Influence of First-Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract of Acacia mearnsii

Background. This study was aimed at evaluating the antibacterial activity of the acetone extract of A. mearnsii and its interactions with antibiotics against some resistant bacterial strains. Methods. The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract. Results. The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception of S. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibit Enterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are in μg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity. Conclusion. The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more rational evidence-based drug combinations with optimized efficiency in the prevention of multidrug resistance and therapy of multifactorial diseases

BIOSYNTHESIS OF SILVER NANOPARTICLES FROM SEAWEED Caulerpa taxifolia AGAINST VECTOR BORNE DISEASE Culex quinquefasciatus

Globally, mosquitoes are transmitting agents for diseases like dengue, malaria, filaria and Japanese encephalitis. In this study, the larvicidal activities of silver nanoparticles (AgNPs) synthesized from seaweed Caulerpa taxifolia extract against the larvae of Culex quinquefasciatus was investigated in vitro. The synthesized AgNPs was further characterized using UV-Vis spectroscopy, FTIR, SEM, XRD, DLS and Zeta potential analysis. From the result, the LC50 value for AgNPs identified was 448.66. The synthesized silver nanoparticles have maximum absorption at 430 nm. The FTIR indicated a specific peak in 3275.11cm-1, 2921.7cm-1 and 1244.28cm-1 range. Scanning electron microscopy resulted in spherical shaped approximately ranging from 1 µm to20 µm in size. The average size distributions of Ag nanoparticles were 72.99 nm and are fairly stable with a zeta potential value of -31.1 mV. The biosynthesis of silver nanoparticles with Caulerpa taxifolia extract provides potential source for the larvicidal activity against mosquito. The present study revealed that green synthesized silver nanoparticles can be used as an eco-friendly means for effective control of vector disease

Pharmacological Assessment of the Medicinal Potential of Acacia mearnsii De Wild.: Antimicrobial and Toxicity Activities

Acacia mearnsii De Wild. (Fabaceae) is a medicinal plant used in the treatment of microbial infections in South Africa without scientific validation of its bioactivity and toxicity. The antimicrobial activity of the crude acetone extract was evaluated by both agar diffusion and macrobroth dilution methods while its cytotoxicity effect was assessed with brine shrimp lethality assay. The study showed that both bacterial and fungal isolates were highly inhibited by the crude extract. The MIC values for the gram-positive bacteria (78.1–312.5) μg/mL, gram-negative bacteria (39.1–625) μg/mL and fungal isolates (625–5000) μg/mL differ significantly. The bacteria were more susceptible than the fungal strains tested. The antibiosis determination showed that the extract was more (75%) bactericidal than bacteriostatic (25%) and more fungicidal (66.67%) than fungistatic (33.33%). The cytotoxic activity of the extract was observed between 31.25 μg/mL and 500 μg/mL and the LC50 value (112.36 μg/mL) indicates that the extract was nontoxic in the brine shrimp lethality assay (LC50 > 100 μg/mL). These results support the use of A. mearnsii in traditional medicine for treatment of microbial infections. The extract exhibiting significant broad spectrum antimicrobial activity and nontoxic effects has potential to yield active antimicrobial compounds

Self-medication with antibiotics for the treatment of menstrual symptoms in southwest Nigeria: a cross-sectional study

