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Pedro Jacob Christoffoleti - One of the best experts on this subject based on the ideXlab platform.
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curvas de dose resposta de biotipos resistente e suscetivel de Bidens pilosa l aos herbicidas inibidores da als
Scientia Agricola, 2002Co-Authors: Pedro Jacob ChristoffoletiAbstract:Weed herbicide resistance is a phenomenon defined as a response reduction of a population to a chemical product sprayed at a recommended rate, as a result of its continuous application. The incidence of herbicide-resistant weeds in Brazil has increased lately, but few scientific studies have been conducted to elucidate the phenomenon. In this regard, experiments aiming to build rate-response curves comparing a resistant (R) and a susceptible (S) biotype of the weed Bidens pilosa L., to ALS inhibitor herbicides, were set up. At the stage of three to four leaves, biotypes R and S of B. pilosa were sprayed with the herbicides chlorymuron-ethyl, metsulfuron-methyl, nicosulfuron and imazethapyr, at multiples of 0.0; 0.001, 0.01, 0.1; 1.0; 10; 100 and 1,000 of the recommended field rates. Results lead to the building of percentage control rate-response curves. The ratio between the C50 of the resistant biotype, divided by the C50 of the susceptible biotype, were 40.92; 173.84; 57.47 and 57.16 for the herbicides chlorymuron-ethyl, nicosulfuron, metsulfuron-methyl and imazethapyr, respectively. The R biotype of B. pilosa had a high degree of resistance in relation to all ALS inhibitor herbicides studied, being also cross resistant to imidazolinone and sulfonylurea.
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analise comparativa do crescimento de biotipos de picao preto Bidens pilosa resistente e suscetivel aos herbicidas inibidores da als
Planta Daninha, 2001Co-Authors: Pedro Jacob ChristoffoletiAbstract:A resistencia de biotipos de plantas daninhas aos herbicidas inibidores da acetolactato sintase (ALS) e causada pela insensibilidade desta enzima aos herbicidas que inibem sua atividade catalitica. A insensibilidade da enzima e decorrente de uma alteracao estrutural, resultado da substituicao de certos aminoacidos no sitio de acao do herbicida. Esta alteracao na enzima pode eventualmente resultar, alem da resistencia ao herbicida, em modificacoes na taxa de crescimento da planta, fato este comprovado para os biotipos resistentes aos herbicidas inibidores do fotossistema II, os quais apresentam taxa de crescimento prejudicada pela alteracao no sitio de acao sofrida pelo herbicida. Esta possivel diminuicao na taxa de crescimento da planta resistente tem consequencias diretas na competitividade do biotipo e, portanto, na sua dinâmica dentro da populacao, afetando diretamente as estrategias de manejo da resistencia. A presente pesquisa foi desenvolvida com o objetivo de comparar a taxa de crescimento de dois biotipos da planta daninha picao-preto (Bidens pilosa), sendo um resistente e um suscetivel aos herbicidas inibidores da ALS. Um experimento foi montado em casa de vegetacao, em vasos com capacidade de 5 L, sendo uma planta de cada biotipo por vaso, coletando-se a biomassa seca destas plantas e a area foliar semanalmente, iniciando-se 14 dias apos o plantio. Os resultados de crescimento da biomassa e area foliar foram ajustados utilizando-se a funcao de Richards (log-logistica). Desta analise, foram derivadas a taxa de crescimento absoluto (TCA), a taxa de crescimento relativo (TCR) e a taxa de assimilacao fotossintetica liquida (TAL). O biotipo suscetivel apresentou peso de biomassa seca superior ao resistente nas primeiras fases do crescimento, porem no final do ciclo o biotipo resistente igualou-se em tamanho de area foliar, pois apresentou, principalmente no inicio do ciclo de crescimento, TCA, TCR e TAL maiores que o suscetivel. Dessa forma, concluiu-se que o biotipo de Bidens pilosa resistente aos herbicidas inibidores da ALS apresenta a mesma eficiencia de producao de biomassa no final do ciclo. E provavel que, quando em competicao entre si e com as culturas, possua a mesma competitividade, sendo a dominância numerica de um biotipo sobre o outro decorrente apenas da pressao de selecao causada pelo herbicida.
Theophile Dimo - One of the best experts on this subject based on the ideXlab platform.
