 2 and methyl 3,8-dihydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylate displayed selective carboxylesterase inhibition activity at concentration of 100 µg/mL. Therefore, the waste solid substrate for production of A. sonchi spores can be re-utilized for the isolation of a number of valuable natural products.

Ten-membered lactones (nonenolides) demonstrate phytotoxic, antimicrobial, and fungicidal activity promising for the development of natural product-derived pesticides. The fungus Stagonospora cirsii is able to produce phytotoxic stagonolides A (1), J (2), K (3) and herbarumin I (4) with high yield. The aim of this study was to create a set of structurally related nonenolides and to reveal the structural features that affect their biological activity. Stagonolide A (1) and C-7 oxidized stagonolide K (11) showed the highest phytotoxicity in leaf puncture assay and agar seedlings assay. The oxidation of C-7 hydroxyl group (as in 1, acetylstagonolide A (10) and (11) led to the manifestation of toxicity to microalgae, Bacillus subtilis and Sf9 cells regardless of the configuration of C-9 propyl chains (R in 1 and 10, S in 11). C-7 non-oxidized nonenolides displayed none or little non-target activity. Notably, 7S compounds were more phytotoxic than their 7R analogues. Due to the high inhibitory activity against seedling growth and the lack of side toxicity, mono- and bis(acetyl)- derivatives of herbarumin I were shown to be potent for the development of pre-emergent herbicides. The identified structural features can be used for the rational design of new herbicides.

Introduction.Among the different groups of drugs, diuretics are one the most popular classes that have been used for treatment of cardiovascular system and kidney diseases. At the same time, synthetic diuretics which are widely used, cause large amounts of side effects, such as violation of electrolyte, acid-base and water balances, carbohydrate and lipid metabolism. Therefore, it is important to search for individual compounds of plant origin – potential pharmaceutical substances for the treatment of urinary tract diseases. In this study individual compounds were isolated from the terrestrial parts of Ononis arvensis L. and Solidago canadensis L. The diuretic activity of the summary extracts of Ononis arvensis and Solidago canadensis has previously been proven.Aim.Method development for the isolation of individual compounds, using modern physicochemical methods of analysis, from the terrestrial parts of Ononis arvensis and Solidago canadensis and the elucidation of their structure.Materials and methods.Aerial parts of Ononis arvensis and Solidago canadensis were collected in the Saint Petersburg State Chemical-Pharmaceutical University (SPCPU) Nursery Garden of Medicinal Plants (Leningrad region, Vsevolozhsky district, Priozersk highway, 38 km) in August 2019 and identified by Dr. Goncharov Mikhail of the Saint-Petersburg chemical-pharmaceutical university, Saint-Petersburg, Russia. Fraction analysis were preformed with analytical high-performance liquid chromatography using a LC-20 Prominence (Shimadzu corp., Japan) with a SPD-M20A diode-array detector. Isolation of individual compounds was carried out by preparative high-performance liquid chromatography using a Smartline (Knauer, Germany). The structures of the isolated compounds were elucidated using 1D and 2D NMR experiments (Bruker Avance III 400 MHz) along with HR-ESI-MS (Bruker Micromass Q-TOF).Results and discussion.Using the developed methods, from the aerial part of the field restharrow (O. arvensis) we managed to isolate and characterised three individual compounds (1-3). Compounds 1 and 2 are isloflavonoids – pseudobaptigenin-7-О-ß-D-glucopyranoside and formononetin-7-О-ß-D-glucopyranoside, respectively. Compound (3) is a flavonoid – kaempferol-3-O-ß-D-glucopyranoside (astragalin). All compounds were isolated for O. arvansis for the first time. Along with this, four individual compounds (4-7) were isolated from the aerial part of the canadian goldenrod (S. canadensis), namely, quercetin-3-O-ß-D-6''-acetylglucopyranoside, isoramnetin-3-О-ß-D-rutinoside (narcissin), quercetin-3-О-rutinoside (rutin) and quercetin, respectively.Conclusion.As a result of the research, methods have been developed for the isolation of 7 individual compounds, using modern physicochemical methods of analysis, from the aerial parts of Ononis arvensis and Solidago canadensis, the structures of all the isolated compounds were elucidated. Future assessment of the isolated compounds biological activity is presumed.

