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)

Can mouth washes containing chlorhexidine 0.12% be used as synonym of a water solution of chlorhexidine 0.12%? / Pode lavagens da boca contendo 0.12 % de clorexidina ser utilizado como sinónimo de uma solução aquosa de cloro-hexidina 0.12 % ?

Chlorhexidine digluconate (CHX) is a gold standard drug in dentistry and is widely used as a reference in both in vitro and in vivoexperiments. Due to ease of access, mouth washes containing CHX 0.12% are used as a substitute for aqueous CHX 0.12% solution in laboratory experiments. Additionally, it is well known that for product flavor purposes, volatile compounds are added to mouth washes formulations. Volatiles added to CHX 0.12% may improve wash's antibacterial ability. Volatiles add potency to the mouth wash formulation. Compared with an aqueous CHX 0.12% solution, it is proposed that CHX solutions and Periogard^® would have antimicrobial activity. Antimicrobial activity was assessed in the present study via disk diffusion assays against Streptococcus mutans, Streptococcus sanguinisand Escherichia coli. Periogard^® showed a significantly higher antibacterial activity in relation to CHX 0.12% (p<0.05) and a similar activity in relation to CHX 1% (p>0.05). Periogard^(r) volatiles were analyzed by gas-chromatography/mass spectrometry (GCMS) and the presence of antibacterial menthol, menthone, isomenthol, menthyl acetate, trans-anethol and eugenol was verified. Finally, the use of Periogard^® as a synonym of CHX 0.12% must be avoided, because its antibacterial activity is closely related to CHX 1%...

Gluconato de clorexidina (CHX) é um fármaco considerado padrão ouro, em Odontologia, amplamente usado como referência em estudos in vitro e in vivo. Em razão da facilidade de acesso, enxaguatórios bucais que contêm CHX 0,12% são usados em substituição à solução aquosa de clorexidina (CHX 0,12%), em experimentos laboratoriais. É sabido que devido à palatabilidade do produto, os mesmos enxaguatórios bucais contêm compostos voláteis em sua formulação, além da CHX 0.12%. Visto que voláteis adicionados podem acrescentar poder antibacteriano à formulação, a comparação da resposta antibacteriana da solução aquosa de CHX em diferentes concentrações e de Periogard^® é proposta no presente artigo. Para tanto, utilizou-se o ensaio do disco de difusão em ágar com inóculos de Streptococcus mutans, Streptococcus sanguinis e Escherichia coli. Periogard^® mostrou atividade antibacteriana significativa contra as três cepas analisadas, quando comparada à atividade de CHX 0.12% (p<0,05) e atividade similar à CHX diluída a 1% (p>0,05). A presença de compostos voláteis no Periogard^® foi analisada por GC-MS e observou-se que mentol, mentona, isomentol, acetato de mentila, trans-anetol e eugenol estão presentes na formulação. Deste modo, o uso de Periogard^(r) como sinônimo de CHX 0,12% deve ser evitado, uma vez que sua atividade se assemelha àquela da CHX diluída a 1%...

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.