The silkworm (Bombyx mori) gut microbiota is involved in metabolic detoxification by glucosylation of plant toxins

Abstract Herbivores have evolved the ability to detoxify feed components through different mechanisms. The oligophagous silkworm feeds on Cudrania tricuspidata leaves (CTLs) instead of mulberry leaves for the purpose of producing special, high-quality silk. However, CTL-fed silkworms are found to have smaller bodies, slower growth and lower silk production than those fed mulberry leaves. Here, we show that the high content of prenylated isoflavones (PIFs) that occurred in CTLs is converted into glycosylated derivatives (GPIFs) in silkworm faeces through the silkworm gut microbiota, and this biotransformation is the key process in PIFs detoxification because GPIFs are found to be much less toxic, as revealed both in vitro and in vivo. Additionally, adding Bacillus subtilis as a probiotic to remodel the gut microbiota could beneficially promote silkworm growth and development. Consequently, this study provides meaningful guidance for silk production by improving the adaptability of CTL-fed silkworms

Bibenzyl-Based Meroterpenoid Enantiomers from the Chinese Liverwort <i>Radula sumatrana</i>

Six new pairs of bibenzyl-based meroterpenoid enantiomers, (±)-rasumatranin A–D (<b>1</b>–<b>4</b>) and (±)-radulanin M and N (<b>5</b> and <b>6</b>), and six known compounds were isolated from the adnascent Chinese liverwort, <i>Radula sumatrana.</i> Their structures were elucidated based on spectroscopic data and chiral phase HPLC-ECD analyses. The structures of <b>1</b> and <b>7</b> were also confirmed by single-crystal X-ray diffraction analysis. Cytotoxicity tests of the isolated compounds showed that 6-hydroxy-3-methyl-8-phenylethylbenzo­[<i>b</i>]­oxepin-5-one (<b>8</b>) showed activity against the human cancer cell lines MCF-7, PC-3, and SMMC-7721, with IC₅₀ values of 3.86, 6.60, and 3.58 μM, respectively, and induced MCF-7 cell death through a mitochondria-mediated apoptosis pathway

Highly Rigid Labdane-Type Diterpenoids from a Chinese Liverwort and Light-Driven Structure Diversification

Two unprecedented labdane-type diterpenoids haplomintrins A (<b>1</b>) and B (<b>2</b>) with six rings system were isolated from a Chinese liverwort <i>Haplomitrium mnioides</i>. Light-driven reaction of homologous haplomitrenonolides C (<b>6</b>), A (<b>4</b>), and D (<b>3</b>) afforded haplomintrins A–C (<b>1</b>, <b>2</b>, and <b>7</b>), respectively, while <b>4</b> was converted to more complex congeners haplomintrins D–G (<b>8</b>–<b>11</b>) through intramolecular cyclization. Formation of <b>1</b> and <b>2</b> from compounds <b>6</b> and <b>4</b>, respectively, helps us to postulate that a photochemical reaction is involved in the biosynthetic pathway. These structure features can be used as molecular markers of <i>H. mnioides</i>, and their allelopathic effects are also preliminarily tested

Scapairrins A–Q, Labdane-Type Diterpenoids from the Chinese Liverwort <i>Scapania irrigua</i> and Their Cytotoxic Activity

Seventeen new labdane-type diterpenoids, scapairrins A–Q (<b>1</b>–<b>17</b>), including six pairs of diastereoisomers, and three known analogues (<b>18</b>–<b>20</b>) were isolated from the Chinese liverwort <i>Scapania irrigua</i>. The structures of <b>1</b>–<b>17</b> were determined based on a combination of the analysis of their MS and NMR spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Cytotoxicity testing showed that compounds <b>7</b>–<b>10</b> exhibited inhibitory activities against a small panel of human cancer cell lines

Sacculatane Diterpenoids from the Liverwort Plagiochila nitens Collected in China

