Quantitative Analysis of Camellia oleifera Seed Saponins and Aqueous Two-Phase Extraction and Separation.

At present, the technology used for the extraction and purification of Camellia oleifera saponins generally has the problems of high cost and low purity, and the quantitative detection of Camellia oleifera saponins also has the problems of low sensitivity and easy interference from impurities. To solve these problems, this paper aimed to use liquid chromatography for the quantitative detection of Camellia oleifera saponins, and to adjust and optimize the related conditions. In our study, the average recovery of Camellia oleifera saponins obtained was 100.42%. The RSD of precision test was 0.41%. The RSD of the repeatability test was 0.22%. The detection limit of the liquid chromatography was 0.06 mg/L, and the quantification limit was 0.2 mg/L. In order to improve the yield and purity, the Camellia oleifera saponins were extracted from Camellia oleifera Abel. seed meal by methanol extraction. Then, the extracted Camellia oleifera saponins were extracted with an ammonium sulfate/propanol aqueous two-phase system. We optimized the purification process of formaldehyde extraction and aqueous two-phase extraction. Under the optimal purification process, the purity of Camellia oleifera saponins extracted by methanol was 36.15%, and the yield was 25.24%. The purity of Camellia oleifera saponins obtained by aqueous two-phase extraction was 83.72%. Thus, this study can provide a reference standard for rapid and efficient detection and analysis of Camellia oleifera saponins for industrial extraction and purification.

Synthesis and Shape-Selective Catalytic Application of Ordered Cubic Ia3Ì d Supermicroporous Materials Templated by Rosin-Derived Quaternary Ammonium Salt with a Hydroxyl Radical in the Headgroup.

We described the comprehensive synthesis, characterization, and catalytic performance of a novel type of the ordered cubic Ia3̅d supermicroporous silicas by using tetraethyl orthosilicate as a silicon source and a hydroxyl-functionalized quaternary ammonium salt as a template under alkali conditions. The effects of various reaction conditions on the pore structure and morphology of the silica materials were thoroughly investigated. Our results showed that under a wide range of reaction conditions, supermicroporous silicas with a highly ordered cubic Ia3̅d structure can be produced with a large BET specific surface area of 1741 m2/g, high pore volume of 0.91 cm3/g, concentrated pore size at 19.1 Å, and crystalline morphology. After Al doping, the obtained aluminosilicates preserved a highly ordered cubic supermicroporous structure. By using the H-form aluminosilicates as catalysts, we selectively dimerized ß-pinene. The catalysts exhibited an excellent catalytic activity for ß-pinene dimerization with a conversion yield up to 100%. Compared with conventional mesoporous H-form Al-MCM-48 catalysts, the prepared supermicroporous catalysts exhibited superior catalytic performance due to their excellent shape-selective properties, producing the ß-pinene dimer in a yield up to 72.4% with dimer/oligomer ratios in the range of 7.5-10.1. This study featured a detailed preparation and characterization of supermicroporous silica with novel microstructures and showed its utility in catalytic dimerization.

Design, Synthesis, Antibacterial, Antifungal and Anticancer Evaluations of Novel ß-Pinene Quaternary Ammonium Salts.

