In Vitro Anti-Tubulin Activity on MCF10A Cell Line and In Silico Rigid/Semiflexible-Residues Docking, of Two Lignans from Bursera Fagaroides var. Fagaroides.

Podophyllotoxins are natural lignans with known cytotoxic activity on several cell lines. The structural basis for their actions is mainly by the aryltetralin-lignan skeleton. Authors have proposed a cytotoxic mechanism of podophyllotoxins through the topoisomerase-II inhibition activity; however, several studies have also suggested that podophyllotoxins can inhibit the microtubules polymerization. In this work, the two possible mechanisms of action of two previously isolated compounds from the stem bark of Bursera fagaroides var. fagaroides: acetylpodophyllotoxin (1) and 5'-desmethoxydeoxypodophyllotoxin (2), was analyzed. An in vitro anti-tubulin epifluorescence on the MCF10A cell line and enzymatic topoisomerase II assays were performed. The binding affinities of compounds 1 and 2 in the colchicine binding site of tubulin by using rigid- and semiflexible-residues were calculated and compared using in silico docking methods. The two lignans were active by the in vitro anti-tubulin assay but could not inhibit TOP2 activity. In the in silico analysis, the binding modes of compounds into both rigid- and semiflexible-residues of tubulin were predicted, and only for the semiflexible docking method, a linear correlation between the dissociation constant and IC50 previously reported was found. Our results suggest that a simple semiflexible-residues modification in docking methods could provide an in vitro correlation when analyzing very structurally similar compounds.

Inner bark as a crucial tissue for non-structural carbohydrate storage across three tropical woody plant communities.

Non-structural carbohydrates (NSC) are crucial for forest resilience, but little is known regarding the role of bark in NSC storage. However, bark's abundance in woody stems and its large living fraction make it potentially key for NSC storage. We quantified total NSC, soluble sugar (SS) and starch concentrations in the most living region of bark (inner bark, IB), and sapwood of twigs, trunks and roots of 45 woody species from three contrasting tropical climates spanning global extremes of bark diversity and wide phylogenetic diversity. NSC concentrations were similar (total NSC, starch) or higher (SS) in IB than wood, with concentrations co-varying strongly. NSC concentrations varied widely across organs and species within communities and were not significantly affected by climate, leaf habit or the presence of photosynthetic bark. Starch concentration tended to increase with density, but only in wood. IB contributed substantially to NSC storage, accounting for 17-36% of total NSC, 23-47% of SS and 15-33% of starch pools. Further examination of the drivers of variation in IB NSC concentration, and taking into account the substantial contribution of IB to NSC pools, will be crucial to understand the role of storage in plant environmental adaptation.

Diverse patterns of stored water use among saplings in seasonally dry tropical forests.

Tree species in seasonally dry tropical forests likely vary in their drought-survival mechanisms. Drought-deciduousness, which reduces water loss, and low wood density, which may permit dependence on stored water, are considered key traits. For saplings of six species at two distinct sites, we studied these and two associated traits: the seasonal amount of water released per stem volume ("water released") and the hydraulic capacitance of the stem (C). Two deciduous species with low stem density, Cavanillesia platanifolia and Bursera simaruba, had high C and high dry-season stem water potential (Ψ(stem)), but differed in dry-season water released. C. platanifolia did not use stored water during the dry season whereas B. simaruba, in a drier forest, released stored water. In both, water released was highest while flushing leaves, suggesting that stored water supports leaf flushing. In contrast, two deciduous species with intermediate stem density, Annona hayesii and Genipa americana, had intermediate C, low dry-season Ψ(stem), and high seasonal change in water released. Meanwhile, two evergreen species with intermediate stem density, Cojoba rufescens and Astronium graveolens, had relatively low C, low dry-season Ψ(stem), and intermediate seasonal change in water released. Thus, at least three, distinct stored-water-use strategies were observed. Additionally, bark relative water content (RWC) decreased along with Ψ(stem) during the dry season while xylem RWC did not change, suggesting that bark-stored water buffers Ψ(stem) seasonally. Together these results suggest that seasonal use of stored water and change in Ψ(stem) are associated with functional groups that are characterized by combinations of deciduousness and stem density.

