Longipes Roots Research Articles

Affinin, Isolated from Heliopsis longipes, Induces an Antihypertensive Effect That Involves CB1 Cannabinoid Receptors and TRPA1 and TRPV1 Channel Activation.

In previous studies, we demonstrated that the ethanolic extract of Heliopsis longipes roots and its main alkamide, affinin, elicit a vasorelaxant effect through a mechanism involving activation of the gasotransmitter pathways and stimulation of cannabinoid type 1 receptors and transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 channels. However, it has not yet been demonstrated whether the EEH and affinin are capable of lowering high blood pressure. Therefore, the aim of the present study was to determine the effect of the oral administration of the EEH and affinin on the systolic blood pressure of NG-nitro-L-arginine methyl ester-induced hypertensive rats and to explore the participation of cannabinoid receptors and transient receptor potential channels in the mechanism of action of this alkamide. Our results showed that the ethanolic extract of H. longipes and affinin significantly lowered systolic blood pressure and induced an improvement in endothelial function, which is associated with increased serum nitric oxide levels. Inhibition of cannabinoid type 1 receptors by rimonabant (3 mg/kg), transient receptor potential ankyrin 1 channels by HC-030031 (8 mg/kg), and transient receptor potential vanilloid 1 channels by capsazepine (5 mg/kg) significantly decreased the antihypertensive effect induced by affinin, suggesting that the blood pressure-lowering effect of this alkamide involves activation of cannabinoid type 1 receptors and transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 channels.

Self-microemulsifying system of an ethanolic extract of Heliopsis longipes root for enhanced solubility and release of affinin

Self-microemulsifying or self-nanoemulsifying drug delivery systems (SMEDDS/SNEDDS) are well known to improve the dissolution and increase the oral bioavailability of hydrophobic drugs, including herbal extracts. Organic extracts of Heliopsis longipes root and affinin, its main component, induce a vasodilator effect; however, they are poorly water soluble and therefore are difficult to administer and dose by the oral route. This research aimed to develop, through pseudo-ternary phase diagrams, a self-microemulsifying system prepared from an ethanolic extract of H. longipes root (HL-SMDS). In addition, the optimized lipid-based formulation was characterized and its in vitro gastrointestinal simulated dissolution was determined. The formulation composed of Transcutol, 55% (solubilizer); Tween80/PG, 10% (surfactant/co-solvent); Labrasol, 35% (surfactant); and the herbal extract was selected as optimal and identified as a SMEDDS, since when coming into contact with water, it forms a micro-emulsion with droplet sizes less than 100 nm. The stability tests showed that HL-SMDS remained stable over time under extreme conditions. Furthermore, the amount of affinin released from HL-SMDS at pH 1 and 6.8 was higher than that of the ethanolic extract from H. longipes root. These results indicate that HL-SMDS is a novel alternative to improve the aqueous solubility and therefore the oral bioavailability of the ethanolic extract of H. longipes root.

Proangiogenic Effect of Affinin and an Ethanolic Extract from Heliopsis longipes Roots: Ex Vivo and In Vivo Evidence.

Angiogenesis, the formation of new blood vessels, underlies tissue development and repair. Some medicinal plant-derived compounds can modulate the angiogenic response. Heliopsis longipes, a Mexican medicinal plant, is widely used because of its effects on pain and inflammation. The main bioactive phytochemicals from H. longipes roots are alkamides, where affinin is the most abundant. Scientific studies show various medical effects of organic extracts of H. longipes roots and affinin that share some molecular pathways with the angiogenesis process, with the vasodilation mechanism of action being the most recent. This study investigates whether pure affinin and the ethanolic extract from Heliopsis longipes roots (HLEE) promote angiogenesis. Using the aortic ring rat assay (ex vivo method) and the direct in vivo angiogenesis assay, where angioreactors were implanted in CD1 female mice, showed that affinin and the HLEE increased vascular growth in a dose-dependent manner in both bioassays. This is the first study showing the proangiogenic effect of H. longipes. Further studies should focus on the mechanism of action and its possible therapeutic use in diseases characterized by insufficient angiogenesis.

