Regulation of anti-inflammatory and antioxidant responses by methanol extract of Mikania cordata (Burm. f.) B. L. Rob. leaves via the inactivation of NF-κB and MAPK signaling pathways and activation of Nrf2 in LPS-induced RAW 264.7 macrophages.

Mikania cordata (Burm. f.) B.L. Rob. has been traditionally used in tropical countries throughout Asia and Africa to treat gastric ulcers, dyspepsia, and dysentery. However, the mechanisms responsible for its anti-inflammatory and antioxidant activities are not fully understood. Therefore, this study sought to investigate the anti-inflammatory and antioxidant effects of methanol extracts of M. cordata (MMC) on inflammation and oxidative stress in lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages and elucidate its underlying regulatory mechanism. MMC significantly suppressed the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated RAW 264.7 macrophages by downregulating the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) at both the mRNA and protein levels. Moreover, MMC effectively reduced the mRNA expression levels and production of pro-inflammatory cytokines, including interleukin-6 (IL-6), IL-1ß, and tumor necrosis factor-α (TNF-α). These suppressive effects of MMC on pro-inflammatory mediators and cytokines were mediated through the inhibition of transforming growth factor beta-activated kinase 1 (TAK1), which subsequently blocked the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). MMC also upregulated the nuclear factor erythroid-2-related factor 2 (Nrf2) by inducing the degradation of Kelch-like ECH-related protein 1 (Keap1), an Nrf2-specific E3 ligase. Accordingly, MMC enhanced Nrf2 target gene expression of anti-oxidative regulators such as heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). However, it had minimal effect on the DPPH radical scavenging capacity in vitro. Collectively, these findings demonstrate that MMC holds promise as a potential therapeutic agent for alleviating inflammation-related diseases and oxidative stress.

Mikania micrantha extract enhances cutaneous wound healing activity through the activation of FAK/Akt/mTOR cell signaling pathway.

Mikania micrantha (MM) has been traditionally used for various health benefits, including mental health, anti-inflammatory, wound dressing, and healing of sores. However, the molecular mechanisms and dose required for the wound healing activity of MM have yet to be reported. Therefore, a study was conducted to evaluate the wound healing potential of a cold methanolic extract of MM through in vitro and in vivo studies. Human dermal fibroblast adult (HDFa) cells were treated with 0 (control), 75 ng/ml, 125 ng/ml, 250 ng/ml, and 500 ng/ml of MMmethanolic extract (MME) for 24 h. MME at 75 ng/ml has significantly (p˂0.05) promoted HDFa cell proliferation and migration. Further, MME has also been shown to enhance the invasiveness of human umbilical vascular endothelial cells (HUVECs), indicating the neovasculature for wound healing. The tube formation assay demonstrated a significant (p<0.05) increase in the angiogenic effect of the MME starting at a concentration of 75 ng/ml as compared to the control. Treatment of excision wounds in Wistar rats with 5% and 10% MME ointment significantly enhanced wound contraction compared to control animals. Incision wounds in rats treated with 5% and 10% MME showed a significant (p<0.01) increase in tensile strength compared to control. HDFa cells, and granulation tissue collected on day 14 post-wounding, revealed the modulation of the FAK/Akt/mTOR cell signaling pathway during the enhancement of wound healing. The results of gel zymography showed increased activity of MMP-2 and MMP-9 in the HDFa cells after treatment with the extract.  It is concluded that MMEcan potentially accelerate cutaneous wound healing.

Genome-Wide Identification and Characterization of YUCCA Gene Family in Mikania micrantha.

