Preliminary analysis of Brazilian Amazonian plant extracts using bench-top assays in a through-put basis aiming the identification of potential antioxidant natural product

Plants are a source of compounds that are used for the treatment of human and veterinary diseases. Brazil is one of the richest countries in the world in terms of biodiversity. The present study evaluated extracts using thin-layer chromatography to identify antioxidant activity and determine the presence of groups of compounds, in a large-scale basis. A total of 1,260 aqueous and organic extracts were obtained from plants that were collected in the Amazon and Atlantic rain forests. Thin-layer chromatography was performed to evaluate the presence of alkaloids, anthraquinones, cardioactive glicosides, terpenes, and phenolics and determine antioxidant and radical scavenging activity using the following reagents: Dragendorff's reagent, KOH, Kedde's reagent, sulphuric acid, NP reagent, ß-carotene, and 2,2-diphenyl-1-picrylhydrazyl (DPPH). Of the 1,260 extracts, 837 (66.43%) presented a ß-carotene/bleaching response, and 1,205 (95.63%) presented a radical scavenging response. Alkaloids were found in 203 extracts (16.11%). Anthraquinones were found in 14 extracts (1.11%), cardenolides were found in eight extracts (0.63%). The present findings shows the importance of the Brazilian Amazon plants as sources of antioxidant and radical scavenging active compounds.(AU)

In vitro activity of Amazon plant extracts against Enterococcus faecalis

Previous studies analyzing 2,200 plant extracts indicated anti-enterococcal activity in 25 extracts obtained from Brazilian forests' plants. In the present study, these extracts were subjected to microdilution broth assay (MDBA) and disk diffusion assay (DDA) using planktonic Enterococcus faecalis ATCC® 29212TM and were submitted to phytochemical analysis in TLC and HPLC. Three extracts obtained from Ipomoea alba (MIC < 40 µg/mL), Diclinanona calycina (MIC < 40 µg/mL) and Moronobea coccinea (40 < MIC < 80 µg/mL; MBC = 80 µg/mL) showed significant bactericidal activity in the MDBA and four extracts obtained from I. alba (14.04 ± 0.55 mm diameter) S. globulifera (14.43 ± 0.33 mm and 12.18 ± 0.28 mm diameter) and Connarus ruber var. ruber (13.13 ± 0.18 mm diameter) were active in DDA. Residues H2O obtained from Psidium densicomum (mean of 16.78 mm diameter) and from Stryphnodendron pulcherrimum (mean of 15.97 mm diameter) have shown an improved antibacterial activity after fractionation if compared to that obtained from the respective crude extracts. Antioxidant activity was observed in some residues of the active extracts. TLC analysis showed that phenolic compounds are likely to be found in active extracts. Three molecules were isolated from S. globulifera and were identified by 13C NMR lupeol, α-amyrin and 3β-hydroxyglutin-5-ene. The present chemical and biological findings suggest that these extracts are a potential source of new anti-Enterococcus compounds to be introduced in endodontic therapy.

Anti-Streptococcal activity of Brazilian Amazon Rain Forest plant extracts presents potential for preventive strategies against dental caries

Caries is a global public health problem, whose control requires the introduction of low-cost treatments, such as strong prevention strategies, minimally invasive techniques and chemical prevention agents. Nature plays an important role as a source of new antibacterial substances that can be used in the prevention of caries, and Brazil is the richest country in terms of biodiversity. Objective: In this study, the disk diffusion method (DDM) was used to screen over 2,000 Brazilian Amazon plant extracts against Streptococcus mutans. Material and Methods: Seventeen active plant extracts were identified and fractionated. Extracts and their fractions, obtained by liquid-liquid partition, were tested in the DDM assay and in the microdilution broth assay (MBA) to determine their minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs). The extracts were also subjected to antioxidant analysis by thin layer chromatography. Results: EB271, obtained from Casearia spruceana, showed significant activity against the bacterium in the DDM assay (20.67±0.52 mm), as did EB1129, obtained from Psychotria sp. (Rubiaceae) (15.04±2.29 mm). EB1493, obtained from Ipomoea alba, was the only extract to show strong activity against Streptococcus mutans (0.08 mg/mL<MIC<0.16 mg/mL; MBC=0.16 mg/mL) in the MBA. Conclusions: The active extracts, discovered in the Amazon rain forest, show potential as sources of new antibacterial agents for use as chemical coadjuvants in prevention strategies to treat caries. .

New trends in dentistry: plant extracts against Enterococcus faecalis. The efficacy compared to chlorhexidine

Enterococcus faecalis is an important pathogen associated with endodontic diseases, and its elimination and control are of paramount importance, as it represents one of the major causes of failure in the treatment of endodontic disease. Twenty-five plant extracts obtained from Brazilian forests were found to be effective against planktonic E. faecalis and were subjected to two traditional antibacterial assays, the microdilution broth assay (MDBA) and the disk diffusion assay (DDA), using chlorhexidine (CHX) as a control. Seven out of 25 extracts showed significant antibacterial activity and were tested in a biofilm assay, and three of these extracts were subjected to chemical fractionation. Residues were tested for their antibacterial activity, and the first chemical findings were described based on thin layer chromatography (TLC). Extracts obtained from Ipomoea alba, Symphonia globulifera and Moronobea coccinea showed significant bactericidal activity in the MDBA. The same I. alba and S. globulifera extracts, as well as the extract obtained from Connarus ruber var. ruber, showed significant activity in the DDA. RH2O obtained from Psidium densicomum and Stryphnodendron pulcherrimum showed better antibacterial activity compared to the respective crude extracts and CHX. TLC analysis showed that phenolic compounds and triterpenes represent the first findings of chemical groups that may occur in all species. The results of the present study include the discovery of six active extracts against planktonic E. faecalis and support further testing via assays involving biofilm formation, as well as the determination of the compounds' chemical profiles, as their activity was significantly better than that observed for CHX.