De novo transcriptome sequencing, assembly and characterization of Heliopsis longipes roots vs. leaves to discover putative genes involved in specialized metabolites biosynthesis

Heliopsis longipes is a valuable source of specialized metabolites (or secondary metabolites) with medicinal properties mainly in roots. However, little is known about genes involved in the biosynthesis of these metabolites, primarily due to the lack of genome or transcriptome resources. In this work, the genes of the biosynthetic pathway of the specialized metabolism from H. longipes roots and leaves through de novo RNA sequencing (RNA-Seq) using the platform of Illumina paired-end sequencing were studied. After de novo transcriptome assembly using the software Newbler, a total of 172,342 non-redundant transcripts with an N50 value of 816 bp was obtained. Further functional classification and annotation with Gene Ontology (GO), BLAST2GO, Kyoto Encyclopedia of Genes and Genome (KEGG), and KEGG automatic annotation server (KAAS), revealed that active genes in tissues are predominately involved in the metabolic process and biosynthesis of specialized metabolite pathways. Differential expression analysis of roots vs. leaves using Cuffdiff software (p-value ≤0.05 and log-fold change ratio (log2) ≥1) revealed that differentially expressed genes (DEGs) were in an organ-specific manner, such as in leaf, DEGs were significantly enriched in photosynthesis, while in roots, were a higher enriched function of plant hormone signal transduction. A total of 63 transcripts DEGs were related to 9 specialized metabolites pathways, in roots the most abundant was the phenylpropanoid biosynthesis, and in leaves was the carotenoids biosynthesis. Several regulatory genes including the basic-helix-loop-helix and basic leucine zipper domain, transcriptions factor families involved in the regulation of phenylpropanoids and carotenoid biosynthesis, respectively, were discovered. This study established a global transcriptome dataset for H. longipes. Data shall be useful to study the functional genomics or genetic engineering of this specie. These results will promote the understanding of the genetic mechanism involved in the biosynthesis of specialized metabolites in H. longipes

Down-regulation of aflatoxin biosynthetic genes in Aspergillus parasiticus by Heliopsis longipes roots and affinin for reduction of aflatoxin production

Affinin present in Heliopsis longipes roots has been identified as an anti-aflatoxin molecule. However, its mechanism of action has yet to be clarified. Aflatoxins biosynthesis involves not less than 27 enzymatic reactions. In this work, the genes aflG, aflH, aflI, aflK, aflL, aflM, aflO, aflP, and aflQ of the aflatoxins cluster and the aflS gene encoding an internal regulatory factor involved in aflatoxins biosynthesis in Aspergillus parasiticus, were studied by qRT-PCR. Results demonstrated that ethanolic extract of H. longipes roots and affinin inhibit aflatoxin biosynthesis and fungal growth in a dose-dependent manner. At 300 µg/mL, ethanolic extract and affinin presented the highest inhibition of radial growth (86% and 94%) and aflatoxin production (68% and 80%). The qRT-PCR analysis demonstrated that nine tested genes were down-regulated by affinin and ethanolic extract. The most down-regulated was the aflK, a gene that encodes an enzyme cyclase with double function during the aflatoxin biosynthesis. While no significant down-regulation was obtaining for aflH gene. Exposure to affinin also resulted in decreased transcript levels of the internal regulator factor aflS. Based on our results, a model showing the regulatory mechanism in aflatoxin biosynthesis and its role in gene expression was proposed. In conclusion, affinin modulates the expression of several aflatoxin biosynthetic genes, leading to mycotoxin biosynthesis inhibition. Therefore, H. longipes roots is a suitable candidate to developed control strategies via lowering gene expressions as a future perspective in reducing aflatoxin contamination.

