Inhibition Of Microbial Growth Research Articles

Rational design and characterization of cell-selective antimicrobial peptides based on a bioactive peptide from Crocodylus siamensis hemoglobin

Antimicrobial resistance is a growing health concern. Antimicrobial peptides are a potential solution because they bypass conventional drug resistance mechanisms. Previously, we isolated a peptide from Crocodylus siamensis hemoglobin hydrolysate, which has antimicrobial activity and identified the main peptide from this mixture (QL17). The objective of this work was to evaluate and rationally modify QL17 in order to: (1) control its mechanism of action through bacterial membrane disruption; (2) improve its antimicrobial activity; and (3) ensure it has low cytotoxicity against normal eukaryotic cells. QL17 was rationally designed using physicochemical and template-based methods. These new peptide variants were assessed for: (1) their in vitro inhibition of microbial growth, (2) their cytotoxicity against normal cells, (3) their selectivity for microbes, and (4) the mode of action against bacteria using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and confocal microscopy. The results indicate that all designed peptides have more potent antimicrobial efficacy than QL17 and IL15 peptides. However, only the most rationally modified peptides showed strong antimicrobial activity and minimal toxicity against normal cells. In particular, IL15.3 (hydrophobicity of 47% and net charge of + 6) was a potent antimicrobial agent (MIC = 4–12 μg/mL; MBC = 6–25 μg/mL) and displayed excellent selectivity for microbes (cf. human cells) via FACS assays. Microscopy confirmed that IL15.3 acts against bacteria by disrupting the cell membrane integrity and penetrating into the membrane. This causes the release of intracellular content into the outer environment leading to the death of bacteria. Moreover, IL15.3 can also interact with DNA suggesting it could have dual mode of action. Overall, a novel variant of QL17 is described that increases antimicrobial activity by over 1000-fold (~ 5 μg/mL MIC) and has minimal cytotoxicity. It may have applications in clinical use to treat and safeguard against bacteria.

Green synthesis of Multifunctional Zinc oxide Nanoparticles from Cordia myxa gum; and their Catalytic Reduction of Nitrophenol, Anticancer and Antimicrobial Activity

In situ exfoliated natural polysaccharide Cordia myxa (CMX) is used to promote the utilization of zinc-oxide nanoparticles for eco-friendly catalytic hydrogenation of p-nitrophenol (p-NP) and microbial growth inhibition. Polysaccharide-mediated biosynthetic nanocomposite materials are interesting because they are cheap, green, and environmentally friendly. This study uses CMX gum as a bioreduction to produce multifunctional, environmentally friendly zinc-oxide nanocomposites (ZnO NPs). The process involves a low reaction time and temperature and utilizes CMX as a reducing and stabilizing agent. The structural, morphological, and optical properties of the CMX-ZnO nanocomposite were characterized. The biosynthetic CMX-ZnO NPs exhibited robust catalytic activity and recycling capacity for rapidly oxidizing hazardous p-NPs. The complete reduction of 4-NP to CMX-ZnO NPs in excess NaBH4 was achieved within 15 min, with recyclability and pseudo-first-order kinetics with a rate constant of 0.2571 min−1. Additionally, human colon cancer (HCT116) and 3T3L1 cell lines were remarkably sensitive to the cytotoxic effects of ZnO nanoparticles. CMX-ZnO NPs exhibited potent antibacterial properties against human pathogenic gram-positive and gram-negative bacteria (Bacillus, Salmonella, E. coli, and Pseudomonas aeruginosa) based on the zone of inhibition measured by the disc-diffusion method. The significant antibacterial activity of CMX-ZnO NPs can overcome the current limitations associated with removing water-soluble organic pollutants and microbiological contaminants for long-term environmental sustainability.

