Publications by authors named "Ropke C"

Despite the vast global botanical diversity, the pharmaceutical development of herbal medicinal products (HMPs) remains underexploited. Of over 370,000 described plant species, only a few hundred are utilized in HMPs. Most of these have originated from traditional use, and only a minority come from megadiverse countries.

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Enterococci are gram-positive, widespread nosocomial pathogens that in recent years have developed resistance to various commonly employed antibiotics. Since finding new infection-control agents based on secondary metabolites from organisms has proved successful for decades, natural products are potentially useful sources of compounds with activity against enterococci. Herein are reported the results of a natural product library screening based on a whole-cell assay against a gram-positive model organism, which led to the isolation of a series of anacardic acids identified by analysis of their spectroscopic data and by chemical derivatizations.

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Schistosomiasis is a disease caused by parasites of the genus Schistosoma, currently affecting more than 200 million people. Among the various species of this parasite that infect humans, S. mansoni is the most common.

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Agricultural expansion and intensification are major threats to tropical biodiversity. In addition to the direct removal of native vegetation, agricultural expansion often elicits other human-induced disturbances, many of which are poorly addressed by existing environmental legislation and conservation programmes. This is particularly true for tropical freshwater systems, where there is considerable uncertainty about whether a legislative focus on protecting riparian vegetation is sufficient to conserve stream fauna.

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Alfred Russel Wallace proposed classifying Amazon rivers based on their colour and clarity: white, black and clear water. Wallace also proposed that black waters could mediate diversification and yield distinct fish species. Here, we bring evidence of speciation mediated by water type in the sailfin tetra (Crenuchus spilurus), a fish whose range encompasses rivers of very distinct hydrochemical conditions.

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This study investigated a lycopene-rich extract from red guava (LEG) for its chemical composition using spectrophotometry, mass spectrometry, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), and computational studies. The cytotoxic activity of LEG and the underlying mechanism was studied in human breast adenocarcinoma cells (MCF-7), murine fibroblast cells (NIH-3T3), BALB/c murine peritoneal macrophages, and sheep blood erythrocytes by evaluating the cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and flow cytometry. Spectrophotometry analysis showed that LEG contained 20% of lycopene per extract dry weight.

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This study investigated the anti-inflammatory activity of the extract (LEG) and purified (LPG) lycopene from guava (Psidium guajava L.), as well as some mechanisms possibly involved in this effect. The anti-inflammatory activity was initially assessed using paw edema induced by Carrageenan, Dextran, Compound 48/80, Histamine and Prostaglandin E2 in Swiss mice.

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Combined effects of climate change and deforestation have altered precipitation patterns in the Amazon. This has led to changes in the frequency of extreme events of flood and drought in recent decades and in the magnitude of the annual flood pulse, a phenomenon that influences virtually all aspects of river-floodplain ecosystem dynamics. Analysis of long-term data revealed abrupt and synchronous changes in hydrology and fish assemblage structure of a floodplain lake near the confluence of Amazon and Negro rivers.

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The temporal effect of discharge and limnology on fish composition and species diversity in a floodplain lake at the confluence of the Amazon and Negro Rivers was evaluated. Species richness, abundance and assemblage composition were strongly influenced by seasonal discharge of the Amazon and Negro Rivers, which affects lateral connectivity, water conductivity and temperature. As a consequence, temporal β-diversity was high in the lake and the assemblage was dominated by seasonally transient species.

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Ethnopharmacological Relevance: There are ethnopharmacological reports supporting the use of neem (Azadirachta indica A. Juss) leaf against bacterial and worm infections. However there is a lack of studies about its effect on bacterial biofilm formation and Schistosoma mansoni worms.

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The infusion of aerial parts of Ilex paraguariensis is widely consumed. Its antioxidant activity suggests an important role of this plant in the treatment/prevention of oxidative stress related diseases. Plant extract active compounds are frequently found in esterified form that may be poorly absorbed.

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Chlorogenic acid is a natural potent antioxidant. It can be used in cosmetics formulations, but for this purpose its photochemical stability should be determined to ensure that the compound will not be degraded after UV radiation exposure. To evaluate this possibility, the concentration of a chlorogenic acid solution was determined by HPLC before and after UVA and UVB irradiation.

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Article Synopsis
  • This study investigated the effects of Pothomorphe umbellata extract on skin damage caused by UVB radiation in hairless mice.
  • Results showed that UVB exposure decreased thymine dimer-positive and apoptotic cells, while increasing p53 and proliferating cell nuclear antigen-positive cells.
  • After prolonged UVB exposure, treatment with P. umbellata led to reduced skin hyperplasia and an increase in protective p53-positive cells, indicating its potential to protect against UVB-induced skin damage.
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Pothomorphe umbellata, a native Brazilian plant, is popularly known to be effective in the treatment of skin lesions. This benefit is attributed to 4-nerolidylcatechol (4-NC), a compound extracted from P. umbellata.

