Appreciable Inhibitory Effect Research Articles

Halogen-substituted meso-BODIPY ethers as effective photosensitizers for antimycotic photodynamic therapy

We conducted a comprehensive study of the influence of the molecular structure and solvent nature on the photophysical properties of the halogen-substituted meso-BODIPY ethers. The compounds were found to be stable over a wide range of pH values and exhibited intense chromophoric properties (lgε ∼ 4.60–5.02) at 497–536 nm. The halogenation at the 2,6-positions of the pyrrole rings of dyes causes a noticeable (up to 36 nm and 44 nm) red shift of the maximum of the absorption and fluorescence bands, respectively, and sharp fluorescence quenching up to φfl ∼ 2–32 %. The introduction of a bulky ester substituent into the meso-position of the dipyrromethene core increases the photostability of the dyes up to ∼ 2.7 times due to screening of the methine spacer. Moreover, the halogen-substituted BODIPYs demonstrated a high ability to generate singlet oxygen (up to ФΔ ∼50–78 %) regardless of the nature of the solvent. Among the studied dyes, the diiodo-substituted meso-BODIPY ether has an appreciable inhibitory effect on the vital activity of fungal cells. In summary, the combination of the meso-substitution and halogenation of the BODIPY core is an excellent way to enhance the affinity of dyes to biostructures and to increase the possibilities of the practical application of dyes as effective photosensitizers for antibacterial photodynamic therapy.

Bioprospective studies of pigmented ink from Sepioteuthis lessoniana and its molecular identification using CO1 gene

5BackgroundThe present-day world is teeming with numerous diseases due to the changing environment. The enormous growth of population has overburdened the prevailing resources of drugs; hence, drug manufacturers are in the lookout to develop effective and safe drugs in the pharmaceutical field. Marine environment is well known for its secondary metabolites, having a high potential in the research world of medicines. Several successful researches have explored the bioactivities of the marine organisms. In this regard, this study highlights the bioprospective activities of squid ink and identification of the organism using CO1 gene marker.ResultsIn the present study, anti-inflammatory activity evaluated by human red blood cell (HRBC) membrane stabilization assay revealed protection of human blood cells in hypotonic solution confirming ant-inflammatory property of squid ink extract. Bovine serum protein denaturation method for investigating in vitro anti-arthritic activity proved that the ink extract has appreciable inhibitory effect on denatured proteins. The in vitro antioxidative property of the squid ink disclosed remarkable free radical scavenging activity. The squid ink exhibited potent antibacterial activity against three microbial pathogens such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. From the molecular study using CO1 gene sequencing, it was found that the given species of squid showed 100% similarity with a species in NCBI GenBank and it was identified to be Sepioteuthis lessoniana.ConclusionsIt is evident from the study that squid ink extract is a good source of anti-inflammatory, antioxidative, anti-arthritic and antimicrobial agents which would replace the existing cost of effective investigations intending to purify these active compounds and its identification of new molecular skeleton can give idea to the development of either the base or a new drug itself in the future.

Network pharmacology-based elucidation of bioactive compounds in propolis and putative underlying mechanisms against type-2 diabetes mellitus

Propolis is a common remedy in Chinese medicine. We have previously demonstrated the anti-diabetic potentials of Nigerian propolis. However, the underlying mechanisms against type-2 diabetes mellitus (T2DM) remain unclear. This study used network pharmacology-based analysis to unravel the possible mechanisms of NP's anti-T2DM activity. Previously identified compounds in NP were retrieved from literature, screened for drug-likeness, and used to retrieve targets associated with T2DM, from which compound-target, protein-protein interaction, and target-pathways networks were constructed. Network pharmacology-based and enrichment analyses were conducted on the networks. Further, NP's inhibitory activity against targets identified in network analyses was assessed in-vitro. Library search revealed 202 previously reported compounds in NP; 96 were retained after screening for drug-likeness. However, only 44 NP compounds interacted with T2DM-associated targets, with 2-ethyl-1,4-dimethoxybenzene as the most active component. Network analyses revealed 167 putative targets, with HSP90AA1, JUN, ESR1, STAT3, CYP3A4, PTGS2, RELA, VEGFA, CYP2C9, and PPARG as the core anti-T2DM targets of NP compounds. Gene ontology analyses indicated that these targets were predominantly localised in the plasma membrane and cytoplasm and primarily involved in regulatory, signal transduction and cellular response processes. KEGG pathway enrichment implicated metabolic pathways (involving lipids), AGE-RAGE, and calcium/cAMP, among others, in the anti-T2DM effects of the compounds. Furthermore, in vitro pharmacological assessment demonstrated appreciable inhibitory effects of 2-ethyl-1,4-dimethoxybenzene against α-amylase, α-glucosidase, and HMG-CoA reductase. This study provides holistic mechanistic insights into the anti-T2DM activities of the constituents of Nigerian propolis.

