Test Organisms Research Articles

Cytogenetic and photosynthetic responses of plants after exposure to water from a lake environment.

Plants are sensitive to environmental pollutants and are excellent organisms for genetic and physiological testing. Plant-based test systems are often used to study aquatic, aerial, and terrestrial pollution, especially Allium cepa, but studies with Tradescatia pallida specimens have gained prominence due to their sensitivity and applicability. Among the biomarkers, cytogenetic damage and chlorophyll levels are used in stress studies due to their responses to single or combined factors. The aim of this study was to evaluate cytogenetic and photosynthetic responses in T. pallida, and cytogenetic responses in A. cepa exposed to water from three sampling stations in the Juara lagoon (Municipality of Serra, ES, Brazil), collected in two sampling campaigns. The cytotoxic, genotoxic, and mutagenic potentials were analyzed using the T. pallida root tip mitosis assay and the Allium cepa test. Chloroplast pigment levels were measured in T. pallida leaves after chronic exposure to the lagoon water. The cytogenetic tests showed cytogenetic alterations at two sampling stations in at least one sampling campaign, suggesting the presence of potential pollutants, the effects of which were maximized during the rainy season. The study of photosynthetic metabolism in T. pallida showed a relationship between the levels of chloroplast pigments and the amount of nutrients present in the water.

Collembola growth in heavy metal-contaminated soils.

Collembola play a key role in soil ecosystems by decomposing organic matter. Most of them inhabit the upper layers of the soil and are susceptible to contamination present in the pore water. These arthropods serve as model organisms in ecotoxicology for short and long-term exposure. This study aimed to assess the toxicity of three heavy metals (lead [Pb], cadmium [Cd], and copper [Cu]) using the springtail species Folsomia candida as the test organism, with mortality and growth inhibition as the measure of toxicity. We hypothesised that increasing metal concentrations in the soil would correspond to a growth reduction of Collembola. Each heavy metal was tested at a minimum of eight increasing concentrations in six replications. Twenty 10-12-day-old individuals were introduced into each test container filled with contaminated or control soil and incubated for 14 days. The test endpoints included growth inhibition determined by comparing F. candida growth rates in contaminated soil with those in control soil, as well as mortality rates. The EC50 values (mg/kg) for heavy metals were as follows: Cd = 66.89, Cu = 791.01, Pb = 10075.48. Our findings suggest that growth inhibition is a reliable indicator of Collembola toxicity to heavy metals.

Evaluation of Antibacterial Activity of Milk Peptides Released during the Growth of Lactobacilli in Milk

The present study is carried out to evaluate the antibacterial peptides released during the growth of lactobacilli in milk. Among 8 isolates of lactobacilli and yoghurt cultures used for study, the yoghurt culture released the maximum quantity of peptides (90 ± 1.25 µg/ml). When tested for antibacterial activity only yoghurt culture filtrate showed the antibacterial potential. Further, yoghurt culture lysate was prepared, which was used to treat the milk to bring in proteolysis. The supernatant obtained after centrifugation of this treated milk was used to partially purify peptides by gel filtration using Sephadex G-50. One of the three fractions (F2) showed antibacterial activity against test organisms, E. coli, Salmonella sp. and Shigella dysentriae. The peptide fraction was incorporated into curd samples inoculated with different lactic cultures and spiked with E. coli to determine antibacterial activity. It was found that peptide showed a bacteriostatic effect on E. coli, and the viable count of it was almost reduced by two log cycles when compared with the control.

Cuminaldehyde in Combination with Ciprofloxacin Shows Antibiofilm Activity against Clinical Strains of Pseudomonas aeruginosa: A Study to Explore the Underlying Mechanism