A novel formulation of triethyl orthoformate mediated durable, smart and antibacterial chitosan cross-linked cellulose fabrics

Antibacterial, durable and smart cotton fabrics was developed using chitosan-based formulation. The cellulose was covalently cross-linked with chitosan using TEOF. The antibacterial activity of prepared smart fabrics and CS was studied against S. aureus and E. coli strains. The FTIR, SEM and XRD were employed to confirm the linkage of CS molecules with cellulose in cotton fabrics. The CS of 160 KDa extracted from shrimp shell showed the optimum antibacterial activity. The prominent asymmetric, symmetric alkyl CH peaks of CS were shifted to 2930 and 2845 (cm−1), respectively. Moreover, the shifted peaks at 1590 and 1400 (cm−1) indicate the CO stretching and NH2 bending bands of CS, respectively. This confirm the existence of new imine functional group that was generated after cross-linking of NH2 groups of CS. The SEM results showed more uniform morphology of TEOF cross-linked fabrics versus CS coated fabrics, which revealed a promising microbial growth inhibition activity. The TEOF as a cross-linker has been unveiled, showcasing the effectiveness of this innovative crosslinking approach. The fabric treated with cross-linked CS exhibited remarkable antibacterial properties that endured even after undergoing 30 washing cycles. These antibacterial textiles possess substantial commercial potential across a diverse range of industries.

Effects of ultrasound, microwave, and their combined treatments on the shelf life and quality characteristics of fresh litchi juice

This study investigated the effects of ultrasound and microwave and their combinations on preserving the quality of litchi juice during 21 days of storage. The physiochemical analysis exhibited that, the pH and Vitamin C content decreased gradually, whereas TSS, TA, and color values increased over the storage period. It was observed that the synergistic approach of sonication and microwave had positively impacted the bioactive components of fresh litchi juice. The results indicate that the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant properties of fresh litchi juice were changed significantly (p≤0.05) and reduced with increases in the treatment time. For instance, combined treatment (T6) exhibited the TPC (81.84±0.72 to 55.74±0.47 mg GAE/100 mL of juice) and TFC (3.31±0.136 to 3.12±0.126 mg QE/100 mL of juice) for 0 to 21 days of storage. On the other hand, the DPPH radical scavenging activity of litchi juices was increased notably (p≤0.05) and subsequently decreased after treatments, where the values ranged between 106.35±0.66 to 123.42±1.09 mg AAE/100 mL of juice at initial storage. The highest microbial growth inhibition was found in T6, and the values were (4.05-5.01 log10 cfu/mL) for total plate count and (3.63-4.78 log10 cfu/mL) for total yeast and mold during initial storage. Therefore, the combined treatment of sonication and microwave could be employed without chemical preservatives to treat fresh litchi juice with better retention of physicochemical attributes and bioactive phytochemicals.

Photocatalytic titanium dioxide reduces postharvest decay of nectarine fruit packaged in different materials through modulating central carbon and energy metabolisms

The capacity of titanium dioxide (TiO2) photocatalysis photocatalytic reactor to prevent and control pathogen infection in nectarine fruit packed in laminated nylon/LDPE, low density polyethylene and microperforated LDPE films was evaluated. Results showed that TiO2 combined with microperforated LDPE packaging (TPL) exhibited superior inhibition of microbial growth, reducing total viable counts by 4.18 log CFU g−1 and yeast and mold counts by 3.20 log CFU g−1, compared to microperforated LDPE packaging alone. TiO2 photocatalysis primed the defense systems in nectarine fruit packed in microperforated LDPE, improving the activity of defense-related enzymes. Metabolomics analysis indicated that l-aspartate, oxaloacetate, and succinic acid involved in central carbon metabolism including the glycolysis and tricarboxylic acid cycle pathways, were significantly upregulated by TPL. TiO2 increased the activity of energy metabolism-related enzymes, adenosine triphosphate, adenosine diphosphate, and energy charge levels to provide adequate energy, thus reducing fruit decay.

Zinc oxide enhanced the antibacterial efficacy of biodegradable PBAT/PBS nanocomposite films: Morphology and food packaging properties

Enhancing the antimicrobial functions of biodegradable polyesters facilitates the utilization of sustainable food packaging. Poly(butylene succinate) (PBS) and polybutylene adipate terephthalate (PBAT) blends were compounded with zinc oxide (ZnO) nanoparticles (up to 4.5%) into a master batch via twin-screw extrusion. Biodegradable films were produced via cast extrusion, and the morphologies and packaging properties were determined. Adding ZnO nanoparticles up to 2.7% modified the film's surface topography, causing non-homogeneity and voids. ZnO tended to form aggregates at higher loading, while phase separation of metal oxide from PBAT/PBS matrices occurred. Dispersion of ZnO nanoparticles reduced water vapor permeability, with the lowest effects on oxygen permeability. Adding ZnO in combination with the molecular orientation of the polymer effectively reinforced the matrices and improved the mechanical properties of PBAT/PBS blends. PBAT/PBS/ZnO films exhibited antimicrobial capacity against Escherichia coli and Bacillus cereus. PBAT/PBS with ZnO >2.7% delayed discoloration of red pigments in packaged minced pork due to efficient inhibition of microbial growth and UV blocking. ZnO-loaded polyester enhanced antimicrobial functions, producing sustainable active nanocomposite packaging.