Corrosion inhibition, surface adsorption and computational studies of new sustainable and green inhibitor for mild steel in acidic medium

• After soaking in 0.4 g/L at 303 K, the inhibition efficiency reached 94.1% and 91.6% for OEAq and OEEt, respectively. • SEM and EDX studies support the formation of inhibitors film on steel surface. • Theoretical and experimental results are in good agreement. The inhibitory effect investigation of aqueous and ethanolic extracts of Origanum elongatum Plant (will be referred to in this paper, respectively, as “OEAq and OEEt” ) on mild steel corrosion in HCl solutions has been evaluated. The analysis and characterization of both products extracted ( OEAq and OEEt ) were performed using HPLC-UV-ELSD-MS techniques. Various electrochemical techniques was used such as weight loss measurements, potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in order to advance in the inhibition process. An appreciable inhibitory effect for both tested inhbitory has been obtained from all the combined results. Experimental results revealed that OEAq and OEEt can be considered as good green inhibitors and that OEAq is more efficient than OEEt with a maximum inhibition efficiency of 94.1% at 0.4 g/L at 303 K. The inhibition efficiency of each inhibitor increases sharply with increasing concentration and a decreasing of efficiency was observed with increasing temperature for both inhibitors. Both OEAq and OEEt were seen to act as a mixed type inhibitors from PDP study and according to EIS technical, their corrosion process is charge transfer controlled. Thermodynamic and activation parameters were determined to discuss the inhibitory behaviour of tested extracts molecules. The two extracts OEAq and OEEt obey to Langmuir adsorption isotherm model as a result of their adsorption on mild steel surface. Morphology of the metal specimen surface without and with inhibitors was investigated using Scanning electron microscopy (SEM) and EDX spectrum. The electronic characteristics of major compounds of OEAq and OEEt ( MC-OEAq and MC-OEEt ) were studied using the DFT method (density functional theory), the Fukui indices and MD (molecular dynamics) modelling in order to predict the spontaneous adsorption.

Homalolides C-D, two new sesquiterpenoids from the rhizomes of Homalomena pendula

Two new sesquiterpenoids, homalolides C − D (1‒2), were co-isolated from the rhizomes of Homalomena pendula (Blume) Bakh.f collected in Vietnam with five known ones, aromadendrane-4α,10α-diol (3), bullatantriol (4), 1β,4β,6α-trihydroxy-eudesmane (5), 1β,4β,6β-trihydroxyeudesmane (6), and 1β,4β,7α-trihydroxy-eudesmane (7). The structures and relative configuration of new compounds were elucidated by 1 D-/2D-NMR, IR, UV and HRESIMS analyses, and by comparisons to the reported data in the literature. Homalolide C presented an unprecedented skeleton with the 4/8 bicyclic system. All isolates did not exhibit appreciable inhibitory effects on LPS-induced NO production in the RAW 264.7 macrophage cell line and on the growth of human lung cancer cell line (SK-LU-1).

Characterization of Bacillus velezensis E2 with abilities to degrade ochratoxin A and biocontrol against Aspergillus westerdijkiae fc-1

