Sensing of mercury ion using light induced aqueous leaf extract mediated green synthesized silver nanoparticles of Cestrum nocturnum L.

In this study, a simple, one-pot, and eco-friendly biosynthesis of silver nanoparticles (AgNPs) was accomplished with the use of aqueous leaves extract of Cestrum nocturnum L.(AECN). Different techniques like ultraviolet-visible (UV-Vis) spectrophotometry, Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning area electron diffraction were used to investigate the optical, operational, and physical properties of the green synthesized AECN-AgNPs.The AECN-AgNPs were further used for the detection of Hg2+ by UV-Vis and electrochemical methods. The disintegration of the AECN-AgNPs solution caused the formation of an Ag-Hg amalgam, which caused discoloration of the solution. Sensing performance for a variety of metals such as Na+, K+, Mg2+, Ca2+, Ni2+, Cu 2+, Fe3+, Zn2+, Co2+, Cd2+, Pb2+, As3+, and Mn2+ at 10-mM concentrations was measured in order to determine the selectivity of the sensor towards the Hg2+. For the electrochemical determination of 2 + Hg2+ , AECN-AgNPs were immobilized on a glassy carbon (GC) electrode, and the resulting modified electrode (GC/AECN-AgNPs) was characterized by cyclic voltammetry. This phenomenon is advantageously used for the sensitive determination of trace level Hg2+. GC/AECN-AgNPs demonstrated a linear calibration range of 100 nM to 10 µM and a limit of detection of 21 nM for Hg2+ determination.

Light-Mediated Green Synthesis of DNA-Capped Silver Nanoparticles and Their Antibacterial Activity.

Green synthesis offers an eco-friendly and low-cost approach for the synthesis of silver nanoparticles (AgNPs). Many studies have reported on the use of biomolecules, especially plant extracts, as reducing and/or stabilizing agents in place of toxic chemicals. This study reports on the use of bacterial genomic DNA as an alternative stabilizing agent for the green synthesis of AgNPs under light activation. With both increased DNA quantities and reaction times under light exposure, more stabilized AgNPs formed as indicated by the surface plasmon resonance intensities. The synthesized AgNPs were spherical with an average size of 61.36±10.15 nm as calculated using the dynamic light scattering (DLS) technique. The X-ray diffraction, selected area electron diffraction, and high resolution transmission electron microscope (TEM) analyses confirmed the formation of face-centered cubic (fcc) structured AgNPs. The produced AgNPs exhibited antibacterial activities against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, suggesting its potential application as an antibacterial agent.

Evaluation of photocatalytic fuel cell (PFC) for electricity production and simultaneous degradation of methyl green in synthetic and real greywater effluents.

Recycling of alternative water sources particularly greywater and recovery of energy from wastewater are gaining momentum due to clean water scarcity and energy crisis. In this study, the photocatalytic fuel cell (PFC) employing ZnO/Zn photoanode and CuO/Cu photocathode was successfully designed for effective greywater recycling as well as energy recovery. The photoelectrodes were analyzed using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and fourier transform infrared (FTIR) spectroscopy. The PFC performance in terms of electricity generation and parallel methyl green (MG) degradation were evaluated under operating parameters such as electrolyte type, initial MG concentration and solution pH. The results showed that the addition of Na2SO4 electrolyte, MG concentration of 40 mg L-1 and solution pH of 5.2 improved the short circuit current density (Jsc) and power density (Pmax) in the as-constructed PFC. Such a system also afforded highest MG and chemical oxygen demand (COD) removal efficiencies after 4 h of irradiation. The photoanodes used in this study demonstrated great recyclability after four repetition tests. The COD removal was reduced to some extents when the PFC treatment was tested in the real greywater under optimal conditions. Various greywater quality parameters including ammoniacal nitrogen (NH3-N), turbidity, pH and biochemical oxygen demand (BOD5) were also monitored. The phytotoxicity experiments via Vigna radiate seeds indicated a reduction in the phytotoxicity.