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leaf methanol extract of Bidens pilosa prevents and attenuates the hypertension induced by high fructose diet in wistar rats
Journal of Ethnopharmacology, 2002Co-Authors: Theophile Dimo, S V Rakotonirina, Paul V Tan, J Azay, Etienne Dongo, Gerard CrosAbstract:Chronic fructose treatment in rats has repeatedly been shown to elevate blood pressure in association with insulin resistance and hyperinsulinemia. The purpose of the current study was to investigate the effect of the leaf methanol extract of Bidens pilosa on systolic blood pressure (SBP) and plasma glucose, insulin, cholesterol, triglycerides and creatinine levels in rats with fructose-induced hypertension. Wistar rats that drank a 10% fructose solution for 3-6 weeks showed significant increase not only in plasma insulin and cholesterol levels but also in SBP. B. pilosa extract was able to prevent the establishment of hypertension and lower elevated blood pressure levels. The extract also reduced the highly elevated plasma insulin levels provoked by the high fructose diet. These results suggest that the leaf methanol extract of B. pilosa exerts its antihypertensive effect in part by improving insulin sensitivity.
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effects of the aqueous and methylene chloride extracts of Bidens pilosa leaf on fructose hypertensive rats
Journal of Ethnopharmacology, 2001Co-Authors: Theophile Dimo, J Azay, Gerard Cros, Jacques Pellecuer, Marc Bopelet, Jean Jacques SerranoAbstract:Abstract We investigated the effects of the aqueous (150–350 mg/kg) and methylene chloride (150–300 mg/kg) extracts of Bidens pilosa on fructose-induced hypertension in rats. Food and liquid intake were measured as well as systolic blood pressure and plasma levels of glucose, insulin, cholesterol, triglycerides and creatinine. Fructose feeding for 6 weeks induced hypertension, hyperinsulinemia and increased plasma triglyceride levels in male Wistar rats. The aqueous and methylene chloride extracts of B. pilosa reversed the high blood pressure and hypertriglyceridemia developed due to fructose feeding but did not have any effects on plasma levels of insulin and glucose. High doses of the extracts reduced plasma creatinine levels and tended to increase plasma cholesterol. These results suggest that the extracts of B. pilosa possess hypotensive effects whose mechanism of action is not related to insulin sensitivity.
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effects of methanol cyclohexane and methylene chloride extracts of Bidens pilosa on various gastric ulcer models in rats
Journal of Ethnopharmacology, 2000Co-Authors: Theophile Dimo, Etienne DongoAbstract:Abstract Ethnobotanical studies have revealed that Bidens pilosa is used in the traditional management of wounds and chronic gastro–duodenal ulcers. This led us to screen the methanol, cyclohexane and methylene chloride extracts of the plant for anti-ulcerogenic activity using the HCl/ethanol gastric necrotizing solution. The methylene chloride extract, which showed the highest activity (100% inhibition) at a dose of 750 mg/kg compared with the methanol and cyclohexane extracts (41 and 46% inhibition, respectively), was further tested using the indomethacin-HCl/ethanol-, absolute ethanol- and pylorus ligation-induced ulcer methods. Pre-treatment with indomethacin significantly reduced the protective effect of the extract against HCl/ethanol solution to 31%. The extract had very little gastric mucosal protection against absolute ethanol (9.8% inhibition at 750 mg/kg) compared with the controls and neither reduced gastric acid secretion in vivo nor the acidity of gastric juice following in vitro incubation.
Rufino R.j.n. - One of the best experts on this subject based on the ideXlab platform.
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Estudos anatômicos de folhas de espécies de plantas daninhas. II - Bidens pilosa, Emilia sonchifolia, Ageratum conyzoides e Sonchus asper
Planta Daninha, 2002Co-Authors: Ferreira E.a., Procópio S.o., Silva E.a.m., Silva A.a., Rufino R.j.n.Abstract:O objetivo deste trabalho foi de estudar a anatomia das folhas das espécies de plantas daninhas de grande ocorrência no Brasil: Bidens pilosa, Emilia sonchifolia, Ageratum conyzoides e Sonchus asper, visando aprofundar o conhecimento sobre as barreiras que cada espécie impõe à penetração dos herbicidas e, assim, fornecer subsídios para a busca de estratégias para superar esses obstáculos. As folhas completamente expandidas do terceiro ao quinto nó foram coletadas de plantas de ocorrência espontânea no campo. Das folhas de cada espécie foram obtidas três amostras da região central mediana, com aproximadamente 1 cm2. Foram realizados estudos de estrutura e clarificação e observações em microscópio eletrônico de varredura (MEV). Todas as espécies avaliadas são anfiestomáticas. As principais barreiras potenciais foliares à penetração de herbicidas constatadas na planta daninha B. pilosa foram a alta densidade tricomática, a baixa densidade estomática na face adaxial e o alto teor de cera epicuticular, principalmente na