Average Minimum Inhibitory Concentration Research Articles

Chemical Analysis and Biological Activities of Various Parts of Securidaca longipedunculata From South Africa

Objective The objective of our study was to investigate the chemical composition and the biological activities of different parts of Securidaca longipedunculata from South Africa. Methodologies The chemical analysis methods, including chromatography and spectroscopy, were employed to identify the diverse array of compounds present in the roots, leaves, and stems of S longipedunculata. Results The proximate analysis revealed that the leaf extracts had higher ( P < .05) crude protein, gross energy, and ether extract contents when compared to the stem bark and the root bark. A similar trend was observed with the mineral analysis where copper, iron, magnesium, and zinc were in abundance in the leaves. Concurrently, bioassays reveal significant biological activities, such as antioxidant, antimicrobial, and anti-inflammatory properties, associated with these plant parts. The extracts demonstrated high lipid peroxidation inhibitory activity at the concentration of 250 μg/mL, with the highest percentage inhibition of 94% recorded in the dark leaf extract, followed by 92% and 73% at the concentrations of 125 and 62.5 μg/mL, respectively. The antimicrobial analysis revealed that the root bark extract was active against Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis with the average minimum inhibitory concentration of 1.67 mg/mL (dark type) and 0.63 mg/mL (light type). Conclusion Our findings emphasize the medicinal potential of S longipedunculata and underscore the importance of understanding its chemical makeup in explaining its therapeutic effects. This research provides valuable insights into the pharmacological properties of S longipedunculata, offering a foundation for further exploration in drug development and natural product discovery.

Plants with Antimicrobial Activity against Escherichia coli, a Meta-Analysis for Green Veterinary Pharmacology Applications.

Antimicrobial resistance (AMR) poses a critical global health threat, necessitating innovative strategies to combat infectious diseases. Plants and their extracts offer alternatives/support to traditional antibiotics, and their diverse phytocomplexes with antimicrobial properties can be exploited. The Mediterranean hosts a high number of biodiverse plant species known for their bioactive compounds. This study focuses on identifying plant species and phytochemical constituents with antimicrobial activity against Escherichia coli (E. coli). Utilizing a systematic literature review and meta-analysis approach, we screened 3037 entries, yielding 70 studies suitable for MIC (minimum inhibitory concentration) annotation. The results highlighted Lavandula spp., Plectranthus spp. and Lupinus jaimehintoniana as the most effective plants with average MICs of, respectively, 0.144 mg/mL, 0.260 mg/mL, and 0.140 mg/mL. These results might help to fight AMR via the discovery of complementary natural antimicrobial agents to support the development of green veterinary pharmacology. Further exploration of these resources promises valuable insights for future support to antimicrobial strategies.

Earthworm Infusion as an Antimicrobial Against Bacteria Causing Diarrhea

Diarrhea is the second most common disease worldwide after Acute Respiratory Infection (ARI). One of the causes of diarrhea is the gastrointestinal infection caused by disease bacteria (microbe) such as Salmonella sp., Escherichia coli, Shigella sp., and Vibrio cholerae. The earthworm species Lubricus sp can be used as an alternative medication believed to be able to cure digestive diseases such as typhus, dysentery, and other indigestion like gastritis. This research is laboratory experimental research. The antibacterial activity is measured by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values of earthworm infusion (Lumbricus rubellus) using the tube dilution test. The bacteria used in this research are Escherichia coli, Shigella dysentriae, and Vibrio cholerae, isolated from the feces of diarrhea patients. This research aims to examine the earthworm infusion antibacterial (Lumbricus rubellus) activity to several bacteria that commonly cause diarrhea. The research results show that the average MIC value of earthworm infusion (Lumbricus rubellus) against Escherichia coli is >50%, Shigella dysentriae 0,098%, and Vibrio cholerae >50%. The average MBC value of earthworm infusion against Shigella dysentriae is 50%. .

Green Synthesis and Investigation of Antimicrobial Activity and Compressive Resilience of Glass Ionomer Cement Modified With Zirconia Nanoparticles: An In Vitro Study.