Influence of transcutaneous electrical stimulation on heterotopic ossification: an experimental study in Wistar rats

Heterotopic ossification (HO) is a metaplastic biological process in which there is newly formed bone in soft tissues, resulting in joint mobility deficit and pain. Different treatment modalities have been tried to prevent HO development, but there is no consensus on a therapeutic approach. Since electrical stimulation is a widely used resource in physiotherapy practice to stimulate joint mobility, with analgesic and anti-inflammatory effects, its usefulness for HO treatment was investigated. We aimed to identify the influence of electrical stimulation on induced HO in Wistar rats. Thirty-six male rats (350-390 g) were used, and all animals were anesthetized for blood sampling before HO induction, to quantify the serum alkaline phosphatase. HO induction was performed by bone marrow implantation in both quadriceps of the animals, which were then divided into 3 groups: control (CG), transcutaneous electrical nerve stimulation (TENS) group (TG), and functional electrical stimulation (FES) group (FG) with 12 rats each. All animals were anesthetized and electrically stimulated twice per week, for 35 days from induction day. After this period, another blood sample was collected and quadriceps muscles were bilaterally removed for histological and calcium analysis and the rats were killed. Calcium levels in muscles showed significantly lower results when comparing TG and FG (P<0.001) and between TG and CG (P<0.001). Qualitative histological analyses confirmed 100% HO in FG and CG, while in TG the HO was detected in 54.5% of the animals. The effects of the muscle contractions caused by FES increased HO, while anti-inflammatory effects of TENS reduced HO.

Influence of transcutaneous electrical stimulation on heterotopic ossification: an experimental study in Wistar rats.

Heterotopic ossification (HO) is a metaplastic biological process in which there is newly formed bone in soft tissues, resulting in joint mobility deficit and pain. Different treatment modalities have been tried to prevent HO development, but there is no consensus on a therapeutic approach. Since electrical stimulation is a widely used resource in physiotherapy practice to stimulate joint mobility, with analgesic and anti-inflammatory effects, its usefulness for HO treatment was investigated. We aimed to identify the influence of electrical stimulation on induced HO in Wistar rats. Thirty-six male rats (350-390 g) were used, and all animals were anesthetized for blood sampling before HO induction, to quantify the serum alkaline phosphatase. HO induction was performed by bone marrow implantation in both quadriceps of the animals, which were then divided into 3 groups: control (CG), transcutaneous electrical nerve stimulation (TENS) group (TG), and functional electrical stimulation (FES) group (FG) with 12 rats each. All animals were anesthetized and electrically stimulated twice per week, for 35 days from induction day. After this period, another blood sample was collected and quadriceps muscles were bilaterally removed for histological and calcium analysis and the rats were killed. Calcium levels in muscles showed significantly lower results when comparing TG and FG (P<0.001) and between TG and CG (P<0.001). Qualitative histological analyses confirmed 100% HO in FG and CG, while in TG the HO was detected in 54.5% of the animals. The effects of the muscle contractions caused by FES increased HO, while anti-inflammatory effects of TENS reduced HO.

Exposed collagen in resin bonds to caries-affected dentin after dentin treatment with aqueous and alcoholic chlorhexidine solutions.