Medicamentos Fitoterápicos na odontologia: evidências e perspectivas sobre o uso da aroeira-do-sertão (Myracrodruon urundeuva Allemão) / Phytotherapy medicines in dentistry: evidence and perspectives on the use of "Aroeira-do-sertão" (Myracrodruon Urundeuva Allemão)

Nas pesquisas com fitoterápicos o uso popular pode sugerir espécies potencialmente importantes, porém, faz-se necessário uma série de estudos, entre eles, a identificação de espécies com comprovada ação farmacológica e/ou substâncias biologicamente ativas. O uso de fármacos fitoterápicos na prática clínica, tratamento e prevenção de afecções de menor severidade vêm sendo reconhecido pelo SUS ultimamente. Apesar da utilização de plantas medicinais na odontologia ser ainda pouco explorada, existe pesquisa científica sobre os efeitos antimicrobiano, analgésico e antinflamatório de algumas espécies, entre elas: óleo de copaíba, extrato de romã, cravo da Índia, malva, tanchagem, amoreira, sálvia, e camomila. Nesta revisão o objetivo foi reunir informação sobre o potencial da aroeira-do-sertão (M. urundeuva All), planta utilizada na medicina tradicional nordestina e em alguns países da América do Sul, como fitoterápico na odontologia. Os extratos de aroeira são obtidos através do preparo das folhas, raízes, entrecasca e casca do tronco e galhos. Da casca de M. urundeuva já foram isoladas: chalconas diméricas: urundeuvina A, B, C, e matosina. Encontramos pesquisas sobre os seguintes efeitos da aroeira-do-sertão: ação antimicrobiana; antiinflamatória/cicatrizante no tratamento de ferimentos; gastrites; úlceras gástricas; cervicites; vaginites e hemorróidas. A aroeira conta com bons resultados em pesquisas que avaliaram o controle de microorganismo relacionado à patologias bucais, tal como S. mutans. No entanto, necessita-se de estudos para comprovar seu mecanismo de ação e definir condições seguras para seu uso em patologias específicas.

With regards to the studies of phytotherapeutic medicines, their popular use proves to be potentially important; however, a series of studies are necessary focusing on the identification of the species that have proven pharmacological action and/or biologically active components. The use of phytotherapy medicines in the clinical practice, treatment and prevention of less severe disorders is being recently recognized by the Brazilian SUS. Particularly in dentistry, the use of medicinal plants is still underexplored. However, some studies were conducted with plants of popular medicine use, such as: copaiba oil, pomegranate extract, clove, malva, plantain, mulberry, sage and chamomile, among others, in the search for antimicrobial, analgesic and anti-inflammatory qualities. Some of these qualities were later proven in scientific studies. In this review, we aimed to highlight the potential of the "aroeira-do-sertão" tree (M. urundeuva All), which is a plant utilized in traditional medicine in the Northeast region of Brazil and in some South America countries, as a phytotherapeutic medicine in dentistry. The extracts of the "aroeira-do-sertão" tree are acquired through the preparation of the leaves, roots and bark of the trunk and branches. The dimeric chalcones, urundeuvina A, B, C and matosine were isolated in the M. urundeuva bark. Some published studies have investigated the effects of the "aroeira-do-sertão" such as; antimicrobial action, anti-inflammatory action, healing in the treatment of wounds, gastritis, gastric ulcers, cervicitis, vaginitis, and hemorrhoids. In this regard, the "aroeira-do-sertão" has shown good results in studies involving the control of microorganism related to oral conditions, such as S. mutans. However, further studies are needed to confirm its mechanism of action and establish safe conditions for its use in specific situations (i.e. diseases).