ß-pinene is a monoterpene isolated from turpentine oil and numerous other plants' essential oils, which has a broad spectrum of biological activities. In the current work, six novel ß-pinene quaternary ammonium (ß-PQA) salts were synthesized and evaluated in vitro for their antifungal, antibacterial and anticancer activities. The in vitro assay results revealed that compounds 4a and 4b presented remarkable antimicrobial activity against the tested fungi and bacteria. In particular, compound 4a showed excellent activities against F. oxysporum f.sp. niveum, P. nicotianae var.nicotianae, R. solani, D. pinea and Fusicoccumaesculi, with EC50 values of 4.50, 10.92, 9.45, 10.82 and 6.34 µg/mL, respectively. Moreover, compound 4a showed the best antibacterial action against E. coli, P. aeruginosa, S. aureus and B. subtilis, with MIC at 2.5, 0.625, 1.25 and 1.25 µg/mL, respectively. The anticancer activity results demonstrated that compounds 4a, 4b, 4c and 4f exhibited remarkable activity against HCT-116 and MCF-7 cell lines, with IC50 values ranged from 1.10 to 25.54 µM. Notably, the compound 4c displayed the strongest cytotoxicity against HCT-116 and MCF-7 cell lines, with the IC50 values of 1.10 and 2.46 µM, respectively. Furthermore, preliminary antimicrobial mechanistic studies revealed that compound 4a might cause mycelium abnormalities of microbial, cell membrane permeability changes and inhibition of the activity of ATP. Altogether, these findings open interesting perspectives to the application of ß-PQA salts as a novel leading structure for the development of effective antimicrobial and anticancer agents.

Derivatization of Natural Compound ß-Pinene Enhances Its In Vitro Antifungal Activity against Plant Pathogens.

BACKGROUND: The development of new antifungal agents has always been a hot research topic in pesticide development. In this study, a series of derivatives of natural compound ß-pinene were prepared, and the antifungal activities of these derivatives were evaluated. The purpose of this work is to develop some novel molecules as promising new fungicides. METHODS: Through a variety of chemical reactions, ß-pinene was transformed into a series of ß-pinene-based derivatives containing amide moieties and acylthiourea moieties. The antifungal activities of these derivatives against five plant pathogens including Colletotrichum gloeosporioides, Fusarium proliferatum, Alternaria kikuchiana, Phomopsis sp. and Phytophthora capsici were tested; preliminary structure-activity relationship was discussed. RESULTS: Some derivatives exhibited moderate or significant antifungal activity due to the fusion of the amide moiety or the acylthiourea moiety with the pinane skeleton. The structure-activity relationship analysis showed that the fluorine atom and the strong electron withdrawing nitro group, or trifluoromethyl group on the benzene ring of the derivatives had a significant effect on the improvement of the antifungal activity against Colletotrichum gloeosporioides, Fusarium proliferatum, Alternaria kikuchiana and Phomopsis sp. Meanwhile, the introduction of an ethyl group at the meta-position on the benzene ring of the derivatives could improve the antifungal activity against Phytophthora capsici. Compounds 4e, 4h, 4q, 4r exhibited broad-spectrum antifungal activity against the tested strains. Compound 4o had significant antifungal activity against Phytophthora capsici (IC50 = 0.18 µmol/L). These derivatives were expected to be used as precursor molecules for novel pesticide development in further research.

Hydronopylformamides: Modification of the Naturally Occurring Compound (-)-ß-Pinene to Produce Insect Repellent Candidates against Blattella germanica.

The development of a novel repellent plays an important role in the integrated control of Blattella germanica. A series of novel hydronopylformamides derivatives were synthesized from a naturally occurring compound (-)-ß-pinene. The structures of these hydronopylformamides derivatives were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹H-NMR and 13C-NMR), and electron impact mass spectrometry (EI-MS). Repellency of these hydronopylformamides derivatives against Blattella germanica was evaluated by the using petri dish arena method. The results showed that four derivatives (compounds 8a, 8b, 8c and 8e) exhibited repellency against Blattella germanica at a concentration of 20 mg/mL. Compound 8a was the most active compound among these derivatives, where the repelling ratios of compound 8a against Blattella germanica were 66.10%, 50.46%, 48.26%, at concentrations of 20 mg/mL, 10 mg/mL, and 5 mg/mL, respectively. In addition, compound 8a showed better repellency than the traditional insect repellent N, N-diethyl-3-methylbenzamide (DEET), which indicated that compound 8a had a good application prospect in the prevention of Blattella germanica. This research hopes to promote the value-added utilization of (-)-ß-pinene and the development of novel German cockroach repellents.

