Inhibition of Soluble Epoxide Hydrolase by Cembranoid Diterpenes from Soft Coral Sinularia maxima: Enzyme Kinetics, Molecular Docking, and Molecular Dynamics.

Soluble epoxide hydrolase (sEH) is essential for converting epoxy fatty acids, such as epoxyeicosatrienoic acids (EETs), into their dihydroxy forms. EETs play a crucial role in regulating blood pressure, mediating anti-inflammatory responses, and modulating pain, making sEH a key target for therapeutic interventions. Current research is increasingly focused on identifying sEH inhibitors from natural sources, particularly marine environments, which are rich in bioactive compounds due to their unique metabolic adaptations. In this study, the sEH inhibitory activities of ten cembranoid diterpenes (1-10) isolated from the soft coral Sinularia maxima were evaluated. Among them, compounds 3 and 9 exhibited considerable sEH inhibition, with IC50 values of 70.68 µM and 78.83 µM, respectively. Enzyme kinetics analysis revealed that these two active compounds inhibit sEH through a non-competitive mode. Additionally, in silico approaches, including molecular docking and molecular dynamics simulations, confirmed their stability and interactions with sEH, highlighting their potential as natural therapeutic agents for managing cardiovascular and inflammatory diseases.

Ectopic expression of GmHP08 enhances resistance of transgenic Arabidopsis toward drought stress.

KEY MESSAGE: Ectopic expression of Glycine max two-component system member GmHP08 in Arabidopsis enhanced drought tolerance of transgenic plants, possibly via ABA-dependent pathways. Phosphorelay by two-component system (TCS) is a signal transduction mechanism which has been evolutionarily conserved in both prokaryotic and eukaryotic organisms. Previous studies have provided lines of evidence on the involvement of TCS genes in plant perception and responses to environmental stimuli. In this research, drought-associated functions of GmHP08, a TCS member from soybean (Glycine max L.), were investigated via its ectopic expression in Arabidopsis system. Results from the drought survival assay showed that GmHP08-transgenic plants exhibited higher survival rates compared with their wild-type (WT) counterparts, indicating better drought resistance of the former group. Analyses revealed that the transgenic plants outperformed the WT in various regards, i.e. capability of water retention, prevention of hydrogen peroxide accumulation and enhancement of antioxidant enzymatic activities under water-deficit conditions. Additionally, the expression of stress-marker genes, especially antioxidant enzyme-encoding genes, in the transgenic plants were found greater than that of the WT plants. In contrary, the expression of SAG13 gene, one of the senescence-associated genes, and of several abscisic acid (ABA)-related genes was repressed. Data from this study also revealed that the ectopic expression lines at germination and early seedling development stages were hypersensitive to exogenous ABA treatment. Taken together, our results demonstrated that GmHP08 could play an important role in mediating plant response to drought, possibly via an ABA-dependent manner.

The Drought-Mediated Soybean GmNAC085 Functions as a Positive Regulator of Plant Response to Salinity.

Abiotic stress factors, such as drought and salinity, are known to negatively affect plant growth and development. To cope with these adverse conditions, plants have utilized certain defense mechanisms involved in various aspects, including morphological, biochemical and molecular alterations. Particularly, a great deal of evidence for the biological importance of the plant-specific NAM, ATAF1/2, CUC2 (NAC) transcription factors (TFs) in plant adaptation to abiotic stress conditions has been reported. A previous in planta study conducted by our research group demonstrated that soybean (Glycine max) GmNAC085 mediated drought resistance in transgenic Arabidopsis plants. In this study, further characterization of GmNAC085 function in association with salt stress was performed. The findings revealed that under this condition, transgenic soybean plants overexpressing GmNAC085 displayed better germination rates than wild-type plants. In addition, biochemical and transcriptional analyses showed that the transgenic plants acquired a better defense system against salinity-induced oxidative stress, with higher activities of antioxidant enzymes responsible for scavenging hydrogen peroxide or superoxide radicals. Higher transcript levels of several key stress-responsive genes involved in the proline biosynthetic pathway, sodium ion transporter and accumulation of dehydrins were also observed, indicating better osmoprotection and more efficient ion regulation capacity in the transgenic lines. Taken together, these findings and our previous report indicate that GmNAC085 may play a role as a positive regulator in plant adaptation to drought and salinity conditions.