Phenolic compounds and antioxidant activity of methanolic extracts from leaves and flowers of chilcuague ( Heliopsis longipes , Asteraceae)

Background: Heliopsis longipes root is the widely used organ from the plant due to its culinary and medicinal importance. Nevertheless, during its collection the foliage is discarded. Therefore, it is required to perform studies about the phytochemical content with biological activity present in the different plant organs of the foliage, for a better exploitation of the plant.
 Hypothesis: The concentration of phenolic compounds with antioxidant activity varies according to the type of plant organ and the geographic location of the plant collection.
 Study species: Heliopsis longipes 
 Site and years of study: The H. longipes plants were collected in three locations (Conca, San Juan Buenaventura and Beltran) from Sierra Gorda of Mexico, between 2017 and 2018.
 Methods: In this study, they were analyzed the methanolic extracts from H. longipes leaves and flowers, in order to determine the content of the phenolic compounds and scavenging of radicals activity (DPPH• and ABTS•+). Further characterization of the extracts was carried out by chromatography (UPLC).
 Results: The total content of polyphenols, flavonoids and condensed tannins varied in depending on the type of plant organ and the origin site of H. longipes , being the leaves of Beltran those that represent the best source of phenolic compounds with scavenging activity of the radicals DPPH• and ABTS•+. In the extracts, phenolic acids and flavonoids were identified.
 Conclusions: The geographical climatic conditions influence the phenolic content and antioxidant activity of the methanolic extracts from leaves and flowers of H. longipes .

Global gene expression analyses of the alkamide-producing plant Heliopsis longipes supports a polyketide synthase-mediated biosynthesis pathway.

BackgroundAlkamides are plant-specific bioactive molecules. They are low molecular weight N-substituted α-unsaturated acyl amides that display biological explicit activities in different organisms from bacteria, fungi, insects to mammals and plants. The acyl chain has been proposed to be biosynthesized from a fatty acid; however, this has not been demonstrated yet. Heliopsis longipes (Asteraceae) accumulates in root a C10 alkamide called affinin in its roots, but not in leaves. The closely related species Heliopsis annua does not produce alkamides. To elucidate the biosynthetic pathway of the alkamides acyl chain, a comparative global gene expression analysis contrasting roots and leaves of both species was performed.MethodsTranscriptomics analysis allowed to identify genes highly expressed in H. longipes roots, but not in tissues and species that do not accumulate alkamides. The first domain searched was the Ketosynthase (KS) domain. The phylogenetic analysis using sequences of the KS domain of FAS and PKS from different organisms, revealed that KS domains of the differentially expressed transcripts in H. longipes roots and the KS domain found in transcripts of Echinacea purpurea, another alkamides producer species, were grouped together with a high bootstrap value of 100%, sharing great similarity. Among the annotated transcripts, we found some coding for the enzymatic domains KS, AT, ACP, DH, OR and TE, which presented higher expression in H. longipes roots than in leaves. The expression level of these genes was further evaluated by qRT-PCR. All unigenes tested showed higher expression in H. longipes roots than in any the other samples. Based on this and considering that the acyl chain of affinin presents unsaturated bonds at even C numbers, we propose a new putative biosynthesis pathway mediated by a four modules polyketide synthase (PKS).ResultsThe global gene expression analysis led to the selection of a set of candidate genes involved in the biosynthesis of the acyl chain of affinin, suggesting that it may be performed by a non-iterative, partially reductive, four module type I PKS complex (PKS alk) previously thought to be absent from the plant kingdom.

Unveiling pharmacological studies provide new insights on Mangifera longipes and Quercus gomeziana.

Mangifera longipes and Quercus gomeziana both is an ethnomedicinally important Asian herb that has been known for numerous healing activity of tribal people. The present research aims to investigate the phytochemical analysis with in vitro, in vivo possibilities of the soluble ethanol extract of M. longipes root (EEMLR) and Q. gomeziana leaves (EEQGL) by an experimental approach. The plant extract of EEMLR and EEQGL was found secondary metabolites, notably steroids, glycosides, tannins, flavonoids, saponins, gums, and alkaloids. Additionally, the extract showed significant activity in antioxidant, antipyretic, anti-inflammatory, membrane stabilization, cytotoxic, thrombolytic, and analgesic activities while no response in antibacterial activity. Our findings reveal that soluble ethanol extract of EEMLR and EEQGL is safe, which can be an effective source for exploring new medicinal products. This research's outcomes may provide potentials for mitigating pyrexia, inflammation, pain, cellular toxicity, and coagulation.

