Evaluation of the in vitro antibacterial activity of the solvent fractions of the leaves of Rhamnus prinoides L'Herit (Rhamnaceae) against pathogenic bacteria

Rhamnus prinoides leaf extract loaded polycaprolactone-cellulose acetate nanofibrous scaffold as potential wound dressing: An in vitro study

Rhamnus prinoides leaf contains carbohydrates, saccharides, phenolic acids, and diterpenes with antibacterial, wound-healing, and anti-inflammatory properties. In this study, Rhamnus prinoides leaf extract was successfully incorporated into polycaprolactone-cellulose acetate (PCL-CA) nanofibers through electrospinning technique for the first time. The mats' morphology, diameter, chemical, and crystalline structure were characterized. The study investigated the mats' antibacterial activity, wound healing, cytotoxicity, drug release behaviour, hydrophilicity, and water absorbency properties. The results revealed that the mats exhibited continuous, smooth, without-beads, and interconnected structures, with average fiber diameters ranging from 385 ± 21 nm to 332 ± 74 nm. The antibacterial effeciency was remarkable against S. aureus and E. coli, achieving bacterial reduction percentages exceeding 99 % at concentrations of 3 % and above against S. aureus and 5 % and above against E. coli. Cytotoxic tests showed low-cytotoxicity up to an extract concentration of 7 %. The extract release increases with an increase in concentration. In vitro wound healing assay, the mats enhanced cell migration to the wound area. Additionally, the incorporation of Rhamnus prinoides significantly improved the hydrophilicity and water absorbency of the nanofibers. Overall, the study highlights the mats' broad antimicrobial and wound healing properties with less cytotoxicity, hydrophilicity, and water absorbency, making them promising for use as wound dressings.

Synthesis of 2-Ethylhexyl 5-Bromothiophene-2-Carboxylates; Antibacterial Activities against Salmonella Typhi, Validation via Docking Studies, Pharmacokinetics, and Structural Features Determination through DFT

A new class of thiophene-based molecules of 5-bromothiophene-2-carboxylic acid (1) have been synthesized in current research work. All analogs 4A-4G were synthesized with optimized conditions by coupling reactions of 2-ethylhexyl 5-bromothiophene-2-carboxylate (3) with various arylboronic acids. The results indicated that the majority of compounds showed promising effective in vitro antibacterial activity. Herein, 2-ethylhexyl-5-(p-tolyl)thiophene-2-carboxylate (4F), in particular among the synthesized analogs, showed outstanding antibacterial action (MIC value 3.125 mg/mL) against XDR Salmonella Typhi compared to ciprofloxacin and ceftriaxone. The intermolecular interaction was investigated by using a molecular docking study of thiophene derivatives 4A-4G against XDR S. Typhi. The values of the binding affinity of functionalized thiophene molecules and ciprofloxacin were compared against bacterial enzyme PDB ID: 5ztj. Therefore, 4F appears to be a promising antibacterial agent and showed the highest potential value. Density functional theory (DFT) calculations were executed to examine the electronic, structural, and spectroscopic features of the newly synthesized molecules 4A-4G.

Analysis and comparison of bioactive phytochemical composition and antibacterial property of two Ethiopian indigenous medicinal plants

Indigenous medicinal plants with naturally inherited antimicrobial properties are promising sources of antimicrobial agents. Two indigenous Ethiopian traditional medicinal plants (Rhamnus prinoide and Croton macrostachyus) extracted using different solvents and the yield percentage, phytochemical analysis and antimicrobial activity of the plant extracts were examined and compared. The results of this study revealed that Rhamnus prinoide leaf extract using aqueous methanol/ethanol (1 : 1) had the highest yield (15.12 %), a minimum inhibitory concentration of 0.625 mg/mL, and a minimum bactericidal concentration of 10 mg/mL against S. aureus. Croton macrostachyus leaves showed a yield of 14.7 ±0.37 %, a minimum inhibitory concentration of 40 mg/mL, and a minimum bactericidal concentration of 40 mg/mL against S. aureus and E. coli. GC-MS analysis revealed that aqueous methanol/ethanol (1 : 1) of Rhamnus prinoide and Croton macrostachyus leaf extracts were composed of bioactive carbohydrates, flavonoid acid phenols, and terpenoids, while Croton macrostachyus extract contained primarily phytol (30.08 %). The presence of bioactive compounds confirms the traditional use of these plant leaves to treat various diseases, including wounds, leading to the conclusion that they could be applied to textiles for wound dressing in future studies.