Pseudomonas aeruginosa poses a serious threat in healthcare settings. This bacterium can develop resistance to many antibiotics, rendering even last-resort treatments ineffective. Additionally, it forms protective biofilms that shield it from the immune system, making infection treatment challenging. This study investigated the susceptibility of five clinically isolated strains of the test bacteria to a combination of ciprofloxacin and cuminaldehyde. Cuminaldehyde (a natural phytochemical) and ciprofloxacin (an antibiotic) were separately found to show antimicrobial effect against test organism. However, the combination of selected compounds showed an additive effect in their microbial growth inhibitory activity. The mentioned compounds at their sub-MIC doses subjected to test whether they could show any extent of biofilm inhibition or disintegration property against the clinical strains of P. aeruginosa. The chosen concentrations of the compounds demonstrated significant antibiofilm activity against all the tested clinical strains. Additionally, it was observed that the compounds not only accumulated reactive oxygen species (ROS) but also enhanced the cell membrane permeability of the clinical strains. These findings suggest that the combination of ciprofloxacin and cuminaldehyde could explore new directions in fighting P. aeruginosa-linked infections.

Improving the biodiesel production in the marine diatom Thalassiosira pseudonana cultivated in nutrient deficiency and sewage water.

The use of microalgae as a feedstock in biofuel production is highly encouraging. The marine diatom in this study, Thalassiosira pseudonana, was used as a test organism to evaluate the impact of nitrogen or phosphorus limitation and sewage water on improving biodiesel production. The growth rate is more affected in cultures without phosphorus by 41.8% lower than in control and the highest dry weight estimated in control. The cellular dry weight significantly increased in cultures treated with mix1 and mix2 wastewater compared to the control cultures. Chlorophyll a content decreased in the absence of nitrogen and phosphorous and in sewage water cultures. Lipid content in algal cultures without nitrogen or phosphorus and in sewage water accumulated nearly twice as much lipid content in synthetic medium. T. pseudonana showed high FAME contents; the two most abundant fatty acids, stearic acid (C18:0) and palmitoleic acid (C16:1), in the algal extracts revealed that T. pseudonana was predominantly composed of these fatty acids. T. pseudonana grown in nitrogen or phosphorus-deficient conditions exhibited an extreme percentage of saturated fatty acids (SFAs) by 87.38% and 85.47%, respectively, of the total fatty acids (TFAs). More importantly, the low polyunsaturated fatty acid content in oils indicates a high cetane number, low iodine value, and low corrosion for biodiesel quality indicators. Producing biodiesel that closely meets worldwide biodiesel requirements (ASTM D6751 and EN 14214) is the goal of this work, which shows that growing T. pseudonana under nutrient limitations leads to algal metabolism in that direction.

Antimicrobial activities and bacteriocins of lactic acid bacteria isolated from Nigeria indigenous fermented cowmilk “nunu”

Nunu is a nutritious fermented yoghurt-like milk beverage that can serve as a source of lactic acid bacteria (LAB) with antimicrobial and bacteriocin potentials. Nunu samples were screened for LAB with antimicrobial activity against test organisms. Three LAB, namely Lactobacillus parafarraginis OCLP1, L. fermentum CSL58 and L. buchneri MZE12 out of a total of 14 isolates produced antimicrobial activity against Bacillus anthracis CHF-2011-32b, B. cereus DHM5-1, Providencia vermicola KSVDL-09-71600, P. rettgeri SIRT3, P. stuartti SILT11 and other test organisms. Antimicrobial factors were assayed in LAB cell-free extracts (CFE), neutralized CFE, and ammonium sulphate precipitants of the CFE, and Lactobacillus parafarraginis OCLP1 demonstrated highest activity with zone of inhibition = 20.33±3.51 mm­, 13.33±1.09 mm and 25.33±2.52 mm respectively. The CFE of the LAB especially L. parafarraginis OCLP1 demonstrated wide activity spectra by inhibiting both the gram-positive and gram-negative bacteria tested. Result of plasmid curing of the LAB indicate that the bacteriocins of L. parafarraginis OCLP1 was plasmid-encoded while the others have their gene clusters on the chromosome. This study concluded that bacteriocin-producing LAB can be found in “nunu” and recommend the use of the isolated LAB as starter in fermented food production after ensuring their safety through toxicological studies.