Ochratoxin A (OTA), primarily produced by the fungi belonging to the species of Aspergillus and Penicillium, is one of the most common mycotoxins found in cereals and fruits. In addition to resulting in huge economic losses, OTA contamination also poses considerable threat to human and livestock health. Microbial degradation of mycotoxins has been considered with great potential in mycotoxins decontamination. In a previous study, Bacillus velezensis E2 was isolated by our laboratory and showed appreciable inhibitory effect on Aspergillus flavus growth and aflatoxin production in rice grains. In this study, B. velezensis E2 was investigated for its ability to remove OTA and biocontrol against the ochratoxigenic Aspergillus westerdijkiae fc-1. The results revealed that B. velezensis E2 has considerable inhibitory effect on A. westerdijkiae fc-1 both on PDA medium and pear fruits, with inhibitory rate of 51.7% and 73.9%, respectively. In addition, its ability to remove OTA was evaluated in liquid medium and the results showed that more than 96.1% of OTA with an initial concentration of 2.5 μg/mL could be removed by B. velezensis E2 in 48 h. Further experiments revealed that enzymatic transformation and alkaline hydrolysis might be the main mechanisms related to OTA degradation by B. velezensis E2, with ring open ochratoxin α (OP-OTα) as a possible degradation product. Our study indicated that the B. velezensis E2 strain could be a potential bacterial candidate in biodegradation of OTA and biocontrol against A. westerdijkiae fc-1.

Susceptibility of Multi-Drug Resistant Wound Pathogens to Extracts and Fractions of Ficus Vogelii (Miq) and Telfairia occidentalis(Hook F.) and Bactericidal kinetics

Background: Wound infection is the third most common nosocomial infection worldwide, with resultant high mortality and morbidity rates in developing countries. Many pathogenic microrganisms implicated in wound infections have evolved antimicrobial resistance, necessitating a focused search for important therapeutic bioactive compounds from natural sources.
 Objective: To investigate the antimicrobial potential of leaf extracts and fractions of Ficus vogelii and Telfairia occidentalis against wound clinical isolates.
 Materials and Methods: Pulverized plant leaves were screened for the presence of phytochemicals. Extraction of ground leaves was by cold maceration with methanol, and fractions were obtained by partitioning into hexane, ethyl acetate and methanol. Antibiogram of clinical isolates was determined via disc diffusion method. Antimicrobial susceptibility of test isolates was determined by agar-well diffusion while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by microbroth dilution assay. Time-kill assay of the methanol fraction of plants was carried out using the viable count technique.
 Results: Alkaloids, anthraquinones, cardiac glycosides, flavonoids, saponins, steroids, tannins, and terpenoids were the phytochemicals detected. The plant extracts and fractions had appreciable inhibitory effects against the multi-rug resistant test organisms, with MIC and MBC values ranging from 3.125 to 12.5 mg/mL and 12.5 to > 50 mg/mL, respectively. A total kill of the organisms was achieved at 24 hours at 3.125mg/mL and 6.25 mg/mL of methanol fractions of both plants.
 Conclusion: Ficus vogelii and Telfairia occidentalis contain bioactive compounds that can be developed into standard chemotherapeutics for the management and treatment of wound infections.

Staphyloxanthin as a Potential Novel Target for Deciphering Promising Anti-Staphylococcus aureus Agents.

Staphylococcus aureus is a fatal Gram-positive pathogen threatening numerous cases of hospital-admitted patients worldwide. The emerging resistance of the pathogen to several antimicrobial agents has pressurized research to propose new strategies for combating antimicrobial resistance. Novel strategies include targeting the virulence factors of S. aureus. One of the most prominent virulence factors of S. aureus is its eponymous antioxidant pigment staphyloxanthin (STX), which is an auspicious target for anti-virulence therapy. This review provides an updated outline on STX and multiple strategies to attenuate this virulence factor. The approaches discussed in this article focus on bioprospective and chemically synthesized inhibitors of STX, inter-species communication and genetic manipulation. Various inhibitor molecules were found to exhibit appreciable inhibitory effect against STX and hence would be able to serve as potential anti-virulence agents for clinical use.

New tirucallane-type triterpenoids from the resin of Boswellia carteriiand their NO inhibitory activities.

Six new tirucallane-type triterpenoids (1-6), along with ten known triterpenoids, were isolated from methylene chloride extract of the resin of Boswellia carterii Birdw. By the application of the comprehensive spectroscopic data, the structures of the compounds were clarified. The experimental electronic circular dichroism spectra were compared with those calculated, which allowed to assign the absolute configurations. Compounds 5 and 6 possesed a 2, 3-seco tirucallane-type triterpenoid skeleton, which were first reported. Their inhibitory activity against NO formation in LPS-activated BV-2 cells were evaluated. Compound 9 showed appreciable inhibitory effect, with an IC50 value of 7.58 ± 0.87 μmol·L-1.