Background Glass ionomer cement (GIC) serves as a crucial biomaterial in dental restoration, offering applications in filling, lining, and adhesive procedures. Nevertheless, its mechanical properties often fall short, particularly in regions subjected to considerable stress. To address this issue, zirconia nanoparticles are incorporated at specific levels. Aim To assess the antimicrobial efficacy and compressive resilience of GIC modified with zirconia nanoparticles synthesized through green synthesis methods. Material and methods Zirconia nanoparticles were synthesized via a green method utilizing aloe vera extract in solvent form. These nanoparticles were then mixed into GIC at different concentration levels. Group I incorporated zirconia nanoparticles at a concentration of 3%, Group II at 5%, and Group III at 10%, while Group IV was the control, consisting of traditional GIC. Following that, samples were prepared and underwent characterization through various analytical techniques. The ability to inhibit microbial growth and the compressive resilience of the groups were examined. Microbial inhibition against the bacterial strains was assessed through minimum inhibitory concentration (MIC), and the ability to withstand compression was gauged by measuring the maximum force the specimen could endure before fracturing. Data underwent analysis with Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 24.0, Armonk, NY). Repeated measures of analysis of variance (ANOVA) were utilized to gauge average MIC values and compressive strength. Following this, Tukey's post hoc test was employed for pairwise comparisons. Results The findingsindicated, incorporating zirconia nanoparticles into GIC led to an improvement in its antimicrobial effectiveness, with a noticeable enhancement observed as the weight percent (% wt) of the additive increased. This improvement was notably noticeable in its effectiveness against Streptococcus mutans and Lactobacillus, exceeding that of the control with a noteworthy distinction. Furthermore, there were significant enhancements in compressive strength, in Group I (180.48 ± 1.02), Group II (191.25 ± 0.52), and Group III (197.52 ± 0.75), compared to Group IV (167.22 ± 1.235), with significant disparities (p < 0.05). Conclusion The research illustrates that introducing green-synthesized zirconia nanoparticles into GIC leads to heightened bactericidal potency and compressive resilience when contrasted with the control group (Group IV). Notably, the highest concentration of 10% demonstrated the most favourable antimicrobial attributes alongside enhanced strength. Consequently, integrating green-synthesized zirconia nanoparticles into GIC holds potential as a proficientmaterial. In future studies, there should be an exploration of molecular chemistry and bonding mechanisms to enhance our comprehension of its capabilities.

The inhibitory effects of carvacrol, nystatin, and their combination on oral candidiasis isolates

BackgroundCandida, a common oral microbiota, can cause opportunistic fungal infections. With rising Candida infections and limited effective antifungals, new treatments are needed. This study investigates carvacrol essential oil’s effect on oral candidiasis, alone and with nystatin, compared to nystatin alone.Materials and methodsIn this study, oral samples were collected from dental clinic patients, especially denture users. The presence of Candida was confirmed and cultured from these samples. Candidiasis was detected by observing Candida colonies. Drug sensitivity was tested on 100 positive samples. The minimum concentration of inhibition and lethality of each isolate was evaluated using nystatin and carvacrol. The results were compared using two-way analysis of variance. Finally, the minimum inhibitory concentration (MIC) of nystatin and carvacrol was calculated individually and in combination.ResultsThe present study found that Candida albicans and non-albicans species were equally prevalent. Carvacrol showed significant biological activity against all Candida species, with an average MTT of 50.01%. The average MIC value of carvacrol was 24.96 µg/ml, indicating its potential to inhibit Candida growth. The mean Minimum Fungicidal Concentration (MFC) value of carvacrol was 23.48 µg/ml, suggesting its effectiveness in killing the fungi.ConclusionThe study’s findings reveal that the MIC of carvacrol was significantly lower than that of nystatin and the combination of nystatin and carvacrol. This suggests that carvacrol holds potential as an effective herbal remedy for candidiasis.