Protective Effects of Compounds from Cimicifuga dahurica against Amyloid Beta Production in Vitro and Scopolamine-Induced Memory Impairment in Vivo.

Cimicifuga dahurica has traditionally been used as an antipyretic, analgesic, and anti-inflammatory agent and as a treatment for uterine and anal prolapse. This study has investigated the potential beneficial effects of this medicinal plant and its components on Alzheimer's disease (AD) with a focus on amyloid beta (Aß) production and scopolamine-induced memory impairment in mice. An ethanol extract from C. dahurica roots decreased Aß production in APP-CHO cells [Chinese hamster ovarian (CHO) cells stably expressing amyloid precursor protein (APP)], as determined by an enzyme-linked immunosorbent assay and Western blot analysis. Then, the compounds isolated from C. dahurica were tested for their antiamyloidogenic activities. Four compounds (1-4) efficiently interrupted Aß generation by suppressing the level of ß-secretase in APP-CHO cells. Moreover, the in vivo experimental results demonstrated that compound 4 improved the cognitive performances of mice with scopolamine-induced disruption on behavioral tests and the expression of memory-related proteins. Taken together, these results suggest that C. dahurica and its constituents are potential agents for preventing or alleviating the symptoms of AD.

Dendrodoristerol, a cytotoxic C20 steroid from the Vietnamese nudibranch mollusk Dendrodoris fumata.

Using various chromatographic separations, four steroids including one new C20 steroid namely dendrodoristerol (1), were isolated from the Vietnamese nudibranch mollusk Dendrodoris fumata. The structure elucidation was confirmed by combination of spectroscopic experiments including 1D and 2D NMR, HR QTOF MS, and CD. Compound 1 was found to exhibit significant in vitro cytotoxic activity against six human cancer cell lines as HL-60, KB, LU-1, MCF-7, LNCaP, and HepG2. In addition, 1 induced HL-60 cancer cell death by apoptosis and necrosis.

Wedtrilosides A and B, two new diterpenoid glycosides from the leaves of Wedelia trilobata (L.) Hitchc. with α-amylase and α-glucosidase inhibitory activities.

In the ongoing research to find new diabetes constituents from the genus Wedelia, the chemical constituent of Wedelia trilobata leaves, a Vietnamese medicinal plant species used to treat type 2 diabetes mellitus, was selected for detailed investigation. From a methanolic extract, two new ent-kaurane diterpenoids, wedtrilosides A and B (1 and 2), along with five known metabolites (3-7), were isolated from W. trilobata. The chemical structures of (1-7) were assigned via spectroscopic techniques (IR, 1D, 2D NMR and HR-QTOF-MS data) and chemical methods. The isolates were evaluated for α-amylase and α-glucosidase inhibitory activities compared to the clinical drug acarbose. Among them, compounds 4, 6, and 7 showed the most potent against α-glucosidase enzyme with IC50 values of 27.54 ±â€¯1.12, 173.78 ±â€¯2.37, and 190.40 ±â€¯2.01 µg/mL. While moderate inhibitory effect against α-amylase was observed with compounds 6 and 7 (with IC50 = 181.97 ±â€¯2.62 and 52.08 ±â€¯0.56 µg/mL, respectively). The results suggested that the antidiabetic properties from the leaves of W. trilobata are not simply a result of each isolated compound, but are due to other factors such as the accessibility of polyphenolic groups to α-amylase and α-glucosidase activities.

The Soybean GmNAC019 Transcription Factor Mediates Drought Tolerance in Arabidopsis in an Abscisic Acid-Dependent Manner.

