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Plumbago scandens L. (Plumbaginaceae) occurs in all regions of Brazil. It has been described as toxic to cattle and goats. Caustic lesions in the upper digestive tract characterize poisoning. P. scandens contains a naphthoquinone named plumbagin, which presents high cytotoxic activity. Plumbago auriculata Lam., a widely used ornamental plant, is considered potentially toxic, but there is limited data about its toxicity. This work aimed to validate analytical methodologies for determining the levels of plumbagin in samples of leaves, stems, and rumen content to be used as an auxiliary chemical marker in the laboratory diagnosis of intoxication. One methodology used thin layer chromatography (TLC), and another used high-performance liquid chromatography (HPLC). The presence of palisade grass (Urochloa brizantha (Hochst. ex A.Rich.) R.D.Webster), Guinea grass (Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L.Jacobs), corn silage, and rumen content did not interfere with plumbagin in the two methodologies. The TLC methodology generates qualitative results but is simple to implement and has a low cost. The HPLC methodology showed a limit of detection (LOD) of 0.01 μg/mL and a limit of quantification (LOQ) of 0.05 μg/mL. Leaf and stem samples of P. scandens evaluated showed high levels of plumbagin (0.261 ± 0.087 % and 0.327 ± 0.055 %, respectively). In contrast, leaves of P. auriculata did not show detectable levels of the toxin, and some stem samples showed low levels (up to 0.000114 %). Thus, these methodologies can be used to confirm or rule out the consumption of P. scandens in rumen content from animals suspected of poisoning. [Display omitted] • TLC and HPLC methods for detecting plumbagin from Plumbago scandens in rumen and plant samples were validated. • The leaves and stem of Plumbago scandens showed high levels of plumbagin. • Plumbago auriculata showed no detectable levels in the leaves and low levels in the steams. [ABSTRACT FROM AUTHOR]

Limonium brasiliense is a common plant on the southern coast of Brazil. The roots are traditionally used for treatment of premenstrual syndrome, menstrual disturbances and genito-urinary infections. Pharmaceutical preparations obtained from its roots and used for these purposes were marketed in Brazil in the 1980s and 1990s. Currently, the Brazilian Drug Agency (National Health Surveillance Agency, ANVISA) has canceled the registration of these products, and their use was discontinued because of a lack of studies to characterize the plant raw material and ensure the effectiveness and safety of its use. The aim of the present study was to develop and validate an analytical method to determine the content of total polyphenols (TP) in an extract from L. brasiliense roots, by the UV/Vis spectrophotometric method. L. brasiliense roots were extracted in acetone:water (7:3, v/v-10% w/v). The crude extract was used to develop a method for TP assay. The method was validated according to national and international guidelines. The optimum conditions for analysis time, wavelength, and standard substance were 30 min, 760 nm, and pyrogallol, respectively. Under these conditions, validation by UV/Vis spectrophotometry proved the method to be linear, specific, precise, accurate, reproducible, robust, and easy to perform. This methodology complies with the requirements for analytical application and to ensure the reliability of the results. [ABSTRACT FROM AUTHOR]