In silico aquatic toxicity prediction of chemicals toward Daphnia magna and fathead minnow using Monte Carlo approaches

The fast-increasing use of chemicals led to large numbers of chemical compounds entering the aquatic environment, raising concerns about their potential effects on ecosystems. Therefore, assessment of the ecotoxicological features of organic compounds on aquatic organisms is very important. Daphnia magna and Fathead minnow are two aquatic species that are commonly tested as standard test organisms for aquatic risk assessment and are typically chosen as the biological model for the ecotoxicology investigations of chemical pollutants. Herein, global quantitative structure–toxicity relationship (QSTR) models have been developed to predict the toxicity (pEC(LC)50) of a large dataset comprising 2106 chemicals toward Daphnia magna and Fathead minnow. The optimal descriptor of correlation weights (DCWs) is calculated using the notation of simplified molecular input line entry system (SMILES) and is used to construct QSTR models. Three target functions, TF1, TF2, and TF3 are utilized to generate 12 QSTR models from four splits, and their statistical characteristics are also compared. The designed QSTR models are validated using both internal and external validation criteria and are found to be reliable, robust, and excellently predictive. Among the models, those generated using the TF3 demonstrate the best statistical quality with R 2 values ranging from 0.9467 to 0.9607, Q 2 values ranging from 0.9462 to 0.9603 and RMSE values ranging from 0.3764 to 0.4413 for the validation set. The applicability domain and the mechanistic interpretations of generated models were also discussed.

Phytochemical and volatile components evaluation of antimicrobial root extracts of <i>Dichrostachys cinerea</i> (sickle bush)(<i>Fabaceae</i>) (L) Wight & Arn

The crude ethanolic extract of the root of Dichrostachys cinerea (Fabaceae) was screened for phytochemicals and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aureginosa, Salmonella typhi, and Candida albicans using agar-well diffusion method. The phytochemical screening of the root extract results showed the presence of alkaloids, flavonoids, essential oils, phenols, terpenes, tannins, unsaturated sterols, and saponins. However, coumarins, and anthocyanins were absent. The crude extract was subjected to column chromatographic fractionation to give nine fractions of which two, DCR1 and DCR2, were subjected to gas chromatography-mass spectrometry (GC-MS) analysis. The crude extract and column chromatographic fractions DCR1 and DCR2 gave MIC of 1 mg/mL against Staphylococcus aureus, but were not active against the other test organisms. The gas chromatography-mass spectrometry analysis of the antibacterial fractions, DCR1 and DCR2, based on standard MS library data revealed the presence of caryophellene, phthalates, a phenol and fatty acids and their ester derivatives. These phytoconstituents could account for the biological properties of the extracts of the plant. The results of this work therefore support its use in ethno-medicinal preparations, particularly against infections.

Evaluation of the effects of two commercial pesticides on Daphnia magna in different feeding environments using morphological and biochemical markers

ABSTRACT In this study, the impact of exposure to a glyphosate-based herbicide (GBH) and a trifloxystrobin-based fungicide (TBF) on Daphnia magna in diverse feeding environments was assessed through the analysis of morphological and biochemical markers. The test organisms selected for analysis were Chlorella vulgaris and D. magna. First, the 48-hour median lethal concentrations (LC50) of GBH and TBF for D. magna were determined to be 253.1 mg/L and 20.7 µg/L, respectively. Secondly, the lethality, length, width, and spin length of D. magna were evaluated following exposure to sublethal pesticide concentrations, selected based on the LC50 values, in different feeding environments. Thirdly, the activities of glutathione S-transferase (GST), glutathione reductase, catalase (CAT), carboxylesterase, and acetylcholinesterase, as well as the levels of reduced glutathione, were measured in D. magna exposed to sublethal pesticide concentrations in different feeding environments. Both pesticides caused an increase in CAT activity, while GBH also caused an increase in GST activity in the unfed and mixed-fed groups. Conversely, it can be concluded that feeding with C. vulgaris reduces oxidative stress and toxic effects since there was a lesser increase in GST and CAT activities in the C. vulgaris-fed group for both pesticides, similar to the lethality.