Background: Self-medication with antibiotics is an important factor contributing to the development of bacterial antibiotic resistance. The purpose of this study was to evaluate the prevalence of self-medication with antibiotics for the treatment of menstrual symptoms among university women in Southwest Nigeria. Methods: A cross-sectional survey was administered to female undergraduate and graduate students (n = 706) at four universities in Southwest Nigeria in 2008. The universities were selected by convenience and the study samples within each university were randomly selected cluster samples. The survey was self-administered and included questions pertaining to menstrual symptoms, analgesic and antibiotic use patterns, and demographics. Data were analyzed using descriptive statistics and logistic regression. Results: The response rate was 95.4%. Eighty-six percent (95% CI: 83-88%) of participants experienced menstrual symptoms, and 39% (95% CI: 36-43%) reported using analgesics to treat them. Overall, 24% (95% CI: 21-27%) of participants reported self-medicated use of antibiotics to treat the following menstrual symptoms: cramps, bloating, heavy bleeding, headaches, pimples/acne, moodiness, tender breasts, backache, joint and muscle pain. Factors associated with this usage were: lower levels of education (Odds Ratio (OR): 2.8, 95% CI: 1.1-7.1, p-value: 0.03); nonscience major (OR: 1.58, 95% CI: 1.03-2.50, p-value: 0.04); usage of analgesics (OR: 3.17, 95% CI: 2.07-4.86, p-value: <0.001); and mild to extreme heavy bleeding (OR: 1.64, 95% CI: 1.01-2.67, p-value: 0.05) and pimples/acne (OR: 1.57, 95% CI: 0.98-2.54, p-value: 0.06). Ampicillin, tetracycline, ciprofloxacin and metronidazole were used to treat the most symptoms. Doctors or nurses (6%, 95% CI: 4-7%), friends (6%, 95% CI: 4-7%) and family members (7%, 95% CI: 5-8%) were most likely to recommend the use of antibiotics for menstrual symptoms, while these drugs were most often obtained from local chemists or pharmacists (10.2%, 95% CI: 8-12%). Conclusions: This is the first formal study to report that approximately 1 out of 4 university women surveyed in Southwest Nigeria self-medicate with antibiotics to treat menstrual symptoms. This practice could provide monthly, low-dose exposures to antibiotics among users. Further studies are necessary to evaluate the impacts of selfmedication on student health

Ultrastructure and X-ray Microanalysis of the Antibacterial Effects of Stem Bark Ethanol Extract of Acacia mearnsii De Wild Against Some Selected Bacteria

To investigate the ultrastructural changes, X-ray microanalysis and leakages of protein and lipids from bacteria treated with the ethanolic extract of Acacia mearnsii. The ultrastructural changes were investigated using scanning electron microscope (SEM). The X-ray microanalyses were determined using electron dispersive spectroscopy (EDS) while the protein and lipid leakages were determined spectrophotometrically. The scanning electron microscopy indicated varied ultrastructural changes in the morphology of bacterial cells treated with the ethanol extract. The X-ray microanalysis showed significant differences between the elemental contents of extract-treated and broth-cultured and untreated bacteria strains. Lipids and proteins were leaked to a greater extent from the extract-treated bacterial strains in comparison with the broth-cultured and untreated ones used as controls. The possible antibacterial effects of the ethanol extract of A. mearnsii could be inhibition of a significant step in peptidoglycan assembly, inhibition of metabolic processes as well as the cell wall and cell membrane disruptions resulting in the efflux of lipid and protein in all the bacteria tested. This is a report identifying elemental components and associating their disintegrations in bacterial isolates with the antibacterial activities of medicinal plants. While ethanol extract of A. mearnsii caused ultrastructural changes, breakdown of elemental components into different elements and leaked lipid and protein from treated bacteria, the physiological damages to the cell wall further justify the bactericidal ability of the extract

Synergistic Interactions of Methanolic Extract of Acacia mearnsii De Wild. with Antibiotics against Bacteria of Clinical Relevance

Abstract: With the emergence of multidrug-resistant organisms, combining medicinal plants with synthetic or orthodox medicines against resistant bacteria becomes necessary. In this study, interactions between methanolic extract of Acacia mearnsii and eight antibiotics were investigated by agar diffusion and checkerboard assays. The minimum inhibitory concentrations (MICs) of all the antibiotics ranged between 0.020 and 500 µg/mL while that of the crude extract varied between 0.156 and 1.25 mg/mL. The agar diffusion assay showed that extract-kanamycin combination had zones of inhibition ≥20 ± 1.0 mm in all the bacteria tested (100%), followed by extract-chloramphenicol (90%)&gt; extract-ciprofloxacin = extract-tetracycline (70%)&gt; extract-amoxicillin (60%)&gt; extract-nalidixic acid (50%)&gt; extract-erythromycin (40%)&gt; extract-metronidazole (20%). The checkerboard showed synergistic interaction (61.25%), additivity/indifference (23.75%) and antagonistic (15%) effects. The synergistic interaction was most expressed by combining the extract with tetracycline, metronidazole, amoxicillin, ciprofloxacin, chloramphenicol and nalidixic acid against E. coli (ATCC 25922), erythromycin, metronidazole, amoxicillin, chloramphenicol and kanamycin against S. aureus (ATCC 6538), erythromycin, tetracycline, amoxicillin, nalidixic acid and chloramphenicol against B. subtilis KZN, erythromycin, metronidazol