Auxin is a general coordinator for growth and development throughout plant lifespan, acting in a concentration-dependent manner. Tryptophan aminotransferases (YUCCA) family catalyze the oxidative decarboxylation of indole-3-pyruvic acid (IPA) to form indole-3-acetic acid (IAA) and plays a critical role in auxin homeostasis. Here, 18 YUCCA family genes divided into four categories were identified from Mikania micrantha (M. micrantha), one of the world's most invasive plants. Five highly conserved motifs were characterized in these YUCCA genes (MmYUCs). Transcriptome analysis revealed that MmYUCs exhibited distinct expression patterns in different organs and five MmYUCs showed high expression levels throughout all the five tissues, implying that they may play dominant roles in auxin biosynthesis and plant development. In addition, MmYUC6_1 was overexpressed in DR5::GUS Arabidopsis line to explore its function, which resulted in remarkably increased auxin level and typical elevated auxin-related phenotypes including shortened roots and elongated hypocotyls in the transgenic plants, suggesting that MmYUC6_1 promoted IAA biosynthesis in Arabidopsis. Collectively, these findings provided comprehensive insight into the phylogenetic relationships, chromosomal distributions, expression patterns and functions of the MmYUC genes in M. micrantha, which would facilitate the study of molecular mechanisms underlying the fast growth of M. micrantha and preventing its invasion.

Genome-Wide Characterization of PIN Auxin Efflux Carrier Gene Family in Mikania micrantha.

Mikania micrantha, recognized as one of the world's top 10 pernicious weeds, is a rapidly spreading tropical vine that has invaded the coastal areas of South China, causing serious economic losses and environmental damage. Rapid stem growth is an important feature of M. micrantha which may be related to its greater number of genes involved in auxin signaling and transport pathways and its ability to synthesize more auxin under adverse conditions to promote or maintain stem growth. Plant growth and development is closely connected to the regulation of endogenous hormones, especially the polar transport and asymmetric distribution of auxin. The PIN-FORMED (PIN) auxin efflux carrier gene family plays a key role in the polar transport of auxin and then regulates the growth of different plant tissues, which could indicate that the rapid growth of M. micrantha is closely related to this PIN-dependent auxin regulation. In this study, 11 PIN genes were identified and the phylogenetic relationship and structural compositions of the gene family in M. micrantha were analyzed by employing multiple bioinformatic methods. The phylogenetic analysis indicated that the PIN proteins could be divided into five distinct clades. The structural analysis revealed that three putative types of PIN (canonical, noncanonical and semi-canonical) exist among the proteins according to the length and the composition of the hydrophilic domain. The majority of the PINs were involved in the process of axillary bud differentiation and stem response under abiotic stress, indicating that M. micrantha may regulate its growth, development and stress response by regulating PIN expression in the axillary bud and stem, which may help explain its strong growth ability and environmental adaptability. Our study emphasized the structural features and stress response patterns of the PIN gene family and provided useful insights for further study into the molecular mechanism of auxin-regulated growth and control in M. micrantha.

Integrated Analysis of Transcriptome and Small RNAome Reveals the Regulatory Network for Rapid Growth in Mikania micrantha.

M. micrantha has caused huge ecological damage and economic losses worldwide due to its rapid growth and serious invasion. However, the underlying molecular mechanisms of its rapid growth and environmental adaption remain unclear. Here, we performed transcriptome and small RNA sequencing with five tissues of M. micrantha to dissect miRNA-mediated regulation in M. micrantha. WGCNA and GO enrichment analysis of transcriptome identified the gene association patterns and potential key regulatory genes for plant growth in each tissue. The genes highly correlated with leaf and stem tissues were mainly involved in the chlorophyll synthesis, response to auxin, the CAM pathway and other photosynthesis-related processes, which promoted the fast growth of M. micrantha. Importantly, we identified 350 conserved and 192 novel miRNAs, many of which displayed differential expression patterns among tissues. PsRNA target prediction analysis uncovered target genes of both conserved and novel miRNAs, including GRFs and TCPs, which were essential for plant growth and development. Further analysis revealed that miRNAs contributed to the regulation of tissue-specific gene expression in M. micrantha, such as mmi-miR396 and mmi-miR319. Taken together, our study uncovered the miRNA-mRNA regulatory networks and the potential vital roles of miRNAs in modulating the rapid growth of M. micrantha.

Exogenous phytohormone application and transcriptome analysis of Mikania micrantha provides insights for a potential control strategy.