Biotransformation of diclofenac by Stenotrophomonas humi strain DIC_5 and toxicological examination of the resulting metabolites

The widely used non-steroidal anti-inflammatory drug, diclofenac, detected in increasing concentrations in freshwater ecosystems, is among the most pressing environmental problems today. In this study, the bacterial isolate Stenotrophomonas humi strain DIC_5 was capable of degrading diclofenac. It eliminated 75.1% of diclofenac at an initial concentration of 1.5 mg/L after 8 days in the presence of glucose (3.0 g/L). During the process, nitro-diclofenac was identified as a resulting metabolite, whose concentration increased significantly in the bacterial medium from the 7th day of the experiment, while the concentration of diclofenac decreased correspondingly. The ecotoxicological tests on Aliivibrio fischeri and zebrafish embryos showed that the bacterial metabolites without diclofenac have a higher toxicity (up to 35.5% bacterial bioluminescence inhibition and 36.7% embryo mortality) than the diclofenac degradation residues (28% and 26.7%, respectively). Based on these results, neither diclofenac nor its degradation products exhibit toxic effects on the test organisms. Conversely, the toxic effect caused by the bacteria was reduced in the presence of diclofenac. Our work highlights the importance of using biotic controls in biotransformation trials, especially when the foreign material is applied in intermediate or environmentally relevant concentration ranges.Key points• Biotransformation of diclofenac by bacteria isolated from a bacterial biofilm.• Biotransformation of diclofenac led to the formation of nitro-diclofenac.• Microorganisms are alternatives for reducing the concentration of diclofenac in water.

Ecotoxicological risk assessment of active pharmaceutical ingredients (APIs) against different aquatic species leveraging intelligent consensus prediction and i-QSTTR modeling

The increasing presence of active pharmaceutical ingredients (APIs) in aquatic ecosystems, driven by widespread human use, poses significant risks, including acute and chronic toxicity to aquatic species. However, the scarcity of experimental toxicity data on APIs and related compounds due to the high costs, time requirements, and ethical concerns associated with animal testing hinders comprehensive risk assessment. In response, we developed quantitative structure-toxicity relationship (QSTR) and interspecies quantitative structure toxicity-toxicity relationship (i-QSTTR) models for three key aquatic species: zebrafish, water fleas, and green algae, using NOEC as an endpoint, following OECD guidelines. Algae, daphnia, and fish, recognized as standard organisms in toxicity testing, are crucial bio-indicators due to their size, transparency, adaptability, and regulatory acceptance. We used partial least squares (PLS) and multiple linear regression (MLR) methods for model development alongside machine learning techniques such as Random Forest (RF), Support Vector Machines (SVM), K-nearest Neighbor (kNN), and Neural Networks (NN) to enhance the predictivity. Lipophilicity, electronegativity, unsaturation, a molecular cyclized degree in molecular structure, large fragments, aliphatic secondary C(sp2), and R–CR–R groups were identified as critical biomarkers for API toxicity. Screening of the PPDB (pesticide properties databases) and DrugBank validated the practical application of these models, offering valuable tools for regulatory decisions, safer API design, and the preservation of aquatic biodiversity.

Antibacterial Potentials and Phytochemical Screening of Eucalyptus globulus Leaves Extract against Selected Isolates

In recent decades, medicinal plants have been of great interest as they have been the sources of natural products. As a result, there is a need to analyse the phytochemical and antibacterial properties of Eucalyptus globulus against Escherichia coli, Bacillus cereus, Staphylococcus aureus and Pseudomonas aeruginosa. This study was carried out to determine the percentage yield, phytochemical properties, antibacterial activity, minimum inhibitory and minimum bactericidal concentration (MIC/MBC) of the crude extracts using the reflux extraction, qualitative phytochemical, agar well diffusion and broth dilution method respectively; while aqueous, normal hexane and ethyl acetate were used as extraction solvents. Aqueous extract has the highest yield of 16.08%, ethyl acetate extract (8.76%) while n-hexane extract had 3.84%. Phytochemicals such as tannins, alkaloids, and phenols were present in all three solvent extracts; while terpenoids, glycosides and steroids were absent. Saponins and flavonoids were present in water extract, flavonoids were present only in the ethyl acetate extract. The most active with mean inhibition zone (MIZ) diameter of 13.33±0.58mm and 10.33±0.58mm against Bacillus cereus and Staphylococcus aureus respectively at 50mg/mL while the lowest activity of MIZ diameter of 8.00±2.00mm was obtained with same extract and concentration against Escherichia coli. N-hexane and ethyl acetate extracts show no activity against the test organisms. The lowest MIC of 15.6mg/mL and MBC of 31.3mg/mL were obtained against Escherichia coli. Based on these results, it can be concluded that Eucalyptus globulus leaf extracts possess antibacterial activity against some of the test organisms and can be considered for drug development.

