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Tithonia diversifolia is a perennial bushy plant found in South America with significant ethnopharmacological importance as an antimalarial, antidiabetic, antibacterial, and anticancer agent. The aim of the present study was to determine the cytotoxicity of the ethanolic extract from leaves of T. diversifolia (TdE) on human cancer cell lines (HCT-116, SNB-19, NCIH-460 and MCF-7), as well as the mechanism of action involved in cell death and cellular modulation of oxidative stress. The TdE exhibited significant activity with IC50 values ranging from 7.12 to 38.41 µg/ml, with HCT-116 being the most sensitive cell line. Subsequent experiments were conducted with HCT-116 cell line. TdE decreased the number of viable cells, followed by induction of apoptotic events, increase in mitochondrial membrane permeabilization, and enhanced G2/M phase of the cell cycle. Pro-oxidative effects including elevated acidic vesicular organelle formation, lipid peroxidation, and nitric oxide by-products, as well as reduced levels of intracellular glutathione and reactive oxygen species production were also observed following incubation with TdE, which may lead to DNA damage followed by apoptotic cell death. These results demonstrate the potential of TdE ethanolic leaf extraction for biological activity and enhance the importance of continuing to study natural sources of plants for the development of anticancer agents.

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Historical climate changes and interspecific gene flow have played an important role in shaping the distribution and genetic diversity of the biota in the Neotropics. In this study, we explored the role of both the Pleistocene climate changes and hybridization on the contemporary geographic structure of two Neotropical weedy species: Tithonia tubaeformis and T. rotundifolia. Distribution shifts under past and current climate conditions were explored through ecological niche modelling (ENM). We then tested these hypotheses using chloroplast microsatellite (cpSSR) data in T. tubaeformis and compared the patterns deduced with those previously reported for T. rotundifolia using the same cpSSR loci. Lastly, we searched for shared haplotypes between species. Both species exhibited significant downwards altitudinal shifts during the last interglacial (LIG) and the Last Glacial Maximum (LGM). For instance, T. rotundifolia showed large suitable habitat areas since the LIG at xeric conditions in western Mesoamerica. Tithonia tubaeformis showed a ~five-fold range contraction during the LIG compared to current climate conditions, followed by a range expansion in the LGM. Despite the large shared refugial areas predicted through ENM, we found a low number of shared haplotypes, suggesting a minor role of hybridization in shaping the geographic structure of these species. Our results provide additional patterns of the population history of the northern Neotropics during the Quaternary, and we suggest that weedy widespread species are a well-suited group for the study of the effects of historic climatic changes on the biota of this region.

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Two assays were conducted to study the Tithonia diversifolia (Td) plant: (1) chemical analysis and in vitro dry matter digestibility (IVDMD) of plant parts and (2) productive performance of lambs fed a traditional diet or a Td diet (30% of Td plus 70% of the traditional diet). The plant parts studied were leaves (L), leaves and petioles (LP); and leaves, petioles and stems (LPS). Feed intake, weight gain and feed conversion were registered weekly during five weeks of experimentation. The L showed higher (P<0.05) crude protein content (26.7%) than LP and LPS (25.5 and 19.7%, respectively). Crude fiber (11.2%), neutral detergent fiber (45.4%), cellulose (16.9%) and hemicellulose (33.5%) were lower in L than in LP (12.5, 46.7, 18.0 and 35.7%, respectively) and LPS (22.6, 59.2, 27.0 and 43.5%, respectively). The L and LP showed the highest IVDMD (89.2 and 88.2%, respectively vs. 77.2% of LPS). The Td diet resulted in greater feed intake and weight gain and lower feed conversion than the traditional diet. Therefore, Tithonia diversifolia is a forage plant of good quality for lambs which does not affect the productive performance.(AU)

