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Abstract A series of terpenoids (1–17), comprising six new compounds designated bipolariterpenes A-F (1–6) and eleven recognized compounds (7–17), were isolated from the wheat culture of the potato endophytic fungus Bipolaris eleusines. Their structures and stereochemistry were clarified by HRESIMS, NMR, DP4 + probability analyses, and computations for electronic circular dichroism (ECD). All compounds are made up of six meroterpenoids, four sesterterpenes and seven sesquiterpenes. Among them, four sesterterpenes (4, 5, 10, 11) were investigated for their antifungal, antibacterial and cytotoxic properties, and six meroterpenoids (1–3, 7–9) were evaluated for their antifungal properties. The compounds 7, 9, and 10 had substantial antifungal activity against Epidermophyton floccosum at a concentration of 100 µM. No antibacterial and cytotoxic activities were observed. Graphical Abstract

Abstract Three hitherto undescribed Stemona alkaloids, named stemajapines A–C (1–3), along with six known alkaloids (4–9), were isolated and identified from the roots of Stemona japonica (Blume) Miq. (Stemonaceae). Their structures were established by the analysis of the mass data, NMR spectra, and computational chemistry. Stemjapines A and B were degraded maistemonines without spiro-lactone ring and skeletal methyl from maistemonine. Concurrence of alkaloids 1 and 2 revealed an undescribed way to form diverse Stemona alkaloids. Bioassay results disclosed the anti-inflammatory natural constituents stemjapines A and C with IC50 values of 19.7 and 13.8 µM, respectively, compared to positive control dexamethasone with 11.7 µM. The findings may point out a new direction of Stemona alkaloids inaddition to its traditional antitussive and insecticide activities.

Abstract Five undescribed alkaloids were isolated from the seeds of Cephalotaxus oliveri along with 27 known ones. The new structures were elucidated based on spectroscopic data including 1D and 2D NMR, MS and calculated ECD spectra. Among them, (+)-acetylcephalofortine C was an enantiomeric Cephalotaxine alkaloids. The performed bioassay revealed that those alkaloids were not cytotoxic against cancer cells and had no neuroprotective properties in the HEI-OC-1 cells model.

A total of eleven new dimeric chromanones, paecilins F-P (2–12), were isolated from the endophytic fungus Xylaria curta E10, along with four known analogs (1, 13–15). Their structures and absolute configurations were determined by extensive experimental spectroscopic methods, single-crystal X-ray diffraction, and equivalent circulating density (ECD) calculations. In addition, the structure of paecilin A, which was reported to be a symmetric C8-C8′ dimeric pattern, was revised by analysis of the nuclear magnetic resonance (NMR) data, and single-crystal X-ray diffraction. Compound 1 showed antifungal activity against the human pathogenic fungus Candida albicans with a minimum inhibitory concentration of 16 μg/mL, and Compounds 8 and 10 showed antibacterial activity against the gram-negative bacterium Escherichia coli with the same minimum inhibitory concentration of 16 μg/mL.

There is a previously neglected influence of geochemical conditions on plant phytochemistry. In particular, high concentrations of dissolved salts can affect their biosynthesis of natural products. Detoxification is most likely an important aspect for the plant, but additional natural products can also give it an expanded range of bioactivities. During the phytochemical analysis a Palicourea luxurians plant collected in a sulfate-rich environment (near the Río Sucio, Costa Rica) showed an interesting natural product in this regard. The structure of this compound was determined using spectroscopic and computational methods (NMR, MS, UV, IR, CD, optical rotation, quantum chemical calculations) and resulted in a megastigmane sulfate ester possessing a β-ionone core structure, namely blumenol C sulfate (1, C13H22O5S). The levels of sulfur and sulfate ions in the leaves of the plant were determined using elemental analysis and compared to the corresponding levels in comparable plant leaves from a less sulfate-rich environments. The analyses show the leaves from which we isolated blumenol C sulfate (1) to contain 35% more sulfur and 80% more sulfate than the other samples. Antimicrobial and antioxidant activities of compound 1 were tested against Escherichia coli, E. coli ampR and Bacillus subtilis as well as measured using complementary in vitro FRAP and ATBS assays, respectively. These bioactivities are comparable to those determined for structurally related megastigmanes. The sulfur and sulfate content of the plant leaves from the sulfate-rich environment was significantly higher than that of the other plants. Against this background of salt stress, we discuss a possible biosynthesis of blumenol C sulfate (1). Furthermore, there appears to be no benefit for the plant in terms of extended bioactivities. Hence, the formation of blumenol C sulfate (1) probably primarily serves the plant detoxification process.

Four new eremophilane-type sesquiterpenes, boeremialanes A–D (1–4) were obtained from solid substrate cultures of Boeremia exigua (Didymellaceae), an endophytic fungus isolated from Fritillaria hupehensis (Liliaceae). Boeremialanes A–C (1–3) are highly oxygenated eremophilanes with a benzoate unit attached at the C-13 position and are rarely found in nature. Their structures and absolute configurations were determined by extensive spectroscopic methods, electronic circular dichroism (ECD), and nuclear magnetic resonance (NMR) calculations with DP4+ analysis. Boeremialane D (4) potently inhibited nitric oxide production in lipopolysaccharide-treated RAW264.7 macrophages with an IC50 of 8.62 μM and was more potent than the positive control, pyrrolidinedithiocarbamate (IC50 = 23.1 μM).

Abstract Three new monoterpene indole alkaloids, 3α-hydroxymethyl-ibogamine (1), 3α-acetatemethoxyl-ibogamine (2), 16α-hydroxyl-ibogamine (3) together with six known alkaloids were isolated from the branches and leaves of Tabernaemontana divaricata (Apocynaceae). The structures of these alkaloids were determined by spectroscopic analyses. All isolated compounds showed no significant cytotoxicity against SGC-7901 gastric cancer, HeLa, and A-549 lung cancer cell lines (IC50 > 20 µM). Graphical Abstract

Two previously undescribed cationic indole alkaloids, named ophiorrhines L (1) and M (2), was isolated from the Ophiorrhiza japonica. The structures were elucidated based on spectroscopic data and quantum calculations as well as X-ray crystallographic analysis. Alkaloids 1 and 2 exhibited moderate inhibitory activities on XOD (Xanthine Oxidase) with IC50 values 42.5 and 22.6 μM, respectively. [ABSTRACT FROM AUTHOR]

A previously undescribed chromanol derivative, named currephila A (1), was isolated from the endophytic fungus Curreya pityophila, along with two known compounds (2 and 3). Their structures were elucidated based on spectroscopic methods, electronic circular dichroism, and spin-spin coupling constants. The cytotoxic activities of compounds 1 and 2 against human breast adenocarcinoma MCF-7 cells were evaluated. [ABSTRACT FROM AUTHOR]