Biological activities and biosorption potential of red algae (Corallina officinalis) to remove toxic malachite green dye

This research aims to use eco-friendly Corallina officinalis as an adsorbent for removing harmful malachite green dye streams from industrial effluent, promoting sustainable living and effective microbial growth inhibition. Corallina officinalis biomass was tested for textile dye biosorption, as well as its antibacterial, antioxidant, and cytotoxic properties. The effects of certain parameters, involving pH solution, initial dye concentration, algae dose, and contact time, were investigated on the sorption of dye. Fourier transform infrared spectroscopy and scanning electron microscopy were also used and, the results showed that the functional groups on the surface of algae played an important part in the biosorption process. It was noted that the kinetic data were significantly prominent by the Pseudo-second-order model with regression correlation coefficient {r}_{2}^{2} values with an average of 0.95232. The biosorption was compatible with both the Freundlich (R2 = 0.9843), and Langmuir (R2 = 0.9653) isotherms, and the maximum removal efficiency for dye reached up to 99.9% in 2 h, 27 °C, stirring speed 120 rpm, pH 6, initial dye concentration 20 mg L−1, and biomass dose 0.03 g L−1. Corallina officinalis had higher antimicrobial activity, with values of minimum inhibitory concentrations ranging from 0.156 to 5 mg mL−1. Corallina officinalis exerted significant radical scavenging activity against tested free radicals. The extract was examined for cytotoxic activity using nine cancer cell lines, which exhibited high cytotoxicity for colon adenocarcinoma with an IC50 value of 25.895 µg mL−1.

Morroniside interaction with poly (ADP-ribose) polymerase accentuates metabolic mitigation of alloxan-induced genotoxicity and hyperglycaemia: a molecular docking based in vitro and in vivo experimental therapeutic insight

The present study tends to evaluate the possible potential of bio-active Morroniside (MOR), against alloxan (ALX)-induced genotoxicity and hyperglycaemia. In silico prediction revealed the interaction of MOR with Poly (ADP-ribose) polymerase (PARP) protein which corroborated well with experimental in vitro L6 cell line and in vivo mice models. Data revealed the efficacy of MOR in the selective activation of PARP protein and modulating other stress proteins NF-κB, and TNF-α to initiate protective potential against ALX-induced genotoxicity and hyperglycaemia. Further, the strong interaction of MOR with CT-DNA (calf thymus DNA) analyzed through CD spectroscopy, UV-Vis study and ITC data revealed the concerted action of bio-factors involved in inhibiting chromosomal aberration and micronucleus formation associated with DNA damage. Finally, MOR does not play any role in microbial growth inhibition which often occurs due to hyperglycemic dysbiosis. Thus, from the overall findings, we may conclude that MOR could be a potential drug candidate for the therapeutic management of induced-hyperglycaemia and genotoxicity. Communicated by Ramaswamy H. Sarma

Enhancement of cell migration and wound healing by nano-herb ointment formulated with biosurfactant, silver nanoparticles and Tridax procumbens.

Ointments are generally used as a therapeutic agent for topical medication or transdermal drug delivery, such as wound healing and skin lesions. In this study, Tridax procumbens plant extract (0.7 g/mL) was used to prepare herbal-infused oil as the oil phase and gelatin-stabilized silver nanoparticle (G-AgNPs) (0.3 g/mL) as the aqueous phase. To blend the oil and aqueous phases, rhamnolipid biosurfactant with a critical micelle concentration of 55 mg/L from strain Pseudomonas aeruginosa PP4 has been used for herb ointment preparation. The average size of the synthesized G-AgNPs was observed between 10-30 nm and confirmed as spherical-shaped particles by TEM analysis. Subsequently, GC-MS and FTIR characterization are used to confirm herb ointment's chemical and functional characteristics. Based on the antibacterial studies, the highest microbial growth inhibition was observed for herb ointment, about 19.5 mm for the pathogen Staphylococcus aureus at the concentration of 100 μg/mL, whereas 15.5 mm was obtained for Escherichia coli, respectively. In addition, the minimum inhibitory concentration (MIC) assay showed negligible bacterial growth at 100 μg/mL for S. aureus and E. coli, respectively. Moreover, the cell viability assay for herb ointment exhibited low cytotoxic activity at higher concentrations (100 μg/mL) in Vero cell lines. In this study, wound scratch assay showed a significant cell migration rate (90 ± 2%) in 3 days of incubation than the control (62 ± 2%). As a result, the biosurfactant-based nano-topical herb ointment revealed a low cytotoxic and higher cell migration capacity. Altogether, these findings highlighted the utility of this herb ointment in therapeutic applications such as wound healing.