Changes in affinin contents in Heliopsis longipes (chilcuague) after a controlled elicitation strategy under greenhouse conditions

Heliopsis longipes (H. longipes) is an endemic plant of the Sierra Gorda, Mexico, whose root crude extract is used as an analgesic, anti-inflammatory and anti-ulcerative. Affinin is the main substance that provides these properties. Affinin concentrations have been seen to vary depending on the time of the year in which it is collected. Controlled cultivation of H. longipes may reduce the synthesis of affinin but using elicitation technique it might be possible to increase and standardize the biosynthesis of this specialized metabolite. The aim of this research was to determine the changes in the affinin contents in H. longipes roots after controlled elicitation using salicylic acid and hydrogen peroxide as elicitors under greenhouse conditions. After a period of acclimation of 150 days for chilcuague plants, both elicitors were foliarly sprayed for two weeks. Besides affinin contents, changes on the biomass production, catalase, superoxide dismutase, phenylalanine ammonia-lyase and valine decarboxylase enzymatic activities in H. longipes were evaluated. The results showed that low doses of both elicitors significantly increased affinin contents in roots in comparison with controls without affecting morphological variables. This increase in affinin was correlated with concomitant increases in enzymatic activities related to stress responses as catalase (CAT), superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), as well as the increase in valine decarboxylase activity (VDC), an enzyme related with biosynthesis of aliphatic alkamides as affinin. Thus, controlled elicitation might be an interesting strategy to increase affinin contents in chilcuague cultivated under greenhouse conditions.

Antifungal and anti-aflatoxigenic activity of Heliopsis longipes roots and affinin/spilanthol against Aspergillus parasiticus by downregulating the expression of alfD and aflR genes of the aflatoxins biosynthetic pathway

In the present study, ethanolic extract from Heliopsis longipes roots and affinin/spilanthol against Aspergillus parasiticus growth and aflatoxins production were studied in relation to the expression of aflD and aflR, two key genes of aflatoxins biosynthetic pathway. Phytochemical analysis of the ethanolic extract by GC-EIMS identified affinin/spilanthol (7.84 ± 0.27 mg g−1) as the most abundant compounds in H. longipes roots. The antifungal and anti-aflatoxigenic assays showed that affinin/spilanthol at 300 µg mL−1 produced the higher inhibition of radial growth (95%), as well as, the higher aflatoxins production inhibition (61%) in comparison to H. longipes roots (87% and 48%, respectively). qRT-PCR revealed that the expression of aflD and aflR genes showed a higher downregulation in affinin/spilanthol at 300 µg mL−1. The expression ratio of alfD was suppressed by affinin/spilanthol in 79% and aflR in 84%, while, a lower expression ratio suppressed by H. longipes was obtained, alfD (55%) and aflR (59%). Affinin/spilanthol possesses higher antifungal and anti-aflatoxigenic activity against A. parasiticus rather than H. longipes roots, and this anti-aflaxotigenic activity occurring via downregulation of the aflD and aflR genes. Thus, H. longipes roots and affinin/spilanthol can be considered potent antifungal agents against aflatoxigenic fungus, especially, affinin/spilanthol.

EFFECT OF THE ROOTS EXTRACT FROM Heliopsis longipes ON Aspergillus parasiticus GROWTH

The organic extracts from Heliopsis longipes roots possess interesting biological and pharmacological activities. However, the effect on Aspergillus parasiticus has not been investigated so far. This study was aimed to evaluate the antifungal effect of the ethanolic extract from H. longipes roots against A. parasiticus growth. Four extract concentrations, 50, 75, 150 and 200 μg/mL were evaluated for antifungal effect, and the anti-aflatoxigenic assay was tested at 150 and 200 μg/mL. The minimal inhibitory concentration that inhibited 50 and 99% of growth (MIC50 and MIC99) were determined. Ethanolic extract was characterized by GC-EIMS analysis and its main bioactive compounds were identified. All tested concentrations inhibit the radial growth of A. parasiticus and the MIC50 and MIC99 were 116.94 and 1593.98 μg/mL, respectively. These results showed the first evidence of the antifungal effect of H. longipes on the radial growth and spore germination rate of this pathogenic fungus. The antifungal activity of H. longipes extract was attributed to affinin (7.24 ± 0.13 mg/g of fresh tissue), the most abundant alkamide detected by GC-EIMS analysis. Although, the extract did not inhibit the aflatoxins´ production, it can be used to prevent A. parasiticus growth before the mycotoxins production occur. Therefore, the extract has potential as natural antifungal agent against A. parasiticus contamination.