PURPOSE: To evaluate the effect of saturation of demineralized dentin with aqueous and alcoholic excipients of chlorhexidine (CHX) on the exposure of collagen fibrils in resin-dentin bonds in sound and caries-affected dentin. MATERIALS AND METHODS: Flat midcoronal dentin surfaces were prepared from 24 noncarious molars, and artificial caries was induced in half of the sample. For each substrate, the surfaces were assigned to 4 groups (n = 3) according to the saturation solution of the dentin: water, ethanol, 1% CHX aqueous or alcoholic solution. Infected dentin was removed by abrasive papers. After acid etching, the dentin surface was saturated with each solution for 60 s followed by application of Single Bond. The specimens were processed for Goldner's trichrome staining and the thickness of the exposed collagen zone (ECZ) at the resin/dentin interfaces was measured under optical microscopy. Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests (α = 0.05). RESULTS: Regardless of the saturation solution, caries-affected dentin presented a thicker ECZ at the bottom of the hybrid layer than did sound dentin. For both substrates, 100% ethanol had a negative influence on collagen exposure in comparison with water, but the same was not observed for the CHX alcoholic solution. CHX solutions did not differ significantly from each other or from their respective solvents. CONCLUSION: The saturation of phosphoric acid-demineralized dentin with either CHX aqueous or alcoholic solutions did not affect the exposure of collagen fibrils in the resin-dentin bonds produced in sound and caries-affected dentin. A thicker zone of exposed collagen was found in hybridized caries-affected dentin compared to noncarious dentin.

Percentage exposure of root dentin collagen after application of two irrigation protocols with manual or rotary instrumentation and two methacrylate resin-based sealers.

PURPOSE: To compare the percentage of collagen exposed in dentin root thirds after two irrigation protocols with manual or rotary instrumentation using two methacrylate resin-based sealers. MATERIALS AND METHODS: Forty-eight single-root human teeth were prepared with manual (n = 24) or nickeltitanium ProFile rotary (n = 24) instrumentation, using 5% NaOCl between instruments and 5 ml 17% EDTA as final irrigant or 20% citric acid + 2% chlorhexidine (CHX) between instruments and as the final irrigant. RealSeal or EndoREZ were used as filling materials. One 1-mm slice per third was abraded and stained with Masson's trichrome method. Mean exposed collagen values were obtained in four areas from each section (at 60X magnification) and a complete factorial ANOVA was used to analyze the influence of the study variables. Non-parametric Mann-Whitney's test was used to compare groups. Differences with p < 0.05 were considered significant. RESULTS: A significantly higher percentage of collagen was exposed in all thirds with the use of the 20% citric acid + 2% CHX protocol with rotary vs manual instrumentation, but percent collagen exposed did not differ as a function of the filling material. After the 5% NaOCl + 17% EDTA protocol, the percentage of collagen exposed did not differ between rotary and manual instrumentation but was higher with the use of RealSeal. CONCLUSION: The highest percentage exposure of collagen was with 20% citric acid + 2% CHX using rotary instrumentation, regardless of the filling material.

Effects of intracavernous injection of adipose-derived stem cells on cavernous nerve regeneration in a rat model.

The aim of this study was to investigate effects of intracavernous injection of adipose-derived stem cells (ADSCs) on cavernous nerve (CN) regeneration and functional status in a nerve-crush rat model. Thirty Sprague-Dawley male rats were randomly divided into three equal groups: one group underwent sham operation, while two groups underwent bilateral CN crush. Crush-injury group was treated at the time of injury with intracavernous injection of ADSCs, or injured control group with no further intervention. Erectile function was assessed by CN electrostimulation after 3 months. Penile tissue and crushed nerves were collected for histology. Three months after surgery, in the group that underwent bilateral nerve crushing with no further intervention, the functional evaluation showed a lower mean maximal intracavernous pressure (ICP) and maximal ICP per mean arterial pressure (MAP) with CN stimulation than those in the sham group. In the group with an immediate intracavernous injection of ADSCs, the mean maximal ICP and maximal ICP/MAP were significantly higher than those in the injured control group. Histologically, the group with the intracavernous injection of ADSCs had more myelinated axons of CNs and more NADPH-diaphorase-positive nerve fibers than the injured control group but fewer than the sham group. Intracavernous injection of ADSCs treatment had beneficial effects on the smooth muscle/collagen ratio in the corpus cavernosum. These results show that the intracavernous injection of ADSCs to the site of CN-crush injury facilitates nerve regeneration and recovery of erectile function. Our research indicates that penile injection of ADSCs can improve recovery of erectile function in a rat model of neurogenic ED.