Impact of diethyl phthalate on freshwater planarian behaviour, regeneration, and antioxidant defence

Diethyl phthalate (DEP) has been widely used as a plasticiser in various consumer products, including cosmetics, personal care items, and pharmaceuticals, and recent studies reported a higher abundance of this priority phthalate in the aquatic environment. DEP is a potential endocrine disruptor, affecting immune systems in humans and wildlife even at low-level chronic exposure. As concern over phthalates increases globally, regulatory bodies focus more on their environmental impact. However, limited research is available, particularly using model organisms like planarians. Planarians are ideal for toxicological studies and may provide insightful information on pollutants' neurotoxic, developmental, and ecological effects, especially in freshwater environments where planarians play a vital role in ecosystem balance. Therefore, the objective of the current study was to examine the toxicity of DEP using the freshwater Dugesia sp., as an experimental animal. The LC50 for the test organism was calculated using DEP concentrations of 800, 400, 200, 100, and 50 µM, with an estimated LC50 of 357.24 µM. Furthermore, planarians were exposed to sub-lethal DEP concentration (178.62 µM) for one day as well as eight days to evaluate the impact of DEP on planarian locomotion, feeding behaviour, and regeneration ability. At sub-lethal concentration, locomotion and feeding ability were decreased, and regeneration was delayed. Furthermore, neuro-transmittance in planaria was altered by sub-lethal DEP concentration, as indicated by a reduced acetylcholinesterase (AChE) activity. DEP exposure induced oxidative damage in the tested planarians as shown by a marked increase in stress biomarkers, including lipid peroxidation levels and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and glutathione S-transferase (GST). Our study revealed that DEP exposure may prove fatal to freshwater organisms, such as planarians. The observed alterations in behaviour and regeneration ability demonstrate the severity of the effects exerted by DEP as a toxicant in aquatic ecosystems, thereby indicating the need to restrict its usage to protect aquatic environments.

Development of toxicity tests for Polyurethane foams

Polyurethanes (PUs) are a special class of polymeric materials that differ significantly from most other types of plastic in many aspects. They can be utilized in a wide range of products, including paints, coatings, elastomers, insulators, elastic fibers, and foams. PU foams are especially important as part of various convenience products. PU products often end up in landfills when they are no longer useful and can release toxic compounds when damaged by humans or microbes. Therefore, the ecotoxicological assessment of PU foams is essential. In this paper, five PU foam samples were prepared with different NCO indices (NCO-0.8, 0.9, 1.0, 1.1, and 1.2) and together with the Control sample (a previously tested non-toxic foam sample) were applied to develop toxicity tests procedure, while intentionally prepared Toxic foam has been used to verify the accuracy of the developed testing procedure. Two test organisms were successfully applied, Sinapis alba (white mustard) seeds and Escherichia coli (non-pathogenic) bacterial model organisms, and toxicity tests were adapted for the examination of PU-derived substances. Regarding Sinapis alba test, the highest NCO index (NCO-1.2) significantly reduced root length by 9.8 % compared to the Control sample. In the bacterial test, it was observed that the samples containing NCO-1.1 and NCO-1.2 had lower colony numbers (5.0 × 108 and 4.9 × 108 CFU/mL respectively) in comparison to the Control plate (9.6 × 108 CFU/mL). All in all, two toxicity tests were successfully adapted for PU foams, and both are applicable in their ecotoxicological assessment.

