T6SS nuclease effectors in Pseudomonas syringae act as potent antimicrobials in interbacterial competition.

Type VI secretion system (T6SS) is a potent weapon employed by various Pseudomonas species to compete with neighboring microorganisms for limited nutrients and ecological niches. However, the involvement of T6SS effectors in interbacterial competition within the phytopathogen Pseudomonas syringae remains unknown. In this study, we examined two T6SS clusters in a wild-type P. syringae MB03 and verified the involvement of one cluster, namely, T6SS-1, in interbacterial competition. Additionally, our results showed that two T6SS DNase effectors, specifically Tde1 and Tde4, effectively outcompeted antagonistic bacteria, with Tde4 playing a prominent role. Furthermore, we found several cognate immunity proteins, including Tde1ia, Tde1ib, and Tde4i, which are located in the downstream loci of their corresponding effector protein genes and worked synergistically to protect MB03 cells from self-intoxication. Moreover, expression of either Tde1 or C-terminus of Tde4 in Escherichia coli cells induced DNA degradation and changes in cell morphology. Thus, our results provide new insights into the role of the T6SS effectors of P. syringae in the interbacterial competition in the natural environment. IMPORTANCE: The phytopathogen Pseudomonas syringae employs an active type VI secretion system (T6SS) to outcompete other microorganisms in the natural environment, particularly during the epiphytic growth in the phyllosphere. By examining two T6SS clusters in P. syringae MB03, T6SS-1 is found to be effective in killing Escherichia coli cells. We highlight the excellent antibacterial effect of two T6SS DNase effectors, namely, Tde1 and Tde4. Both of them function as nuclease effectors, leading to DNA degradation and cell filamentation in prey cells, ultimately resulting in cell death. Our findings deepen our understanding of the T6SS effector repertoires used in P. syringae and will facilitate the development of effective antibacterial strategies.

Pseudoamaolide P, a 1,2:3,4:9,10:9,19-tetraseco-cycloartane triterpene spiroketal lactone from seeds of Pseudolarix amabilis.

A 1,2:3,4:9,10:9,19-tetraseco-cycloartane triterpene spiroketal lactone, pseudoamaolide P (1), two new labdane-type diterpenoids, pseudoamains A and B (2-3), and four known cembrane-type diterpenoids (4-7) were isolated from the seeds of Pseudolarix amabilis. The structures of these compounds were elucidated by spectroscopic analyses, including HRESIMS, 1D-, and 2D-NMR. The anti-inflammatory activities of the compounds were evaluated by suppressing the transcription of the NF-κB-dependent reporter gene in LPS-induced 293 T/NF-κB-luc cells. All compounds do not show potent activity.

Silver Nanoparticles Encapped by Dihydromyricetin: Optimization of Green Synthesis, Characterization, Toxicity, and Anti-MRSA Infection Activities for Zebrafish (Danio rerio).

To achieve the environmentally friendly and rapid green synthesis of efficient and stable AgNPs for drug-resistant bacterial infection, this study optimized the green synthesis process of silver nanoparticles (AgNPs) using Dihydromyricetin (DMY). Then, we assessed the impact of AgNPs on zebrafish embryo development, as well as their therapeutic efficacy on zebrafish infected with Methicillin-resistant Staphylococcus aureus (MRSA). Transmission electron microscopy (TEM) and dynamic light-scattering (DLS) analyses revealed that AgNPs possessed an average size of 23.6 nm, a polymer dispersity index (PDI) of 0.197 ± 0.0196, and a zeta potential of -18.1 ± 1.18 mV. Compared to other published green synthesis products, the optimized DMY-AgNPs exhibited smaller sizes, narrower size distributions, and enhanced stability. Furthermore, the minimum concentration of DMY-AgNPs required to affect zebrafish hatching and survival was determined to be 25.0 µg/mL, indicating the low toxicity of DMY-AgNPs. Following a 5-day feeding regimen with DMY-AgNP-containing food, significant improvements were observed in the recovery of the gills, intestines, and livers in MRSA-infected zebrafish. These results suggested that optimized DMY-AgNPs hold promise for application in aquacultures and offer potential for further clinical use against drug-resistant bacteria.

[Research progress on active ingredients of Coicis Semen].