Psoralea corylifolia L. and its active component isobavachalcone demonstrate antibacterial activity against Mycobacterium abscessus

Ethnopharmacological relevancePsoralea corylifolia L. (Fabaceae) is a traditional medicinal herb used to treat various diseases, including kidney disease, asthma, psoriasis and vitiligo. Aim of the studyTo explore the antibacterial activity of Psoralea corylifolia L. and its bioactive components against Mycobacterium abscessus (M. abscessus). Materials and methodsUltra high performance liquid chromatography was utilized to analyze the bioactive fractions and compounds present in 30%, 60%, and 90% ethanol extracts of Psoralea corylifolia L.. The antibacterial effects of Psoralea corylifolia L. and potential active ingredients were determined by minimum inhibitory concentration (MIC). The bactericidal activity of the active ingredient isobavachalcone was evaluated and then scanning electron microscopy was used to explore the bactericidal mechanism of isobavachalcone. ResultsThe 90% ethanol extracts of Psoralea corylifolia L. showed significant antibacterial activity against M. abscessus, with an MIC of 156 μg/mL. Isobavachalcone was identified as the bioactive ingredient, and testing of 118 clinical isolates of M. abscessus indicated their MICs ranged from 2 to 16 μg/mL, with an average MIC of 8 μg/mL. Furthermore, the minimum bactericidal concentration/MIC ratio and the time-kill test indicated rapid bactericidal activity of isobavachalcone against M. abscessus. Finally, we found that the bactericidal mechanism of isobavachalcone involved damage to the bacterial cell membrane, causing wrinkled and sunken cell surface and a noticeable reduction in bacterial length. ConclusionPsoralea corylifolia L. ethanol extracts as well as its active component isobavachalcone show promising antimicrobial activity against M. abscessus.

Preparing and evaluating the anti-microbial effect of Allium jesdianum mouthwash on some of the most common oral microorganisms.

Due to the increasing resistance of bacteria to antibiotics and anti-bacterial compounds in plants, Allium jesdianum Boiss plant extract can be used in mouthwash compounds with its anti-microbial activity. The anti-bacterial and anti-fungal activity of A. jesdianum mouthwash was investigated on Streptococcus mutans, Streptococcus sanguis, S. salivarius and Candida albicans, and Candida tropicalis. To analyse the anti-microbial effect of this mouthwash, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the broth microdilution method. The average MIC and MBC of A. jesdianum mouthwash for S. mutans were 1.56 and 3.12 (mg/ml), respectively, for S. salivarius, 0.25 and 0.65 (mg/ml), and for S. sanguis, respectively, 0.25 and 0.65 (mg/ml). The highest MIC and MBC values were for S. mutans, and the MIC and MBC values were equal for S. sanguis and S. salivarius. Average MIC and MBC were determined as 2.41 and 4.16 (mg/ml) for C. albicans and 2.34 and 5.72 (mg/ml) for C. tropicalis, respectively. MIC values of mouthwash were higher for C. albicans and MBC values for C. tropicalis. Our results showed a promising anti-fungal-anti-bacterial effect of A. jesdianum extract. A. jesdianum extract may be used as an alternative to chemical mouthwashes.

Superior Performance of Iron-Coated Silver Nanoparticles and Cefoxitin as an Antibiotic Composite Against Methicillin-Resistant Staphylococcus aureus (MRSA): A Population Study.

The synergistic effects of antimicrobial nanostructures with antibiotics present a promising solution for overcoming resistance in methicillin-resistant Staphylococcus aureus (MRSA). Previous studies have introduced iron as a novel coating for silver nanoparticles (AgNPs) to enhance both economic efficiency and potency against S. aureus. However, there are currently no available data on the potential of these novel nanostructures to reverse MRSA resistance. To address this gap, a population study was conducted within the MRSA community, collecting a total of 48 S. aureus isolates from skin lesions. Among these, 21 isolates (43.75%) exhibited cefoxitin resistance as determined by agar disk diffusion assay. Subsequently, a PCR test confirmed the presence of the mecA gene in 20 isolates, verifying them as MRSA. These results highlight the cefoxitin disk diffusion susceptibility test as an accurate screening method for predicting mecA-mediated resistance in MRSA. Synergy tests were performed on cefoxitin, serving as a marker antibiotic, and iron-coated AgNPs (Fe@AgNPs) in a combination study using the checkerboard assay. The average minimal inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) of cefoxitin were calculated as 11.55mg/mL and 3.61mg/mL, respectively. The findings indicated a synergistic effect (FIC index < 0.5) between Fe@AgNPs and cefoxitin against 90% of MRSA infections, while an additive effect (0.5 ≤ FIC index ≤ 1) could be expected in 10% of infections. These results suggest that Fe@AgNPs could serve as an economically viable candidate for co-administration with antibiotics to reverse resistance in MRSA infections within skin lesions. Such findings may pave the way for the development of future treatment strategies against MRSA infections.