Being master regulators of gene expression, transcription factors (TFs) play important roles in determining plant growth, development and reproduction. To date, many TFs have been shown to positively mediate plant responses to environmental stresses. In the current study, the biological functions of a stress-responsive NAC [NAM (No Apical Meristem), ATAF1/2 (Arabidopsis Transcription Activation Factor1/2), CUC2 (Cup-shaped Cotyledon2)]-TF encoding gene isolated from soybean (GmNAC019) in relation to plant drought tolerance and abscisic acid (ABA) responses were investigated. By using a heterologous transgenic system, we revealed that transgenic Arabidopsis plants constitutively expressing the GmNAC019 gene exhibited higher survival rates in a soil-drying assay, which was associated with lower water loss rate in detached leaves, lower cellular hydrogen peroxide content and stronger antioxidant defense under water-stressed conditions. Additionally, the exogenous treatment of transgenic plants with ABA showed their hypersensitivity to this phytohormone, exhibiting lower rates of seed germination and green cotyledons. Taken together, these findings demonstrated that GmNAC019 functions as a positive regulator of ABA-mediated plant response to drought, and thus, it has potential utility for improving plant tolerance through molecular biotechnology.

The insight of in vitro and in silico studies on cholinesterase inhibitors from the roots of Cimicifuga dahurica (Turcz.) Maxim.

Cholinesterases (ChEs) are enzymes that break down neurotransmitters associated with cognitive function and memory. We isolated cinnamic acids (1 and 2), indolinones (3 and 4), and cycloartane triterpenoid derivatives (5-19) from the roots of Cimicifuga dahurica (Turcz.) Maxim. by chromatography. These compounds were evaluated for their inhibitory activity toward ChEs. Compound 1 was determined to have an IC50 value of 16.7 ± 1.9 µM, and to act as a competitive inhibitor of acetylcholinesterase (AChE). Compounds 3, 4 and 14 were found to be noncompetitive with IC50 values of 13.8 ± 1.5 and 6.5 ± 2.5 µM, and competitive with an IC50 value of 22.6 ± 0.4 µM, respectively, against butyrylcholinesterase (BuChE). Our molecular simulation suggested each key amino acid, Tyr337 of AChE and Asn228 of BuChE, which were corresponded with potential inhibitors 1, and 3 and 4, respectively. Compounds 1 and 4 were revealed to be promising compounds for inhibition of AChEs and BuChEs, respectively.

Soluble epoxide hydrolase inhibitors of indolinone alkaloids and phenolic derivatives from Cimicifuga dahurica (Turcz.) Maxim.

The aim of this study was to search for potential therapeutic agents by identifying novel inhibitors of soluble epoxide hydrolase (sEH) from natural plants using an in silico approach. We found that an ethanolic extract from the roots of Cimicifuga dahurica (Turcz.) Maxim. significantly inhibited sEH in vitro. In a phytochemical investigation using assay-guided fractionation of the dichloromethane extract of C. dahurica, we isolated two new indolinone alkaloids (5 and 6) and five related constituents (1-4, and 7) and established their structures based on an extensive analysis using 1D and 2D NMR, and MS methods. All of the isolated compounds inhibited sEH enzymatic activity in a dose-dependent manner, with IC50 values ranging from 0.8±0.0 to 2.8±0.4µM. A kinetic analysis of compounds 1-7 revealed that compound 2 was non-competitive; 1, 3, and 7 were mixed-type; and 4-6 were competitive inhibitors. Molecular docking was employed to further elucidate their receptor-ligand binding characteristics. These results demonstrated that compounds from C. dahurica are potential sEH inhibitors.

Inhibition Potential of Cycloartane-Type Glycosides from the Roots of Cimicifuga dahurica against Soluble Epoxide Hydrolase.