As a common medicinal and edible resource in China, Coicis Semen has a long history of cultivation and medicinal use. Traditional Chinese medicine(TCM) clinically believes that Coicis Semen has the effect of strengthening the spleen and tonifying the lungs, clearing heat and dampness, removing pus and paralysis, and stopping diarrhea. Therefore, it is used to treat edema, foot odor, spleen deficiency, diarrhea, and other symptoms. The above effects are closely related to the active ingredients of Coicis Semen, such as esters, fatty acids, polysaccharides, proteins, as well as phenolic acids, sterols, flavonoids, lactams, triterpenes, alkaloids, and adenosine. Modern research has found that Coicis Semen also has anti-cancer, anti-inflammatory, antioxidant, hypoglycemic, and hypotensive effects and other pharmacological activities, and it can improve immunity and regulate lipid metabolism. Coicis Semen is widely distributed in China, mainly produced in Guizhou, Yunnan, Fujian, Sichuan, and other places, and the quality of Coicis Semen from different origins varies. From ancient times to the present, Coicis Semen processing methods have experienced the process from simple to complex, and the types of auxiliary materials are more extensive, such as soil, bran, and river sand. These processing methods have been inherited from generation to generation. Nowadays, the commonly used methods are bran-fried, stir-fried, sand-fried, etc. In this paper, by reviewing the relevant literature in China and abroad in recent years, the main active ingredients and related pharmacological effects of Coicis Semen are sorted out, and the effects of different origins and processing methods on the chemical composition of Coicis Semen are summarized, with a view to providing references for the comprehensive development and utilization of Coicis Semen and the further study of its mechanism of action.

Two-dimensional Janus pentagonal MSeTe (M = Ni, Pd, Pt): promising water-splitting photocatalysts and optoelectronic materials.

Inspired by the interesting and novel properties exhibited by Janus transition metal dichalcogenides (TMDs) and two-dimensional pentagonal structures, we here investigated the structural stability, mechanical, electronic, photocatalytic, and optical properties for a class of two-dimensional (2D) pentagonal Janus TMDs, namely penta-MSeTe (M = Ni, Pd, Pt) monolayers, by using density functional theory (DFT) combined with Hubbard's correction (U). Our results showed that these monolayers exhibit good structural stability, appropriate band structures for photocatalysts, high visible light absorption, and good photocatalytic applicability. The calculated electronic properties reveal that the penta-MSeTe are semiconductors with a bandgap range of 2.06-2.39 eV, and their band edge positions meet the requirements for water-splitting photocatalysts in various environments (pH = 0-13). We used stress engineering to seek higher solar-to-hydrogen (STH) efficiency in acidic (pH = 0), neutral (pH = 7) and alkaline (pH = 13) environments for penta-MSeTe from 0% to +8% biaxial and uniaxial strains. Our results showed that penta-PdSeTe stretched 8% along the y direction and demonstrates an STH efficiency of up to 29.71% when pH = 0, which breaks the theoretical limit of the conventional photocatalytic model. We also calculated the optical properties and found that they exhibit high absorption (13.11%) in the visible light range and possess a diverse range of hyperbolic regions. Hence, it is anticipated that penta-MSeTe materials hold great promise for applications in photocatalytic water splitting and optoelectronic devices.

Watching Food Videos Leads to Postparotidectomy Salivary Fistula.

Salivary fistula is a common postparotidectomy complication, and eating sour or spicy food ranks among the leading causes. Here we report a rare postparotidectomy salivary fistula case, a 31-year-old female patient who affirmed that she did not eat any irritating foods but admitted that she had been watching food videos for up to 4 hours every day since she left hospital. This case offers a cautionary tale about postparotidectomy precautions.

Research Progress on the Preparation and Function of Antioxidant Peptides from Walnuts.

Food-derived peptides have good antioxidant activity and are highly safe for humans; consequently, there has been continuous growth in research on antioxidants, with potential applications in food, medicine, cosmetics, and other fields. Among food-derived peptides, walnut-derived peptides have attracted increasing attention as food-derived peptides rich in eight essential amino acids. This review summarizes the progress made in the development and identification of antioxidant peptides in walnut proteins. This article mainly describes the interaction between reactive oxygen species and cellular antioxidant products, modulation of enzyme content and activity, and regulation of the redox signaling pathways and analyzes the mechanisms of reduction in oxidative stress. Finally, the complex structure-activity relationships of walnut-derived peptides are analyzed based on their amino acid composition and secondary structure of the polypeptides. This review provides a theoretical basis for the production of walnut-derived antioxidant peptides and could help promote the development of the walnut industry.