Trends in antimicrobial resistance amongst Salmonella Paratyphi A isolates in Bangladesh: 1999-2021.

Typhoid and paratyphoid remain common bloodstream infections in areas with suboptimal water and sanitation infrastructure. Paratyphoid, caused by Salmonella Paratyphi A, is less prevalent than typhoid and its antimicrobial resistance (AMR) trends are less documented. Empirical treatment for paratyphoid is commonly based on the knowledge of susceptibility of Salmonella Typhi, which causes typhoid. Hence, with rising drug resistance in Salmonella Typhi, last-line antibiotics like ceftriaxone and azithromycin are prescribed for both typhoid and paratyphoid. However, unlike for typhoid, there is no vaccine to prevent paratyphoid. Here, we report 23-year AMR trends of Salmonella Paratyphi A in Bangladesh. From 1999 to 2021, we conducted enteric fever surveillance in two major pediatric hospitals and three clinics in Dhaka, Bangladesh. Blood cultures were performed at the discretion of the treating physicians; cases were confirmed by culture, serological and biochemical tests. Antimicrobial susceptibility was determined following CLSI guidelines. Over 23 years, we identified 2,725 blood culture-confirmed paratyphoid cases. Over 97% of the isolates were susceptible to ampicillin, chloramphenicol, and cotrimoxazole, and no isolate was resistant to all three. No resistance to ceftriaxone was recorded, and >99% of the isolates were sensitive to azithromycin. A slight increase in minimum inhibitory concentration (MIC) is noticed for ceftriaxone but the current average MIC is 32-fold lower than the resistance cut-off. Over 99% of the isolates exhibited decreased susceptibility to ciprofloxacin. Salmonella Paratyphi A has remained susceptible to most antibiotics, unlike Salmonella Typhi, despite widespread usage of many antibiotics in Bangladesh. The data can guide evidence-based policy decisions for empirical treatment of paratyphoid fever, especially in the post typhoid vaccine era, and with the availability of new paratyphoid diagnostics.

Optimizing extraction of Pelargonium sidoides roots: Impact of ethanol concentration on biological activity of extracts

Pelargonium sidoides DC. (Geraniaceae) is an important indigenous medicinal plant in South Africa, historically employed by various ethnic groups to treat respiratory and gastrointestinal ailments. The proprietary herbal tincture, Umckaloabo®, utilizes an ethanolic extract (EPs® 7630) from the roots of P. sidoides, and has demonstrated effectiveness in alleviating symptoms of respiratory infections.P. sidoides roots contain numerous highly oxygenated coumarins and phenolic metabolites, notably the marker compound umckalin. While Umckaloabo® is prepared using 11 % ethanol extraction, the South African commercial market predominantly employs 60 % ethanol extraction due to its consistent umckalin yield and antimicrobial activity. The effects of these extraction methods on chemical composition and in vitro pharmacological activity remain poorly understood.This study confirmed superior antibacterial and antifungal activity in the 60 % ethanol extracts prepared from six root samples compared to the 11 % ethanol extracts. MIC values for both Gram-negative and Gram-positive bacteria ranged from 0.078 to 2.5 mg/mL in the 60 % extracts. Remarkably, two of the root extracts exhibited excellent to very good activity against C. albicans and C. neoformans with MIC values of 0.039 and 0.078 mg/mL, respectively.A positive correlation was identified between total minimum inhibitory concentration (MIC) levels and polyphenol content, rather than umckalin levels. The influence of these extracts on the pro-inflammatory cytokine IL-6 was assessed. Both 60 % and 11 % root extracts of P. sidoides at 100 µg/mL significantly reduced IL-6 production, with the 60 % extracts demonstrating a more pronounced effect (p = 0.008).Statistical analysis revealed significant differences between 11 % and 60 % ethanol extractions in terms of average MIC overall, average Gram-negative MIC, average Gram-positive MIC, fungal MIC, and IL-6 levels. Extracts with higher polyphenol values exhibited superior antimicrobial activity and antioxidant potential, suggesting that polyphenol content may serve as a more reliable indicator of antimicrobial activity than umckalin levels. Additionally, polyphenol levels in the roots may vary with altitude and other environmental factors, warranting further research.