One-pot synthesis and antimicrobial evaluation of novel 3-cyanopyridine derivatives of (-)-ß-pinene.

A series of novel 3-cyanopyridine derivatives of (-)-ß-pinene were designed and synthesized by one-pot four-component domino reactions. The targeted compounds were evaluated for their antimicrobial activity against four bacteria (Klebsiella pneumoniae, Enterobacter aerogenes, Staphylococcus aureus, Staphylococcus epidermidis) and a fungus (Candida albicans). The results showed that most of the minimal inhibitory concentrations (MICs) of these 3-cyanopyridine derivatives against the tested strains was in the range of 15.6-125 mg/L. Among these 3-cyanopyridine derivatives, the MICs of compound 5h against S. epidermidis and C. albicans were 15.6 mg/L, which revealed that compound 5h featured double fluoro substituents at meta- and para-position was the most active compound. In addition, the preliminary structure-activity relationship analysis indicated that the change of substituents on the pyridine ring and benzene ring of 3-cyanopyridine derivatives was an important factor for inducing antimicrobial activity. This research would promote the development of heterocyclic derivatives of ß-pinene with antimicrobial activity.

Molecular interactions between terpenoid mosquito repellents and human-secreted attractants.

Molecular interactions between terpenoid mosquito repellents and three typical human-secreted attractants, ammonia, 1-octen-3-ol, and formic acid were studied. Relative energies, bond distances, and bond angles of the molecular interactions were obtained at HF level to evaluate the interaction intensity and types. The effects of molecular interactions on repellency were investigated by the subsequent quantitative structure-activity relationship (QSAR) study. The results of this study suggest that attractant-repellent interaction should not be ignored and could be helpful for future research on the repelling mechanism of mosquito repellents.

Antibacterial activity of cinnamon essential oil and its main component of cinnamaldehyde and the underlying mechanism.

Background: Plant essential oils have long been regarded as repositories of antimicrobial agents. In recent years, they have emerged as potential alternatives or supplements to antimicrobial drugs. Although literature reviews and previous studies have indicated that cinnamon essential oil (CIEO) and its major component, cinnamaldehyde (CID), possess potent antibacterial activities, their antibacterial mechanisms, especially the in vivo antibacterial mechanisms, remain elusive. Methods: In this study, we utilized the in vivo assessment system of Caenorhabditis elegans (C. elegans) to investigate the effects and mechanisms of high dose (100 mg/L) and low dose (10 mg/L) CIEO and CID in inhibiting Pseudomonas aeruginosa (P. aeruginosa). In addition, we also examined the in vitro antibacterial abilities of CIEO and CID against other common pathogens including P. aeruginosa and 4 other strains. Results: Our research revealed that both high (100 mg/L) and low doses (10 mg/L) of CIEO and CID treatment significantly alleviated the reduction in locomotion behavior, lifespan, and accumulation of P. aeruginosa in C. elegans infected with the bacteria. During P. aeruginosa infection, the transcriptional expression of antimicrobial peptide-related genes (lys-1 and lys-8) in C. elegans was upregulated with low-dose CIEO and CID treatment, while this trend was suppressed at high doses. Further investigation suggested that the PMK-1 mediated p38 signaling pathway may be involved in the regulation of CIEO and CID during nematode defense against P. aeruginosa infection. Furthermore, in vitro experimental results also revealed that CIEO and CID exhibit good antibacterial effects, which may be associated with their antioxidant properties. Conclusion: Our results indicated that low-dose CIEO and CID treatment could activate the p38 signaling pathway in C. elegans, thereby regulating antimicrobial peptides, and achieving antimicrobial effects. Meanwhile, high doses of CIEO and CID might directly participate in the internal antimicrobial processes of C. elegans. Our study provides research basis for the antibacterial properties of CIEO and CID both in vivo and in vitro.