Antimicrobial activity, toxicity and retrospective clinical effectiveness of Kantinka BA and Kantinka Herbaltics, two multi-component-herbal products used in the management of infectious diseases in Ghana

There is an upsurge in the incidence of persons living with infectious diseases and their associated symptoms. Also, there is increased resistance and high cost of available synthetic antimicrobial therapeutic agents. This calls for screening candidate herbal products to examine the risk-to-benefit ratio for users. Moreover, there are inadequate proven scientific studies to assess the quality, effectiveness, and toxicity of herbal products that traditional medicine practitioners in Ghana commonly use for the management of infectious diseases such as those caused by Neisseria gonorrhoeae, Candida albicans and the symptomatic management of symptoms associated with infections like cough, skin infections among others and gastritis. Kantinka BA and Kantinka Herbaltics, two multicomponent herbal products, have been used to manage the above-mentioned disease conditions. The study aims to evaluate the in vitro antibacterial activity, assess the retrospective clinical effectiveness (clinical responses; the disappearance of presenting signs and symptoms associated with infections, gastritis), and the quality and toxicity of Kantinka BA and Kantinka Herbaltics. The products are registered by the Food and Drugs Authority (FDA). Data on 200 patients who were diagnosed with infectious diseases such as Human Immunodeficiency Virus (HIV) / Acquired Immunodeficiency Syndrome (AIDS) and associated symptoms from January 2018 to June 2018 was obtained from the Adom Herbal Clinic, and the Tafo Government Herbal Medicine Records Unit was assessed. The antibacterial activity of the products was evaluated using the HT-SPOTi method. Phytochemical screening, microbial load, and pH were carried out according to standard procedures. Acute toxicity was carried out according to the Organization for Economic Cooperation and Development (OECD) guideline 425. Phytochemical screening, pH, and microbial load have been established for both products. Binding toxicity studies revealed that the products are non-toxic at a 2000 mg/kg dose. The two products exhibited antimicrobial activities against the test organisms with Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC) determined for Kantinka BA and Kantinka Herbaltics as 5% and 10% and <80, respectively, against C. albicans and N. gonorrhoeae - the signs and symptoms associated with infections disappeared during the management period. The products are safe and may effectively manage some infectious diseases and associated symptoms.

Activity antibacterial from honey kelulut (Trigona sp.) against bacteria Staphylococcus epidermidis

Honey kelulut is derived from the kelulut bee (Trigona sp.), which is native to Kalimantan and belongs to the Trigona genus of stingless bees. The honey produced by the Trigona genus has a well-documented antibacterial property. Study objective accomplished. This text discusses the potent antibacterial action of kelulut honey. The antibacterial testing method employed is the well diffusion method, utilizing the bacterium Staphylococcus epidermidis as the test organism. An antibacterial test was conducted by measuring the diameter of the zone of inhibition against bacteria. The results were obtained from concentrations of 40%, 60%, 80%, and 100%. Then the resistance diameter was measured for each concentration. The most optimal outcomes were achieved in the antibacterial test using honey kelulut. The honey kelulut with an 80% concentration exhibited a medium resistance level of 10.2 mm, while the 100% concentration demonstrated a strong resistance level of 13.7 mm.

Phytotoxicity Testing of Atmospheric Polycyclic Aromatic Hydrocarbons

Atmospheric polycyclic aromatic hydrocarbons (PAHs) have well-known phytotoxicity on higher plants. However, while numerous bioindication studies have been targeted on how different symptoms indicate the deleterious effects of PAHs in the field, laboratory-scale phytotoxicity tests are much rarer. While ecotoxicity tests might rely on the very same end-points as bioindication studies, they have to comply with quality assurance criteria, repeatability being the most important. As such, proper reporting involves the description of the test compound, experimental design and conditions, test organism used, and end-points measured. The recent review intends to give an overview of studies available in the literature complying with these requirements. PAHs occur in the atmosphere both in gaseous form and bound to particles. As plants are exposed to both phases, test protocols available represent different exposure pathways, fumigation chambers vs. direct foliar treatment. Reported studies, therefore, are grouped based on the exposure route they intend to simulate.