face adaxial. Alto teor de cera epicuticular, grande espessura da cutícula da face adaxial e baixa densidade estomática nas duas faces foram os obstáculos constatados nas folhas de E. sonchifolia. Já em relação a A. conizoides, a baixa densidade estomática na face adaxial foi o principal obstáculo detectado. S. asper apresentou como principais barreiras foliares à penetração de herbicidas a baixa densidade estomática na face adaxial e a grande espessura da epiderme da face adaxial.This research aimed to study leaf anatomy in the widely common Brazilian weed species Bidens pilosa, Emilia sonchifolia, Ageratum conyzoides and Sonchus asper, to acquire a better understanding of the barriers each species imposes upon herbicide penetration, and provide information on how to overcome these obstacles. The completely expanded leaves from the third to the fifth nodes were collected from plants spontaneously occurring in the field. From the leaves of each species, three samples with approximately 1 cm2 were taken at the central portion and used for structure, and clarification studies and scanning-electron microscope (SEM) observations. All species were found to be amphistomatic. The main leaf barriers against herbicide penetration in B. pilosa were found to be high trichome density and low stomatic density in the adaxial side. High content of epicuticular wax, high cuticle thickness in the adaxial side and low stomatic density on both sides were the herbicide barriers observed in the leaves of E. sonchifolia, while in A. conyzoides the barrier was low stomatic density in the adaxial side. S. asper's main leaf barriers were low stomatic density in the adaxial side and high epiderm thickness in the adaxial side
Chunching Lin - One of the best experts on this subject based on the ideXlab platform.
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anti herpes simplex virus activity of Bidens pilosa and houttuynia cordata
The American Journal of Chinese Medicine, 2003Co-Authors: Lienchai Chiang, Jungsan Chang, Chichain Chen, Chunching LinAbstract:The present study evaluated the antiviral activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb., using cytotoxicity test with XTT-based colorimetric assay. BCC-1/KMC ...
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antileukemic activity of Bidens pilosa l var minor blume sherff and houttuynia cordata thunb
The American Journal of Chinese Medicine, 2001Co-Authors: Jungsan Chang, Lienchai Chiang, Chichain Chen, Liteh Liu, Kuochih Wang, Chunching LinAbstract:To evaluate the anti-leukemic activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb., cytotoxicity tests with an XTT-based colorimetric assay were used. Five leukemic ceil lines, namely L1210, U937, K562, Raji and P3HR1, were cultured with hot water extracts of B. pilosa var. minor or H. cordata. Hot water extracts of B. pilosa var. minor inhibited these five leukemic cells with IC50s between 145 μg/ml and 586 μg/ml. The effect was greatest on four cell line, namely L1210, P3HR1, Raji and K562, with IC50s below 200 μg/ml and a selective index of more than 5. Hot water extract of H. cordata inhibited these five leukemic cells with IC50s between 478 μg/ml and 662 μg/ml. The selective index was between 1.5 and 2.1. B. pilosa var. minor was more effective than H. cordata in inhibiting most of the leukemic cells in our study. We suggest that B. pilosa L. var. minor (Blume) Sherff may prove to be a useful medicinal plant for treating leukemia.
R.j.n. Rufino - One of the best experts on this subject based on the ideXlab platform.
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Estudos anatômicos de folhas de espécies de plantas daninhas: II - Bidens pilosa, Emilia sonchifolia, Ageratum conyzoides e Sonchus asper
Planta Daninha, 2002Co-Authors: Evander Alves Ferreira, Antonio Alberto Da Silva, Sergio De Oliveira Procópio, E.a.m. Silva, R.j.n. RufinoAbstract:This research aimed to study leaf anatomy in the widely common Brazilian weed species Bidens pilosa, Emilia sonchifolia, Ageratum conyzoides and Sonchus asper, to acquire a better understanding of the barriers each species imposes upon herbicide penetration, and provide information on how to overcome these obstacles. The completely expanded leaves from the third to the fifth nodes were collected from plants spontaneously occurring in the field. From the leaves of each species, three samples with approximately 1 cm2 were taken at the central portion and used for structure, and clarification studies and scanning-electron microscope (SEM) observations. All species were found to be amphistomatic. The main leaf barriers against herbicide penetration in B. pilosa were found to be high trichome density and low stomatic density in the adaxial side. High content of epicuticular wax, high cuticle thickness in the adaxial side and low stomatic density on both sides were the herbicide barriers observed in the leaves of E. sonchifolia, while in A. conyzoides the barrier was low stomatic density in the adaxial side. S. asper's main leaf barriers were low stomatic density in the adaxial side and high epiderm thickness in the adaxial side.