Various Extracts of Some Medicinal Plants as Inhibitors for Beta-lactamase Activity

The inhibitory effect of acetone, ethanol, and aqueous extracts of ten medicinal plants on β-lactamase from Staphylococcus sciuri and Klebsiella pneumoniae was investigated in vitro by starch-iodine agar plate method. The results revealed the success of starch-iodine method for the detection of the inhibition of β-lactamase activity by the various extracts of each individual plant. The acetone extracts of Catharanthus roseus, Eucalyptus camaldulensis, and Schinus terebinthifolius induced an inhibitory effect on β-lactamase from Staphylococcus sciuri. On the other hand, acetone extracts from only Eucalyptus camaldulensis, and Schinus terebinthifolius expressed strong inhibitory effect on β-lactamase from Klebsiella pneumoniae. The acetone extracts expressed the highest inhibition for β-lactamases activity compared to ethanolic and aqueous extracts which exhibited appreciable inhibitory effect. β-lactamase from S. sciuri was inhibited by extracts from C. roseus, E. camaldulensis and S. terebinthifolius whereas β-lactamase from K. pneumoniae was inhibited only by extracts from E. camaldulensis and S. terebinthifolius.

A new sulphur containing heterocycles having azo linkage: Synthesis, structural characterization and biological evaluation

The present study aims the development of new S-heterocyclic azo dyes synthesized from 1, 3-benzothiazole-2-thiol with various amines by diazo-coupling method and their structures are established by physico-chemical techniques. The target molecules were screened for antimicrobial, antitubercular, anticancer, and molecular docking studies. These compounds have shown appreciable inhibitory effect against studied microbial strains. The in silico molecular docking study exposed the significant interaction properties of the azo compounds against target receptor RpsA and showed an appreciable binding affinity of −4.3 to −5.5 kcal/mol.

INHIBITORY EFFECTS OF POD EXTRACT OF ACACIA NILOTICA AGAINST SOME PATHOGENIC BACTERIA

This study assessed the inhibitory effects of the pod extract of Acacia nilotica against some pathogenic bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococccus pyogenes). Fresh pods of Acacia nilotica were air-dried and then ground into fine powder. Thereafter, pod powder was extracted using ethanol and distilled water in the ratio 3 to 2 (v/v). The crude extract was concentrated in vacuo and lyophilized. Afterwards, screened for phytochemicals and tested for antibacterial activity against the bacterial isolates. Antibacterial potential, minimum inhibitory concentrations (MIC), and minimum bactericidal concentrations (MBC) of the extract were determined using standard microbiological method. Zone of inhibition shown by the crude extract at 50 mg/mL on the isolates ranged between 10 mm and 18 mm while MIC ranged between 1.56 mg/mL and 25 mg/mL. Minimum bactericidal concentrations ranged between 3.13 mg/mL and 50.00 mg/mL. The phytochemical screening of the extract revealed the presence of tannins, alkaloids, flavonoids, saponins and cardiac glycosides. This study, therefore, showed that pod extract of Acacia nilotica exhibited appreciable inhibitory effects on the test isolates. Hence, there is need for in vivo studies to complement the present findings.

In-vitro Inhibitory Effects of Polyphenolic Extract of Ichnocarpus Frutescens on Carbohydrate Digestive Enzymes

Background: Ichnocarpus frutescens has been used as Ayurvedic herbal medicine by Gond tribes in India to treat several diseases such as diabetes mellitus and Jaundice. The growing incidence of diabetes mellitus and its complications have headed to the search of novel therapeutic approaches engrossed on preventing postprandial hyperglycemia. The practice of carbohydrate breakdown enzyme inhibitors from plant resources might be a potential approach to prevent glucose absorption with the least adverse effects. Aims: The objective of the present investigation was to provide in-vitro evidence for the potential inhibitory activity of polyphenolic extract (PPE) of Ichnocarpus frutescens on amylase and glucosidase enzymes. Methods: the in the vitro inhibitory effect of polyphenolic extract (PPE) of Ichnocarpus frutescens focused on the evaluation of pancreatic amylase inhibition, rat serum amylase inhibition and rat intestinal glucosidase inhibition of polyphenolic extract (PPE) of Ichnocarpus frutescens by in vitro. The different concentrations of polyphenolic extract were subjected to amylase and glucosidase inhibitory assay and the percentage of amylase and glucosidase inhibitory activity and IC50 values were calculated. Results: Polyphenolic extract shows appreciable pancreatic amylase inhibitory activity in vitro. The extract also showed an appreciable glucosidase inhibitory effect in a concentration-dependent manner with a moderate amylase inhibitory activity. The in vitro examination of the inhibitory effect of PPE on maltase and sucrase activities revealed that PPE inhibited rat small intestine disaccharidase ( glucosidase) activity. Conclusion: Taken together, these results suggest that inhibitory effect of PPE on amylase and glucosidase activities may delay carbohydrate digestion and absorption with subsequent lowering of blood glucose level leading to prevention of postprandial hyperglycemia in diabetes and its complication.

