Two cardenolide glycosides from the seed fairs of Asclepias curassavica and their cytotoxic activities / 中国天然药物

Two cardenolide glycosides, corotoxigenin 3-O-[β-D-glucopyranosyl-(1→4)-6-deoxy-β-D-glucopyranoside] (1) and coroglaucigenin 3-O-[β-D-glucopyranosyl-(1→4)-6-deoxy-β-D-glucopyranoside] (2), were isolated from the seed fairs of Asclepias curassavica. The structures of 1-2 were determined based on the combination of the analysis of their MS, NMR spectroscopic data and acid hydrolysis. The inhibitory effects of compounds 1 and 2 on human colorectal carcinoma cells (HCT116), non-small cell lung carcinoma cells (A549) and hepatic cancer cells (SMMC-7721) were evaluated. The results showed that both compounds 1 and 2 significantly inhibited the viability, proliferation, and migration of A549, HCT116 and SMMC-7721 cells, suggesting that compounds 1 and 2 can be applied in the treatment of lung, colon and liver cancers in clinical practice. This study may not only provide a scientific basis for clarifying the active ingredients in A. curassavica, but also help to understand its antitumor activity, which can promote the application of A. curassavica in clinical treatment of various cancers.

Low level resistance of wild poinsettia biotypes to glyphosate and alternative chemical control / Resistência de nível baixo de biótipos de leiteira ao glyphosate e alternativas quimicas de controle

In the State of Rio Grande do Sul (RS), Southern Brazil, glyphosate has not been capable of controlling wild poinsettia (Euphorbia heterophylla L.) in soybean fields, thus, suggesting resistanceto this herbicide. Therefore, this study aimed at evaluating sensitivity of wild poinsettia biotypes to glyphosate, identifying the occurrence of resistance of wild poinsettia to the herbicide in RS state and determining the resistance factor of wild poinsettia biotypes under suspicion, besides assessing other herbicides as alternative controls. Two greenhouse experiments, which lasted two years, were conducted by a completely randomized design with four replications. Six biotypes (Factor A) and eight doses of glyphosate (Factor B) were used for getting the dose-response curve. Regarding the alternative control, post-emergence herbicides for soybean and corn crops were tested. Control and dry mass of the shoot were analyzed as variables. Resistance factors of resistant biotypes 20.2 and 21.1 were 4.83 and 5.29, respectively, by comparison with the susceptible biotype (11.4). In RS state, there has currently been high selection pressure due to the intensive use of glyphosate against wild poinsettia plants, as the result of the occurrence of biotypes 20.2 and 21.1 which have low levels of resistance to glyphosate and very little control by ALS-inhibiting herbicides. Therefore, an alternative to mitigate the problem is the use of herbicides with different mechanisms of action.

As falhas de controle de leiteira (Euphorbia heterophylla L.) após aplicação de glyphosate em lavouras de soja do Rio Grande do Sul (RS) são frequentes, sugerindo a resistência ao herbicida. Diante disso, os objetivos foram avaliar a sensibilidade de biótipos de leiteira ao herbicida glyphosate, identificar a ocorrência da resistência, determinar o fator de resistência de biótipos de leiteira com suspeita de resistência e avaliar herbicidas alternativos para o seu controle. Foram conduzidos dois experimentos em casa de vegetação, em delineamento inteiramente casualizado com quatro repetições ambos realizados em dois anos. No experimento de curva dose-resposta foram utilizados cinco biótipos (fator A) e oito doses do herbicidaglyphosate (fator B). Para o controle alternativo, foram testados herbicidas em pós emergência das culturas de soja e milho. As variáveis analisadas foram controle e massa seca da parte aérea. O fator de resistência dos biótipos resistentes (20.2 e 21.1) foram 4,83 e 5,29 comparativamente ao biótipo suscetível (11.4) respectivamente. Existe elevada pressão de seleção pelo glyphosate em plantas de leiteira no RS, observando-se a ocorrência de biótipos 20.2 e 21.1 com resistência de nível baixo ao herbicida e com controle reduzido pelos herbicidas inibidores de ALS. Portanto, uma alternativa para atenuar o problema é o uso de herbicidas com diferentes mecanismos de ação

Validación del uso tradicional de especies de asclepias contra el veneno de bothrops diporus (yarará chica) en el nordeste de Argentina / Validation of the traditional use of asclepias species against bothrops diporus (yarará chica) venom in northeast of Argentina

La familia Asclepiadaceae posee tradición en etnomedicina. En el nordeste argentino, A.mellodora y A. curassavica se utilizan como cataplasmas en accidentes de ofidios. En este trabajo, los extractos acuosos, etanólicos y hexánicos de A. mellodora y A. curassavica se evaluaron por SDS-PAGE para determinar su actividad alexitérica. El estudio in vitro de la capacidad inhibitoria de las actividades proteolítica, hemolítica indirecta y coagulante permitieron determinar que ambas especies manifiestan actividad, siendo A. mellodora más activa. Estadísticamente los extractos de A. mellodora fueron igualmente activos contra el veneno de Bothrops diporus y no mostraron diferencias significativas respecto del órgano utilizado en la inhibición de la actividad coagulante. Este resultado está en consonancia con la forma tradicional de su uso como cataplasma. Sobre el extracto etanólico de las raíces de A. mellodora se realizó un fraccionamiento bioguiado que permitió identificar fracciones de compuestos responsables de la actividad.