Effective and complete control of the invasive weed Mikania micrantha is required to avoid increasing damages. We exogenously applied indole 3-acetic acid (IAA), gibberellin (GA), and N-(2-Chloro-4-pyridyl)-N'-phenylurea (CPPU), and their combinations i.e. IAA + CPPU (IC), GA + CPPU (GC), and GA + IAA + CPPU (GIC), at 5, 10, 25, 50, and 75 ppm against distilled water as a control (CK), to examine their effects on the weed. The increasing concentrations of these hormones when applied alone or in combination were fatal to M. micrantha and led towards the death of inflorescences and/or florets. CPPU and GIC were found as the most effective phytohormones. Transcriptome analysis revealed differential regulation of genes in auxin, cytokinin, gibberellin and abscisic acid signaling pathways, suggesting their role in the prohibition of axillary bud differentiation. Collectively, CPPU and GIC at a high concentration (75 ppm) could be used as a control measure to protect forests and other lands from the invasion of M. micrantha.

The potential of Mikania micrantha (Chinese creeper) to hyperaccumulate heavy metals in soil contaminated by electronic waste.

The objective of this study is to investigate the contributions of Mikania micrantha (chinese creeper) to remediate heavy metal pollutants present in an e-waste-contaminated soil. Different proportions of e-waste soil (0%, 25%, 50%, 75%, and 100% w/w) planted with Cynodon dactylon together with the test species were prepared for testing relative seed germination (RSG), relative root growth (RRG), and germination index (GI) tests. A significant higher value of GI (77.8%) was found in M. micrantha than that of the other species when planting in 100% e-waste-contaminated soil. A significant correlation (< 0.05) was found between heavy metal concentration and germination assays in M. micrantha. A significant decrease in heavy metal concentration of the polluted soil after the experiment indicated that biomolecule development studies to determine the aggregate benefit of M. micrantha for phytoremediation remain to be studied in future.

Nutrient addition does not increase the benefits of clonal integration in an invasive plant spreading from open patches into plant communities.

One benefit of clonal integration is that resource translocation between connected ramets enhances the growth of the ramets grown under stressful conditions, but whether such resource translocation reduces the performance of the ramets grown under favourable conditions has not produced consistent results. In this study, we tested the hypothesis that resource translocation to recipient ramets may reduce the performance of donor ramets when resources are limiting but not when resources are abundant. We grew Mikania micrantha stolon fragments (each consisting of two ramets, either connected or not connected) under spatially heterogeneous competition conditions such that the developmentally younger, distal ramets were grown in competition with a plant community and the developmentally older, proximal ramets were grown without competition. For half of the stolon fragments, slow-release fertiliser pellets were applied to both the distal and proximal ramets. Under both the low and increased soil nutrient conditions, the biomass, leaf number and stolon length of the distal ramets were higher, and those of the proximal ramets were lower when the stolon internode was intact than when it was severed. For the whole clone, the biomass, leaf number and stolon length did not differ between the two connection treatments. Connection did not change the biomass of the plant communities competing with distal ramets of M. micrantha. Although clonal integration may promote the invasion of M. micrantha into plant communities, resource translocation to recipient ramets of M. micrantha will induce a cost to the donor ramets, even when resources are relatively abundant.

Evaluation of genotoxicity and coumarin production in conventional and organic cultivation systems of Mikania glomerata Spreng.

Mikania glomerata Sprengel, popularly known as "guaco," is used in Brazilian folk medicine for several inflammatory and allergic conditions. Besides, the popular use "guaco" is indicated by the Brazilian Ministry of Health as a safe and effective herbal medicine. The biological activity of M. glomerata extracts is due to the presence of the coumarins, a large family of phenolic substances found in plants and is made of fused benzene and α-pyrone rings. Considering that there are few data on the biological effects of the extracts of M. glomerata, mainly in genetic level, this work aims to evaluate, in vitro, the genotoxicity and coumarin production in M. glomerata in conventional and organic growing. The data showed that the organic culture system showed double the concentration of coumarin being significantly more productive than the conventional system. Besides, the results of comet assay suggest that extracts of M. glomerata cultivated in a conventional system was genotoxic, increased DNA damage levels while the organic extracts seem to have antigenotoxic effect possibly due to the concentration of coumarins. Additional biochemical investigations are necessary to elucidate the mechanisms of action of M. glomerata extracts, which were found to have a role in protection against DNA damage.

Influence of environmental factors on the volatile composition of two Brazilian medicinal plants: Mikania laevigata and Mikania glomerata.