Evaluation of the Anti-microbial Activities of the Extracts of the Leaf and Stem Bark of Alstonia congensis on Some Human Pathogenic Bacteria

Background: Prohibitive cost of treatments in developing countries is a challenge under poor economic circumstances. Side effects of several synthetic drugs and the development of resistance to currently used antibiotics for infectious diseases have led to increased emphasis on the use of plant materials as a source of medicine for a wide variety of human ailments. In addition to this and the high level of poverty in developing countries, the use of alternate medicine to cure some diseases is now encouraged in Nigeria to serve as an alternative for orthodox medicine. In this study, phytochemical screening and the anti-microbial capability of parts of a popular African medicinal plant, Alstonia congensis , was evaluated. Materials and Methods: The effects of the plant parts extracts on some human pathogenic bacteria viz; Escherichia coli, Neisseria gonorrhoeae, Staphylococcus aureus, Salmonella typhi, Proteus mirabilis, Pseudomonas aeruginosa and Klebsiella pneumoniae were examined in vitro using hexane, ethanol, petroleum ether and water (aqueous) as extractants and at concentrations of 120, 80, 60, 48 and 40mg/ml respectively. Agar well diffusion technique was employed throughout the experimentation. It was discovered that petroleum ether and ethanolic extracts of the leaves and stem bark showed appreciable inhibitory effects on the test bacteria (the leaf extracts were more potent than the stem bark extracts). The Minimum Inhibitory Concentration (MIC) of each of the extracts was determined. Results: Petroleum ether as well as ethanolic extracts of the leaves was effective on all the bacterial isolates at MIC between 40 mg/ml and 60mg/ml respectively while the aqueous extract of the leaf was slightly effective on E. coli , N. gonorrhoeae , Staphylococcus aureus , S. typhi and P. mirabilis at MIC between 60mg/ml and 80mg/ml. It was only the hexane extract of the leaf that was not effective against any of the test bacteria. The ethanolic and petroleum ether extracts of the stem bark was effective against Staphlococcus aureus , S. typhi , P. mirabilis and Klebsiella pneumoniae at MIC between 40mg/ml and 60mg/ml while ethanolic extract of the leaf was not effective against E. coli . Likewise, the hexane extract of the stem bark was not effective against Neisseria gonorrhoeae. The aqueous extract of the stem bark showed no effect against Escherichia coli but slightly effective against other isolates at MIC of 80mg/ml for Neisseria gonorrhoeae, Staphylococcus aureus , Salmonella typhi , Proteus mirabilis , Pseudomonas aeruginosa and at120mg/ml for Klebsiella pneumoniae . Hexane extract of the stem bark did not have any effect against Neisseria gonorrhoeae , Staphylococcus aureus, Salmonella typhi and Pseudomonas aeruginosa but very effective against Escherichia coli and Proteus mirabilis at MIC of 60mg/ml but at 40mg/ml for Klebsiella pneumoniae . Petroleum ether and ethanolic extracts showed much wider zones of inhibition on each of the test bacteria and therefore regarded as the best solvents for extraction. The result of the Standard Antibiotics Disc (SAD) showed that E.coli was inhibited by Ofloxacin (21mm), Klebsiella pneumoniae (22mm), P.aeruginosa (24mm), N. gonorrhoeae (25mm), S. typhi and P. mirabilis (30mm). E. coli and N. gonorrhoeae was inhibited by Nalidixic acid (22mm), S. typhi and P. aeruginosa (20mm) and Klebsiella pneumoniae (10mm). Also, Gentamycin inhibited E.coli (9mm), N. gonorrhoeae (13mm), S. typhi (12mm), P. mirabilis (13mm ) and P.aeruginosa (15mm) except Staphylococcus aureus which was not inhibited by any of these antibiotics. On the other hand, all the isolates exhibited resistance to Amoxycillin while E. coli , N. gonorrhoeae , S. typhi , Klebsiella pneumoniae , P.mirabilis and P. aeruginosa were resistant to Chloramphenicol, Tetracycline, Cloxacillin, Erythromycin, Augmentin and Streptomycin. Conclusion: The plant’s parts were found to possess antibacterial activities. The ethanol and petroleum ether were the best solvents for their extraction.