Isolation, identification, and synergistic mechanism of a novel antimicrobial peptide and phenolic compound from fermented walnut meal and their application in Rosa roxbughii Tratt spoilage fungus

This study aimed to identify an antimicrobial peptide and phenolic compound combination derived from fermented walnut meal against Penicillium. victoriae, a fungus responsible for Rosa. roxbughii Tratt spoilage, and ultimately investigate their synergistic mechanism. YVVPW and salicylic acid (SA) had the highest antifungal activity among identified 4 antimicrobial peptides, including FGGDSTHP, ALGGGY, YVVPW, and PLLRW, and 15 phenolic compounds, respectively. Molecular docking verified that YVVPW bound to regulatory subunit via hydrogen-bond, hydrophobic, and π-π conjugate interactions. YVVPW and SA exhibited synergistic effects with average minimal inhibitory concentration decreasing by 85.44 ± 8.04%. Fluorescence spectroscopy demonstrated quenching of intrinsic Trp and Tyr fluorescence by interaction. FTIR and molecular docking results revealed formation of 3 hydrogen bonds via OH, CO, NH, and CH bonds in YVVPW + SA, with π-π stacking occurring between the benzene ring and five-membered ring. These reinforce potential application of this combination as an effective fungistatic combination in fruit preservation.

Green Synthesized Iron-Coated Silver Nanoparticles: Economic Bimetallic Nanoparticles Potential Against Methicillin-Resistance Staphylococcus aureus.

Iron coating was introduced as one of the novel techniques to improve physicochemical and biological properties of silver nanoparticles (AgNPs). In the current experiment, impact of iron coating on the antimicrobial potency of AgNPs was investigated against methicillin-resistanceStaphylococcus aureus (MRSA). To obtain more accurate data about the antimicrobial potency of examined nanostructures, the experiment was done on the 10 isolates of MRSA which were isolated from skin lesions. AgNPs and iron-coated AgNPs (Fe@AgNPs) were fabricated based on a green one-pot reaction procedure. Minimal inhibitory concentration (MIC) of Fe@AgNPs was not significantly different with MIC of AgNPs against eight out of 10 examined MRSA isolates. Also, by iron coating a reduction in the minimal inhibitory concentration (MIC) of AgNPs was observed against two MRSA isolates. The average MIC of AgNPs against 10 MRSA isolates was calculated to be 2.16 ± 0.382mg/mL and this value was reduced to 1.70 ± 0.638mg/mL for Fe@AgNPs. However, this difference was not considered significant statistically (P-value > 0.05). From productivity point of view, it was found that iron coating would improve the productivity of the synthesis reaction more than fivefold. Productivity of AgNPs was calculated to be 1.02 ± 0.07g/L, meanwhile this value was 5.25 ± 0.05g/L for Fe@AgNPs. Iron coating may provide another economic benefit to reduce final price of AgNPs. It is obvious that the price of a particular nanostructure made of silver and iron is significantly lower than that of pure silver. These findings can be considered for the fabrication of economic and potent antimicrobial nanoparticles.

In-vitro Cytotoxicity, Anti-bacterial and Anti-inflammatory Activities of Ecklonia radiata and Jania verrucosa from Eastern Cape, South Africa

