Pyricularia's Capability of Infecting Different Grasses in Two Regions of Mexico.

The genus Pyricularia includes species that are phytopathogenic fungi, which infect different species of Poaceae, such as rice and sorghum. However, few isolates have been genetically characterized in North America. The current study addresses this lack of information by characterizing an additional 57 strains of three grasses (Stenotaphrum secundatum, Cenchrus ciliaris and Digitaria ciliaris) from two distant regions of Mexico. A Pyricularia dataset with ITS sequences retrieved from GenBank and the studied sequences were used to build a haplotype network that allowed us to identify a few redundant haplotypes highly related to P. oryzae species. An analysis considering only the Mexican sequences allowed us to identify non-redundant haplotypes in the isolates of C. ciliaris and D. ciliaris, with a high identity with P. pennisetigena. The Pot2-TIR genomic fingerprinting technique resulted in high variability and allowed for the isolates to be grouped according to their host grass, whilst the ERIC-PCR technique was able to separate the isolates according to their host grass and their region of collection. Representative isolates from different host grasses were chosen to explore the pathogenic potential of these isolates. The selected isolates showed a differential pathogenic profile. Cross-infection with representative isolates from S. secundatum and C. ciliaris showed that these were unable to infect D. ciliaris grass and that the DY1 isolate from D. ciliaris was only able to infect its host grass. The results support the identification of pathogenic strains of Pyricularia isolates and their cross-infection potential in different grasses surrounding important crops in Mexico.

Nematicidal Effect of Shiitake (Lentinula edodes) Extracts Against Haemonchus contortus.

During the previous decades, the indiscriminate use of anthelmintics for the control of gastrointestinal nematodes has generated anthelmintic resistance in different parts of the world. It is necessary to search for new sustainable control alternatives, such as the use of extracts from plants and edible mushrooms. Therefore, the aim of the present study was to evaluate the nematicidal activity of extracts and fractions of the edible mushroom Lentinula edodes against Haemonchus contortus eggs and infective larvae. The basidiomata of L. edodes ECS-401 were provided by the Tropical Fungi Laboratory of El Colegio de la Frontera Sur and were extracted with ethyl acetate, methanol, and water. Fractionation of the most active extract was carried out by open column chromatography. The bioassays were performed in 96-well microtiter plates using 100 eggs/larvae, a final volume of 100 µL, and different concentrations of extracts/fractions (n = 4). Bioassay readings were taken at 48 h for egg hatching inhibition (EHI) and at 24, 48 and 72 h for larval mortality (LM). The ethyl acetate extract exhibited the highest percentage of EHI (100%). For the LM bioassay, the aqueous extract was the most active (69%), but its fractions did not show larvicidal activity. The chemical profile of the aqueous extract was analyzed by high-performance liquid chromatography, which showed the presence of phenols, flavonoids, and terpenes. L. edodes extracts showed ovicidal and/or larvicidal activity.

Improving the production of podophyllotoxin in hairy roots of Hyptis suaveolens induced from regenerated plantlets.

Ten Hyptis suaveolens hairy root lines were established by infecting nodal explants with K599+pGus-GFP+ and ATCC15834+pTDT strains from Agrobacterium rhizogenes. Genetic transformation was confirmed by epifluorescence and plagiotropic hairy root growth in absence of growth regulators. Cytotoxicity was determined using the sulforhodamine B method, and the production of podophyllotoxin (PTOX) was measured by high performance thin layer chromatography scanning. Through these methodologies, HsTD10 was identified as the hairy root line with the highest cytotoxicity and PTOX production, which was corroborated by liquid chromatography-mass spectrometry and micrOTOF-Q II. A suspension culture of HsTD10 was established in which PTOX and carbohydrate consumption during growth kinetics were quantified by high-performance liquid chromatography. Procedures to increase the production and retrieval of PTOX in the HsTD10 line included selection of culture medium, addition of thiamine, and modification of the PTOX extraction method. The best combination of these variables was MS medium at 75% of its components with the addition of 2 mg L-1 of thiamine, extraction with methanol-dichloromethane, and sonication at 40 ± 5°C. During kinetics, growth-associated PTOX accumulation was observed. The specific growth rate (µ) was 0.11 d-1. The highest concentration of PTOX obtained with HsTD10 (5.6 mg g-1 DW) was 100 times higher than that reported for roots of wild plants and 56 times higher than that for in vitro nontransformed roots of H. suaveolens.

Antibacterial activity of Morinda citrifolia Linneo seeds against Methicillin-Resistant Staphylococcus spp.

In traditional medicine, Morinda citrifolia (Noni) is used to treat various ailments, including skin and respiratory-tract infections. In this work, a bio-directed study (seed extracts) with five bacteria was carried out against four clinical isolates of Methicillin-Resistant Staphylococcus (MRS) and Staphylococcus aureus ATCC 29213 strain to find molecules capable of inhibiting them. Three organic extracts were obtained by maceration of the noni seeds with ascending polarity solvents (n-hexane, dichloromethane and methanol) that were evaluated as antibacterial in the model of bioautography and broth microdilution techniques. The results showed that the methanolic extract was the most active against all bacteria (MIC = 16 mg/mL). The chromatographic fractionation performed on this extract allowed obtaining six fractions (EMF1-EMF6), of which F1, F2 and F5 exhibited activity against some of the bacteria. EMF1 fraction reached an MIC of 25 µg/mL against S. haemolyticus twice as much as the positive control, in which the chemical content is mainly composed of a mixture of γ-butyrolactones (1-2) and esterified fatty acids (3-9); chemical characterization of the nine compounds was carried out based on gas chromatography coupled to masses. EMF2 fraction, presented an MIC of 200 µg/mL against S. aureus 0198 and S. haemolyticus 562B, where a coumarin known as scopoletin (10) was isolated and active against S. aureus 0198 (MIC = 100 µg/mL). EMF5 fraction demonstrated an MIC of 200 µg/mL against S. aureus 0198, S. haemolyticus 562B and S. epidermidis 1042, in which a neolignan known as americanin A (11) was identified, showing activity against S. haemolyticus 562B and S. epidermidis 1042 (MIC = 100 µg/mL). The chemical characterization of isolated compounds 10 and 11 was performed by the analysis of 1H and 13C NMR. Therefore, the methanolic extract, identified and isolated compounds showed important antibacterial activity against the MRS, validating its use in traditional medicine.