[Diterpenoid constituents in Pseudolarix amabilis and their antitumor activities in vitro].

By various chromatographic techniques and extensive spectroscopic methods, 17 abietane diterpenoids were isolated from the dichloromethane fraction of the 95% ethanol cold-soak extracts of the seeds of Pseudolarix amabilis, namely pseudoamaol A(1), 12α-hydroxyabietic acid(2), 12-methoxy-7,13-abietadien-18-oic acid(3), 13-hydroxy-8,11,13-podocarpatrien-18-oic acid(4), 15-hydroxy-7,13-abietadien-12-on-18-oic acid(5), 8(14)-podocarpen-13-on-18-oic acid(6), holophyllin K(7), metaglyptin B(8), 7α-hydroxydehydroabietinsaure-methylester(9), 7-oxodehydroabietic acid(10), 15-hydroxy-7-oxodehydroabietinsaure-methy-lester(11), 15-methoxydidehydroabietic acid(12), 7-oxo-15-hydroxy-dehydroabietic acid(13), 15-hydroxydehydroabietic acid(14), 8,11,13-abietatriene-15,18-diol(15), 8,11,13-abietatriene-15-hydroxy-18-succinic acid(16), and 7ß-hydroxydehydroabie-tic acid(17). Compound 1 was a new compound. The isolated compounds were evaluated for their antitumor activities(HepG2, SH-SY5Y, K562), and compounds 8 and 17 showed potential cytotoxic activity against K562 cells, with IC_(50) values of 26.77 and 37.35 µmol·L~(-1), respectively.

RsmA3 modulates RpoS through the RetS-Gac-Rsm signalling pathway in response to H2 O2 stress in the phytopathogen Pseudomonas syringae.

Reactive oxygen species are a fatal challenge to the plant pathogenic bacterium Pseudomonas syringae. In this study, we reveal that the global regulatory protein RsmA3 from the RetS-Gac/Rsm signalling pathway modulates RpoS in the early-log growth phase in the P. syringae wild-type strain MB03, thereby regulating oxidative tolerance to H2 O2 and ultimately affecting pathogenicity to the host plant. Following increased H2 O2 by external addition or endogenous induction by menadione, the resistance of the mutant strain ΔretS to H2 O2 is significantly enhanced due to rapid increases in the transcription of Rsm-related non-coding small RNAs (nc sRNAs), a sigma factor RpoS, and H2 O2 -detoxifying enzymes. Moreover, the ΔretS mutant is significantly less pathogenic in cucumber leaves. Seven Rsm-related nc sRNAs (namely, rsmZ, rsmY and rsmX1-5 ) show functional redundancy in the RetS-Gac-Rsm signalling pathway. External addition of H2 O2 stimulates increases in the transcription of both rsmY and rsmZ. Thus, we propose a regulatory model of the RetS-Gac-Rsm signalling pathway in P. syringae MB03 for the regulation of H2 O2 tolerance and phytopathogenicity in the host plant.

Estimating leaf area index using unmanned aerial vehicle data: shallow vs. deep machine learning algorithms.

Measuring leaf area index (LAI) is essential for evaluating crop growth and estimating yield, thereby facilitating high-throughput phenotyping of maize (Zea mays). LAI estimation models use multi-source data from unmanned aerial vehicles (UAVs), but using multimodal data to estimate maize LAI, and the effect of tassels and soil background, remain understudied. Our research aims to (1) determine how multimodal data contribute to LAI and propose a framework for estimating LAI based on remote-sensing data, (2) evaluate the robustness and adaptability of an LAI estimation model that uses multimodal data fusion and deep neural networks (DNNs) in single- and whole growth stages, and (3) explore how soil background and maize tasseling affect LAI estimation. To construct multimodal datasets, our UAV collected red-green-blue, multispectral, and thermal infrared images. We then developed partial least square regression (PLSR), support vector regression, and random forest regression models to estimate LAI. We also developed a deep learning model with three hidden layers. This multimodal data structure accurately estimated maize LAI. The DNN model provided the best estimate (coefficient of determination [R2] = 0.89, relative root mean square error [rRMSE] = 12.92%) for a single growth period, and the PLSR model provided the best estimate (R2 = 0.70, rRMSE = 12.78%) for a whole growth period. Tassels reduced the accuracy of LAI estimation, but the soil background provided additional image feature information, improving accuracy. These results indicate that multimodal data fusion using low-cost UAVs and DNNs can accurately and reliably estimate LAI for crops, which is valuable for high-throughput phenotyping and high-spatial precision farmland management.