Affinin (Spilanthol), Isolated from Heliopsis longipes, Induces Vasodilation via Activation of Gasotransmitters and Prostacyclin Signaling Pathways.

Heliopsis longipes roots have been widely used in Mexican traditional medicine to relieve pain, mainly, toothaches. Previous studies have shown that affinin, the major alkamide of these roots, induces potent antinociceptive and anti-inflammatory activities. However, the effect of H. longipes root extracts and affinin on the cardiovascular system have not been investigated so far. In the present study, we demonstrated that the dichloromethane and ethanolic extracts of H. longipes roots, and affinin, isolated from these roots, produce a concentration-dependent vasodilation of rat aorta. Affinin-induced vasorelaxation was partly dependent on the presence of endothelium and was significantly blocked in the presence of inhibitors of NO, H2S, and CO synthesis (NG-nitro-l-arginine methyl ester (l-NAME), dl-propargylglycine (PAG), and chromium mesoporphyrin (CrMP), respectively); K+ channel blockers (glibenclamide (Gli) and tetraethyl ammonium (TEA)), and guanylate cyclase and cyclooxygenase inhibitors (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and indomethacin (INDO), respectively). Our results demonstrate, for the first time, that affinin induces vasodilation by mechanisms that involve gasotransmitters, and prostacyclin signaling pathways. These findings indicate that this natural alkamide has therapeutic potential in the treatment of cardiovascular diseases.

HPLC Determination of the Alkamide Affinin in Fresh and Dry Roots of Heliopsis longipes (Asteraceae) and HS-SPME-GC-MS-TOF Analysis of Volatile Components

Heliopsis longipes (Asteraceae) is a plant whose roots are commonly used in Mexican cuisine as a substitute for hot pepper. This plant is also used in traditional medicine for its therapeutical properties. Previous reports detected the presence of affinin—an alkamide with analgesic properties—in extracts of H. longipes. Here, we describe the development of a high-performance liquid chromatography-UV detector method for the determination of the alkamide affinin (1) as the major component in fresh and dry roots of H. longipes. Compound 1 was quantitatively determined employing a Kromasil 100 C18 3 μm particle size column, using the isocratic mobile phase acetonitrile-water (55 + 45). The flow rate was 0.8 mL/min and the UV detection was at 213 nm. The limits of detection and quantitation were 0.0009 and 7.6 μg/mL, respectively. Compound 1 showed good linearity in the 75 to 150 μg/mL range; recovery was within 99.3 and 101.9 %. Quantities of affinin measured by this method ranged between 6.9 and 8.5 mg per gram of the dry and fresh roots; thus 1 could be used as marker for H. longipes. The LC method described here proved to be reliable, reproducible, accurate, and could be used for quality control of H. longipes medicinal materials. In addition, its volatile chemical composition is described and was assessed via GC-MS using headspace solid-phase microextraction; compounds were identified by matching against the standard mass spectral database of the National Institute of Standards and Technology (NIST). Twenty-eight recognized compounds represent 99.9 % of the total relative content of constituents from H. longipes roots.

Larvicidal activity of affinin and its derived amides from Heliopsis longipes A. Gray Blake against Anopheles albimanus and Aedes aegypti

Heliopsis longipes has been recognized as a potential source of insecticidal compounds called alkamides, which can be used to control populations of insect vector transmitters of several diseases that affect the human health. To determine the insecticidal activity of H. longipes against Anopheles albimanus and Aedes aegypti, crude extract of H. longipes roots and affinin were obtained. Catalytic reduction of affinin was performed to obtain two reduced amides, N-isobutil-2E-decenamide and N-isobutil-decanamide. Crude extract, affinin and its reduced amides were evaluated against third instar larvae of An. albimanus and Ae. aegypti. Results show that crude extract of H. longipes possess larvicidal activity against larval stage of An. albimanus and Ae. aegypti. This effect could be attributed to affinin, on which the conjugated double bonds present in the structure of the molecule are necessary to maintain larvicidal activity. This study demonstrated the potential of H. longipes to control larval stage of An. albimanus and Ae. aegypti, transmitter vectors of malaria and dengue fever, respectively.