INTRODUCTION: Mikania laevigata Sch.Bip. ex Baker and Mikania glomerata Spreng. are medicinal plants popularly known as guaco, used for inflammatory diseases of the respiratory system, included in pharmaceutical formularies and often used without distinction. However, several studies show that the chemical composition varies between these species, as well as in plants are subjected to different environmental stresses. Few studies have been carried out with the volatile compounds of guaco, even less about the changes in volatile composition due to abiotic variation. OBJECTIVE: The aim of this work was to evaluate how volatile compounds vary according to the seasons and at different times of the day and if these compounds are influenced by the variations in the growth conditions such as: temperature, luminosity and water. METHODS: The headspace volatiles of the leaves were sampled by solid phase micro extraction and analyzed by gas chromatography-mass spectrometry. Untargeted metabolomic analysis of the resulting chromatograms and chemometrics was applied. The chemical profile of the volatiles of M. laevigata and M. glomerata were different; being clearly separated in the exploratory grouping analyzes (PCA), followed by analysis of variance of the marker compounds of both species. RESULTS: Only M. laevigata contained coumarin, considered to be the chemical marker of both species and to be responsible for the therapeutic activities. There was no significant difference between the morning and afternoon collections of either species. Coumarin, α-pinene and bicyclogermacrene were more intense in the volatiles of M. laevigata throughout the year and responsible for grouping the samples of this species. For M. glomerata, hexanal and 2-hexenal were responsible for grouping the samples and were more intense in all months. The growth conditions tested affected the intensity of specific compounds in the chromatograms. Some compounds were less intense with the increase of the temperature and in the plants subjected to full sunlight. However, certain volatile compounds-such as pinenes-were more intense in plants suffering drought. CONCLUSION: The variation in composition between species of guaco was greater than those observed in the seasonal and cultivation studies, indicating that these species cannot be used indistinctly.

Seasonal changes and solvent effects on fractionated functional food component yields from Mikania laevigata leaves.

Statistical mixture design extraction and fractionation of Mikania plant samples were carried out to quantitatively study seasonal and solvent composition effects as well as their interactions on secondary metabolites. The mixture design consisted of ethanol, acetone, dichloromethane and chloroform solvents and their binary, ternary and quaternary mixtures. Yields were measured for the crude extract and its neutral, organic, basic, polar and fiber fractions obtained with each solvent composition from samples harvested during 2010. Two-way ANOVA found statistically significant seasonal and solvent effects for the crude extract and all the fractions except for the polar fraction solvent. The best solvent extractor depends the harvest season. High crude, organic and polar fraction yields in the summer are correlated with the coumarin UV-vis absorbance at 274 nm. Crude yields of mixtures containing ethanol are correlated with the coumarin absorbances in summer, winter and spring whereas mixtures without ethanol show no significant correlation.

Mechanistic investigation in ultrasound induced enhancement of enzymatic hydrolysis of invasive biomass species.

This study has assessed four invasive weeds, viz. Saccharum spontaneum (SS), Mikania micrantha (MM), Lantana camara (LC) and Eichhornia crassipes (EC) for enzymatic hydrolysis prior to bioalcohol fermentation. Enzymatic hydrolysis of pretreated biomasses of weeds has been conducted with mechanical agitation and sonication under constant (non-optimum) conditions. Profiles of total reducible sugar release have been fitted to HCH-1 model of enzymatic hydrolysis using Genetic Algorithm. Trends in parameters of this model reveal physical mechanism of ultrasound-induced enhancement of enzymatic hydrolysis. Sonication accelerates hydrolysis kinetics by ∼10-fold. This effect is contributed by several causes, attributed to intense micro-convection generated during sonication: (1) increase in reaction velocity, (2) increase in enzyme-substrate affinity, (3) reduction in product inhibition, and (4) enhancement of enzyme activity due to conformational changes in its secondary structure. Enhancement effect of sonication is revealed to be independent of conditions of enzymatic hydrolysis - whether optimum or non-optimum.

Biotechnological prospecting of foliar endophytic fungi of guaco (Mikania glomerata Spreng.) with antibacterial and antagonistic activity against phytopathogens.