A phytochemical assay-guided fractionation of the 95% ethanol extract of Cimicifuga dahurica roots afforded 29 9,19-cycloartane triterpenoid glycosides, including the new cimiricasides A-F (1-6). The structures of 1-6 were established using contemporary NMR methods and from the HRESIMS data, and the sugar moiety in each case was confirmed by acid hydrolysis and subsequent GC/MS analysis. Compounds 2, 4, 5, 7-9, 18, 25, and 29 showed soluble epoxide hydrolase inhibitory effects with IC50 values of 0.4 ± 0.1 to 24.0 ± 0.2 µM. The compounds were analyzed by enzyme kinetic studies to explore the binding mode between the ligand and receptor. Compounds 4 (mixed type), 8, 18, and 29 (noncompetitive type) bound to a preferred allosteric site, while compounds 2, 5, 7, 9, and 25 had competitive interactions at the active site. The binding mechanism of selected inhibitors was investigated using molecular docking and dynamics simulations.

Transcription Factors and Their Roles in Signal Transduction in Plants under Abiotic Stresses.

In agricultural production, abiotic stresses are known as the main disturbance leading to negative impacts on crop performance. Research on elucidating plant defense mechanisms against the stresses at molecular level has been addressed for years in order to identify the major contributors in boosting the plant tolerance ability. From literature, numerous genes from different species, and from both functional and regulatory gene categories, have been suggested to be on the list of potential candidates for genetic engineering. Noticeably, enhancement of plant stress tolerance by manipulating expression of Transcription Factors (TFs) encoding genes has emerged as a popular approach since most of them are early stress-responsive genes and control the expression of a set of downstream target genes. Consequently, there is a higher chance to generate novel cultivars with better tolerance to either single or multiple stresses. Perhaps, the difficult task when deploying this approach is selecting appropriate gene(s) for manipulation. In this review, on the basis of the current findings from molecular and post-genomic studies, our interest is to highlight the current understanding of the roles of TFs in signal transduction and mediating plant responses towards abiotic stressors. Furthermore, interactions among TFs within the stress-responsive network will be discussed. The last section will be reserved for discussing the potential applications of TFs for stress tolerance improvement in plants.

Role of Ethylene and Its Cross Talk with Other Signaling Molecules in Plant Responses to Heavy Metal Stress.

Excessive heavy metals (HMs) in agricultural lands cause toxicities to plants, resulting in declines in crop productivity. Recent advances in ethylene biology research have established that ethylene is not only responsible for many important physiological activities in plants but also plays a pivotal role in HM stress tolerance. The manipulation of ethylene in plants to cope with HM stress through various approaches targeting either ethylene biosynthesis or the ethylene signaling pathway has brought promising outcomes. This review covers ethylene production and signal transduction in plant responses to HM stress, cross talk between ethylene and other signaling molecules under adverse HM stress conditions, and approaches to modify ethylene action to improve HM tolerance. From our current understanding about ethylene and its regulatory activities, it is believed that the optimization of endogenous ethylene levels in plants under HM stress would pave the way for developing transgenic crops with improved HM tolerance.

Identification of six new lupane-type triterpenoids from Acanthopanax koreanum leaves and their tyrosinase inhibitory activities.

Chemical investigation of Acanthopanax koreanum leaves resulted in the isolation of 13 compounds (1-13), including six new (20,29)-dehydrolupane-type triterpenoids: 3α,11α,30-trihydroxylup-20(29)-en-23,28-dioic acid (1), 3α,11α,30-trihydroxylup-20(29)-en-28-oic acid (2), 3α,11α,30-trihydroxylup-23-al-20(29)-en-28-oic acid (3), 3α, 11α-dihydroxy-20-oxo-30-norlupane-23,28-dioic acid (5), (20S)-3α-hydroxy-30 oxolupane-23,28-dioic acid (8), (20S)-3ß,7ß,29-trihydroxy-lupane-23-al-28-oic acid (10), and one novel compound isolated for the first time, named 3α,20α,29-trihydroxylupane-23,28-dioic acid (9), together with six known compounds (4, 6, 7, and 11-13). Chemical structures of the isolated compounds were evaluated by analyzing and comparing spectroscopic data with those reported in the literature. These compounds were also evaluated for their tyrosinase inhibitory effects. Among them, compounds 3, 7, 9, and 12 showed significant inhibitory effects, with inhibitory concentrations of 50% (IC50) values ranging from 8.61 to 63.5 µM.