Dois ensaios foram realizados para estudar a planta de Tithonia diversifolia (Td): (1) análise química e digestibilidade in vitro da matéria seca (DIVMS) de partes de plantas e (2) desempenho produtivo de cordeiros alimentados com dieta tradicional ou dieta Td (30% de Td mais 70% da dieta tradicional). As partes vegetais estudadas foram folhas (L), folhas e pecíolos (LP); folhas, pecíolos e caules (LPS). O consumo de ração, o ganho de peso e a conversão alimentar foram registrados semanalmente, durante cinco semanas de experimentação. O L apresentou maior (P<0,05) conteúdo de proteína bruta (26,7%) que o LP e o LPS (25,5 e 19,7%, respectivamente). Fibra bruta (11,2%), fibra em detergente neutro (45,4%), celulose (16,9%) e hemicelulose (33,5%) foram menores em L do que em LP (12,5, 46,7, 18,0 e 35,7%, respectivamente) e LPS (22,6, 59,2, 27,0 e 43,5%, respectivamente). O L e o LP apresentaram o maior DIVMS (89,2 e 88,2%, respectivamente vs. 77,2% do LPS). A dieta Td resultou em maior consumo de ração e maior ganho de peso e menor conversão alimentar que a dieta tradicional. Portanto, Tithonia diversifolia é uma planta forrageira de boa qualidade para cordeiros que não afeta o desempenho produtivo.(AU)

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Within the evaluation of the quality of forage resources, the main parameter that defines it is the digestibility of dry matter, which together with the amount of neutral and acidic detergent fibers and crude protein constitutes the basic information to assess forages which are supplied in the diet of the cattle. This research was carried out at the University of Los Llanos (Villavicencio, Colombia), and its objective was to determine the digestibility of three forages in cattle through three different in vitro techniques: inoculation with ruminal fluid and with feces and enzymatic digestibility technique, making the comparison with the in situ technique in order to validate the techniques and equipment that are being used for these procedures. The following species were evaluated: Pennisetum purpureum (PP), Tithonia diversifolia (TD), and Bauhinia variegata (BV), assessing the curve and rate of degradation of dry matter (DM), neutral detergent fiber (NDF), and total protein (TP) (0 to 72 h). A design of repeated measures was used, under which the analysis of variance was carried out to determine the ranges of deviation between the techniques and thus establish the trend of the data; the variables evaluated were the DM, NDF, and TP digestibilities of the three forages using the four techniques (three in vitro and one in situ). After verifying the differences between the variances of the digestibilities and checking the sphericity assumption with the Mauchly test, multiple comparisons were made with the Bonferroni test with a significance of 5%. The digestibility of DM, NDF, and TP varied between 38.62 and 44.22, 54.18 and 66.97, and 47.54 and 57.05%; 49.07 and 70.70, 72.52 and 75.44, and 62.61 and 74.02%; 29.93 and 34.84, 26.21 and 70.88, and 25.67 and 50.60% respectively in forages PP, TD, and BV, depending on the technique used for their estimation. Despite finding statistically significant differences between several of the comparisons made in the digestibility techniques, a high coefficient of determination and a high correlation between the in vitro estimations with respect to the in situ estimation were found; therefore, it is possible to use these techniques routinely thus avoiding the need to have cattle with fistulae to perform digestibility tests, with enzymatic digestibility technique being the most practical one.

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The chemical ecology of plant-insect interactions has been driving our understanding of ecosystem evolution into a more comprehensive context. Chlosyne lacinia (Lepidoptera: Nymphalidae) is an olygophagous insect herbivore, which mainly uses host plants of Heliantheae tribe (Asteraceae). Herein, plant-insect interaction between Tithonia diversifolia (Heliantheae) and Chlosyne lacinia was investigated by means of untargeted LC-MS/MS based metabolomics and molecular networking, which aims to explore its inherent chemical diversity. C. lacinia larvae that were fed with T. diversifolia leaves developed until fifth instar and completed metamorphosis to the adult phase. Sesquiterpene lactones (STL), flavonoids, and lipid derivatives were putatively annotated in T. diversifolia (leaves and non-consumed abaxial surface) and C. lacinia (feces, larvae, pupae, butterflies, and eggs) samples. We found that several furanoheliangolide-type STL that were detected in T. diversifolia were ingested and excreted in their intact form by C. lacinia larvae. Hence, C. lacinia caterpillars may have, over the years, developed tolerance mechanisms for STL throughout effective barriers in their digestive canal. Flavonoid aglycones were mainly found in T. diversifolia samples, while their glycosides were mostly detected in C. lacinia feces, which indicated that the main mechanism for excreting the consumed flavonoids was through their glycosylation. Moreover, lysophospholipids were predominately found in C. lacinia samples, which suggested that they were essential metabolites during pupal and adult stages. These findings provide insights into the natural products diversity of this plant-insect interaction and contribute to uncovering its ecological roles.