Mikania glomerata (Spreng.), popularly known as "guaco", is a plant from the Asteraceae family that has many therapeutic properties. The use of medicinal plants has been examined in studies on endophytic diversity and bioprospecting; endophytes inhabit the interior of plants without harming them. Microorganism-host complex interactions are related to the production of compounds that may confer resistance to pathogens or to production of bioactive compounds or growth regulators. In this study, we evaluated foliar endophytic fungi of M. glomerata to examine the control of plant pathogens, molecular identification, and production of compounds with antimicrobial activity. In the antagonism test, 6-mm diameter disks were placed equidistant from the endophyte and plant pathogen, and pathogen growth area was measured. The endophytic strains G-01, G-02, and G-03 were effective against Fusarium solani and Didymella bryoniae. The endophyte rDNA regions corresponding to internal transcribed spacer 1-5.8S-internal transcribed spacer 2 were sequenced, and the results were compared with sequences deposited in the NCBI database. The G-01, G-02, and G-03 strains were identified as Diaporthe citri. This identification was confirmed by phylogenetic analysis. The crude extract of the secondary metabolites of the G-01 strain was tested against Escherichia coli and Staphylococcus aureus; the metabolites showed antimicrobial activity against S. aureus. The endophytes tested in this study have potential for use in biotechnological applications.

Experimental designs characterizing seasonal variations and solvent effects on the quantities of coumarin and related metabolites from Mikania laevigata.

Statistical design mixtures of acetone, chloroform, dichloromethane and ethanol were used to study the effects of different solvents and their mixtures on the quantities of coumarin and related metabolites extracted from Mikania laevigata samples harvested in each of the four seasons. RP-HPLC-DAD and both positive and negative modes of UPLC-MS analyses were used to determine relative quantities of coumarin, o-coumaric acid and melilotic acids in each season for all the mixture design extracts. The existence and measurement of the relative abundances of melilotic acid in Mikania laevigata have not been reported previously. Highest coumarin concentrations were encountered in the summer whereas its o-coumaric acid precursor and melilotic acid were most abundant in the spring. O-coumaric and melilotic acids concentrations were strongly correlated during the year. Also solvent effects were seen to be significant. Ethanol and 1:1 binary mixtures of ethanol and acetone extracted the largest quantities of coumarin whereas ethanolic binary and ternary mixtures with chloroform and dichloromethane provided the best yields of o-coumaric and melilotic acids. Statistical mixture models indicated that synergic binary interactions, especially those involving ethanol with acetone or chloroform, are important in the Mikania extraction process.

Efeito genotóxico e antiproliferativo de Mikania cordifolia (L. F. ) Willd. (Asteraceae) sobre o ciclo celular de Allium cepa L / Antiproliferative and genotoxic effects of Mikania cordifolia (LF) Willd. (Asteraceae) on the cell cycle of Allium cepa L

As plantas com potencial medicinal têm sido muito utilizadas para o tratamento de doenças no Brasil. O objetivo deste estudo foi avaliar o efeito genotóxico e antiproliferativo de infusões de Mikania cordifolia (L.F.) Willd. sobre o ciclo celular de Allium cepa L. Foram coletadas duas populações no município de Santa Maria, Rio Grande do Sul, e, para cada uma, foram preparados dois tratamentos em duas concentrações: 4g/500mL e 16g/500mL, além de um controle positivo composto por 10% de glifosato em 90% água, um herbicida amplamente utilizado com conhecido potencial genotóxico, e de um controle negativo composto por água destilada. Após período de 24 horas, as radículas foram coletadas das infusões, fixadas em etanol-ácido acético (3:1) por 24 horas e estocadas em etanol 70%. Foram analisadas células em todas as fases do ciclo celular de A. cepa, totalizando 2500, para cada grupo de bulbos. Os índices mitóticos (IM) foram calculados e submetidos à análise estatística pelo teste χ² a 5%. Os resultados mostraram que, em ambas as populações de M. cordifolia, houve redução do IM de todos os tratamentos em relação ao controle negativo. Em ambas as populações, obteve-se aumento nos valores dos índices mitóticos em função do aumento da concentração da infusão. Ocorreram aberrações cromossômicas em ambas as populações estudadas. Concluiu-se que as infusões de M. cordifolia, nas concentrações estudadas, possuem efeito antiproliferativo e mutagênico sobre o ciclo celular de A. cepa.

