Diagnostically analyzing 1H NMR spectra of sub-types in chaetoglobosins for dereplication

Unveiling the impact of imidazole derivative with mechanistic insights into neutralize interfacial polymerized membranes for improved solute-solute selectivity

Domestic wastewater (DWW) contains a reservoir of nutrients, such as nitrogen, potassium, and phosphorus; however, emerging micropollutants (EMPs) hinder its applications in resource recovery. In this study, a novel class of nanofiltration (NF) membranes was developed; it enabled the efficient removal of harmful EMP constituents while preserving valuable nutrients in the permeate. Neutral (IM-N) and positively charged (IM-P) imidazole derivative compounds have been used to chemically functionalize pristine polyamide (PA) membranes to synchronously inhibit the hydrolysis of residual acyl chloride and promote their amination. Owing to their distinct properties, these IM modifiers can custom-build the membrane physicochemical properties and structures to benefit the NF process in DWW treatment. The electroneutral NF membrane exhibited ultrahigh solute-solute selectivity by minimizing the Donnan effects on ion penetration (K, N, and P ions rejection < 25%) while imposing remarkable size-sieving obstruction against EMPs (rejection ratio > 91%). Moreover, the hydrophilic IM-modifier synergistically led to enhanced water permeance of 9.2 L m^-2 h^-1 bar^-1, reaching a 2-fold higher magnitude than that of the pristine PA membrane, along with excellent antifouling/antibacterial fouling properties. This study may provide a paradigm shift in membrane technology to convert wastewater streams into valuable water and nutrient resources.

Artificial intelligence-guided discovery of anticancer lead compounds from plants and associated microorganisms

Plants and associated microorganisms are essential sources of natural products against human cancer diseases, partly exemplified by plant-derived anticancer drugs such as Taxol (paclitaxel). Natural products provide diverse mechanisms of action and can be used directly or as prodrugs for further anticancer optimization. Despite the success, major bottlenecks can delay anticancer lead discovery and implementation. Recent advances in sequencing and omics-related technology have provided a mine of information for developing new therapeutics from natural products. Artificial intelligence (AI), including machine learning (ML), has offered powerful techniques for extensive data analysis and prediction-making in anticancer leads discovery. This review presents an overview of current AI-guided solutions to discover anticancer lead compounds, focusing on natural products from plants and associated microorganisms.

Hydrazine-Containing Heterocycle Cytochalasan Derivatives From Hydrazinolysis of Extracts of a Desert Soil-Derived Fungus Chaetomium madrasense 375

"Diversity-enhanced extracts" is an effective method of producing chemical libraries for the purpose of drug discovery. Three rare new cytochalasan derivative chaetoglobosins B1-B3 (1-3) were obtained from chemically engineered crude broth extracts of Chaetomium madrasense 375 prepared by reacting with hydrazine monohydrate and four known metabolite chaetoglobosins (4-7) were also identified from the fungus. The structures were identified by NMR and MS analysis and electronic circular dichroism simulation. In addition, the antiproliferative activities of these compounds were also evaluated, and the drug-resistant activities of cytochalasans were evaluated for the first time. Compound 6 possessed potent activity against four human cancer cells (A549, HCC827, SW620, and MDA-MB-231), and two drug-resistant HCC827 cells (Gefitinib-resistant, Osimertinib-resistant) compared with the positive controls.

Naturally Occurring seco-Sativene Sesquiterpenoid: Chemistry and Biology

seco-Sativenes are a small group of sesquiterpenoids with a unique bicyclo[3.2.1]octane core carbon skeleton, which implies the unusual biosynthetic pathway. Up to date, there are 40 seco-sativene analogues with diverse post-modifications isolated from different fungi. Interestingly, some seco-sativene analogues display strong phytotoxic effects, whereas others possess plant-growth-promoting biological activities. The possible mechanism of actions about phytotoxic or growth-promoting activities are partly elucidated, but structure-activity relationships are still not clear. This review provides a comprehensive overview on the structures, ¹H nuclear magnetic resonance features, bioactivities, and biosynthesis of seco-sativene sesquiterpenoids from 1956 to 2020.

Revision of the structure of isochaetoglobosin Db based on NMR analysis and biosynthetic consideration

Isochaetoglobosin D_b is a new chaetoglobosin possessing a unique 3,4-substituted pyrrole ring isolated and named by Qiu et al., and it is different from any one of the 14 sub-types in the macrocyclic ring of chaetoglobosins classified in our previous work. Its chemical shift values, coupling constants and biosynthetic consideration implied that the proposed structure of isochaetoglobosin D_b was incorrect. In this report, based on detailed NMR data analysis together with biosynthetic consideration, the structure of isochaetoglobosin D_b is suggested to be revised to that of penochalasin C. The NMR spectra of penochalasin C measured in the same solvent (DMSO-d₆) as that of isochaetoglobosin D_b supported the above conclusion. The results imply that reasonable biosynthetic consideration could complement spectroscopic structural determination, and also support that the ¹H-NMR rule of chaetoglobosin summarized in our previous work can provide help for dereplication and rectification.

Isochaetoglobosin D_b is a new chaetoglobosin possessing a unique 3,4-substituted pyrrole ring isolated and named by Qiu et al., and it is different from any one of the 14 sub-types in the macrocyclic ring of chaetoglobosins classified in our previous work.