An Overview on the Anti-inflammatory Potential and Antioxidant Profile of Eugenol.

The bioactive compounds found in foods and medicinal plants are attractive molecules for the development of new drugs with action against several diseases, such as those associated with inflammatory processes, which are commonly related to oxidative stress. Many of these compounds have an appreciable inhibitory effect on oxidative stress and inflammatory response, and may contribute in a preventive way to improve the quality of life through the use of a diet rich in these compounds. Eugenol is a natural compound that has several pharmacological activities, action on the redox status, and applications in the food and pharmaceutical industry. Considering the importance of this compound, the present review discusses its anti-inflammatory and antioxidant properties, demonstrating its mechanisms of action and therapeutic potential for the treatment of inflammatory diseases.

Inhibition of pancreatic lipase and amylase by extracts of different spices and plants

The aim of this study is to search new anti-obesity and anti-diabetic agents from plant and spices crude extracts as alternative to synthetic drugs. The inhibitory effect of 72 extracts was evaluated, in vitro, on lipase and amylase activities. Aqueous extracts of cinnamon and black tea exhibited an appreciable inhibitory effect on pancreatic amylase with IC50 values of 18 and 87 μg, respectively. Aqueous extracts of cinnamon and mint showed strong inhibitory effects against pancreatic lipase with IC50 of 45 and 62 μg, respectively. The presence of bile salts and colipase or an excess of interface failed to restore the lipase activity. Therefore, the inhibition of pancreatic lipase, by extracts of spices and plants, belongs to an irreversible inhibition. Crude extract of cinnamon showed the strongest anti-lipase and anti-amylase activities which offer a prospective therapeutic approach for the management of diabetes and obesity.

Glutathione analogues as substrates or inhibitors that discriminate between allozymes of the MDR-involved human glutathione transferase P1-1.

Glutathione (GSH) structure-guided tripeptide analogues were designed and synthesized by solid phase technology, purified (≥95%) by RP and/or GF column chromatography, to identify those that, compared with GSH, exhibited similar or higher binding and catalytic efficiency toward the MDR-involved human GSTP1-1 isoenzyme, and could discriminate between the allozymic expression products of the polymorphic human GSTP1 gene locus, designated as hGSTP1*A (Ile(104) /Ala(113) ), hGSTP1*B (Val(104) /Ala(113) ), and hGSTP1*C (Val(104) /Val(113) ). The analogues bear single amino acid alterations as well as alterations in more than one position. Some analogues showed remarkable allozyme selectivity, binding catalytically to A (I, II, IV, XII), to C (V and XVI), to A and C (III, VII, XIV) or to all three allozymes (XV). A heterocyclic substituent at positions 1 or 2 of GSH favors inhibition of A, whereas a small hydrophobic/hydrophilic amide substituent at position 2 (Cys) favors inhibition of B and C. Heterocyclic substituents at position 1, only, produce catalytic analogues for A, whereas less bulky and more flexible hydrophobic/hydrophilic substituents, at positions 1 or 3, lead to effective substrates with C. When such substituents were introduced simultaneously at positions 1 and 3, the analogues produced have no catalytic potential but showed appreciable inhibitory effects, instead, with all allozymes. It is anticipated that when GSH analogues with selective inhibitory or catalytic binding, were conjugated to allozyme-selective inhibitors of hGSTP1-1, the derived leads would be useful for the designing of novel chimeric inhibitors against the MDR-involved hGSTP1-1 allozymes. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 330-344, 2016.