Neolignans from Aristolochia elegans as antagonists of the neurotropic effect of scorpion venom.

ETHNOPHARMACOLOGICAL RELEVANCE: The high frequency of poisoning by sting or bite from venomous animals has begun to be a serious public health problem in Mexico where scorpion sting is the most common. Because of this, there is the need to seek active substances in plant species with an antagonistic effect against neurotropic activity of scorpion venom. The aim of this work was to demonstrate which of the compounds contained in the n-hexane extract from Aristolochia elegans roots display activity against scorpion venom. MATERIAL AND METHODS: Antagonist activity displayed by extract, fractions and isolated compounds obtained from Aristolochia elegans was guided by the inhibition of smooth muscle contraction induced by scorpion venom (Centruroides limpidus limpidus) in a model of isolated guinea pig ileum. The neolignans obtained from this extract were isolated and analyzed by chromatographic methods including HPLC. The chemical characterization of these compounds was performed by the analysis of (1)H and (13)C NMR spectra. RESULTS: The bio-guided chromatographic fractionation allowed us to isolate 4 known neolignans: Eupomatenoid-7 (1), licarin A (2), licarin B (3), eupomatenoid-1 (4) and other new neolignan which was characterized as 2-(3'-hydroxy-4'-methoxyphenyl)-3-methyl-5-[(E)-α-propen-γ-al]-7-methoxy-benzo [b] furan (5). This compound was named as eleganal. Compounds 1 and 2 were purified from the most active fraction AeF3 (EC50 of 149.9µg/mL, Emax of 65.66%). A doses-response analysis of eupomatenoid-7(1) and licarin A(2) allowed us to establish EC50 values (65.96µg/mL and 51.96µg/mL) respectively. CONCLUSIONS: The antagonistic effect against Centuroides limpidus limpidus scorpion venom displayed by the n-hexane extract from Aristolochia elegans roots is due to the presence of neolignans 1-2 contained in the fraction AeF3. Chemical analysis of fraction AeF2 allowed the isolation of a new compound which was identified as 2-(3'-hydroxy-4'-methoxyphenyl)-3-methyl-5-[(E)-α-propen-γ-al]-7-methoxy-benzo[b]furan (5), denominated as eleganal.

Isosakuranetin-5-O-rutinoside: a new flavanone with antidepressant activity isolated from Salvia elegans Vahl.

Ursolic acid (1) and a new flavanone, 5-O-(6-rhamnosylglucoside)-7-hydroxy-4'-methoxyflavanone (2), were isolated from the leaves of Salvia elegans Vahl. These natural products displayed antidepressant activity in mice as determined by means of a forced swimming test (FST) evaluation. Structural elucidation was carried out by chemical derivatization (acetylation) and spectroscopic analyses, such as 1H- and 13C-NMR and two-dimensional (2-D) COSY, heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple-bond correlation (HMBC) spectroscopy experiments.

Inhibition of acetylcholinesterase activity by hidroalcoholic extractand their fractions of Bouvardia ternifolia (Cav. ) Shcltdl (Rubiaceae) / Inhibición de la actividad de acetilcolinesterasa por el extracto hidroalcohólico y sus fracciones de Bouvardia ternifolia (Cav. ) Shcltdl (Rubiaceae)

The hydroalcoholic extract (BtHA) and its fractions of Bouvardia ternifolia were evaluated as inhibitors of the activity of the acetylcholinesterase enzyme utilizing the in vitro method (Ellman). BtHA inhibited the acetylcholinesterase enzyme competitively (IC50 = 0.6 ug/ml); the ethyl acetate fraction (BtF-AcOEt) caused mixed-type inhibition (IC50 = 0.96 ug/ml). A fraction insoluble on methanol (Bt-Faq-1) showed a mixed-type inhibition (CI50 = 0.96 ug/ml). Finally, the methanol-soluble fraction (Bt-Faq-2), presented complex, mixed-type inhibition that corresponds to the C5 system ( alpha= 0.740 and beta = 0.842). Rutin, quercetin, kaempferol and ursolic acid were detected by HPLC and the concentration of these compounds was different in each fraction.

El extracto hidroalcohólico (BtHA) y fracciones provenientes de Bouvardia ternifolia fueron evaluadas como inhibidores de la enzima acetilcolinesterasa utilizando el método enzimático propuesto por Ellman. BtHA inhibe a la enzima de manera competitiva (IC50 = 0.6 ug/ml); la fracción de acetato de etilo (BtF-AcOEt) provoca una inhibición mixta (IC50 = 0.96 ug/ml). La fracción insoluble en metanol (Bt-Faq-1) mostró una inhibición tipo mixta (CI50 = 0.96 ug/ml). Finalmente la fracción soluble en metanol, Bt-Faq-2, inhibe a la enzima presentando una inhibición mixta que corresponde a un sistema C5 ( alfa= 0.740 and beta= 0.842). Mediante HPLC se detectó rutina, quercetina, canferol y ácido ursólico la concentración de estos compuestos fue diferente en cada fracción.