The Effects of New Herbal Formula (KBMSI-1) on the Penile Erection and Corpus Cavernosum in Streptozotocin-induced Diabetic Rats / 대한남성과학회지

PURPOSE: The aim of this study was to investigate the effects of new herbal formula (KBMSI-1) on erectile dysfunction in streptozotocin-induced diabetic rat model. MATERIALS AND METHODS: We used male Sprague-Dawley rats aged 12 weeks and divided into three groups; control (n=8), diabetes (DM) (n=8), DM+KBMSI-1 200 mg/kg treatment (n=8) groups. The DM groups received a single intraperitoneal injection of streptozotocin (STZ). Distilled water was administered in the control and DM group. To investigate the penile erection, intracavernosal pressure (ICP) and intracavernosal pressure/mean arterial pressure (ICP/MAP) were recorded in all groups. Serial sections of the penis were used to perform Masson's trichrome stain. We analyzed the expression of nNOS and eNOS concentration in the isolated corpus cavernosum by western blotting. RESULTS: Peak ICP/MAP ratio was markedly increased in the treatment group with KBMSI-1 compared with DM group (p<0.05). Masson's trichrome staining of corpus cavernosum showed increase in smooth muscle volume and the regular arrangement of collagen fibers in KBMSI-1 treatment group compared with DM group. Western blot analysis revealed that the penile expressions of nNOS and eNOS protein were significantly higher in KBMSI-1-treated group than in DM group. CONCLUSIONS: This study showed that herbal formulation of KBMSI-1 enhances the penile erection and the level of eNOS and nNOS expression of penile corpus cavernosum in streptozotocin-induced diabetic rat model.

Novel methodology to evaluate the effect of residual moisture on epoxy resin sealer/dentine interface: a pilot study.

AIM: To evaluate the sealer/dentine interface associated with an epoxy resin sealer using the combination of Goldner's trichrome stain (GTS) and scanning electron microscopy (SEM) to verify the use of the experimental methodology. METHODOLOGY: Extracted human maxillary incisors (6) were subjected to root canal treatment. Subsequent to pulp removal, canal instrumentation and smear layer removal using EDTA and NaOCl, teeth were randomly and equally assigned to a 'wet' or 'dry' group. The 'dry' group was desiccated (95% ethanol/suction/paper points/air-drying), whilst the 'wet' group was treated with a saline rinse/suction/single paper point. Canals were then filled with an epoxy-based resin sealer and warm vertical gutta-percha compaction. After 7-day storage at 37°C, roots from each group were sectioned into apical, middle and coronal horizontal subsections that were cut and split into paired halves and evaluated with GTS or SEM. With GTS sections, hybrid layer and sealer tubular penetration were measured (n=15 measurements/intracanal location/condition) and evaluated using a two-factor repeated measures analysis of variance. The SEM qualitative analysis of paired sections was included as a complementary confirmation of GTS analyses. RESULTS: In dry and wet groups, there was no conspicuous sealer/dentine interface hybrid layer, irrespective of canal location. However, dry specimens exhibited more uniform sealer distribution with deeper tubular penetration in the coronal and middle third (P<0.05). In contrast, there was decreased sealer distribution and tubule penetration in the apical third, regardless of moisture condition (P<0.05). CONCLUSIONS: The experimental methodology (combination of GTS and SEM) can be used to evaluate the intracanal resin sealer/dentine interface. The pilot data indicated that thorough drying of the root canal system may result in improved epoxy resin sealer distribution and deeper resin sealer tubular penetration, especially in the coronal and middle thirds of root canals.

Grape seed proanthocyanidins increase collagen biodegradation resistance in the dentin/adhesive interface when included in an adhesive.