Synthesis, antifungal activity and action mechanism of novel citral amide derivatives against Rhizoctonia solani.

BACKGROUND: Rice sheath blight caused by Rhizoctonia solani is a severe threat to the yield and quality of rice. Due to the unscientific abuse of common fungicides causing resistance and environmental issues, the development of new fungicides is necessary. In this study, we used citral as the lead compound, designed and synthesized a series of novel citral amide derivatives, and evaluated their antifungal activity and mode of action against R. solani. RESULT: Bioassay results indicated that the antifungal activities of most citral amide derivatives against R. solani were significantly improved compared to citral, with EC50 values ranging from 9.50-27.12 mg L-1. Among them, compound d21 containing the N-(pyridin-4-yl)carboxamide group exhibited in vitro and in vivo fungicidal activities, with curative effects at 500 mg L-1 as effectively as the commercial fungicide validamycin·bacillus. Furthermore, d21 prolonged the lag phase of the growth curve of R. solani, reduced the amount of growth, and inhibited sclerotium germination and formation. Mechanistically, d21 deformed the mycelia, increased cell membrane permeability, and inhibited the activities of antioxidant and tricarboxylic acid cycle (TCA)-related enzymes. Metabolome analysis showed the abundance of some energy-related metabolites within R. solani increased, and simultaneously the antifungal substances secreted by itself reduced. Transcriptome analysis showed that most genes encoding ATP-binding cassette (ABC) transporters and peroxisomes upregulated after the treatment of d21 and cell membrane destruction. CONCLUSION: This study indicates that novel citral amide derivatives possess antifungal activity against R. solani and are expected to develop an alternative option for chemical control of rice sheath blight. © 2024 Society of Chemical Industry.

Antifungal Activity and Mechanism of Camphor Derivatives against Rhizoctonia solani: A Promising Alternative Antifungal Agent for Rice Sheath Blight.

Rice sheath blight, caused by the fungus Rhizoctonia solani, poses a significant threat to rice cultivation globally. This study aimed to investigate the potential mechanisms of action of camphor derivatives against R. solani. Compound 4o exhibited superior fungicidal activities in vitro (EC50 = 6.16 mg/L), and in vivo curative effects (77.5%) at 500 mg/L were significantly (P < 0.01) higher than the positive control validamycin·bacillus (66.1%). Additionally, compound 4o exhibited low cytotoxicity and acute oral toxicity for adult worker honeybees of Apis mellifera L. Mechanistically, compound 4o disrupted mycelial morphology and microstructure, increased cell membrane permeability, and inhibited both PDH and SDH enzyme activities. Molecular docking and molecular dynamics analyses indicated a tight interaction of compound 4o with PDH and SDH active sites. In summary, compound 4o exhibited substantial antifungal efficacy against R. solani, serving as a promising lead compound for further optimization of antifungal agents.

Further Improvement Based on Traditional Nanocapsule Preparation Methods: A Review.

Nanocapsule preparation technology, as an emerging technology with great development prospects, has uniqueness and superiority in various industries. In this paper, the preparation technology of nanocapsules was systematically divided into three categories: physical methods, chemical methods, and physicochemical methods. The technological innovation of different methods in recent years was reviewed, and the mechanisms of nanocapsules prepared via emulsion polymerization, interface polymerization, layer-by-layer self-assembly technology, nanoprecipitation, supercritical fluid, and nano spray drying was summarized in detail. Different from previous reviews, the renewal iteration of core-shell structural materials was highlighted, and relevant illustrations of their representative and latest research results were reviewed. With the continuous progress of nanocapsule technology, especially the continuous development of new wall materials and catalysts, new preparation technology, and new production equipment, nanocapsule technology will be used more widely in medicine, food, cosmetics, pesticides, petroleum products, and many other fields.

Novel Design of Citral-Thiourea Derivatives for Enhancing Antifungal Potential against Colletotrichum gloeosporioides.