Seven new terpenoids, including six sacculatane diterpenoids plagiochilarins A–F (1–6), and one ent-2,3-seco-aromandrane sesquiterpenoid plagiochilarin H (8) with a 6/7/3/5 tetracyclic scaffold, alongside three known compounds, were obtained from the Chinese liverwort Plagiochila nitens Inoue. Plagiochilarin B (2) was unpredictably converted to the more stable artifact 7 under acid catalysis through cyclic ether formation. The reaction mechanism was reasonably deduced and experimentally verified. The structures of these terpenoids were determined by analysis of MS and NMR spectroscopic data and single-crystal X-ray diffraction. The inhibitory effect of all of the isolates was evaluated on the growth of two C. albicans strains, wild strain SC5314 and efflux pump-deficient strain DSY654. However, only plagiochilarin H (8) showed a MIC value of 16 μg/mL against C. albicans DSY654

Sacculatane Diterpenoids from the Liverwort Plagiochila nitens Collected in China

Seven new terpenoids, including six sacculatane diterpenoids plagiochilarins A–F (1–6), and one ent-2,3-seco-aromandrane sesquiterpenoid plagiochilarin H (8) with a 6/7/3/5 tetracyclic scaffold, alongside three known compounds, were obtained from the Chinese liverwort Plagiochila nitens Inoue. Plagiochilarin B (2) was unpredictably converted to the more stable artifact 7 under acid catalysis through cyclic ether formation. The reaction mechanism was reasonably deduced and experimentally verified. The structures of these terpenoids were determined by analysis of MS and NMR spectroscopic data and single-crystal X-ray diffraction. The inhibitory effect of all of the isolates was evaluated on the growth of two C. albicans strains, wild strain SC5314 and efflux pump-deficient strain DSY654. However, only plagiochilarin H (8) showed a MIC value of 16 μg/mL against C. albicans DSY654

Preparative Scale MS-Guided Isolation of Bioactive Compounds Using High-Resolution Flash Chromatography: Antifungals from Chiloscyphus polyanthos as a Case Study

In natural products research, the efficient purification of molecules from large amount of complex extracts is a key element. In this regard, an integrative strategy for efficient mass spectrometry (MS)-guided isolation of antifungal compounds has been developed. First, at-line HPLC antifungal activity based profiling and HPLC-PDA-MS profiling were used to localise the compounds of interest on the analytical scale. Then, the analytical gradient was geometrically transferred to the flash chromatographic level. Finally, an MS-triggered isolation of the localized bioactive molecules was realized using high resolution flash chromatographic columns (15 µm spherical particles) coupled to a single quadrupole mass spectrometer via a splitter system. This isolation strategy was applied for the MS-targeted purification of the antifungal principles from the Chinese liverwort Chiloscyphus polyanthos (L.) Cord. This rational methodology has a high potential for the targeted large-scale purification of bioactive compounds avoiding the need to repeat a given bioassay at each isolation step. Seven sesquiterpene lactones were isolated, of which five were found bioactive and one was reported as a new compound. The absolute configuration of some compounds was established for the first time by electronic circular dichroism (ECD) spectroscopy

Sacculatane Diterpenoids from the Liverwort Plagiochila nitens Collected in China

Seven new terpenoids, including six sacculatane diterpenoids plagiochilarins A–F (1–6), and one ent-2,3-seco-aromandrane sesquiterpenoid plagiochilarin H (8) with a 6/7/3/5 tetracyclic scaffold, alongside three known compounds, were obtained from the Chinese liverwort Plagiochila nitens Inoue. Plagiochilarin B (2) was unpredictably converted to the more stable artifact 7 under acid catalysis through cyclic ether formation. The reaction mechanism was reasonably deduced and experimentally verified. The structures of these terpenoids were determined by analysis of MS and NMR spectroscopic data and single-crystal X-ray diffraction. The inhibitory effect of all of the isolates was evaluated on the growth of two C. albicans strains, wild strain SC5314 and efflux pump-deficient strain DSY654. However, only plagiochilarin H (8) showed a MIC value of 16 μg/mL against C. albicans DSY654