OBJECTIVES: Contemporary methods of dentin bonding could create hybrid layers (HLs) containing voids and exposed, demineralised collagen fibres. Proanthocyanidins (PA) have been shown to cross-link and strengthen demineralised dentin collagen, but their effects on collagen degradation within the HL have not been widely studied. The purpose of this study was to compare the morphological differences of HLs created by BisGMA/HEMA model adhesives with and without the addition of grape seed extract PA under conditions of enzymatic collagen degradation. METHODS: Model adhesives formulated with and without 5% PA were bonded to the acid etched dentin. 5-µm-thick sections cut from the bonded specimens were stained with Goldner's trichrome. The specimens were then exposed to 0.1% collagenase solution for 0, 1, or 6 days. Following collagenase treatment, the specimens were analysed with SEM/TEM. RESULTS: Staining did not reveal a difference in the HLs created with the two adhesives. SEM showed the presence of intact collagen fibrils in all collagenase treatment conditions for specimens bonded with adhesive containing PA. These integral collagen fibrils were not observed in the specimens bonded with adhesive without PA after the same collagenase treatment. TEM confirmed that the specimens containing PA still showed normal collagen fibril organisation and dimensions after treatment with collagenase solution. In contrast, disorganised collagen fibrils in the interfacial zone lacked the typical cross-banding of normal collagen after collagenase treatment for specimens without PA. CONCLUSIONS: The presence of grape seed extract PA in dental adhesives may inhibit the biodegradation of unprotected collagen fibrils within the HL.

Should trichrome stain be used on all post-liver transplant biopsies with hepatitis C virus infection to estimate the fibrosis score?

Recurrent hepatitis C is virtually universal after liver transplantation; however, an individual patient's clinical course and disease burden are highly variable and difficult to predict. The fibrosis score determined on posttransplant biopsies appears to be a sensitive and specific marker of disease progression and severity. Currently, the fibrosis score is determined from hematoxylin and eosin (H&E)-stained tissue sections supplemented by variable use of trichrome stain or other connective tissue-specific stains. In this study, we compare the fibrosis score on H&E stain with that obtained with trichrome stain in posttransplant liver biopsies of patients with hepatitis C. A total of 197 liver biopsies from 105 allograft patients with hepatitis C were reviewed. The mean fibrosis stage was 1.0 +/- 1.25 with H&E stain versus 1.69 +/- 1.42 with trichrome stain (P < 0.00001). The trichrome staging score was higher in 53.3%, lower in 3%, and the same in 43.7%. The fibrosis stage was raised by 2 or more points in 17.8% and elevated into a bridging category in 14.7%. No significant differences in clinical and laboratory levels were measured in patients with higher fibrosis scores. In conclusion, the hepatic fibrosis score is significantly underestimated by H&E stain in the posttransplant setting in patients with hepatitis C. The fibrosis stage may be an indicator of significant liver damage in these patients. Accuracy of its determination may be most easily facilitated by employment of a connective tissue stain.

Physiochemical interactions at the interfaces between self-etch adhesive systems and dentine.

OBJECTIVES: The purpose of this study is to provide direct and comprehensive information regarding morphology, quality and chemistry of the interfaces between three self-etching primers/adhesives and dentine. MATERIALS AND METHODS: The occlusal one-third of the crown was removed from 18 unerupted human third molars. The prepared dentine surfaces were randomly selected for treatment with one of three commercial self-etching bonding agents according to manufacturers' instructions. One two-step self-etching adhesive (Clearfil SE Bond) and two one-step self-etching adhesives (One-Up Bond F and Prompt L-Pop) were selected. Five-micron-thick sections of adhesive/dentine interface specimens were cut and stained with Goldner's trichrome for light microscopy. Companion slabs were analysed with micro-Raman spectroscopy and scanning electron microscopy (SEM). RESULTS: It was shown that the difference in aggressiveness of these three contemporary self-etching systems produced different thickness of hybrid layer. Staining technique showed a distinct coloured line/zone at the adhesive/dentine interfaces for all three bonding systems. The width of this line varied, and was approximately 1, 1-2, 2-3 microm for Clearfil SE Bond, One-Up Bond F and Prompt L-Pop, respectively. The colour differences in the stained interface sections, which is reflected by the extent to which the adhesive encapsulates the demineralised dentine matrix, indicated that collagen fibrils at the interfaces were not totally encased in all three self-etching adhesives. Raman results showed that Prompt L-Pop is the most aggressive systems in this study. It almost totally demineralised the 2-microm deep subsurface dentine, while Clearfil SE is mild, only partially demineralised the first micron deep dentine. CONCLUSIONS: The complementary techniques, i.e. SEM, staining and micro-Raman spectroscopy, hold considerable promise for comprehensive physicochemical characterisation of self-etching adhesive/dentine interfaces. In comparison with two-step self-etching system, the aggressive one-step system produces more complex interfaces.