Rat intestinal sucrase inhibited by minor constituents from the leaves and twigs of Archidendron clypearia (Jack.) Nielsen.

In the search for plants, containing compounds with α-glucosidase inhibitory activity, we found that a methanolic extract from the leaves and twigs of Archidendron clypearia (Jack.) Nielsen significantly inhibited rat intestinal sucrase in vitro. A phytochemical investigation of the aqueous layer of an A. clypearia extract led to the isolation of 14 compounds (1-14). Their structures were established through extensive 1D and 2D NMR, CD data, and MS analysis. The methanolic extract, as well as the water layer at a concentration of 3.0mg/mL, showed potent sucrase inhibitory activity, with 67.78±2.53% and 95.33±2.15% inhibition, respectively. In addition, compounds 6, 7, and 10 (1.0mM) showed potent sucrase inhibition (88.36±1.15%, 81.57±1.07%, and 66.32±4.73% inhibition, respectively), which was comparable to that of the positive control, acarbose, which exhibited 89.54±0.91% inhibition. Other compounds showed moderate or weak inhibitory activity at the same concentration. The sucrase inhibitory activity of the extracts and purified compounds may provide a novel opportunity to develop a new class of antidiabetic agents.

Identification, characterization, kinetics, and molecular docking of flavonoid constituents from Archidendron clypearia (Jack.) Nielsen leaves and twigs.

In our search for natural soluble epoxide hydrolase (sEH) inhibitors from plants, we found that the methanolic extract of the leaves and twigs of Archidendron clypearia (Jack.) Nielsen (Fabaceae) significantly inhibits sEH in vitro. In a phytochemical investigation of the water layer of A. clypearia, we isolated two new chalcones, clypesides A-B (1-2), 13 flavonoid derivatives (3-15) and established their structures based on an extensive 1D and 2D NMR, CD data, and MS analysis. All of the flavonoid derivatives inhibited sEH enzymatic activity in a dose-dependent manner, with IC50 values ranging from 10.0±0.4 to 30.1±2.1µM. A kinetic analysis of compounds 4, 8-10, 12, 13, and 15 revealed that the compounds 8-10 were non-competitive, 4, 13, and 15 were mixed-type, and 12 was competitive inhibitors. Additionally, molecular docking increased our understanding of their receptor-ligand binding. These results demonstrated that flavonoid derivatives from A. clypearia are potential sEH inhibitors.

Enhancement of Plant Productivity in the Post-Genomics Era.