The Aclepiadaceae family has been reported by its use in ethnomedicine. In the northeast of Argentina, A. mellodora and A. curassavica are traditionally used in ofidic accidents as poultices. In this work, aqueous, alcoholic and hexanoic extracts were analyzed by SDS-PAGE to determine their anti-snake activity. The in vitro study of the inhibitory ability of the following activities: proteolytic, indirect hemolytic activity and inhibition of the coagulant activity, allowed demonstrating that both species were active against venom, being A. mellodora the most active. Statistically, all extracts of A. mellodora were active against venom in the inhibition of the coagulant activity, without significant differences with respect to the organ used; which is consistent with the traditional use as external poultice. The alcoholic extract of A. mellodora roots was subjected to a bio-guided separation. The fractions obtained were enriched in compounds which could probably be responsible for the activity against venom.

Diagnose of the ingestion of Asclepias mellodora St. Hil. by sheep through microhistological analysis of their digestive contents / Diagnose da ingestão de Asclepias mellodora St. Hil. por ovinos através da análise micro-histológica de seu conteúdo digestivo

Asclepias mellodora St. Hil. is a native acute toxic species frequent in the grasslands of the Buenos Aires province, Argentina, whose toxicity had not been assessed until now. This study evaluates the minimal lethal dose of this species for sheep, and the possibility of microscopically recognizing its fragments in gastrointestinal contents as a complementary diagnostic tool in necropsies. Three Frisona sheep (average LW=55±4.5 kg) were dosed via an esophageal tube with each one of the following doses of asclepias: 8.0, 5.0, 2.0 and 0.8 g DM.kg LW-1. Sheep poisoned with the three higher doses died between 10 and 85 h after intoxication, but those receiving the lower dose did not. During necropsies we: 1) determined the dry weight of the contents of rumen+reticulum, omasum+abomasum, and large intestine, 2) estimated the percentages of asclepias fragments by microanalysis correcting for digestion effects on fragment recognition, and 3) calculated the total mass of asclepias in the digestive tract of each animal. For the three higher doses, the mass of asclepias identified in the total ingesta was 12.3±3.4 percent of the amount supplied, possibly because of the strong diarrhea its ingestion produced. The percentages of asclepias in rumen+reticulum did not differ from the average quantified for the entire tract. The results of this study indicate that the minimal lethal doses of asclepias for sheep is between 2.0 and 0.8g DMÀkg LW-1, and that the microhistological analysis of the rumen+reticulum, the easiest region to sample, can be used to confirm the ingestion of this toxic species, although the estimated percentage will be not a good estimator of the ingested percentage.

Asclepias mellodora St. Hil. é uma espécie nativa de aguda toxicidade, frequente nos campos da província de Buenos Aires, Argentina. A sua toxicidade não foi avaliada até agora. Este estudo avalia a dose mínima letal desta espécie, para os ovinos, bem como a possibilidade de reconhecer microscopicamente seus fragmentos no conteúdo gastrointestinal como uma ferramenta complementar de diagnóstico em necropsias. Três ovinos Frisona (PV média = 55±4,5 kg) foram dosados através de uma sonda esofágica em cada uma das seguintes doses de Asclepias: 8,0, 5,0, 2,0 e 0,8 g DM.kg PV-1. Ovinos intoxicados com as três maiores doses morreram entre 10-85 h após a intoxicação, mas não aqueles que receberam a dose menor. Durante as necropsias se: 1) determinou o peso seco do conteúdo do rúmen + retículo, omaso + abomaso e intestino grosso, 2) estimou as porcentagens de fragmentos de Asclepias por microanálise, fazendo a correção para efeitos de digestão no reconhecimento dos fragmentos, e 3) calculou a massa total de Asclepias no trato digestivo de cada animal. Para as três doses maiores, a massa de Asclepias identificada na ingesta total foi de 12,3±3,4 por cento da quantidade fornecida, possivelmente por causa da forte diarréia produzida pela sua ingestão. As porcentagens de Asclepias no rúmen + retículo não diferiram da média quantificada para o trato completo. Os resultados deste estudo indicam que a dose letal mínima de Asclepias em ovinos é de entre 2,0 e 0,8 g kg PV ò DM-1, e que a análise micro-histológica do rúmen + retículo, a região mais fácil de amostrar, pode ser usada para confirmar a ingestão desta espécie tóxica, embora a percentagem estimada não será um bom estimador da porcentagem ingerida.