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Pothomorphe umbellata is a native plant widely employed in the Brazilian popular medicine. This plant has been shown to exert a potent antioxidant activity on the skin and to delay the onset and reduce the incidence of UVB-induced skin damage and photoaging. The aim of this work was to optimize the appearance, the centrifuge stability and the permeation of emulsions containing P.

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The in vitro ability of Pothomorphe umbellata ethanolic crude extract to inhibit matrix metalloproteinase (MMP) in normal cornea and in cornea after alkali injury was demonstrated. Corneas of albino rabbits were injured with 1 N NaOH for 20 s. After 48 h the corneas were excised, homogenized and analyzed for MMP-9 (92 kDa), pro-MMP-2 (72 kDa) and MMP-2 (67 kDa) activity by gelatin zymography.

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No satisfactory treatment is currently available for metastatic malignant melanoma. Recently, the flavonoid quercetin was suggested as a potential treatment due to its anti-tumorogenic properties. Some of these properties appeared to correspond to those published for UVB irradiation.

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Article Synopsis
  • Exposure to UV radiation increases the production of matrix metalloproteinases (MMPs), which are enzymes that break down cellular structures, making them targets for therapeutic interventions.
  • The study investigated the effects of the plant Pothomorphe umbellata's ethanolic root extract on two specific MMPs, MMP-2 and MMP-9, finding that the extract inhibited these enzymes more effectively than the isolated active compound 4-nerolidylcatechol (4-NC).
  • Results demonstrated that P. umbellata could inhibit MMP-9 activity in vivo after UVB exposure, supporting its potential use in preventing skin damage and possibly treating skin cancer.
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Article Synopsis
  • Pothomorphe umbellata, known for its antioxidant and photoprotective properties, is being considered for cosmetic and pharmaceutical applications due to the compound 4-nerolidylcathecol (4-NC) found in its roots.
  • The study assessed the photostability, chemical stability, and SPF of P. umbellata root extract in a gel formulation using high-performance liquid chromatography and UV spectrophotometry.
  • Results showed that 4-NC remained stable at lower temperatures but degraded at 45°C; after UV exposure, its SPF was low (3.35), indicating that its antioxidant effects are more significant than its sun protection capabilities.
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Purpose: To examine the effect of human retinal pigment epithelial (RPE) cells on phytohemagglutinin (PHA) activation of T cells.

Methods: Resting peripheral blood lymphocytes (PBLs) were stimulated with PHA with or without the presence of gamma-irradiated RPE cells. Proliferation and the cell cycle profile were thereafter investigated by 3H-thymidine incorporation and flow cytometric analysis.

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In this study we evaluated the activity of Pothomorphe umbellata root extract on hairless mice chronically exposed to UVB radiation (76.5 mJ/cm(2), 4 days per week for 22 weeks). Mouse dorsal surfaces were treated topically with 20 mg/cm(2) of a carbomer 940 gel (vehicle) with or without P.

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A characteristic feature of neoplastic transformation is a perpetual activation of oncogenic proteins. Here, we studied signal transducers and activators of transcription (STAT) in patients with mycosis fungoides (MF)/cutaneous T-cell lymphoma (CTCL). Malignant lymphocytes in dermal infiltrates of CTCL tumors showed frequent and intense nuclear staining with anti-PY-STAT3 antibody, indicating a constitutive activation of STAT3 in vivo in tumor stages.

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To study cell motility in different phases of the cell cycle, time-lapse recording by computer-assisted microscopy of unsynchronised cells from three mammalian cell lines (L929, BT4Cn, HeLa) was used for the determination of the displacements of individual cells. The displacements were used for calculation of three key parameters describing cell motility: speed, persistence time and rate of diffusion. All investigated cell lines demonstrated a lower cell displacement in the G2 phase than in the G1/S phases.

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Human papillomavirus type 16 (HPV-16) is the major risk factor for development of cervical cancer. The major oncoprotein E7 enhances cell growth control. However, E7 has in some reports been shown to induce apoptosis suggesting that there is a delicate balance between cell proliferation and induction of cell death.

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In this work we evaluated the influence of topical application of P. umbellata root extract gel, containing 0.1% of 4-nerolidylcathecol, on the antioxidant network in UV-induced oxidative damage in hairless mouse skin.

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