Antimicrobial potential of unstressed and heat stressed Allium sativum

Garlic (Allium sativum) is generally known to be of medicinal value, possessing potentials that include antimicrobial activity, but are often consumed in foods after subjection to cooking heat. The antimicrobial potential of heat stressed garlic may become decreased or lost when cooked, making its medicinal benefit unavailable to consumers. The potential of uncooked and cooked extracts from garlic imported to Jamaica, to inhibit the growth of eight microbes of clinical significance was investigated. Aqueous extracts of fresh garlic of 15 g/100 ml (fw), and dried and pulverized garlic cloves of 12.5 g/100 ml, 25 g/100 ml, 50 g/100 ml, and 100 g/100 ml (dw), were tested for inhibition of microbial growth. Extracts were tested uncooked, and cooked by boiling for 5, 10, and 15 min respectively. Of all the microbes studied, C. albicans incurred the largest zone of inhibition (57.7 ± 0.6 mm at the 100 g/100 ml of the dried extract, F(3, 8) = 51.778, p < 0.001, ω2 = 0.93). Cooking of garlic extracts resulted in statistically significant decreases in zones of inhibition of microbes, as evident in the linear regression and one-way ANOVA analyses, and/or complete loss of microbial inhibition. C. albicans was the most inhibited microbe, followed by E. coli, and Salmonella sp., respectively. The use of uncooked garlic may be the best route for obtaining the greatest antimicrobial potential of garlic against susceptible bacteria and fungi because cooking heat stress resulted in the decrease and complete loss of the antimicrobial potentials of the garlic.

Multifunctional chromone-incorporated poly(hydroxybutyrate) luminescent film for active and intelligent food packaging

The major objective of present work was to fabricate poly(hydroxybutyrate) based luminescent films for genuine food packaging applications. These films were synthesized by incorporating varying Chromone (CH) concentrations (5, 10, 15, 20, and 25 wt%) into poly(hydroxybutyrate) (PHB) matrix through solvent-casting. Different characteristics of prepared films were examined using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), Mechanical testing, and Time-resolved photoluminescence (TRPL). UV-blocking properties and water vapor permeation were also examined. FTIR spectra indicated the occurrence of hydrogen bonding between PHB and CH. Among all prepared film samples, PHB/CH15 showed maximum tensile strength (22.5 MPa) with enhanced barrier ability against water vapor and UV rays, thermal stability, and luminescent performance. After overall analysis, PHB/CH15 film was selected to investigate its X-ray diffraction, release behavior, DPPH scavenging, and antimicrobial potential. Release kinetics revealed that the cumulative release percentage of CH was higher in fatty acid stimulant. Moreover, results suggested that this film demonstrated antioxidant activity (>55 %) and superior antimicrobial potential against Aspergillus niger, Staphylococcus aureus, and Escherichia coli. Furthermore, packaging of bread samples using PHB/CH15 film demonstrated the complete inhibition of microbial growth in bread up to 10 days of storage and ensure the safety of genuine food products.

Biovalorization of Fruit Wastes for Development of Biodegradable Antimicrobial Chitosan-Based Coatings for Fruits (Tomatoes and Grapes).