Obtaining high plant yield is not always achievable in agricultural activity as it is determined by various factors, including cultivar quality, nutrient and water supplies, degree of infection by pathogens, natural calamities and soil conditions, which affect plant growth and development. More noticeably, sustainable plant productivity to provide sufficient food for the increasing human population has become a thorny issue to scientists in the era of unpredictable global climatic changes, appearance of more tremendous or multiple stresses, and land restriction for cultivation. Well-established agricultural management by agrotechnological means has shown no longer to be effective enough to confront with this challenge. Instead, in order to maximize the production, it is advisable to implement such practices in combination with biological applications. Nowadays, high technologies are widely adopted into agricultural production, biological diversity conservation and crop improvement. Wang et al. has nicely outlined the utilization of DNA-based technologies in this field. Among these are the applications of (i) DNA markers into cultivar identification, seed purity analysis, germplasm resource evaluation, heterosis prediction, genetic mapping, cloning and breeding; and (ii) gene expression data in supporting the description of crop phenology, the analytic comparison of crop growth under stress versus non-stress conditions, or the study of fertilizer effects. Besides, various purposes of using transgenic technologies in agriculture, such as generating cultivars with better product quality, better tolerance to biotic or abiotic stress, are also discussed in the review. One of the important highlights in this issue is the review of the benefits brought by high-throughput sequencing technology, which is also known as next-generation sequencing (NGS). It is not so difficult to recognize that its application has allowed us to carry out biological studies at much deeper level and larger scale. In their article, Onda and Mochida detailed how to use these technologies in fully characterizing the genetic diversity or multigenecity within a particular plant species. The authors discussed the constant innovation of sequencing platforms which has made sequencing technologies become more superior and more powerful than ever before. Additionally, the efforts result in not only further cut down of the sequencing cost and increase in the sequencing speed, but also improvement in sequencing accuracy and extended sequencing application to studies at both DNA and RNA levels. Such knowledge will help the scientists interpret, at least partially, how plants can adapt to various environmental conditions, or how different cultivars can respond differently to the same stress. Another article by Ong et al. also laid emphasis on the importance of various high-throughput sequencing platforms, thanks to which a large number of genomic databases supplied with detailed annotation and useful bioinformatics tools have been established to assist geneticists. Readers can find in this review the summary of available plant-specific genomic databases up-to-date and popular web-based resources that are relevant for comparative genomics, plant evolution and phylogenomics studies. These, along with other approaches, such as quantitative trait locus and genome-wide association study, will lay foundation for prediction and identification of genes or alleles responsible for valuable agronomic traits, contributing to the enhancement of plant productivity by genetic engineering approach. In this thematic issue, specific examples for crop improvement are also demonstrated. The first showcase is given by Nongpiur et al. who provided evidence that synergistic employment of genomics approaches and high-throughput gene expression methods have aided in dissecting the salinity-responsive signaling pathway, identifying genes involved in the stress response and selecting candidate genes for further characterization aimed at generating new cultivars with better salinity stress tolerance. This paper is also a good reference source for readers who wish to get an overview about the general process from gene prediction to validation by experiments, including the details on techniques and approaches used. Another demonstration is provided by Khan et al. whose interest is enhancement of drought tolerance in crops. The focus of this article is to overview our current understanding of mechanisms regulating plants responses to drought. Evaluation of plant performance to drought and production of new elite varieties with better drought tolerance on the basis of using phenotyping and genomics-assisted breeding are also well discussed. In addition to the topics of environmental stress tolerance in plants, current knowledge on improving biotic stress tolerance is also summarized in our issue. Current picture on crosstalk of signaling mechanisms in rice between its immune system and symbiosis with microorganisms is presented by Akamatsu et al. Rice responses to bacteria and fungi via interactions between the plant pattern recognition receptors and the molecular microbe-associated molecular patterns are described in detail and suggested as targets for manipulation in order to increase disease resistance in crops. On the other hand, Bouain et al. are concerned about nutrient deficiency; specifically, how plant root system develops under growing conditions with inadequate phosphate. The authors overviewed our current understanding of the low phosphate-responsive mechanisms in Arabidopsis model plant, which was gained by using a combination of various advanced methods, including high-througput phenotyping, system biology analysis and "omics" technologies. Stress management in plants is proposed to be also achievable by regulating activities of cyclic nucleotide-gated ion channels. As emphasized in the paper of Jha et al., the application of such channels is important in mediating cellular ion homeostasis and plant tolerance to both biotic and abiotic stresses. In summary, with recent progresses in biological and biotechnological areas, especially rapid development of advanced technologies in biological system modeling, functional genomics, computer-based analyzing tools, genetic engineering and molecular breeding, biological control and biotechnological applications in agriculture have brought about an extraordinary revolution and have been considered the most powerful approaches in maintaining or even increasing crop yield. Therefore, in this issue, we would like to introduce to the audience a collection of various strategies used for enhancing crop productivity, with the focus on advanced biological-biotechnological platforms in the post-genomics era.

Bioinformatics Approach in Plant Genomic Research.