Биотестирование меламина с использованием многокомпонентной тест-системы

In recent decades, halogen-containing flame retardants have been gradually replaced by safer flame retardants, including nitrogen-containing compounds. However, their ecotoxicity is poorly studied. The ecotoxicity of melamine, a widely used nitrogen flame retardant, at concentrations equal to MPC in water (4 mg/L), 5 MPC (20 mg/L) and 10 MPC (40 mg/L) was assessed in this study using a complex of test organisms. The assessment of ecotoxicity using the dehydrogenase activity of Dietzia maris AM3 as a test microorganism revealed a stimulating effect of melamine at a concentration equivalent to the MPC; concentrations of 5 and 10 MPC inhibited the activity of dehydrogenases by 19.3% and 10.5%, respectively, indicating low toxicity. No toxic effects were observed on protococcal algae Chlorella vulgaris Beijer at any of the tested concentrations. The effect of melamine solutions on the mortality of crustaceans Daphnia magna Straus was noted only at a concentration of 10 MPC, and the mortality rate was 25%. Lemna growth inhibition test showed that melamine at concentrations equal to the MPC and 5 MPC had an inhibitory effect on the growth of Lemna minor L. It also caused a significant decrease (by 47–52%) in the total chlorophyll content in fronds when exposed to all studied concentrations of melamine.

In vivo Antifungal Efficacy and Safety of Natural Compounds for Topical Treatment of Cutaneous Candidiasis

In vivo toxicity and antifungal therapeutic evaluation of selected natural compounds for topical applications was analyzed using standard methods. The natural compounds, blue vitriol, brimstone, trona, alum, palm ash and black stone were hygienically selected and purchased at a local market in southeastern Nigeria. The test organisms were isolated from high vaginal swab specimens obtained from cases of cutaneous candidiasis. The isolates were identified based on their morphological, physiological and molecular characteristics. The toxicological screening of the test samples was done using Draize’ skin irritancy test, Murine local lymph node assay (LLNA) and necropsy. The in vivo evaluation of antifungal activity of the solutions was done using eight-week-old albino rats weighing 120g – 150g. The animals were infected with the Candida isolates percutaneously; and treated using various formulations of the natural compounds. The skin sections were carefully observed for histopathological changes, before and after treatment. The total yeast counts of the infected skin tissues were also determined. The isolates include Candida albicans, C. glabrata, C. parapsilosis and C. tropicalis. Draize’ skin test and Murine local lymph node assay showed no observable skin irritancy reaction (P>0.05). The normal skin architecture of the infected animals was restored after 5 days of treatment with the test samples; while the total yeast count decreased from 108 CFU/mL to 102 CFU/mL. The findings have revealed that natural compounds are effective as well as non-toxic topically, in treatment of cutaneous candidiasis.

Designing of some VO(II), Co(II) and Hg(II) Schiff base complexes: Synthesis, structure elucidation, anticancer and biopesticidal activities, DFT and docking approaches

New VO(II), Co(II) and Hg(II) chelates of bi- or tetradentate isatin based ligand i.e.:-2-(((E)-2-oxo-1,4-dihydrocyclohepta [b]pyrrol-3(2H)-ylidene)amino)-N-(8-((1-(2-((E)-2-oxoindolin-3-phenyl)vinyl) amino) naphthalen-1-yl) benzamide (H2L) were synthesized and well characterized. The reaction between N,N′-(naphthalene-1,8-diyl)bis(2-aminobenzamide) and di-oxazine-2,4 dione (isatin) yielded the Schiff base (H2L). The compounds have been identified by different physicochemical and spectroscopic approaches and DFT as well. From all measurements square pyramidal, distorted octahedral or square planar configurations have been suggested for the chelates 1, 2 and 3, respectively. The Coats-Redfern equations were used to calculate and define the dynamics properties of decomposition stages from TGA (Ea, A, ΔH*, ΔS*, and ΔG*). The in vitro anticancer property of the obtained compounds towards human hepato (HepG2) and human breast (MCF-7) carcinoma cell lines has been screened. Also, the biopesticidal effect of these compounds against spodoptera littoralis has been examined. Data showed that, the tested [Hg(H2L)(L)] complex (3) possesses the most anticancer efficacy against both HepG2 and MCF-7 cells, with half inhibitory concentration (IC50) = 5.78 ± 0.029, 11.24 ± 0.58 μg/mL, respectively also, this complex considered as good an insecticide with the concentration lethal to 50 percent of test organisms (LC50) = 27585.45 ppm after 72 h. The insecticide and tumor inhibition properties were compared with the theoretical molecular docking findings with the specification of the active species in the designated proteins.