A composição florística e a diversidade de pteridófitas diferem entre a Floresta de Restinga e a Floresta Ombrófila Densa das Terras Baixas do Núcleo Picinguaba/PESM, Ubatuba/SP? / Ferns composition and diversity differ between Restinga and Lowland Rainforest areas in the Serra do Mar?

As pteridófitas constituem um componente importante da flora tropical, representando aproximadamente 10 por cento do total de plantas vasculares de florestas tropicais, sendo o grupo dominante entre a vegetação herbácea. O objetivo do trabalho foi verificar se as comunidades de pteridófitas de duas áreas de Mata Atlântica, Floresta de Restinga (FRS) e Floresta Ombrófila Densa de Terras Baixas (FTB), situadas sobre solos notavelmente distintos e separadas por uma grande rodovia, difeririam em sua composição florística e diversidade. Estas duas fisionomias estão localizadas no Núcleo Picinguaba do Parque Estadual da Serra do Mar, Ubatuba, São Paulo (23° 31' a 23° 34' S e 45° 02' a 45° 05' W). Em cada área delimitamos sete parcelas de 20 × 20 m, nas quais os indivíduos foram coletados, identificados e recenseados. Efetuamos três métodos de análise multivariada (TWINSPAN, UPGMA e PCO) para verificar a existência de grupos florísticos; calculamos o índice de Payandeh para definirmos o nível de agregação de cada espécie em cada uma das duas áreas (FRS e FTB); obtivemos espécies indicadoras para cada área; e realizamos análises de diversidade (riqueza, equabilidade e heterogeneidade). Nas duas áreas amostramos 3.482 indivíduos, dos quais 1.366 ocorrem na FRS e 2.116 na FTB. Encontramos 14 espécies na FRS e 29 na FTB; cinco espécies foram compartilhadas entre as duas áreas. As análises de grupos florísticos mostraram a formação de dois blocos bem definidos (FRS × FTB). Na FRS, relativamente mais espécies apresentaram distribuição agregada e menos espécies apresentaram distribuição aleatória em relação à FTB. Encontramos quatro espécies indicadoras para a FRS e oito para a FTB. As curvas resultantes da rarefação por indivíduos indicaram forte diferença de riqueza específica entre as duas comunidades, favorável à FTB. As diferenças encontradas podem estar relacionadas às características físico-químicas do solo (mais fértil e menos tóxico na FTB), à dinâmica da água (as espécies vegetais da FRS estão, de modo geral, sujeitas ao estresse hídrico) e ao impacto causado pela estrada que corta o Parque. Esses aspectos poderiam estar relacionados a diferentes formas de ocupação de nichos e ao fato de que algumas espécies em ambientes com recursos limitados e distribuídos heterogeneamente no espaço, como é o caso da Restinga estudada, eliminariam as demais.

Ferns are an important component of the tropical flora, representing about 10 percent of all vascular plants of tropical forests, constituting the dominant group among the herbaceous vegetation. The aim of this study was to determine whether the ferns communities in two areas of Atlantic Forest, Restinga (FRS) and Lowland Ombrophilous Dense (FTB) forests, located on soils remarkably distinct and separated by a highway, differ in their floristic composition and diversity. These two faces are located in Picinguaba locality, Parque Estadual da Serra do Mar, Ubatuba, São Paulo (23° 31' to 23° 34' S and 45° 02' to 45° 05' W). We delimited seven plots of 20 × 20 m in each area, collected, identified and listed the fern individuals. We performed three methods of multivariate analysis (TWINSPAN, UPGMA and PCO) to verify the existence of floristic groups; calculated the Payandeh index to define the level of aggregation of each species in each of the two areas (FRS and FTB); obtained indicator species for each area; and performed diversity analysis (richness, evenness and heterogeneity). The two areas sampled 3482 individuals, 1366 of which occur in FRS and 2116 in FTB. We found 14 species in FRS and 29 in FTB; these areas shared five species. We found two well-defined floristic blocks (FRS × FTB) in cluster analysis. In the FRS, relatively most species showed aggregated distribution and fewer species showed random distribution in relation to FTB. We found four indicator species for FRS and eight for FTB. The curves resulting from the individual-based rarefaction indicated a strong difference in species richness between the two communities, in favor to FTB. These differences may be related to physical and chemical characteristics of soil (more fertile and less toxic in the FTB), water dynamics (plant species in the FRS are generally subject to water stress) and the sharp break caused by highway that cuts through the park. These aspects could be related to different forms of occupation of niches and to the fact that some species in environments with limited resources and heterogeneously distributed in space, such as the studied Restinga, would eliminate the others.

Antibacterial activity of Brazilian Amazon plant extracts

Infections caused by multiresistant bacteria are a widespread problem, especially in intensive care units. New antibiotics are necessary, and we need to search for alternatives, including natural products. Brazil is one of the hottest spots in the world in terms of biodiversity, but little is known about the chemical and pharmacological properties of most of the plants found in the Amazon rain forest and the Atlantic Forest. We screened 1,220 organic and aqueous extracts, obtained from Amazon and Atlantic rain forest plants, against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and E. coli. Seventeen organic and aqueous extracts obtained from 16 plants showed activity against both Gram-positive bacteria. None of the extracts showed relevant activity against the Gram-negative E. coli and Pseudomonas aeruginosa.