The advance in genomics technology leads to the dramatic change in plant biology research. Plant biologists now easily access to enormous genomic data to deeply study plant high-density genetic variation at molecular level. Therefore, fully understanding and well manipulating bioinformatics tools to manage and analyze these data are essential in current plant genome research. Many plant genome databases have been established and continued expanding recently. Meanwhile, analytical methods based on bioinformatics are also well developed in many aspects of plant genomic research including comparative genomic analysis, phylogenomics and evolutionary analysis, and genome-wide association study. However, constantly upgrading in computational infrastructures, such as high capacity data storage and high performing analysis software, is the real challenge for plant genome research. This review paper focuses on challenges and opportunities which knowledge and skills in bioinformatics can bring to plant scientists in present plant genomics era as well as future aspects in critical need for effective tools to facilitate the translation of knowledge from new sequencing data to enhancement of plant productivity.

Anti-inflammatory Flavonoid C-Glycosides from Piper aduncum Leaves.

Four new compounds, acacetin 8-C-[ß-D-apiofuranosyl-(1 → 2)-ß-D-glucopyranoside] (1), 7-methoxyacacetin 8-C-[ß-D-apiofuranosyl-(1 → 3)-ß-D-glucopyranoside] (2), 7-methoxyacacetin 8-C-[ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranoside] (3), and 4‴-O-acetylacacetin 8-C-[α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranoside] (4), along with ten known compounds (5-14), were isolated from Piper aduncum leaves. The effects of these compounds on lipopolysaccharide-induced expression of the proinflammatory cytokines IL-12 p40, IL-6, and TNF-α in bone marrow-derived dendritic cells were evaluated. Compounds 2, 3, 6, 8, 9, and 11-13 inhibited the production of both IL-12 p40 and IL-6, with IC50 values ranging from 0.35 ± 0.01 to 1.40 ± 0.04 µM and 1.22 ± 0.02 to 3.79 ± 0.10 µM, respectively. Compounds 5 and 10 only showed strong inhibition effects on the production of IL-12 p40, with IC50 values of 2.76 ± 0.08 and 0.39 ± 0.05 µM, respectively. However, all compounds showed weak activity or no activity on TNF-α production at the tested concentrations.

In vitro anti-inflammatory components isolated from the carnivorous plant Nepenthes mirabilis (Lour.) Rafarin.

CONTEXT: Nepenthes mirabilis (Lour.) Rafarin (Nepenthaceae) is a carnivorous plant used as a folk medicine in the treatment of jaundice, hepatitis, gastric ulcers, ureteral stones, diarrhea, diabetes, and high blood pressure. Neither the phytochemical content nor biological activities of N. mirabilis have been reported. OBJECTIVE: The anti-inflammatory activity from the N. mirabilis methanolic extract led to the isolation of compounds (1-26). MATERIALS AND METHODS: Chromatographic methods were used to isolate compounds from the methanol extract of N. mirabilis branches and leaves. The anti-inflammatory activity of these isolated compounds was investigated in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) using ELISA. Primary BMDCs were used to examine the production of pro-inflammatory cytokines (IL-12 p40, IL-6, and TNF-α, at concentrations of 0.1, 0.2, and 1.0 µM) as compared with a positive control, SB203580 (1.0 µM). MTT assays showed that isolated compounds (1-26) did not exhibit significant cytotoxicity at concentrations up to 20.0 µM. RESULTS: Compound 9 showed potent inhibition of IL-12 p40, IL-6, and TNF-α production (IC50 = 0.17 ± 0.02, 0.46 ± 0.01, and 8.28 ± 0.21 µM, respectively). Compound 4 showed potent inhibition of IL-12 p40 and IL-6 production (IC50 = 1.17 ± 0.01 and 2.15 ± 0.04 µM). In addition, IL-12 p40 inhibition by naphthalene derivatives (1-7, 9, and 10), phenolic compounds (11-15), lupeone (18), and flavonoids (22, 25, and 26) was more potent than with the positive control. The isolated compounds exhibited little and/or no inhibitory effects on TNF-α production in LPS-stimulated BMDCs. DISCUSSION AND CONCLUSION: Taken together, these data suggest that the isolated components have significant inhibitory effects on pro-inflammatory cytokine production and warrant further study concerning their potential medicinal use.