[Mechanism of Euodiae Fructus stir-fried with water decoction of Coptidis Rhizoma in treatment of chronic colitis based on UPLC-Q-TOF-MS, network pharmacology and experimental verification].

To elucidate the mechanism of Euodiae Fructus stir-fried with water decoction of Coptidis Rhizoma in the treatment of chronic colitis, this study employed ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS), network pharmacology, and experimental verification to predict the involved targets and signaling pathways. The chronic colitis mouse model was constructed to verify the core targets. A total of 48 compounds in the herbal medicine were identified by UPLC-Q-TOF-MS. SwissTargetPrediction was used to screen the potential active components and drug targets. GeneCards, OMIM, PharmGKB, and TDD were used to search for the disease targets. A total of 31 active ingredients, 453 targets of the herbal medicine, and 3 960 targets of chronic colitis were obtained. The common targets shared by the herbal medicine and chronic colitis were introduced into STRING to construct the protein-protein interaction(PPI) network, and CytoNCA plug-in was used to screen the key targets. A total of 90 key targets were obtained, and the key active components included isorhamnetin, quercetin, limonin, and oxyberberine. GO annotation and KEGG pathway enrichment for the key targets were carried out via DAVID. The targets were mainly involved in the positive regulation of protein phosphorylation, positive regulation of nitric oxide biosynthetic process, and negative regulation of apoptotic process. The medicine may treat chronic colitis through PI3 K-Akt, VEGF, HIF-1, and TNF signaling pathways. A mouse model of chronic colitis was established and then treated with Euodiae Fructus stir-fried with the water decoction of Coptidis Rhizoma. The experimental results demonstrated that the medicine can alleviate the pathological damage of colon, significantly reduce the levels of IL-1ß, IL-6, and TNF-α, inhibit the activation of PI3 K/Akt pathway, and down-regulate the expression of VEGFA in the treatment of chronic colitis.

Nematicidal effects of 2-methyl-aconitate isomerase from the phytopathogen Pseudomonas syringae MB03 on the model nematode Caenorhabditis elegans.

The pathogenicity of a common phytopathogenic bacterium, Pseudomonas syringae, against animal model hosts, such as mice and Caenorhabditis elegans, has been recently revealed. However, most of the virulence determinants associated with pathogenesis remain elusive. In the current study, we performed predictive analysis of virulence factors against C. elegans in the genome of the wild-type P. syringae strain MB03. Nine predicted nematicidal proteins were expressed and purified in recombinant Escherichia coli strains and were evaluated to define their toxicity against C. elegans in liquid killing assays. Next, we focused on one essential 2-methyl citrate cycle protein, PrpF03, which showed the highest lethal activity against C. elegans compared to the other tested proteins with a half lethal concentration (LC50) of 155.3 (123.4-176.6) µg mL-1 and a half lethal time (LT50) of 3.72 (1.64-4.85) days. Purified PrpF03 also caused adverse effects on the brood size, growth, and motility of C. elegans. Moreover, the PrpF03 protein exhibited pathological activity towards the intestinal tract of C. elegans. We surmise that the PrpF03 protein functions as a virulence factor when it blocks the average circulation of the 2-methyl citrate cycle of C. elegans by accumulating 2-methyl citrate in the gut of C. elegans, which damages and restrains the growth of intestinal tissues that ultimately kill C. elegans. The discovery of specific nematicidal activities of PrpF03 provides a better understanding of the mechanisms of phytopathogenic P. syringae against nematodes and could aid in developing nematode pest-controlling agents in agriculture.

Metabolic profiles of oligosaccharides derived from four microbial polysaccharides by faecal inocula from type 2 diabetes patients.

In vitro digestion of curdlan oligosaccharides (COSs), pullulan oligosaccharides (POSs), xanthan gum oligosaccharides (XGOSs) and gellan gum oligosaccharides (GGOSs) was investigated. These four oligosaccharides showed resistance to simulated saliva and gastric and small intestinal fluid. In further fermentation with faecal microbiota from healthy subjects and type 2 diabetes (T2D) patients, COS fermentation significantly increased the abundance of Bifidobacterium spp. and Lactobacillus spp. and the production of short-chain fatty acids in healthy and T2D groups. Digestion of XGOS enhanced the growth of the Clostridium leptum subgroup and significantly increased butyric acid production in healthy and T2D groups. Sole fermentation with COS, POS, XGOS and GGOS exhibited different metabolic profiles between healthy and T2D groups, and more small molecule polyols were produced in the T2D group than in the healthy group. This study provides a novel perspective on the reconstruction of gut microbiota and metabolism by POS, COS, GGOS and XGOS intervention.