Organic wastes are generated from high consumption of fruits. In this paper, fruit residual wastes collected from fruit-juice centres were transformed into fine powder, and thereafter, proximate analysis along with SEM, EDX and XRD was done to get into the surface morphology, minerals and ash content of fine powder. Aqueous extract (AE) prepared from this powder was studied using gas chromatography-mass spectroscopy (GC-MS). The phytochemicals identified are N-hexadecanoic acid; 1,3-dioxane,2,4-dimethyl-, diglycerol, 4-ethyl-2-hydroxycyclopent-2-en-1-one, eicosanoic acid, etc. AE showed high antioxidant and a low MIC value (2mg/ml) against Pseudomonas aeruginosa MZ269380. AE having acceptance as nontoxic to biological system, formulation of chitosan (2%)-based coating was done with 1% AQ. Surface coatings of tomatoes and grapes showed significant inhibition of microbial growth even after 10days of storage at ambient temperature (25 ± 2°C). Colour, texture, firmness and aceptability of coated fruits showed no degradation compared to negative control. Additionally, the extracts showed insignificance haemolysis of goat RBC and damage of Calf Thymus DNA which exhibited its biocompatible nature. Biovalorization of fruit wastes yields useful phytochemicals and can be utilized in various sectors thereby finding a sustainable solution for disposal of fruit wastes.

Optimisation of edible coating conditions using statistical Response Surface Methodology for shelf life extension of fresh-cut guava

AbstractIn the present study, six different edible coatings were evaluated to assess their microbicidal efficiency on pre-treated disinfected fresh cut guava. Among all coatings viz. alginate, pectin, carboxy methylcellulose, carrageenan, and starch, chitosan showed significant microbial growth inhibition and preservation of physico-chemical characteristics of fresh cut guava. Further, optimisation of coating parameters i.e. concentration (% w/v) and dipping time (min) was performed using Response Surface Methodology. It revealed that the fresh-cut guava dipped in 1% (w/v) chitosan for 3 min had desirability level of 91% and extension of its shelf life up to 9 days, as compared to 5 days shelf life of uncoated fresh-cut guava, maintaining all its physico-chemical parameters and microbial growth under the permissible level. Validation of optimised conditions was conducted at 5.0 kg scale that resulted in firmness of 1.90 (kg), 2.6 g/100 g sugars content, 8.0 °Brix total soluble solids content, 3.4 pH, 4.1 log CFU g−1 total plate count, 3.1 log CFU g−1 yeast and moulds count, and 3.1 log CFU g−1 total coliforms count on fresh-cut guava at 9th day of refrigeration storage. Shelf life analysis revealed that chitosan coated fresh cut guava can stay fresh till 10th day under refrigeration with maintaining all its nutritive, microbiological, and sensory properties in the acceptable range.

Bringing resistance modulation to methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) strains using a quaternary ammonium compound coupled with zinc oxide nanoparticles

Nowadays, there are concerns about the inadequacy of new antimicrobials and the rise of antimicrobial resistance. Hence, novel antibacterial agents need to be discovered. In this respect, the use of nanoparticles (NPs) seems promising. Zinc oxide nanoparticles (ZnONPs) are functional and inexpensive NPs that possess antimicrobial characteristics, stability, microbial selectivity, and an easy manufacturing procedure. Imidazolium is one of the quaternary ammonium compounds (QACs) frequently employed as antimicrobial materials in industrial and clinical fields. The present study successfully employed imidazolium to couple with ZnONPs to improve their antimicrobial properties. The antimicrobial activities of ZnONPs doped with imidazolium (IM@ZnONPs) compared to ZnONPs and zinc (Zn) ions against some pathogen microorganism species including Streptococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Candida albicans (C. albicans) were evaluated by the microdilution method. The minimum inhibitory concentration (MIC) results revealed that the antimicrobial activities of Zn ions, ZnONPs, and IM@ZnONPs were concentration-dependent. Moreover, we found that the nanoparticulate forms of Zn had considerably stronger antibacterial activities, particularly against VRE and MRSA, compared to Zn ions which failed to restrain the microbial strains at the tested microdilutions of this experiment (MIC: ≥512µg/mL). Interestingly, the incorporation of imidazolium into ZnONPs resulted in significant inhibition of microbial growth in antimicrobial-resistant pathogens at low concentrations (MIC: 32µg/mL) and effectively improved the monodispersity of the final coated NPs in terms of size and morphology. To sum up, IM@ZnONPs can be a favorable substitute for conventional antimicrobial agents to combat antimicrobial resistance in many fields, including pharmaceuticals, dental materials, and cosmetic products.