Seaweeds are marine floras constituting in part to over 90% of the oceanic biomass. Despite the enrichments of seaweeds, their potentials are largely unexplored. Hence, this study evaluated the phytochemical screening, antimicrobial, anti-inflammatory and cytotoxicity activities of methanolic extracts of Ecklonia radiata and Jania verrucosa. E. radiata and J. verrucosa were collected from sites on the rocky shores of the Mbashe and Port St. John rivers on the Eastern Cape coast of South Africa during spring low tides. Qualitative phytochemical screening was carried out using standard protocol. The assessment of anti-inflammatory activity was done by inhibition of albumin denaturation assay and antimicrobial analysis was performed against six different pathogenic clinical isolates. The cytotoxicity effect of the methanolic extracts were further investigated on MDA-MB-231, HepG2, CaCo-2 and KMST-6 by (3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay (MTT assay). Phytochemical analysis revealed the presence of tannins, phenols, glycosides, and alkaloid for both extracts. The methanolic extracts of both seed weeds also possess anti-inflammatory activity by inhibiting albumin denaturation. The average minimum inhibitory concentration (MIC) values of the plantextracts ranged from 160-10000 µg/mL. J. verrucosa methanolic extract had the most significant biological activity with the lowest MIC value (160 µg/ml). The cytotoxicity result showed that cells treated with the methanolic extracts of E. radiata and J. verrucosa have more cytotoxicity effect on MDA-MB-231 treated cells followed by HepG2 and CaCo-2. Non-cancerous cell line (KMST-6) however showed some selectivity in their activities. Among the cancer cell lines, HepG2 treated cells were significantly suppressed (p &lt; 0.05) with both extracts compared to 5µM camptothecin (standard drug). In conclusion, E. radiata and J. verrucosa have potential for chemoprevention of human breast, good anti-inflammatory and antibacterial activities.

Antifungal Activity of Plantago lanceolata and Sida ovata Leaf Extracts against Dermatomycotic Fungi.

Plantago lanceolata and Sida ovata have been used as medicinal plants for centuries to cure numerous diseases. This study aimed to evaluate antifungal activity of P. lanceolata and S. ovata leaf extracts against dermatomycotic fungi. Crude extracts from leaves of both plants were prepared using methanol and ethyl acetate. Phytochemical screening of both plants leaves was performed. Antifungal activity of crude extracts was evaluated against three dermatomycotic fungi (Candida albicans, Malassezia furfur, and Malassezia globosa). In addition, minimum inhibitory concentration (MIC) of the extracts was determined by microbroth dilution method. Maximum inhibition zone of 32.00 ± 11.64 mm was exhibited when combined ethyl acetate extract of both plants was applied against M. globosa. Best effect of MIC was demonstrated by ethyl acetate extract against most tested dermatomycotic fungi. Average MIC of ethyl acetate and methanol extracts ranged as follows: (0.19 ± 0.00 to 0.65 ± 0.00 mg/mL and 0.19 ± 0.00 to 0.52 ± 0.22 mg/mL) and (0.65 ± 0.22 to 1.56 ± 0.00 mg/mL and 0.19 ± 0.00 to 0.52 ± 0.00 mg/mL), respectively. Their synergistic effect was better than the effect of individual plant leaf extract. Minimum fungicidal concentration (MFC) values varied across the fungal pathogens when extracts from both plants and their combinations were used. The findings from the current study support the traditional use of P. lanceolata and S. ovata against dermatomycotic fungal infections, which could potentially be exploited for the treatment of superficial infection in humans.

Heteroleptic Transition Metal Complexes of Eflornithine Hydrochloride Monohydrate: Synthesis, Characterization, in silico and in vitro Biological Studies

Incessant development of resistance to drugs by microorganisms remains a major setback associated with the currently available antibiotics, thereby making imperative a continuous search for alternative candidates with improved efficacy. Previous studies have shown enhanced antimicrobial activity of some bioactive molecules upon coordination with metal ions. Thus, in this study, Cu(II), Co(II), and Ni(II) complexes of eflornithine hydrochloride monohydrate (EHM) were synthesized and probed for bactericidal activity via in vitro and in silico. The characterization results such as CHN analysis, FTIR, UV-visible magnetic susceptibility and Electrospray Ionization Mass Spectrometry (ESI-MS) reveal that EHM coordinates as a bidentate ligand to each central metal ion in the molar ratio 1:2 through O and N in the COO- and NH2 group respectively, and also suggest octahedral geometry in each complex. The physicochemical and pharmacokinetics parameters predicted in silico support the bio-applicability and safety of the complexes. From the in vitro antibacterial study, the complexes demonstrate improved activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa with an average minimum inhibitory concentration (MIC) of 0.01 mg/L similar to ciprofloxacin, compared to EHM whose MIC &amp;gt;1.00 mg/L. Although, not all the complexes satisfy Lipinski’s drugability rule of 5 due to their molecular weight, however, coordination with metal ions improves the biological activities of EHM and the complexes demonstrate potential for further transformation into antibiotic therapeutics.