[Chemical constituents of Physalis minima].

Fifteen compounds(1-15) were isolated from the 95% EtOH extract of the whole herb of Physalis minima by various chromatography techniques including silica gel, Sephadex LH-20, middle chromatogram isolated gel(MCI), octadecyl silica(ODS), and semi-preparative high performance liquid chromatography(HPLC). Their structures were elucidated by infrared spectroscopy(IR), ultraviolet spectroscopy(UV), high-resolution electrospray ionization mass spectrometry(HR-ESI-MS), nuclear magnetic re-sonance(NMR), and circular dichroism(CD) as(5S)-5,11-dihydroxy-3-methyl-5-pentylfuran-2(5H)-one(1), withaphysalin R(2), withaphysalin Q(3), withaphysanolide A(4), phaseic acid(5), grasshopper ketone(6), 3S,5R-dihydroxy-6S,7-megastigmadien-9-one(7), vanillic acid(8), 2-trans,4-trans-abscisic acid(9), capillasterolide(10), 5,3'-dihydroxy-3,7,4'-trimethoxyflavone(11),(-)-loliolide(12), 4-hydroxyacetophenone(13), acetosyringone(14), and aurantiamide acetate(15). Compound 1 was a new butenolide, and compounds 5-7 and 10-12 were isolated from the Physalis for the first time. Compounds 4, 13, and 15 were isolated for the first time from P. minima. Moreover, their anti-inflammatory activity was evaluated in vitro. Compound 12 was found to possess an inhibitory effect on the transcription of an NF-κB-dependent reporter gene in LPS-induced 293 T/NF-κB-luc cells at 10 µmol·L~(-1), showing an inhibitory rate of 62.31%±4.8%.

High-consistency fiber-optic Fabry-Perot sensor based on MEMS for simultaneous temperature and liquid refractive index measurement.

We proposed a hybrid Fabry-Perot fiber-optic sensor based on the microelectromechanical system (MEMS) technique for measuring temperature and liquid refractive index simultaneously, and we verify the consistency of four sensors in the same batch. The sensor consists of a groove-array structured glass wafer and two silicon wafers, which are connected by double-sided anodic bonding. The three parts form two independent Fabry-Perot cavities for temperature and liquid refractive index sensing, respectively. We randomly selected three sensors in the same batch and conducted temperature and refractive index experiments to establish the sensing equation. The experimental results demonstrate their high consistency with temperature sensitivities of 81.6, 81.8, and 81.4 pm/°C in the range of 10°C to 80°C, and refractive index sensitivities of 1040.11, 1044.24, 1042.91 nm/RIU in the range of 1.333-1.374. The sensors have low cross-sensitivities that are less than 5.86×10-6 RIU/°C and high precisions of 0.047°C, 2.14×10-6RIU, respectively. To verify the validity of the sensing equation, we made another sensor in the same batch and got maximum errors of 0.36°C and 7.7×10-5RIU, respectively.

A novel multiplex fluorescent competitive PCR for copy number variation detection.

The copy number variation (CNV) is an important genetic marker in cancer and other diseases. To detect CNVs of specific genetic loci, the multiplex ligation-dependent probe amplification (MLPA) is an appropriate approach, but the experimental optimization and probe synthesis are still great challenges. The multiplex competitive PCR is an alternative method for CNV detection. However, the construction of internal competitive template and establishment of a stable multiplex PCR system are the main limiting factors for this method. Here, we introduce a novel multiplex fluorescent competitive PCR (NMFC-PCR) for detecting CNVs. In this method, the blunt hairpin primers are used to rapidly establish a stable multiplex PCR system due to the reduction of non-specific amplification, and limited cycles' amplification is used to obtain the internal competitive template instead of artificial synthesis. With this method, we tested 21 clinical samples with potential LIM homeobox 1 (LHX1) or T-box 6 (TBX6) deletion. Every three segments located on the LHX1 and TBX6 were selected as the target regions, while two segments located on X-chromosome and five segments located on autosome were selected as the reference regions for detecting CNVs. The results showed that the gender information of 21 samples can be accurately inferred by the copy number ratio (CNR) of X-chromosomal reference region to autosomal reference region (X/A), and 2 samples had one copy of LHX1 and 9 samples had one copy of TBX6. To evaluate the accuracy of NMFC-PCR, 5 random samples with CNV were also detected by array-based comparative genomic hybridization (aCGH), and the results of aCGH were consistent with the NMFC-PCR results. To further assess the performance of NMFC-PCR, 60 normal samples were simultaneously tested. The results showed that the gender results were exactly the same as known information, and CNVs of LHX1 or TBX6 were not found. In conclusion, the method is a cheap, efficient, accurate, and convenient competitive PCR method for CNV detection.

