Facile Synthesis and First Antifungal Exploration of Tetracyclic Meroterpenoids: (+)-Aureol, (-)-Pelorol, and Its Analogs.

As an important bioactive molecular backbone, drimane meroterpenoids have drawn a great deal of attention from both pharmacologists and chemists. Inspired by the prevalidated success of conformational restriction in the discovery of novel pharmaceutical leads, two distinct tetracyclic drimane meroterpenoids, (-)-pelorol and (+)-aureol, were synthesized from the inexpensive starting material (-)-sclareol through 10 and 8 steps with 5.6% and 5.4% overall yield, respectively. The mild conditions, operational facility, and scalability enabled the expedient synthesis and biological exploration of not only natural products themselves but also their mimics. The first agrochemical exploration showed (-)-pelorol and (+)-aureol possessed good antifungal activity against Rhizoctonia solani, with EC50 values of 7.7 and 6.9 µM, respectively. This revealed that tetracyclic drimane meroterpenoids are valuable models for antifungal lead discovery.

Degradation-Risk-Inspired Optimization of the Antifungal Oxazolinyl Aniline Lead by a Fusion of Triazole with Nicotinamide.

The discovery of readily available and easily modifiable new models is a crucial and practical solution for agrochemical innovation. Antifungal function-oriented fusion of triazole with the prevalidated lead (R)-LE001 affords a novel framework with a broad and enhanced antifungal spectrum. Characterized by the easy accessibility and adjustability of [1,2,4]triazolo[4,3-a]pyridine, modular fine-tuning provided a set of unprecedented leads (e.g., Z23, Z25, Z26, etc.) with superior antifungal potentials than the positive control boscalid. Candidate Z23 exhibited a more promising antifungal activity against Sclerotinia sclerotiorum, Botrytis cinerea, and Phytophthora capsici with EC50 values of 0.7, 0.6, and 0.5 µM, respectively. This candidate could effectively control boscalid-resistant B. cinerea strains and also exhibit good vivo efficacy in controlling gray mold. Noteworthily, both the SDH-inhibition and the efficiency against Oomycete P. capsici are quite distinct from that of the positive control boscalid. A molecular docking simulation also differentiates Z23 from boscalid. These findings highlight the potential of [1,2,4]triazolo[4,3-a]pyridine amide as a novel antifungal model.

Eudistomins Y-Inspired Design and Divergent Optimization of Heteroaryl Ketones for New Antifungal Leads.

The discovery of structurally distinct leads is imperative in modern agrochemical science. Inspired by eudistomins Y and the framework-related pharmaceuticals, aryl heteroaryl ketone was drawn as a common model intriguing the design and divergent synthesis of 14 kinds of heteroaryl ketones aligned with their oxime derivatives. Antifungal function-oriented phenotypical screen protruded benzothiazolyl-phenyl oxime 5a as a promising model, and the concomitant modification led to benzothiazolyl oxime 5am (EC50 = 5.17 µM) as a superior lead than fluoxastrobin (EC50 = 7.54 µM) against Sclerotinia sclerotiorum. Scaffold hopping of the phenyl subunit identified benzothiazolyl-pyridyl oxime as a novel antifungal scaffold accompanied by acquiring oxime 5bm with remarkable activity (EC50 = 3.57 µM) against Pyricularia oryzae. Molecular docking showed that candidate 5am could form more hydrogen bonds with the amino acid residues of actin than metrafenone. This compound also demonstrated better curative efficacy than that of fluoxastrobin and metrafenone in controlling the plant disease caused by S. sclerotiorum. These results rationalize the discovery of antifungal candidates based on aryl heteroaryl ketone.

Multidimensional Optimization of R-LE001 for New Leads with Enhanced Antifungal Profiles.

Scaffold hopping and structural fine-tuning are important strategies for agrochemical innovation. Multidimensional optimization of the prevalidated antifungal lead R-LE001 was conducted via the design, synthesis, and bioevaluation of 53 new compounds differing in either scaffold or substituent. The antifungal structure-activity relationship (SAR) revealed that a number of amides containing 2-(2-oxazolinyl) aniline (NHPhOx) or 2-(2-thiazolinyl) aniline (NHPhthiOx) demonstrated a more promising antifungal effect than both R-LE001 and the positive control boscalid. Specifically, compound 10 (encoded LEX-K01) shows an excellent antifungal effect against Botrytis cinerea with an EC50 value lower than 0.11 µM. This small change leads to a significant improvement (over 1 order of magnitude) in bioactivity compared to that of either R-LE001 (EC50 = 1.41 µM) or boscalid (EC50 = 2.01 µM) and fluxapyroxad (EC50 = 4.35 µM). With much lower resistance factors, LEX-K01 (10) was more efficacious against the two boscalid-resistant strains of B. cinerea TZ01 and NJBH2017. A combination of LEX-K01 (10) and boscalid in a ratio of 1:3 showed synergistic effects against resistant B. cinerea TZ01 and NJBH2017, with SR values of 3.01 and 2.55, respectively. LEX-K01 (10) has a curative efficacy (70.3%) more prominent than that of boscalid (51.2%) in controlling disease caused by B. cinerea. The molecular docking simulation of LEX-K01 (10) with the SDH protein of B. cinerea displayed four hydrogen bonds with amino acid residues TYR144, ARG88, TRP81, and SER84, rationalizing a stronger affinity than boscalid. The scanning electron microscopy (SEM) characteristic revealed that it could cause an obvious collapse of B. cinerea mycelium. This work indicates that LEX-K01 (10) has the potential to be further explored as a new antifungal agent.