Antifungal activity of selected sea cucumber species from Tukuran, Zamboanga del Sur, Mindanao, Philippines using modified SPOTi assay

Abstract. Ereguero MG, Cordero MA, Dalayap R, Tabugo SR. 2022. Antifungal activity of selected sea cucumber species from Tukuran, Zamboanga del Sur, Mindanao, Philippines using modified SPOTi assay. Biodiversitas 23: 6049-6055. Marine organisms have become essential candidates for discovering novel compounds that can be medically and commercially important. They are believed to yield novel compounds with unique chemical structures and significant biological activities since they managed to survive a milieu of pathogenic microorganisms and essential predators. The quest against fungal infections has been challenging due to acquired resistance to commercially available drugs hence, novel sources to treat infectious diseases caused by fungi have been investigated. Sea cucumbers have been recognized in Asian countries as a rich food source. Apart from that, they have also been studied for their medicinal properties. This study aimed to evaluate the antifungal activity of the selected sea cucumber species found in Brgy. Sugod, Tukuran, Zamboanga del Sur, Mindanao, Philippines using the modified SPOTi assay. Methanol: ethyl acetate crude extracts of Holothuria scabra, Stichopus sp., and Holothuria atra were tested for their antifungal activity against Aspergillus niger and Candida tropicalis. A 96-well plate assay was used, and the growth of fungi was assessed visually for up to 72hrs. The concentration resulting in ‘no fungal growth’ was observed and taken as the Minimum Inhibitory Concentration (MIC) value. The average MIC was calculated. Results showed that sea cucumber crude extracts have MIC values of 0.0333-0.1 mg/mL. Tukey’s posthoc test confirmed that the antifungal activity of the sea cucumber extracts was comparable to the positive control Fluconazole (p&gt;0.05). The present study revealed a potentially effective natural antifungal agent from sea cucumbers.

New Chitosan-Grafted Thymol Coated on Gold Nanoparticles for Control of Cariogenic Bacteria in the Oral Cavity

Chitosan-grafted thymol (CST) coated on gold nanoparticles has been synthesized and characterized for the design of antimicrobial materials. CST was synthesized via adapting the Mannich reaction, and it acted as the capping agent for the synthesis of gold nanoparticles (AuNPs). The grafting of thymol onto the side chain of chitosan has provided a degree of substitution value (%DSNMR) of 10.0%, calculated by nuclear magnetic resonance spectroscopy. UV–visible spectrometry and elemental analysis were used to confirm the successful synthesis of CST through adapting the Mannich reaction. The appropriate concentration of CST for AuNP synthesis was found to be 0.020%w/v. A red-wine colloidal AuNP solution of 2.41–3.30 nM particle size exhibits a strong surface plasmon resonance at 502 nm, which shows negative charges at pH = 9 of −36.37 mV. This result evidenced that the AuNPs showed electrostatic repulsion and CST played a role as a capping agent to provide a good dispersion and stability state. CST coated on the AuNP surface was successfully utilized for the control of cariogenic bacteria in the oral cavity. The results obtained from this study show that the tuning of the capping agent used in the synthesis step strongly influences the latter antimicrobial activity of the nanoparticles against Streptococcus mutans ATCC 25175 and Streptococcus sobrinus ATCC 33402 activity, with an inhibition zone of 15.90 and 14.25 mm, respectively. The average minimum inhibitory concentration values against S. mutans ATCC 25175 and S. sobrinus ATCC 33402 were found to be 25 and 100 mg/L, respectively, whereas the minimum bactericidal concentration values were 100 and 200 mg/L, respectively.

Effect of Biosynthesized Silver Nanoparticles on Bacterial Biofilm Changes in S. aureus and E. coli.