Potential medicinal plants have been widely used for the treatment of diseases in Brazil. The objective of this study was to evaluate the genotoxic and antiproliferative effects of infusions of Mikania cordifolia (LF) Willd. on the cell cycle of Allium cepa L. Two populations were collected in Santa Maria, Rio Grande do Sul, Brazil. For each one, two treatments were prepared in different concentrations: 4g/500mL and 16g/500mL. A positive control consisting of 10% glyphosate in 90% water, which is an herbicide widely used and known for its genotoxic potential, was also prepared. Distilled water was used as negative control. After a 24-hour period, the infusion of the root tips was collected, fixed in ethanol-acetic acid (3:1) for 24 hours and stored in 70% ethanol. Cells were analyzed in all phases of the cell cycle of A. cepa, a total of 2500, for each group of bulbs. The mitotic index (MI) was calculated and statistically analyzed by the χ² test at 5%. Results showed that, in both populations of M. cordifolia, a reduction of the MI in all treatments compared with the negative control was observed. In both populations, an increase in the mitotic index values was obtained with increasing concentration of the infusion. Chromosomal aberrations were observed in both populations studied. In conclusion, infusions of M. cordifolia possess antiproliferative and mutagenic effects for the concentrations tested on the cell cycle of A. cepa.

Non-Additive effects on decomposition from mixing litter of the invasive Mikania micrantha H.B.K. with native plants.

A common hypothesis to explain the effect of litter mixing is based on the difference in litter N content between mixed species. Although many studies have shown that litter of invasive non-native plants typically has higher N content than that of native plants in the communities they invade, there has been surprisingly little study of mixing effects during plant invasions. We address this question in south China where Mikania micrantha H.B.K., a non-native vine, with high litter N content, has invaded many forested ecosystems. We were specifically interested in whether this invader accelerated decomposition and how the strength of the litter mixing effect changes with the degree of invasion and over time during litter decomposition. Using litterbags, we evaluated the effect of mixing litter of M. micrantha with the litter of 7 native resident plants, at 3 ratios: M1 (1∶4, = exotic:native litter), M2 (1∶1) and M3 (4∶1, = exotic:native litter) over three incubation periods. We compared mixed litter with unmixed litter of the native species to identify if a non-additive effect of mixing litter existed. We found that there were positive significant non-additive effects of litter mixing on both mass loss and nutrient release. These effects changed with native species identity, mixture ratio and decay times. Overall the greatest accelerations of mixture decay and N release tended to be in the highest degree of invasion (mix ratio M3) and during the middle and final measured stages of decomposition. Contrary to expectations, the initial difference in litter N did not explain species differences in the effect of mixing but overall it appears that invasion by M. micrantha is accelerating the decomposition of native species litter. This effect on a fundamental ecosystem process could contribute to higher rates of nutrient turnover in invaded ecosystems.

Molecular cloning and characterization of two novel NAC genes from Mikania micrantha (Asteraceae).

NAC proteins, which are plant-specific transcription factors, have been identified to play important roles in plant response to stresses and in plant development. The full-length cDNAs that encode 2 putative NAC proteins, designated as MmATAF1 and MmNAP, respectively, were cloned from Mikania micrantha by rapid amplification of cDNA ends. The full-length cDNAs of MmATAF1 and MmNAP were 1329 and 1072 bp, respectively, and they encoded deduced proteins of 260- and 278-amino acid residues, respectively. The proteins MmATAF1 and MmNAP had a calculated molecular mass of 29.81 and 32.55 kDa and a theoretical isoelectric point of 7.08 and 9.00, respectively. Nucleotide sequence data indicated that both MmATAF1 and MmNAP contained 2 introns and 3 exons and that they shared a conserved genomic organization. Multiple sequence alignments showed that MmATAF1 showed high sequence identity with ATAF1 of Arabidopsis thaliana (61%) and that MmNAP showed high sequence identity with NAP of A. thaliana (67%) and CitNAC of Citrus sinensis Osbeck (62%). Phylogenetic analysis showed that the predicted MmATAF1 and MmNAP proteins were classified into the ATAF and NAP subgroups, respectively. Transient expression analysis of onion epidermal cells indicated nuclear localization of both MmATAF1-GFP and MmNAP-GFP fusion proteins. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis indicated that MmATAF1 was expressed in all the tissues tested, but in varying abundance, while MmNAP was specifically expressed in stems, petioles, shoots, and leaves, but not in roots. The transcript levels of MmATAF1 and MmNAP in shoots and in infected stems were induced and strengthened by wounding, exogenous ZnSO(4), abscisic acid, salicylic acid, and Cuscuta campestris infection on the basis of semi-quantitative RT-PCR and real-time PCR analyses, respectively. Collectively, these results indicated that MmATAF1 and MmNAP, besides having roles in M. micrantha adaptation to C. campestris infection and abiotic stresses, also integrated signals derived from both C. campestris infection and abiotic stresses.