Catalytic inhibition of topoisomerase IIalpha by demethylzeylasterone, a 6-oxophenolic triterpenoid from Kokoona zeylanica.

In a study to evaluate celastroloids as potential anticancer agents, demethylzeylasterone (5), a 6-oxophenolic triterpenoid from Kokoona zeylanica, was found to be an inhibitor of the enzyme topoisomerase IIalpha (IC(50) = 17.6 microM). Studies of the relationship of this inhibitor to both DNA and the enzyme resulted in 5 being classified as a "catalytic inhibitor" of topoisomerase II. Demethylzeylasterone selectively inhibits the growth of the breast cancer cell line MCF-7 (IC(50) = 12.5 microM) without inhibiting the growth of non-small cell lung cancer (NCI-H460) and CNS glioma (SF-268) cell lines. This is the first report of topoisomerase II inhibitory activity in a celastroloid.

Evaluation of the biological activity of crude extracts from plants used in Yucatecan traditional medicine. Part II. DNA-interacting activity.

Extracts from leaves, stems, and roots of twelve plants used commonly in Yucatecan traditional medicine were evaluated in the DNA-methyl green assay. Twenty one extracts showed DNA-interacting activity, and nine of them, belonging to five plant species, presented a displacement activity of 5% or higher. The highest activity (17.6%) was detected in the leaf extract of Heliotropium angiospermum.

A colorimetric assay for high-throughput screening of inhibitors of herpes simplex virus type 1 alkaline nuclease.

Herpes simplex virus type 1 (HSV-1) encodes a deoxyribonuclease that is frequently referred to as alkaline nuclease (AN) because of its elevated pH optimum. Studies with recombinant viruses which contain deletions in the HSV-1 gene encoding AN have indicated that this enzyme is required for efficient virus replication and therefore represents a potential target for novel antiviral therapies. A simple colorimetric assay for deoxyribonuclease activity employing a DNA-methyl green substrate was adapted for use in a high-throughput screen to identify small molecule inhibitors of this enzyme. This screen identified 1,2-benzoisothiazolin-3-one as a specific inhibitor of AN, since it exhibited activity against AN but was completely inactive against bovine pancreatic DNaseI. Subsequent studies revealed that this compound most likely inhibited AN by forming disulfide linkages with one or more exposed cysteine residues on the surface of the enzyme and that AN was sensitive to sulfhydryl-group-modifying reagents in general. These results demonstrated the utility of this DNA-methyl green substrate-based assay in both the rapid identification and the characterization of novel small molecule inhibitors of the AN encoded by HSV-1 and other herpesviruses.

Cytotoxic and DNA interaction activities of extracts from medicinal plants used in Argentina.