Chemical composition, antioxidant activities and antibacterial activities of essential oil from Erythrina caffra Thunb. growing in South Africa

Introduction: Essential oils from plants are recognized as one of the most promising secondary metabolites for the development of cheap and safer drugs. While Erythrina caffra has been prominently used in folk medicine for the treatment of microbial infections, there is dearth of information on the pharmacological effectiveness and chemical composition of its essential oil. The study, therefore, aimed at identifying the chemical composition and biological activities of the essential oil of Erythrina caffra. Methods: In this study, the essential oil was extracted with all-glass Clevenger. The antioxidant activities of the essential oil and antibacterial susceptibility assay by agar well diffusion techniques were assessed while GC-MS analysis was performed to identify the chemical constituents of the essential oil. Results: The study showed that the radical scavenging activity of the essential oil increases as the concentration of the essential oil increases. All bacterial isolates were susceptible to essential oil with the exception of Salmonella typhimurium and Pseudomonas aeruginosa producing inhibition zones ranging between 22 ± 1.3 and 35 ± 2.1 mm in the susceptible isolates. The GC-MS chromatogram indicated there are 35 bioactive compounds in the essential oil and Caryophyllene oxide (53.54%), [1S-(1α,7α,8aβ)]-1,2,3,5,6,7,8,8a-octa-1 - hydro-1,8a-dimethyl-7-(1-methylethenyl)-Naphthalene (7.81%), Kauran-18-al (6.49%), 10,10-Dimethyl-2,6-dimethylenebicy clo[7.2.0]undecan-5.beta.-ol (5.83%), 10s,11s-Himachala-3(12),4-diene (4.51%), Caryophyllene (3.65%) and 1- Hexanol (3.31%) were the most prominent compounds. Conclusion: Excessive production of free radicals or reactive oxygen species (ROS) causes oxidative stress and disease. Oxidative stress resulting from imbalance between excessive generation of free radicals and inadequate antioxidant defense system has been linked to pathogenesis of many diseases. The essential oil of E. caffra stem bark extract possess antimicrobial and good antioxidant activities and its rich level of phytochemicals can be used as either dietary or complementary agents

In vitro Effects of Magnesium-Aluminum Hydroxide (Maalox) on the Antibacterial Activity of Ciprofloxacin against Clinical Bacterial Isolates

To investigate the in vitro effects of interactions between ciprofloxacin (CP) and magnesium-aluminium hydroxide (MA) combined against selected Gram-positive and Gram-negative bacteria. The interaction between CP and MA was accessed by agar diffusion method. Comparing the susceptibility of the isolates to CP alone with those of Ciprofloxacin-Magnesium-aluminum hydroxide (CPMA) combined showed that there were significant antagonistic and synergistic interactions in vitro. Antibacterial activities of ciprofloxacin were increased with 4.5-6.0 µg/ml of the MA but were drastically decreased with concentrations lower and higher than 4.5-6.0 µg/ml while development of resistant colonies within these zones of inhibitions was recorded. The susceptibility of the isolated resistant colonies was lesser than those obtained from the original isolates. The combination of ciprofloxacin (CP) and magnesium-aluminum hydroxide (Maalox) (MA) against bacterial isolates could result in development of resistant colonies. The roles of aluminum and magnesium in resistance development at the molecular level require further studies