One approach for solving the problem of antibiotic resistance and bacterial persistence in biofilms is treatment with metals, including silver in the form of silver nanoparticles (AgNPs). Green synthesis is an environmentally friendly method to synthesize nanoparticles with a broad spectrum of unique properties that depend on the plant extracts used. AgNPs with antibacterial and antibiofilm effects were obtained using green synthesis from plant extracts of Lagerstroemia indica (AgNPs_LI), Alstonia scholaris (AgNPs_AS), and Aglaonema multifolium (AgNPs_AM). Nanoparticles were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The ability to quench free radicals and total phenolic content in solution were also evaluated. The antibacterial activity of AgNPs was studied by growth curves as well as using a diffusion test on agar medium plates to determine minimal inhibitory concentrations (MICs). The effect of AgNPs on bacterial biofilms was evaluated by crystal violet (CV) staining. Average minimum inhibitory concentrations of AgNPs_LI, AgNPs_AS, AgNPs_AM were 15 ± 5, 20 + 5, 20 + 5 μg/mL and 20 ± 5, 15 + 5, 15 + 5 μg/mL against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, respectively. The E. coli strain formed biofilms in the presence of AgNPs, a less dense biofilm than the S. aureus strain. The highest inhibitory and destructive effect on biofilms was exhibited by AgNPs prepared using an extract from L. indica.

Encapsulation of bougainvillea (Bougainvillea spectabilis) flower extract in Urtica dioica L. seed gum: Characterization, antioxidant/antimicrobial properties, and in vitro digestion.

Bougainvillea spectabilis extract (BSE), a rich source of bioactive compounds like phenolic, flavonoid, and anthocyanin, was used for encapsulation with Urtica dioica L. seed gum. The extract was obtained using shaking, bath, and probe ultrasound. The results showed that probe ultrasound extract was more efficient, as reflected by the higher value of total phenolic (4354.15 mg GAE/100 g FW), flavonoid (2431.25 mg CE/100 g FW), and anthocyanin content (106.57 mg CGE/100 g FW). BSE was encapsulated in U. dioica L. seed gum at 1:1 and 1:2 core to coating ratio. In both DPPH radical scavenging and FRAP assay, higher antioxidant activity was observed in the encapsulated extract than in the free extract. Encapsulated extracts exhibited 87.9 nm average diameter (polydispersity index below 0.23) and negative zeta potential. The average minimum inhibitory concentration (MIC) of nanoparticles against Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, and Salmonella enterica was 112.5, 87.5, 112.5, and 87.5 μg/ml, respectively, while MIC of the free extract against S. aureus and E. coli was 150 and 125 μg/ml, respectively. The phenolic compounds are gradually released from the nanoparticles in the gastric and small intestine phase, whereas free extract released phenolic compounds quickly after entering the gastric phase. Considering antioxidant/antimicrobial activity and release properties, nanoparticles with a 1:1 ratio of core to coating had the potential to use as an effective natural preservative agent in food products besides the delivery of bioactive compounds to the human body.

Therapeutic drug monitoring of Amikacin in hospitalized patients: A pilot study

BackgroundAmikacin, an aminoglycoside, is a widely used parenteral antibiotic. Therapeutic drug monitoring (TDM) is recommended for aminoglycosides to avoid toxicity. However, the lack of infrastructure at most places precludes it. This pilot and novel study attempt to estimate the real-world serum levels of Amikacin in hospitalised patients. MethodsThirty admitted patients, given Amikacin injections, were included in the study. In addition, 15 clinical specimens isolated with gram-negative bacteria were tested for minimum inhibitory concentration (MIC) value of Amikacin. Trough and peak serum levels of Amikacin were estimated by high-pressure liquid chromatography (HPLC). ResultsThe average MIC value of Amikacin estimated in our laboratory was 3.92 mcg/mL. Peak and trough serum levels of Amikacin ranged from 12.1 to 66.4 mcg/ml and 1.1 to 20.7 mcg/ml, respectively. More than 83% of our patients achieved peak Amikacin levels of 15 mcg/mL, and 37% had trough levels above 5 mcg/mL. These levels are desirable watersheds as per available literature. ConclusionTrough levels of Amikacin in all cases and a review of dosing according to MIC values are recommended to achieve drug safety and therapeutic efficacy.