An Effective and Promising Strategy for Plant Protection: Synthesis of L-Carvone-Based Thiazolinone-Hydrazone/Nanochitosan Complexes with Antifungal Activity and Sustained Releasing Performance.

The development of novel natural product-derived nano-pesticide systems with loading capacity and sustained releasing performance of bioactive compounds is considered an effective and promising plant protection strategy. In this work, 25 L-carvone-based thiazolinone-hydrazone compounds 4a~4y were synthesized by the multi-step modification of L-carvone and structurally confirmed. Compound 4h was found to show favorable and broad-spectrum antifungal activity through the in vitro antifungal activity evaluation of compounds 4a~4y against eight phytopathogenic fungi. Thus, it could serve as a leading compound for new antifungal agents in agriculture. Moreover, the L-carvone-based nanochitosan carrier 7 bearing the 1,3,4-thiadiazole-amide group was rationally designed for the loading and sustained releasing applications of compound 4h, synthesized, and characterized. It was proven that carrier 7 had good thermal stability below 200 °C, dispersed well in the aqueous phase to form numerous nanoparticles with a size of~20 nm, and exhibited an unconsolidated and multi-aperture micro-structure. Finally, L-carvone-based thiazolinone-hydrazone/nanochitosan complexes were fabricated and investigated for their sustained releasing behaviors. Among them, complex 7/4h-2 with a well-distributed, compact, and columnar micro-structure displayed the highest encapsulation efficiency and desirable sustained releasing property for compound 4h and thus showed great potential as an antifungal nano-pesticide for further studies.

Synthesis, Antifungal Activity, and Molecular Simulation Study of L-Carvone-Derived 1,3,4-Oxadiazole-Thioether Compounds.

To discover potent antifungal molecules with new and distinctive structures, 20 novel L-carvone-derived 1,3,4-oxadiazole-thioether compounds 5 a-5 t were synthesized through multi-step reaction of L-carvone, and their structures were confirmed by FT-IR, 1 H-NMR, 13 C-NMR, and HR-MS. The antifungal activities of compounds 5 a-5 t were preliminarily tested by in vitro method, and the results indicated that all of the title compounds displayed certain antifungal activities against the eight tested plant fungi, especially for P. piricola. Among them, compound 5 i (R=p-F) with the most significant antifungal activity deserved further study for discovering and developing novel natural product-based antifungal agents. Moreover, two molecular simulation technologies were employed for the investigation of their structure-activity relationships (SARs). Firstly, a reasonable and effective 3D-QSAR model was established by the comparative molecular field (CoMFA) method, and the relationship of the substituents linked with the benzene rings and the inhibitory activities of the title compounds against P. piricola was elucidated. Then, the binding mode of compound 5 i (R=p-F) and its potential biological target (CYP51) was simulated by molecular docking, and it was found that compound 5 i could readily bind with CYP51 in the active site, and the ligand-receptor interactions involved three hydrogen bonds and several hydrophobic effects.

Synthesis, Antifungal Activity, and Molecular Docking Study of Novel 3-Carene-Derived 4-Substituted Phenyl-1,2,4-Triazolinthiones Bearing gem-Dimethylcyclopropane Moiety.

For exploring new natural product-based leading compounds with antifungal activity, 15 novel 3-carene-derived 4-substituted phenyl-1,2,4-triazolinthiones 7a∼7o bearing gem-dimethylcyclopropane moiety were synthesized and structurally characterized by UV/VIS, FT-IR, 1 H-NMR, 13 C-NMR, ESI-MS and elemental analysis. The preliminary bioassay at 50 µg/mL showed that all of the target compounds exhibited certain in vitro inhibitory activities against the eight tested fungi, in which compound 7g (R=m, p-Cl) displayed better inhibition activity (85.0 %) against P. piricola than that of the positive control Chlorothalonil. Furthermore, a reasonable and effective 3D structure of phytofungal CYP51 was constructed by homology modeling. Molecular docking study revealed that the total scores of all the target compounds were higher than that of Prothioconazole. In addition, it was found that compound 7g could readily embed into the binding site, and therein shared similar interactions with the case of Prothioconazole. Thus, compound 7g deserved further study as an antifungal leading compound.

[Protective effects of Salvia miltiorrhiza on rats with streptozotocin diabetes and its mechanism].

OBJECTIVE: To explore the effects of Salvia miltiorrhiza on renal morphology and renal function of rats with streptozotocin diabetes. METHODS: Thirty male Wistar rats were randomly divided into three groups, which were normal control group, untreated group and Salvia miltiorrhiza-treated group. Diabetic nephropathy was induced in rats of the last two groups by intraperitoneal injection of streptozotocin after unilateral nephrectomy. Then the rats in the normal control and untreated groups were fed with normal saline while those in the Salvia miltiorrhiza-treated group were fed Salvia miltiorrhiza preparation for 8 weeks. The glomerular volume (VG), kidney-to-body weight ratio (KW/BW), urinary albumin excretion rate (UAER) and creatinine clearance (Ccr) were observed. The expression levels of transforming growth factor-beta1 (TGF-beta1), connective tissue growth factor (CTGF), fibronectin (FN) and plasminogen activator inhibitor-1 (PAI-1) were detected by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) at the end of the experiment. RESULTS: UAER, Ccr, VG and KW/BW ratio were significantly higher in the untreated group than those in the normal control group (P<0.05). The expression levels of TGF-beta1, CTGF, PAI-1 and FN in the untreated group were also significantly higher as compared with those in the normal control group (P<0.05). UAER, Ccr, VG, KW/BW ratio and the levels of TGF-beta1, CTGF, PAI-1 and FN in the Salvia miltiorrhiza-treated group were obviously lower than those in the untreated group (P<0.05). CONCLUSION: Salvia miltiorrhiza can protect rats with streptozotocin diabetes from diabetic nephropathy by suppressing the over-expressions of TGF-beta1, CTGF, PAI-1 and FN in renal cortex.