Achieving stable anaerobic mono-digestion of concentrated waste activated sludge without any pretreatment

Sludge digesters are generally designed using empirical thresholds that were defined several decades ago, typically leading to large digesters displaying low organic loading rates (1–2.5 kgVS.m−3.d−1). However, the state of the art has significantly evolved since these rules were set, especially regarding bioprocess modelling and ammonia inhibition. This study demonstrates that digesters can be safely operated at high sludge concentration and total ammonia concentration up to 3.5 gN.L−1, without any sludge pretreatment. The possibility of operating sludge digesters at organic loading rates of 4 kgVS.m−3.d−1 by feeding concentrated sludge was identified through modelling and experimentally confirmed. Based on these results, the present work proposes a new mechanistic digester sizing strategy based on microbial growth and ammonia-related inhibition in lieu of historical empirical methods. Applying such method to sludge digester sizing could lead to very significant volume reduction (25–55%), which would result in reduced process footprint and more competitive building costs.

Biological synthesis of zinc-oxide nanoparticle using wide-spread Lentinus sajor-caju extract as a carrier for natural-compounds

The use of nanotechnology in industry and medicine has recently become a hot topic of research. This study focused on synthesizing zinc oxide nanoparticles (ZnONPs) using Lentinus sajor-caju extract, followed by applying the nanoparticle as a carrier for natural compounds. Energy dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Field-emission scanning electron microscopy (FESEM), Filed-emission transmission electron microscopy (FETEM), and zeta potential measurements were used to characterize the synthesized nanoparticles. The synthesis of ZnONPs was also confirmed by UV–visible spectroscopy. The ZnONPs had a spherical shape with an average size of 28 nm in diameter, according to FETEM and FESEM. X-ray powder diffraction and selected area electron diffraction showed that the ZnONPs were crystalline in structure. The active components of the L. sajor-caju extracts were found to cap the ZnONPs, according to FTIR analysis. Additionally, EDX analysis revealed test showed the elemental composition of ZnONP's. The performance of the L. sajor-caju-capped ZnONP conjugated with a drug was studied in terms of inhibition of microbial growth against gram-negative and gram-positive bacteria through the disc diffusion method. The results demonstrated a considerable inhibition of both bacteria, demonstrating ZnONP's potential for use in biomedicine.

Screening of antibiotic residues in raw bovine milk in Lombardy, Italy: Microbial growth inhibition assay and LC-HRMS technique integration for an accurate monitoring

Antibiotic residues in food of animal origin is a great concern for public health worldwide in terms of antibiotic resistance development, potential allergic reactions and disruption of intestinal flora equilibrium. In this study the presence of antibiotic residues in raw bovine milk samples collected from farms located in Lombardy region in Italy from 2018 to 2022 was assessed in the context of the national milk quality payment system. Samples were screened with microbiological growth inhibition test Delvotest ® SP NT and a very low positivity rate ranging from 0.1% to 0.07% over the four years was determined. A total of 79 positive samples were further analysed by LC-HRMS screening technique to confirm positivity and detect the specific antibiotic compound contaminating the sample. The β-lactam antibiotics resulted to be the most frequently detected, with the penicillin G being the most abundant compound. The data suggested that low levels of antibiotic contamination are consistently maintained over the last four years and the integration of the techniques used in this study is a valuable tool for a deep and precise monitoring of antibiotic residues in milk.

Comparative study of total reducing and total antioxidant capacity of Escherichia coli on different media composition obtained by response surface methodology

Anti-oxidants are compounds that act against oxidative stress, prevent DNA damage and lipid peroxidation which are usually the major causes of aging and many diseases including cancer, cardio vascular disorders etc. There are many anti-oxidant assays which are used to measure anti-oxidant potential but total anti-oxidant capacity (TAC) and total reductive capability (TRC) are more preferred because of ease to use, good reproducibility and accuracy. Media components were optimized through response surface methodology (RSM) and sixteen different media compositions were obtained at primary level. These media compositions were used for TAC and TRC antioxidant assays. The highest reducing power activity was observed in the form of absorbance in media number 4 (0.0275 for 10 min) in wet biomass and for media number 6 (0.0244 for 10 min) in dry biomass. After 30 min, highest reducing power was reported in media number 5 (0.0286) in wet biomass and for dry biomass it was in media number 6 (0.0230). Total anti-oxidant capacity showed the higher percentage inhibition of microbial growth for wet biomass in media number 4 and media number 13 and for dry biomass, the highest percentage inhibition was in media number 5. Therefore, it was observed that media have same nutrients but different compositions which directly affect the level of TAC and TRC. Hence it is an important parameter that before experiments, media components must be optimized by RSM.