Antibacterial activity of <i>Euphorbia hirta</i> against <i>Streptococcus pneumoniae</i>, <i>Klebsiella pneumoniae</i> and <i>Proteus vulgaris</i>

This investigation was conducted to determine the in-vitro effect of aqueous, ethanol and methanol crude extracts of Euphorbia hirta at concentrations ranging from 10mg/ml – 100mg/ml against three pathogenic bacteria (Streptococcus pneumoniae, Klebsiella pneumoniae and Proteus vulgaris) using cup plate method. The extracts showed appreciable inhibitory effect (6-11mm and 2-20mm) on Streptococcus pneumoniae and Proteus vulgaris when compared to the positive control (penicillin). Klebsiella pneumoniae was resistant to all the extracts. The minimum inhibitory concentration (MIC) was between 60mg/ml – 80mg/ml on Streptococcus pneumoniae and 60mg/ml-100mg/ml on Proteus vulgaris. The minimum bactericidal concentration (MBC) was between 90-100mg/ml on Streptococcus pneumoniae and 100mg/ml on Proteus vulgaris. Phytochemical analysis revealed the presence of tannins, flavonoids, cardiac glycosides and volatile oils. The result from this preliminary study suggests that the plant contains active compounds that could be used for the development of drug for the treatment of ailments associated with the test organisms. More work needs to be done on the separation and purification of active compounds in the plant extract in order to determine the role of each compound in the crude extracts. Keywords: Antibacterial activity, Euphorbia hirta, Crude extracts, Bacterial isolates.

Synthesis and in-vitro antimicrobial evaluation of a high-affinity iron chelator in combination with chloramphenicol

The objectives of this study were first to design and synthesize a hexadentate chelator with high iron(III) affinity and, second, to evaluate its antimicrobial activity in the presence and absence of chloramphenicol. A hexadentate ligand was synthesized by conjugating a protected bidentate compound onto a tripodal structure. The pKa values and iron affinity of the chelator were determined by spectophotometric titration. Minimum inhibitory concentrations were determined by visual inspection of broth turbidity. The bactericidal rates were calculated by counting the colony numbers on a light board after incubation with and without an antimicrobial agent. A hexadentate 3-hydroxypyridin-4-one was found to possess a high affinity for iron(III), with a pFe value of 31.2 (negative logarithm of concentration of the free iron(III) in solution (when [Fe³⁺](Total) = 10⁻⁶) M; [Ligand](Total) = 10⁵ M; pH = 7.4). We found that this chelator had an appreciable inhibitory effect in vitro against the two bacterial strains Providencia stuartii and Staphylococcus aureus, particularly in the presence of chloramphenicol. A 3-hydroxypyridin-4-one hexadentate ligand has potential as an antimicrobial agent. Combination therapy with this iron chelator plus chloramphenicol has potential for the treatment of extracellular infections.

Cytotoxic effect of Mercurialis annua L. methanolic extract on six human solid cancer cell lines

The unprecedented rates of resistance of cancer cells to traditional chemotherapeutic medications necessitated relentless exploration and drug design in an attempt to introduce safe and effective new antineoplastic agents. The latter is a particular pivotal to the treatment of solid tumors malignancies which represent the top causes of cancer deaths. Our laboratory has established a line of research to investigate potential cytotoxic agents of native plant origins. Folkloric anecdotal evidence and initial screening led us to investigate the cytotoxicity of Mercurialis annua L. (Euphorbiaceae) methanolic extract against a variety of cancer cell lines. In total, six different cell lines representing three types of common cancers were used to determine the potential antineoplastic activity of the plant extract. Our results show that the M. annua extract exhibited potent cytotoxic effect on both HRT-18 and T47D cell lines in a dose-dependent manner. HRT-18 is a colorectal adenocarcinoma cell line, while T47D is a breast cancer cell line. The calculated IC50 values of the plant extract against HRT-18 and T47D cell lines were 41 and 270 µg/ml, respectively. On the other hand, there was no appreciable inhibitory effect of the plant extract on the growth of Caco-2, MCF-7, A375-S, and WM136-1A cell lines. The inhibition of cellular growth was cell-type specific. Among the breast cancer cell lines, MCF7 and T47D, only T47D which is a human ductal breast epithelial was sensitive to the plant extract. Likewise, the human epithelial colorectal adenocarcinoma cells (Caco-2) was resistant, while the human rectum adenocarcinoma (HRT-18) was sensitive to the plant extract. Interestingly, the two human malignant melanoma cell lines; A375.S2 and WM136 1A were both resistant to the plant extract. This work is a first step towards unraveling the full pharmacologic potential of M. annua in cancer treatment. Key words: Mercurialis annua L., cancer, cytotoxic, T47D, HRT-18, plant extract.