Effect of pseudolaric acid B on biochemical and physiologic characteristics in Colletotrichum gloeosporioides

β-Caryophyllene oxide inhibits lysine acetylation of histones in Fusarium proliferatum to block ribosomal biosynthesis and function

The natural bicyclic sesquiterpene, β-Caryophyllene oxide (BCPO), has demonstrated inhibitory activity against Fusarium species. While previous studies have documented its antifungal properties through various biochemical mechanisms, the role of BCPO in modulating epigenetic modifications of DNA via histone deacetylases (HDACs) has received comparatively less attention. The study aims to elucidate how BCPO inhibits Fusarium proliferatum by affecting histone acetylation. Our results indicate that BCPO enhances FPRO_01165 (FpSIR2) enzyme activity to 6.01 ng/min/mg, representing a 55.30 % increase. Molecular docking analysis and molecular dynamics simulation confirmed the interaction between BCPO and FpSIR2. Furthermore, high concentrations (HC) of BCPO significantly inhibited the growth of F. proliferatum, resulting in marked reductions in H3K9ac and H3K27ac modification levels. We conducted chromatin immunoprecipitation sequencing (ChIP-seq) to identify enrichments of H3K9ac and H3K27ac, while also obtaining transcriptomic data from the HC treatment group. Combined analyses revealed that decreased levels of H3K9ac and H3K27ac primarily affected ribosomal pathways in F. proliferatum, leading to downregulation of several ribosomal genes and their corresponding proteins, such as RPL4, RPS19, and RPS16. Our findings suggest that BCPO stimulates both the production and activity of FpSIR2, which subsequently inhibits histone lysine acetylation in F. proliferatum. This inhibition suppresses ribosome biosynthesis and function as well as overall growth in this pathogen. The property of BCPO to reduce acetylation provides new insights for developing highly efficient yet low-toxicity antifungal agents.

Synthesis and Biological Activity of Myricetin Derivatives Containing Pyrazole Piperazine Amide

In this paper, a series of derivatives were synthesized by introducing the pharmacophore pyrazole ring and piperazine ring into the structure of the natural product myricetin through an amide bond. The structures were determined using carbon spectrum and hydrogen spectrum high-resolution mass spectrometry. Biological activities of those compounds against bacteria, including Xac (Xanthomonas axonopodis pv. Citri), Psa (Pseudomonas syringae pv. Actinidiae) and Xoo (Xanthomonas oryzae pv. Oryzae) were tested. Notably, D6 exhibited significant bioactivity against Xoo with an EC₅₀ value of 18.8 μg/mL, which was higher than the control drugs thiadiazole-copper (EC₅₀ = 52.9 μg/mL) and bismerthiazol (EC₅₀ = 69.1 μg/mL). Furthermore, the target compounds were assessed for their antifungal activity against ten plant pathogenic fungi. Among them, D1 displayed excellent inhibitory activity against Phomopsis sp. with an EC₅₀ value of 16.9 μg/mL, outperforming the control agents azoxystrobin (EC₅₀ = 50.7 μg/mL) and fluopyram (EC₅₀ = 71.8 μg/mL). In vitro tests demonstrated that D1 possessed curative (60.6%) and protective (74.9%) effects on postharvest kiwifruit. To investigate the active mechanism of D1, its impact on SDH activity was evaluated based on its structural features and further confirmed through molecular docking. Subsequently, the malondialdehyde content of D1-treated fungi was measured, revealing that D1 could increase malondialdehyde levels, thereby causing damage to the cell membrane. Additionally, the EC₅₀ value of D16 on P. capsici was 11.3 μg/mL, which was superior to the control drug azoxystrobin (EC₅₀ = 35.1 μg/mL), and the scanning electron microscopy results indicated that the surface of drug-treated mycelium was ruffled, and growth was significantly affected.

Design, Synthesis, and Antifungal Activity of Novel Chalcone Derivatives Containing a Piperazine Fragment

In an attempt to find the biorational pesticides, 20 novel chalcone derivatives containing a piperazine fragment were designed and synthesized. Their fungicidal activities and preliminarily action mechanism against Rhizoctonia solani were evaluated. Strikingly, the biological activity of compound D2 was obtained by optimizing the structure of the system. Subsequently, the practical value of compound D2 was ascertained by the relative surveys on in vivo anti-R. solani and anti-Colletotrichum gloeosporioides. The results revealed by scanning electron microscopy demonstrated that compound D2 could induce irregular and shrivelled growth of mycelium and rupture of the mycelium surface. This study indicates that chalcone derivatives containing a piperazine skeleton had better inhibitory effect on plant fungi, providing further complementary research on new pesticides.

Pseudolaric acid B induces mitotic arrest and apoptosis in both imatinib-sensitive and -resistant chronic myeloid leukaemia cells

The selective BCR-ABL tyrosine kinase inhibitor imatinib is one of the first-line therapies in the management of chronic myeloid leukaemia (CML). However, acquired resistance to this inhibitor, which is especially conferred by the T315I point mutation in BCR-ABL, impedes the efficacy of imatinib therapy. Therefore, the discovery and development of novel agents to overcome imatinib resistance is urgently needed. Pseudolaric acid B (PAB), a small molecule isolated from the traditional Chinese medicine Cortex pseudolaricis, has been reported to be a potential candidate for immune disorders and cancer treatment. However, its effects on CML and the involved molecular mechanism have not been reported. In the current study, by performing both in vitro and in vivo experiments in CML cells, we showed that PAB blocked the cell cycle at G₂/M phase and subsequently activated the caspase pathway, cleaved the BCR-ABL protein and inhibited the BCR-ABL downstream pathways, ultimately leading to cell proliferation inhibition, cytotoxicity and apoptosis. These events were observed in both imatinib-sensitive and imatinib-insensitive CML cell lines. Moreover, PAB decreased the viability of primary blood mononuclear cells from CML patients and induced apoptosis in these cells. Our findings suggest that PAB could be used as a novel agent to sensitize imatinib-resistant CML.