Rendimento extrativo de cumarina de folhas de guaco (Mikania glomerata Sprengel) submetidas a diferentes temperaturas de secagem / Extraction yield of coumarin from guaco (Mikania glomerata Sprengel) leaves subjected to different drying temperatures

O objetivo deste trabalho foi avaliar o efeito da temperatura do ar de secagem no rendimento extrativo da cumarina de folhas de guaco. Foram empregados 6 tratamentos de secagem, sendo ar ambiente, ar aquecido a 40, 50, 60, 70 e 80ºC. Utilizou-se secador de bandejas, tendo como fonte de aquecimento o gás liquefeito de petróleo (GLP). Os rendimentos extrativos da cumarina, depois de realizada a secagem, foram comparados com os valores obtidos da planta fresca (tratamento testemunha). A extração da cumarina foi realizada pelo método a quente, em banho-maria a 65ºC, sendo a identificação e quantificação realizada por cromatografia líquida de alta eficiência (CLAE). Em função dos resultados obtidos, pôde-se concluir que a temperatura do ar de secagem a 50ºC possibilitou o melhor resultado para o rendimento extrativo de cumarina em folhas de guaco.

The aim of this study was to evaluate the effect of drying on the extraction yield of coumarin from guaco leaves. Six drying treatments were used, being room air, heated air at 40, 50, 60, 70 and 80ºC. A tray dryer was used with liquefied petroleum gas (LPG) as heating source. The extraction yield of coumarin, after drying, was compared to the values obtained from the fresh plant (control treatment). Coumarin extraction was carried out by using the heat method, in water bath at 65ºC, and identification and quantification were done by means of high performance liquid chromatography (HPLC). Considering the obtained results, the temperature of the drying air at 50ºC led to the best result for the extraction yield of coumarin in guaco leaves.

Potential allelochemicals from an invasive weed Mikania micrantha H.B.K.

Phytotoxicity-directed extraction and fractionation of the aerial parts of Mikania micrantha H.B.K. led to the isolation and identification of three sesquiterpenoids: dihydromikanolide, deoxymikanolide, and 2,3-epoxy-1-hydroxy-4,9-germacradiene-12,8:15,6-diolide. These sesquiterpenoids inhibited both germination and seedling growth of tested species with deoxymikanolide possessing the strongest phytotoxicity. In a bioassay against lettuce (Lectuca sativa L.), deoxymikanolide reduced radicle elongation at low concentration (IC50 = 47 microg/ml); dihydromikanolide showed a weaker effect (IC50 = 96 microg/ml), and 2,3-epoxy-1-hydroxy-4,9-germacradiene-12,8:15,6-diolide exhibited the least effect (IC50 = 242 microg/ml). Deoxymikanolide caused yellowish lesions at the root tips of lettuce at a concentration of 50 microg/ml, and a 250 microg/ml solution killed lettuce seedlings. A bioassay against the monocot ryegrass (Lolium multiforum) revealed similar results on radicle elongation, which implied that the growth inhibition by these compounds was not selective. To evaluate their phytotoxicity to plants in natural habitats, three common companion tree species in south China, Acacia mangium, Eucalyptus robusta, and Pinus massoniana, were also tested and similar results were obtained. This is the first report on the isolation of 2,3-epoxy-1-hydroxy-4,9-germacradiene-12,8:15,6-diolide as a naturally occurring product.