Antimicrobial Activity of Warburgia ugandensis on Selected Standard Organisms that Cause Urinary Tract Infections

Background: The antimicrobial effect of Warburgia ugandensis has been recognized for many years in developing countries especially in East Africa. However, limited investigations have focused on its effect on microorganisms causing urinary tract infection.&#x0D; Objective: To determine the antimicrobial activity of Warburgia ugandensis on selected standard microorganisms that cause urinary tract infections i.e. Escherichia coli (ATCC 25922), Candida albicans (ATCC 10231), Proteus mirabilis (ATCC 25933), and Staphylococcus aureus (ATCC 25923).&#x0D; Methods: Warburgia ugandensis stem bark was obtained from Tooro Botanical centre and were shade dried. The aqueous and ethanolic extracts were prepared and evaluated for phytochemical components using semi qualitative phytochemical screening techniques. The antimicrobial activity on three bacteria; Staphylococcus aureus, Escherichia coli, Proteus mirabilis and one fungus Candida albicans was tested by agar well diffusion and broth dilution which to obtain the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the plant extracts respectively.&#x0D; Results: Phytochemical screening showed the presence of tannins, flavonoids, alkaloids, saponins and terpenoids in both the aqueous and ethanolic extracts. The bacteria were susceptible to the aqueous extract which caused significant inhibition of microbial growth with the highest activity observed on Staphylococcus aureus (MIC 0.49mg/ml), while less susceptibility to the ethanolic extract was observed with Staphylococcus aureus having an MIC of 1.95mg/ml and so was MBC/MFC, in which Staphylococcus aureus had an MBC of 7.81mg/ml. Candida albicans showed the same pattern with more susceptibility to the aqueous extract (MFC 15.63mg/ml) as compared to the ethanolic extract (MFC 62.5mg/ml)&#x0D; Conclusion: The aqueous and ethanolic extracts of Warburgia ugandensis exhibit antimicrobial effect against the selected urinary tract infection causing organisms. The aqueous extract showed antimicrobial activity in both agar well diffusion and broth dilution methods. This study further shows the potential of Warburgia ugandensis being a novel source of modern drugs with further studies and these results provide some new perspectives on the traditional uses of Warburgia ugandensis in treating urinary tract infections.

Enzymatic, Antioxidant, and Antimicrobial Activities of Bioactive Compounds from Avocado (Persea americana L.) Seeds

The aim of this research was to identify and quantify biologically active compounds from avocado (Persea americana L.) seeds (AS) utilizing different techniques with the use of ultrasound (US), ethanol (EtOH), and supercritical carbon dioxide (scCO2) for possible applications in (bio)medicine, pharmaceutical, cosmetic, or other relevant industries. Initially, a study of the process efficiency (η) was carried out, which revealed yields in the range of 2.96-12.11 wt%. The sample obtained using scCO2 was found to be the richest in total phenols (TPC) and total proteins (PC), while the sample obtained with the use of EtOH resulted in the highest content of proanthocyanidins (PAC). Phytochemical screening of AS samples, quantified by the HPLC method, indicated the presence of 14 specific phenolic compounds. In addition, the activity of the selected enzymes (cellulase, lipase, peroxidase, polyphenol oxidase, protease, transglutaminase, and superoxide dismutase) was quantified for the first time in the samples from AS. Using DPPH radical scavenging activity, the highest antioxidant potential (67.49%) was detected in the sample obtained with EtOH. The antimicrobial activity was studied using disc diffusion method against 15 microorganisms. Additionally, for the first time, the antimicrobial effectiveness of AS extract was quantified by determination of microbial growth-inhibition rates (MGIRs) at different concentrations of AS extract against three strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas fluorescens) bacteria, three strains of Gram-positive (Bacillus cereus, Staphylococcus aureus, and Streptococcus pyogenes) bacteria, and fungi (Candida albicans). MGIRs and minimal inhibitory concentration (MIC90) values were determined after 8 and 24 h of incubation, thus enabling the screening of antimicrobial efficacy for possible further applications of AS extracts as antimicrobial agents in (bio)medicine, pharmaceutical, cosmetic, or other industries. For example, the lowest MIC90 value was determined for B. cereus after 8 h of incubation in the case of UE and SFE extracts (70 μg/mL), indicating an outstanding result and the potential of AS extracts, as the MIC values for B. cereus have not been investigated so far.