Autocatalytic Self-Sorting in Biomimetic Polymer

Autocatalytic self-sorting in the biomimetic poly­(cystamine methacrylamide hydrochloride) (PCysMA) is presented, whose units comprise lysine-mimetic alkyl­ammonium ions and cystine-mimetic alkyl disulfide spacers. The block copolymer with poly­(2-hydroxy­propyl­methacrylamide) was synthesized directly by RAFT in acidic water under visible light irradiation at 25 °C. Disulfide exchange can be initiated by the terminal thiolates as generated by alkalization-induced aminolysis. 65–67% CysMA units sort into hydrophobic polymer disulfides and water-soluble cystamine at pH 10.5. Moreover, intermediate reactions occur in the presence of copper ions, i.e., Cu­(II)–NH₂ coordination, aminolysis, NH₂-to-SH substitution, and cupric-to-cuprous reduction in metal centers, thus autocatalytic self-sorting with essentially 100% conversion at pH 8.8. UV–vis spectroscopy, ¹H NMR, atomic absorption spectroscopy, and elemental analysis confirmed this ideal self-sorting. Dynamic light scattering and atomic force microscopy identified supramolecular-to-supracolloidal self-assembly with concomitant release of cystamine molecules and intermediate cuprous complexes. Such a self-sorting underlines an amazing prospect for the use of a single polymer to achieve artificial reaction complexity, hierarchy, and metabolic process, with minimal synthetic efforts

Bioactive Dibenzo-α-pyrone Derivatives from the Endophytic Fungus <i>Rhizopycnis vagum</i> Nitaf22

Six new dibenzo-α-pyrones, rhizopycnolides A (<b>1</b>) and B (<b>2</b>) and rhizopycnins A–D (<b>3</b>–<b>6</b>), together with eight known congeners (<b>7</b>–<b>14</b>), were isolated from the endophytic fungus <i>Rhizopycnis vagum</i> Nitaf22 obtained from <i>Nicotiana tabacum</i>. The structures of the new compounds were unambiguously elucidated using NMR, HRESIMS, TDDFT ECD calculation, and X-ray crystallography data. Rhizopycnolides A (<b>1</b>) and B (<b>2</b>) feature an uncommon γ-butyrolactone-fused dibenzo-α-pyrone tetracyclic skeleton (6/6/6/5), while rhizopycnin B (<b>4</b>) was the first amino group containing dibenzo-α-pyrone. Rhizopycnolides A (<b>1</b>) and B (<b>2</b>) are proposed to be biosynthesized from polyketide and tricarboxylic acid cycle pathways. The isolated compounds were tested for their antibacterial, antifungal, and cytotoxic activities. Among them, rhizopycnolide A (<b>1</b>), rhizopycnins C (<b>5</b>) and D (<b>6</b>), TMC-264 (<b>8</b>), penicilliumolide D (<b>11</b>), and alternariol (<b>12</b>) were active against the tested pathogenic bacteria <i>Agrobacterium tumefaciens</i>, <i>Bacillus subtilis</i>, <i>Pseudomonas lachrymans</i>, <i>Ralstonia solanacearum</i>, <i>Staphylococcus hemolyticus</i>, and <i>Xanthomonas vesicatoria</i> with MIC values in the range 25–100 μg/mL. Rhizopycnin D (<b>6</b>) and TMC-264 (<b>8</b>) strongly inhibited the spore germination of <i>Magnaporthe oryzae</i> with IC₅₀ values of 9.9 and 12.0 μg/mL, respectively. TMC-264 (<b>8</b>) showed potent cytotoxicity against five human cancer cell lines (HCT-116, HepG2, BGC-823, NCI-H1650, and A2780) with IC₅₀ values of 3.2–7.8 μM

Bioactive Dibenzo-α-pyrone Derivatives from the Endophytic Fungus <i>Rhizopycnis vagum</i> Nitaf22

Six new dibenzo-α-pyrones, rhizopycnolides A (<b>1</b>) and B (<b>2</b>) and rhizopycnins A–D (<b>3</b>–<b>6</b>), together with eight known congeners (<b>7</b>–<b>14</b>), were isolated from the endophytic fungus <i>Rhizopycnis vagum</i> Nitaf22 obtained from <i>Nicotiana tabacum</i>. The structures of the new compounds were unambiguously elucidated using NMR, HRESIMS, TDDFT ECD calculation, and X-ray crystallography data. Rhizopycnolides A (<b>1</b>) and B (<b>2</b>) feature an uncommon γ-butyrolactone-fused dibenzo-α-pyrone tetracyclic skeleton (6/6/6/5), while rhizopycnin B (<b>4</b>) was the first amino group containing dibenzo-α-pyrone. Rhizopycnolides A (<b>1</b>) and B (<b>2</b>) are proposed to be biosynthesized from polyketide and tricarboxylic acid cycle pathways. The isolated compounds were tested for their antibacterial, antifungal, and cytotoxic activities. Among them, rhizopycnolide A (<b>1</b>), rhizopycnins C (<b>5</b>) and D (<b>6</b>), TMC-264 (<b>8</b>), penicilliumolide D (<b>11</b>), and alternariol (<b>12</b>) were active against the tested pathogenic bacteria <i>Agrobacterium tumefaciens</i>, <i>Bacillus subtilis</i>, <i>Pseudomonas lachrymans</i>, <i>Ralstonia solanacearum</i>, <i>Staphylococcus hemolyticus</i>, and <i>Xanthomonas vesicatoria</i> with MIC values in the range 25–100 μg/mL. Rhizopycnin D (<b>6</b>) and TMC-264 (<b>8</b>) strongly inhibited the spore germination of <i>Magnaporthe oryzae</i> with IC₅₀ values of 9.9 and 12.0 μg/mL, respectively. TMC-264 (<b>8</b>) showed potent cytotoxicity against five human cancer cell lines (HCT-116, HepG2, BGC-823, NCI-H1650, and A2780) with IC₅₀ values of 3.2–7.8 μM