DISTRIBUCIÓN DE Heliopsis longipes (Heliantheae: Asteraceae), UN RECURSO ENDÉMICO DEL CENTRO DE MÉXICO

Heliopsis longipes is a perennial herb endemic to Sierra de Álvarez and Sierra Gorda in central México. It is a species of major economic importance within its genus, due to the traditional uses of its root. Chemical and pharmacological studies have been performed with H. longipes roots, however recent studies regarding its distribution are lacking. The objective of the current study was to establish and document the geographic distribution and existing ecologic conditions of H. longipes. A review of published works regarding this species, as well as an examination of herbarium specimens has been conducted. Explorations in Sierra de Álvarez and Sierra Gorda were also conducted to locate populations of H. longipes. In each site, the physical and biological factors associated with the population were recorded. Heliopsis. longipes is distributed in the states of San Luis Potosí, Guanajuato and Querétaro, in steep canyons with oak and oak-pine forests and substrates of igneous origin, in Sierra de Álvarez and Sierra Gorda.

Antinociceptive, genotoxic and histopathological study of Heliopsis longipes S.F. Blake in mice

Ethnopharmacological relevance H. longipes S.F. Blake (Asteraceae) is a Mexican plant, whose roots are traditionally used as a condiment, as a mouth anesthetic, and as an antiparasitic. Affinin is the alkamide present in higher amounts in the roots of H. longipes. Aim of the study To date, there are no published studies regarding the relation between the analgesic properties, in vivo cytotoxicity, and DNA-damaging potential of H. longipes ethanol extract (HLEE). Materials and methods The HLEE was chromatographically fingerprinted to validate its affinin contents. Biological evaluation was conducted in sets of 6–8 CD1 + mice. Antinociceptive effect was evaluated using the writhing and hot-plate tests, and mutagenic and cytotoxic effects were evaluated with micronucleous test in CD1 + mice. For histopathological studies, biological samples from liver, heart, kidneys, spleen, lung, and brain were collected and stained. Results Oral administration of HLEE (3–100 mg/kg) produced a dose-dependent antinociceptive effect in both assays. In micronucleus assay, the variability in the number of micronucleated polychromatic erythrocytes (MNPE) induced, and PE/NE index, the ratio of polychromatic erythrocytes with respect to the number of normochromatic erythrocytes induced by HLEE in the evaluated schedule, were small and nonsignificant. After histopathological results, HLEE showed polioencephalomalacia with 1000 mg/kg dose. Conclusions This work provides evidence that HLEE exerts analgesic effects, with no genotoxic effects in vivo. These findings would be an important contribution to explain the use of H. longipes root as an effective analgesic in traditional medicine, and to establish for the first time the absence of genotoxic and cytotoxic effects of the root in bioactive doses in vivo.

Analgesic activity of Heliopsis longipes and its effect on the nervous system

Heliopsis longipes S.F. Blake (Asteraceae: Heliantheae) (chilcuague) is used in Mexican traditional medicine against parasites and to alleviate tooth and muscle pains. Its biocide effect has already been experimentally demonstrated; however, its analgesic action and its action on the nervous system (NS) have not been investigated yet. The objectives of this study were to evaluate the analgesic action of affinin and the H. longipes root ethanol extract, as well as their effects on the NS using an animal model. The ethanol extract was obtained by maceration, and affinin was purified from it through chromatographic techniques. Chemical and thermal analgesia were used to assess their analgesic proprieties. Irwin’s test was used to evaluate their stimulating or depressing effects. The ethanol extract and affinin displayed analgesic action similar to ketorolac and stimulating effect comparable to caffeine on the nervous system of adult mice.