A new dihydrochalcone, 2',4'-dimethoxydihydrochalcone (1), together with 7 known compounds, 2',4'-dihydroxydihydrochalcone (2), 2'-hydroxy-4'-methoxydihydrochalcone (3), 2'-hydroxy-4'-methoxychalcone (4), 1-(3,5-dihydroxy-4-methoxyphenyl)-2-(3-hydroxyphenyl) ethane (5), 2,3,4,7-tetramethoxy-9,10-dihydrophenanthrene (6), 5-hydroxy-2,3,4-trimethoxy-9,10-dihydrophenanthrene (7) and 5,7-dihydroxy-6,8-dimethyl flavanone (8) were isolated from the shoots of Empetrum nigrum L. The structures of these compounds were elucidated using 1D and 2D NMR experiments along with HR-ESI-MS. Compound 6 is reported for the genus Empetrum for the first time. Graphical Abstract

Introduction. Urinary tract infections are a common group of diseases worldwide, affecting more than 150 million people every year. In about 30 % of patients with initial infection, UTI becomes chronic. Herbal medicines, along with synthetic diuretics and antibiotics, are widely used for the prevention and treatment of UTIs, which makes the search and isolation of various substances from plant materials an important task. The present study is devoted to the isolation of compounds belonging to the class of proanthocyanidins from the aerial part of the black crowberry (Empetrum nigrum L.).Aim. Method development for the isolation of individual dimeric type A proanthocyanidins from the aerial part of Empetrum nigrum and the elucidation of their chemical structure using modern physicochemical methods of analysis.Materials and methods. Shoots of Empetrum nigrum were collected next to the Saint Petersburg State Chemical-Pharmaceutical University Nursery Garden of Medicinal Plants (Leningrad region, Vsevolozhsky district, Priozerskoe highway, 38 km) in August 2019. Fraction analysis was performed through analytical high-performance liquid chromatography (HPLC) using a Prominence LC-20 (Shimadzu corp., Japan) equipped with a SPD-M20A diode-array detector, as well as by high performance thin layer chromatography (HPTLC) using a CAMAG HPTLC system (Switzerland). The isolation of compounds was carried out by open column chromatography using sorbents with different selectivity, as well as by preparative HPLC using a Smartline system (Knauer, Germany) equipped with a spectrophotometric detector. The structures of the isolated compounds were established by 1D and 2D NMR experiments (Bruker Avance III 400 MHz, Germany), as well as high-resolution mass spectrometry (HR-ESI-MS) (Bruker Micromass Q-TOF, Germany).Results and discussion. Using the developed methods, from the Empetrum nigrum shoots we managed to isolate and characterised three individual compounds belonging to the class of A-type proanthocyanidins. According to NMR and mass spectrometry data, compound 1 is epicatechin-(2β → O → 5, 4β → 6)-epicatechin, with an extremely rare type of intermonomer bond (2β → O → 5, 4β → 6). Compounds 2 and 3 are epicatechin-(2β → O → 7, 4β → 8)-epicatechin (procyanidin A2) and epicatechin-(2β → O → 7, 4β → 8)-catechin (procyanidin A1), respectively. All individual compounds (1-3) were found and isolated from Empetrum nigrum for the first time.Conclusion. As a result of the research, three individual compounds (A-type proanthocyanidins) were isolated from the aerial part of Empetrum nigrum. All individual compounds (1-3) were found and isolated from Empetrum nigrum for the first time. Future assessment of the isolated compounds biological activity is presumed.

Two undescribed (1–2) and five known cyclic diarylheptanoids (3–7) were isolated from the false heartwood of white birch (Betula pubescens Ehrh.). All structures were elucidated through extensive 1D and 2D NMR experiments and HR-ESI-MS data, along with comparison of their spectroscopic data with those reported in the literature. The two new cyclic diarylheptanoids are betuladiol (1) and betulondiol (2). Extracts from false heartwood were evaluated for their antimicrobial activity against Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, Staphylococcus aureus and Cutibacterium acnes together with their antifungal activity against Candida albicans and Candida glabrata. Graphical Abstract