Although much progress has been made in developing botanical fungicides to combat fungal diseases in crops, there remains a great need to improve the efficiency and long-term safety of these fungicides. This study proposes a novel strategy for designing citral-thiourea derivatives that feature such desirable properties. The motivation of the work herein was to enhance the antifungal activity of citral against C. gloeosprioides by exploiting the synergistic effect that arises from combining citral and thiourea compounds, thereby producing citral-thiourea derivatives that exhibit good long-term safety. The results revealed that the generated compounds e1, e3, e6, e18, and g showed remarkable antifungal activities against C. gloeosprioides, with corresponding EC50 values reaching 0.16, 1.66, 1.37, 4.76, and 4.60 mg/L, respectively, showing that the compounds significantly outperformed both the positive control kresoxim-methyl and the commercially available fungicide carbendazim. Furthermore, compound g showed stronger protective efficacy against C. gloeosprioides than carbendazim on mango fruit at 25 mg/L. Investigating the preliminary structure-activity relationship (SAR) of the compounds also revealed that the citral-thiourea derivatives exhibited higher antifungal activities against C. gloeosprioides compared to citral and thiourea compounds. This reinforcement of antifungal activity observed in the derivatives was found to be attributable to the two characteristics of low molecular size and the presence of a fluorine atom in the meta-position of the benzene ring. Beyond this, it was determined from QSAR that two molecular descriptors (the Kier-Hall index (order 3) and Tot dipole of the molecules) were negatively related to the antifungal activity of the citral-thiourea derivatives, while one other (the maximum resonance energy of a C-H bond) was positively related to their antifungal activity. More importantly, the citral-thiourea derivatives with high antifungal activities (i.e., compounds e1, e3, e6, e14, e15, e18, and g) exhibited negligible cytotoxicity to LO2 and HEK293T cell lines. The antifungal mechanism of the generated citral-thiourea derivatives was investigated by scanning electron microscopy (SEM) and relative conductivity. The derivatives were found to affect mycelial morphology and increase fungal cell membrane permeability, thereby resulting in the destruction of fungal cell membranes. These promising results provide novel insights into the study and potential application value of citral-thiourea derivatives as high-efficiency antifungal agents against C. gloeosprioides.

Synthesis, Antifungal Activity, Cytotoxicity and QSAR Study of Camphor Derivatives.

Control of fungal phytopathogens affecting crops and woodlands is an important goal in environmental management and the maintenance of food security. This work describes the synthesis of 37 camphor derivatives, of which 27 were new compounds. Their antifungal effects on six fungi were evaluated in vitro. Compounds 3a, 4a and 5k showed strong antifungal activity against Trametes versicolor, with EC50 values of 0.43, 6.80 and 4.86 mg/L, respectively, which were better than that of tricyclazole (EC50 118.20 mg/L) and close to or better than that of carbendazim (EC50 1.20 mg/L). The most potent compound, 3a, exhibited broad-spectrum antifungal activity towards six fungi with EC50 values within the range of 0.43-40.18 mg/L. Scanning electron microscopy demonstrated that compounds 3a, 4a and 5k gave irregular growth and shriveling of the mycelia. In vitro cytotoxicity evaluation revealed that the tested camphor derivatives had mild or no cytotoxicity for LO2 and HEK293T cell lines. Quantitative structure-activity relationship (QSAR) analysis revealed that the number of F atoms, relative molecular weight, the atomic orbital electronic population and total charge on the positively charged surfaces of the molecules of camphor derivatives have effects on antifungal activity. The present study may provide a theoretical basis for a high-value use of camphor and could be helpful for the development of novel potential antifungals.

Novel Citral-thiazolyl Hydrazine Derivatives as Promising Antifungal Agents against Phytopathogenic Fungi.