Pyoverdine-Mediated Killing of Caenorhabditis elegans by Pseudomonas syringae MB03 and the Role of Iron in Its Pathogenicity.

The pathogenicity of the common phytopathogenic bacterium Pseudomonas syringae toward Caenorhabditis elegans has been recently demonstrated. However, the major virulence factors involved in this interaction remain unknown. In this study, we investigated the nematocidal activity of P. syringae against C. elegans under iron-sufficient/limited conditions, primarily focusing on the role of the ferric chelator pyoverdine in a P. syringae-C. elegans liquid-based pathogenicity model. Prediction-based analysis of pyoverdine-encoding genes in the genome of the wild-type P. syringae strain MB03 revealed that the genes are located in one large cluster. Two non-ribosomal peptide synthetase genes (pvdD and pvdJ) were disrupted via a Rec/TE recombination system, resulting in mutant strains with abrogated pyoverdine production and attenuated virulence against C. elegans. When used alone, pure pyoverdine also showed nematocidal activity. The role of iron used alone or with pyoverdine was further investigated in mutant and MB03-based bioassays. The results indicated that pyoverdine in P. syringae MB03 is a robust virulence factor that promotes the killing of C. elegans. We speculate that pyoverdine functions as a virulence determinant by capturing environmentally available iron for host bacterial cells, by limiting its availability for C. elegans worms, and by regulating and/or activating other intracellular virulence factors that ultimately kills C. elegans worms.

Cationic Pillar[6]arene Induces Cell Apoptosis by Inhibiting Protein Tyrosine Phosphorylation Via Host-Guest Recognition.

We reported for the first time that cationic pillar[6]arene (cPA6) could tightly bind to peptide polymer (MW~20-50 kDa), an artificial substrate for tyrosine (Tyr) phosphorylation, and efficiently inhibit Tyr protein phosphorylation through host-guest recognition. We synthesized a nanocomposite of black phosphorus nanosheets loaded with cPA6 (BPNS@cPA6) to explore the effect of cPA6 on cells. BPNS@cPA6 was able to enter HepG2 cells, induced apoptosis, and inhibited cell proliferation by reducing the level of Tyr phosphorylation. Furthermore, BPNS@cPA6 showed a stronger ability of inhibiting cell proliferation in tumor cells than in normal cells. Our results revealed the supramolecular modulation of enzymatic Tyr phosphorylation by the host-guest recognition of cPA6.

A new ascorbic acid derivative and two new terpenoids from the leaves and twigs of Rhododendron decorum.

The phytochemical study of the ethanol extract of the leaves and twigs of Rhododendron decorum afforded a new ascorbic acid derivative (1), a new ionone analogue (2), a new ursane-type triterpenoid glucoside (3), and four known compounds (4-7). The structures were elucidated by spectroscopic analyses, including HRESIMS, 1D, and 2D NMR. The anti-neuroinflammatory activities of the compounds were evaluated by measuring inhibitory effects of LPS-induced NO production in BV2 cells.

Antinociceptive Diterpenoids from the Leaves and Twigs of Rhododendron decorum.

Three new leucothane-type (1-3), two new micrathane-type (4, 5), eight new grayanane-type diterpenoids (6-13), and four known compounds were obtained from the ethanol extract of the leaves and twigs of Rhododendron decorum. The structures were determined based on NMR spectra, quantum chemical calculations, and X-ray crystallography. The antinociceptive activities of compounds 1, 3, 4, 6, 8, 10-13, and 15-17 were evaluated via the acetic acid-induced writhing test. Compounds 1, 8, 11-13, and 15 exhibited significant antinociceptive activities. In particular, 12 and 15 were found to be effective at doses of 0.8 and 0.08 mg/kg, respectively.