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ETHNOPHARMACOLOGICAL RELEVANCE: Tithonia diversifolia (Helms.) A. Gray, popularly known in Brazil as "margaridão" or "mão-de-Deus" has been used in the folk medicine as anti-inflammatory and against other illnesses in several countries. Indeed, many studies show de effect of T. diversifolia in the inflammatory process, however, any of them have demonstrated the mechanism of cell migration. AIM OF THE STUDY: The aim of this investigation was to show the in vivo and in vitro effects of T. diversifolia leaves ethanol extract on neutrophil trafficking from the blood to the inflamed tissue and on cell-derived secretion of chemical mediators, as well as, the effects on inflammatory resolution and inflammatory pain. MATERIALS AND METHODS: Anti-inflammatory activity was investigated using carrageenan-induced inflammation in the subcutaneous tissue of male Swiss mice orally treated with the T. diversifolia extract (0.1, 1 or 3 mg/kg). The leukocyte influx (optical microscopy) and the secretion of chemical mediators (TNF, IL-6, IL-1ß and CXCL1, by enzyme-linked immunosorbent assay) were quantified in the inflamed exudate. Histological analysis of the pouches was performed. N-Formyl-methionine-leucine-phenylalanine-induced chemotaxis, lipopolysaccharide-induced TNF, IL-6, IL-1ß, CXCL1 and NO production, and adhesion molecule expression (CD62L and CD18, flow cytometry) were in vitro quantified using oyster glycogen recruited peritoneal neutrophils previous treated with the extract (1, 10, or 100 µg/mL). The resolution of inflammation was accessed by efferocytosis assay, and the antinociceptive activity was investigated using carrageenan-induced mechanical hypersensitivity. RESULTS: The oral treatment with T. diversifolia promoted reduction in the neutrophil migration as well as the decrease in total protein, TNF, IL-1ß and CXCL1 levels in the inflamed exudate. In vitro treatment with T. diversifolia shedding of ß2 integrin expressions, without alter CD62L expression. The extract was able to increase the efferocytosis of apoptotic neutrophils, and the increase of the IL-10 and the decrease of TNF secretion. Additionally, the extract reduced the hypersensitivity induced by carrageenan. CONCLUSIONS: Together, the data herein obtained showed that T. diversifolia extract presented anti-inflammatory activity by inhibiting the cytokine and NO production, and also the leukocyte migration. The mechanisms involved in the extract anti-inflammatory effects include the impairment in the leukocyte migration to the inflamed tissue, the pro-resolution activity, and consequently the anti-hypersensitivity.

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The objective of this study was to use different parts of the Tithonia tubaeformis plant in feed for fattening rabbits and then observe the effects on carcass and meat quality. Forty-eight weaned rabbits (35 days of age) were randomly assigned to four groups (n = 12 by treatment). Animals were fed ad libitum a control diet as well as three experimental diets, with addition of Tithonia tubaeformis leaves, whole plant, and stems. Rabbits were slaughtered after 63 days of age without fasting. Results indicate that live weight (0.917), skin (0.79), feet (6.679), and lumbar circumference of the carcass (0.707) have higher positive correlations with hot carcass. There were no significant differences between treatments for all variables measured, except for kidneys and kidney fat. pH and color values were different among treatments. The results indicate that Tithonia tubaeformis leaves or the whole plant could be added to feed for growing rabbits.(AU)

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