To develop new antifungal agents against phytopathogenic fungi, a series of citral-thiazolyl hydrazine derivatives were designed, synthesized, and characterized by FT-IR, 1H NMR, 13C NMR, and HRMS. Antifungal activity results showed that most synthetic compounds exhibited broad-spectrum antifungal activities against six phytopathogenic fungi in vitro. Notably, compounds b and c15 exhibited remarkable antifungal activity against Colletotrichum gloeosprioides, Rhizoctonia solani, Phytophthora nicotianae var. nicotianae, Diplodia pinea, Colletotrichum acutatum, and Fusarium oxysporum f. sp. niveum, which were all superior to the positive control tricyclazole. Structure-activity relationship (SAR) studies demonstrated that introducing electron-withdrawing groups such as F on the benzene ring exhibited outstanding antifungal activities against all the tested fungi. Furthermore, compound b could effectively control rice sheath blight and showed higher curative activities against R. solani than validamycin·bacillus in vivo. In addition, the in vitro cytotoxicity results indicated that compound b possessed moderate cytotoxicity activity, and all citral-thiazolyl hydrazine derivatives exhibited lower or no cytotoxicity to the LO2 and HEK293 cell lines. In addition, the acute oral toxicity test showed that compound b had moderate toxicity (level II) with an LD50 value of 310 mg/kg bw (95% confidence limit: 175-550 mg/kg bw). Finally, a preliminary action mechanism study showed that causing obvious malformation of mycelium and increasing cell membrane permeability are two of the potential mechanisms by which compound b exerts antifungal activity. The present work indicates that some of these derivatives may serve as novel potential fungicides, and compound b is expected to be the leading structure for the development of new antifungal agents.

Turpentine Derived Secondary Amines for Sustainable Crop Protection: Synthesis, Activity Evaluation and QSAR Study.

In this study, we will report on the synthesis and application of efficient botanical agrochemicals from turpentine for sustainable crop protection. Two series of turpentine derived secondary amines were synthesized and identified by FT-IR, 1H NMR, 13C NMR, and HRMS. The herbicidal activities against Echinochloa crus-galli were evaluated. The potential toxicity of the synthesized compounds was tested by MTT cytotoxicity analysis. The effect of structure of the synthesized secondary amines and corresponding Schiff base compounds on their activities was investigated by quantitative structure-activity relationship (QSAR) study. All target products were found to be low toxicity, with similar or higher herbicidal activities than commercial herbicides diuron and Glyphosate. Results of QSAR study showed that a best four-descriptor QSAR model with R2 of 0.880 and Rloo2 of 0.818 was obtained. The four descriptors most relevant to the herbicidal activities are the min valency of a N atom, the max total interaction for a C-H bond, the relative number of aromatic bonds, and the min partial charge (Qmin).

Synthesis of ordered lamellar supermicroporous silica with rigid neutral and long-chain cationic composite templating route.

Using a mixture of neutral primary amine dehydroabietylamine (DHAA) and long-chain cetyltrimethyl ammonium bromide (CTAB) as the template, ordered lamellar supermicroporous silicas were synthesized with NaOH as the base source and tetraethylorthosilicate (TEOS) as the silica source. The concentrations of DHAA, CTAB, and NaOH in the synthesis system had great effects on the structural properties of the samples. When the molar ratio of components was nTEOS:nCTAB:nDHAA:nNaOH:nH2O = 1:0.114:0.00457:0.5:60, the material showed a lamellar phase with the highest ordering degree. By adding only a trace amount of DHAA into the synthesis system, the structure of the samples could be transformed from cubic phase to lamellar phase, since the added DHAA solubilized in CTAB micelles to change the effective surfactant ion pair packing parameter. The dosage of CTAB should be moderate; too high or too low will decay the ordering degree of the lamellar structure.A much higher concentration of NaOH resulted in an ethanol-rich solvent in which the DHAA did not solubilize in the micelles of CTAB, but adsorbed at the hydrophilic headgroup-solvent interface. Accordingly, a structural transformation from lamellar phase to hexagonal phase occurred.