Anti-inflammatory effects of ethanolic extract and alkamides-derived from Heliopsis longipes roots

Ethnopharmacological relevance Heliopsis longipes (A. Gray) Blake (Asteraceae) is a broadly used species in the Mexican, Central and South American Traditional Medicine for its anaesthetic, analgesic, anti-inflammatory and anti-ulcerative properties. The ethanolic extract contains alkamides, mainly affinin (spilanthol). This family of compounds exerts an in vitro inhibitory action on the cyclooxygenase and lipoxygenase enzymes. Aim of the study The present study approaches the anti-inflammatory effect of the extract and its main bioactive component affinin and derived isobutyl-decanamide. Materials and methods The anti-inflammatory effect was evaluated through the mouse ear oedema test by means of two irritating agents, arachidonic acid (AA) and phorbol myristate acetate (PMA). Results Heliopsis longipes, affinin and isobutyl-decanamide displayed a marked anti-inflammatory effect on the AA model with ED 50 = 0.8, 1.2 and 0.9 mg/ear, respectively. Nimesulide (1 mg/ear) was used as a reference drug. In PMA model, the extract and two alkamides also showed a dose-dependent anti-inflammatory effect with ED 50 = 2.0, 1.3 and 1.1 mg/ear, respectively. Indomethacin (3 mg/ear) was used as reference drug. Conclusions These results could represent an important contribution to explain the anti-inflammatory ethnobotanical effects reported for Heliopsis longipes and other species containing affinin (spilanthol). For the first time the topical anti-inflammatory effects of Heliopsis longipes, affinin and isobutyl-decanamide were studied.

Fungistatic and bacteriostatic activities of alkamides from Heliopsis longipes roots: affinin and reduced amides.

This work demonstrates the fungistatic and bacteriostatic activities of affinin, the main alkamide of Heliopsis longipes (Gray) Blake (Asteraceae) roots and two alkamides obtained by catalytic reduction of affinin: N-isobutyl-2E-decenamide and N-isobutyl-decanamide. The bioactivity was tested against Rhizoctonia solani groups AG3 and AG5, Sclerotium rolfsii, Sclerotium cepivorum, Fusarium sp., Vertcillium sp., phytopathogenic fungi; Phytophthora infestans, a phytopathogenic Chromista; Saccharomyces cerevisiae, a nonphytopathogenic ascomycete; and Escherichia coli, Erwinia carotovora, and Bacillus subtilis, bacteria. Affinin, being the primary component of the lipidic fraction, is expected to be responsible for the fungitoxic activity observed in roots of this plant species. Four of the assayed fungi showed an important sensitivity to the presence of affinin: S. rolfsii, S. cepivorum, P. infestans, and R. solani AG-3 and AG-5, displaying a growth inhibition of 100%. S. cerevisiaeshowed a similar growth inhibition with affinin. None of the alkamides obtained by catalytic reduction of affinin showed a fungitoxic activity. Affinin had a definite negative effect on the growth of E. coli and B. subtilis, but E. carotovora carotovora was not sensitive to the highest dose of affinin assayed. N-Isobutyl-2E-decenamide displayed a higher bacteriostatic activity against E. coli and E. carotovora carotovora. In both cases, this alkamide was more potent than affinin. On the other hand, only N-isobutyl-decanamide displayed a significant activity on the growth of B. subtilis.

Antimicrobial properties of alkamides present in flavouring plants traditionally used in Mesoamerica: affinin and capsaicin

The bioactive amides affinin and capsaicin isolated respectively from Heliopsis longipes roots and Capsicum spp fruits, were assayed for activity against Escherichia coli, Pseudomonas solanacearum, Bacillus subtilis and Saccharomyces cerevisiae suspension cultures. The alkamide affinin inhibited growth of E. coli and S. cerevisiae at concentrations as low as 25 μg/ml. Higher concentrations of affinin were necessary to inhibit growth of P. solanacearum and B. subtilis. However, high concentrations of capsaicin only retarded the growth of E. coli and P. solanacearum, whereas growth of B. subtilis was strongly inhibited and that of S. cerevisiae was initially enhanced. Results are discussed in relation to previous reports concerning crude extract and to the molecular structures of the bioactive compounds.