Eight crude extracts from seven Argentine plants with cancer-related ethnobotanical uses have been subjected to a bioscreening study to detect cytotoxic activity. The plants studied were: Aristolochia triangularis, Baccharis grisebachii, Bolax gummifera, Eupatorium hecatanthum, Erythrina crista-galli, Pterocaulon polystachium and Salpichroa origanifolia. Crown gall tumour inhibition, DNA interaction and cytotoxicity towards KB cells were assayed using the potato disc, the DNA-methyl green (DNA-MG) and the KB cells cytotoxicity bioassays respectively. The results obtained indicate that A. triangularis (ED50=47 microg/ml), B. gummifera (ED50=32 microg/ml) and E. hecatanthum (ED50=35 microg/ml) contained cytotoxic compounds against KB cells. All of the plants studied inhibited the growth of crown gall tumours, showing correlation between the experimental data and the uses reported for these plants. Moreover, the results obtained for the extracts of E. hecatanthum and P. polystachium indicate the presence of compounds that interact with DNA (48 and 22% of absorbance decrease, respectively). The results obtained suggest that cytotoxicity could play an important role in the activities claimed for the plants under study.

Low-dose broad-band UVA in morphea using a new method for evaluation.

Until recently, various therapies for localized scleroderma have been used with limited success. Recently, phototherapy, with or without psoralen, was proposed as a successful treatment modality. The aim of this study was to evaluate the effect of broad-band low-dose ultraviolet A (UVA) phototherapy in patients with localized scleroderma, using a new method for evaluation. Twelve patients complaining of morphea were exposed to UVA irradiation at a dose of 20 J/cm2 3 times per week for 20 sessions. Selected covered plaques served as internal controls. The efficacy of therapy was judged clinically by sequential inspection and palpation. In biopsy specimens from exposed and covered plaques stained with hematoxylin and eosin (H & E) and Masson trichrome stains, the concentration of collagen per dermal surface area was measured with the use of a computerized image analyzer. All patients reported remarkable softening of skin lesions, confirmed by sequential palpatory assessment. A significant reduction in the mean concentration of collagen per surface area was detected in the plaques exposed to UVA (the P value being 0.007, P<0.01), whereas in the covered plaques the difference was not statistically significant (the P value being 0.10, P>0.05). The conclusion is that low-dose broad-band UVA phototherapy is a very effective and safe treatment modality for localized scleroderma.

[Antimicrobial activity and interaction with DNA of medicinal plants from the Peruvian Amazon region]. / Actividad antimicrobiana e interacción con el ADN de plantas medicinales de la Amazonia peruana.

Decoctions of four plants used for the treatment of different infections by indigenous groups of the Peruvian Amazon, i.e. Abuta grandifolia, Cyperus articulatus, Gnaphalium spicatum and Pothomorphe peltata were evaluated for antimicrobial activity by the "stroke method" in agar plates. Tested organisms included Staphylococcus aureus, Escherichia coli, Salmonella gallinarum, Klebsiella pneumoniae, Candida albicans, Pseudomonas aeruginosa and Mycobacterium gordonae. All decoctions showed antimicrobial activity against at least one of the tested organisms. The A. grandifolia and C. articulatis decoctions partially inhibited the growth of P. aeruginosa. S. aureus was completely inhibited by C. articulatus decoction and only partially inhibited by G. spicatum and P. peltata. The A. grandifolia decoction also showed a partial inhibition against M. gordonae, showing a clear correlation between the ethnopharmacological use and the observed activity. Methanolic extracts of plants were analyzed by using the DNA-methyl green bioassay. The methanolic extract of P. peltata (concentration 1000 micrograms/ml) showed a decrease of 30% regarding to the initial absorbance of the DNA-MG complex suggesting the possible interaction with DNA.

Bioactivity of certain medicinal latexes used by the Ese'ejas.

Latexes from Croton erythrochilus, Ficus inspidia and Sapium marmieri used traditionally as medicinal by the Ese'ejas were analyzed for bioactivity. The assays run were: the brine shrimp toxicity microplate bioassay, the wheat rootlet growth inhibition and the DNA-methyl green bioassay. The three latexes showed cytotoxicity to the brine shrimp and concentration-related growth inhibition. No interaction with the DNA-methyl green complex was observed with any of the three latex samples. The field bioassays described has demonstrated to be useful for supporting ethnobotanical information.