Intermittent Fasting-Improved Glucose Homeostasis Is Not Entirely Dependent on Caloric Restriction in db/db Male Mice.

Intermittent fasting (IF), which involves prolonged fasting intervals accompanied by caloric restriction (CR), is an effective dietary treatment for obesity and diabetes. Although IF offers many benefits, it is difficult to determine whether these benefits are the consequences of CR. Every-other-day feeding (EODF) is a commonly used IF research model. This study was designed to identify factors, in addition to CR, responsible for the effects of EODF and the possible underlying mechanisms. Diabetic db/db mice were divided into three groups: ad libitum (AL), meal feeding (MF), and EODF. The MF model was used to attain a level of CR comparable to that of EODF, with food distribution evenly divided between 10:00 a.m. and 6:00 p.m., thereby minimizing the fasting interval. EODF yielded greater improvements in glucose homeostasis than MF in db/db mice by reducing fasting glucose levels and enhancing glucose tolerance. However, these effects on glucose metabolism were less pronounced in lean mice. Furthermore, ubiquitination of the liver-specific glucocorticoid (GC) receptor (GR) facilitated its degradation and downregulation of Kruppel-like factor 9 (KLF9), which ultimately suppressed liver gluconeogenesis in diabetic EODF mice. Although GR and KLF9 might mediate the metabolic benefits of EODF, the potential benefits of EODF might be limited by elevated serum GC levels in diabetic EODF mice. Overall, this study suggests that the metabolic benefits of EODF in improving glucose homeostasis are independent of CR, possibly because of the downstream effects of liver-specific GR degradation.

Fabrication of injectable alginate hydrogels with sustained release of 4-octyl itaconate for articular anti-inflammatory.

BACKGROUND: Osteoarthritis (OA) is a chronic and degenerative joint disease that remains a great challenge in treatment due to the lack of effective therapies. 4-octyl itaconate (4-OI) is a novel and potent modulator of inflammation for the treatment of inflammatory disease. However, the clinical usage of 4-OI is limited due to its poor solubility and low bioavailability. As a promising drug delivery strategy, injectable hydrogels offers an effective approach to address these limitations of 4-OI. OBJECTIVE: The aim of the study was to verify that the composite 4-OI/SA hydrogels could achieve a controlled release of 4-OI and reduce damage to articular cartilage in the group of osteoarthritic rats treated with the system. METHODS: In this study, an injectable composite hydrogel containing sodium alginate (SA) and 4-octyl itaconate (4-OI) has been developed for continuous intra-articular administration in the treatment of OA. RESULTS: After intra-articular injection in arthritic rats, the as-prepared 4-OI/SA hydrogel containing of 62.5 µM 4-OI effectively significantly reduced the expression of TNF-α, IL-1ß, IL-6 and MMP3 in the ankle fluid. Most importantly, the as-prepared 4-OI/SA hydrogel system restored the morphological parameters of the ankle joints close to normal. CONCLUSION: 4-OI/SA hydrogel shows a good anti-inflammatory activity and reverse cartilage disruption, which provide a new strategy for the clinical treatment of OA.

Lymphocytes in Patients with Chronic Active Epstein-Barr Virus Disease Exhibited Elevated PD-1/PD-L1 Expression and a Prevailing Th2 Immune Response.

Background And Objectives: Chronic active Epstein-Barr virus disease (CAEBV) is a proliferative disease of EBV+ T or natural killer (NK) cells with an unclear pathogenesis. This study aimed to examine the frequency and exhaustion levels of lymphocyte subsets in patients with CAEBV to further investigate the pathogenesis. Methods: Using flow cytometry, we detected the frequency, expression levels of programmed cell death 1 (PD-1) and programmed death ligand 1 (PD-L1), and EBV infection status of peripheral T subsets and NK cells in patients with CAEBV and healthy individuals. Results: 24 patients and 15 healthy individuals were enrolled in this study. Patients showed notably higher expression levels of PD-1 and PD-L1 in peripheral T subsets and NK cells compared to healthy individuals (P < 0.05). EBV+ lymphocytes exhibited significantly higher PD-L1 expression levels than EBV- lymphocytes. Additionally, the frequency of effector memory T (Tem) cells was significantly increased in patients, and the PD-L1 expression level was positively correlated with the EBV load. Besides, helper T cell 2 (Th2) immune bias, also favoring EBV amplification, was found in patients, including increased Th2 cell frequency, enhanced response capacity, and elevated serum levels of associated cytokines. The distribution and PD-1 expression levels of peripheral T subsets returned to normal in patients who responded to PD-1 blockade therapy. Conclusions: The up-regulation of the PD-1/PD-L1 pathway of peripheral T and NK cells and Th2 immune predominance jointly promoted EBV replication and the development of CAEBV. PD-1 blockade therapy reduced the PD-1 expression level of lymphocytes and helped normalize the distribution of the T subsets.