Endophytic Fungi Isolated from Ageratina adenophora Exhibits Potential Antimicrobial Activity against Multidrug-Resistant Staphylococcus aureus

Multidrug-resistant bacteria such as Staphylococcus aureus (MRSA) cause infections that are difficult to treat globally, even with current available antibiotics. Therefore, there is an urgent need to search for novel antibiotics to tackle this problem. Endophytes are a potential source of novel bioactive compounds; however, the harnessing of novel pharmacological compounds from endophytes is infinite. Therefore, this study was designed to identify endophytic fungi (from Ageratina adenophora) with antibacterial activity against multidrug-resistant bacteria. Using fungal morphology and ITS-rDNA, endophytic fungi with antibacterial activities were isolated from A. adenophora. The results of the ITS rDNA sequence analysis showed that a total of 124 morphotype strains were identified. In addition, Species richness (S, 52), Margalef index (D/, 7.3337), Shannon-Wiener index (H/,3.6745), and Simpson's diversity index (D, 0.9304) showed that A. adenophora have abundant endophytic fungi resources. Furthermore, the results of the agar well diffusion showed that the Penicillium sclerotigenum, Diaporthe kochmanii, and Pestalotiopsis trachycarpicola endophytic fungi's ethyl acetate extracts showed moderate antibacterial and bactericidal activities, against methicillin-resistant Staphylococcus aureus (MRSA) SMU3194, with a MIC of 0.5-1 mg/mL and a MBC of 1-2 mg/mL. In summary, A. adenophora contains endophytic fungi resources that can be pharmacologically utilized, especially as antibacterial drugs.

Medicinal plants used for the management of respiratory diseases in Zimbabwe: Review and perspectives potential management of COVID-19

Respiratory diseases have in the recent past become a health concern globally. More than 523 million cases of coronavirus disease (COVID19), a recent respiratory diseases have been reported, leaving more than 6 million deaths worldwide since the start of the pandemic. In Zimbabwe, respiratory infections have largely been managed using traditional (herbal) medicines, due to their low cost and ease of accessibility. This review highlights the plants' toxicological and pharmacological evaluation studies explored. It seeks to document plants that have been traditionally used in Zimbabwe to treat respiratory ailments within and beyond the past four decades. Extensive literature review based on published papers and abstracts retrieved from the online bibliographic databases, books, book chapters, scientific reports and theses available at Universities in Zimbabwe, were used in this study. From the study, there were at least 58 plant families comprising 160 medicinal plants widely distributed throughout the country. The Fabaceae family had the highest number of medicinal plant species, with a total of 21 species. A total of 12 respiratory ailments were reportedly treatable using the identified plants. From a total of 160 plants, colds were reportedly treatable with 56, pneumonia 53, coughs 34, chest pain and related conditions 29, asthma 25, tuberculosis and spots in lungs 22, unspecified respiratory conditions 20, influenza 13, bronchial problems 12, dyspnoea 7, sore throat and infections 5 and sinus clearing 1 plant. The study identified potential medicinal plants that can be utilised in future to manage respiratory infections.

In vitro antibacterial and antifungal activities of extracts and fractions of leaves of Ricinus communis Linn against selected pathogens

INTRODUCTION

Infectious disease impacts are reduced due to the development of antimicrobial agents. However, the effectiveness of antimicrobial agents is reduced over time because of the emergence of antimicrobial resistance. To overcome these problems, scholars have been searching for alternative medicines. Ricinus communis is used as a traditional treatment for bovine mastitis, wound infection, and other medicinal purposes.

OBJECTIVE

The objective of the present study was to further evaluate the antimicrobial activities of R. communis leaf extracts and fractions.

METHODS

R. communis leaves were macerated in methanol and acetone. The methanol extract showed better antimicrobial activity and subjected to further fractionation via increasing polarity of solvents (n-hexane, chloroform, ethyl acetate, and aqueous). Test microorganisms included in the study were six laboratory reference bacteria (Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, Kleibsella pneumoniae, Pseudomonas aeruginosa and Streptococcus pyogenes), two clinical isolate bacteria (E. coli and S. aureus), and Candida albicans. The agar well diffusion method was employed to determine antimicrobial activity. The minimum inhibitory concentrations (MIC) and minimum bactericidal/fungicidal concentrations (MBC/MFC) were determined through broth microdilution.

RESULTS

The results indicated that the best antimicrobial activity for ethyl acetate fraction ranged from 14.67 mm (clinical E. coli) to 20.33 mm (S. aureus) at 400 mg/ml, however, n-hexane exhibited the lowest antimicrobial activity. Among the tested fractions, ethyl acetate fraction showed the lowest MIC values ranged from 1.5625 mg/ml (S. aureus) to 16.67 mg/ml (Candida albicans). The ethyl acetate fraction showed bactericidal activity against all tested microorganisms.

CONCLUSION

Hence, ethyl acetate fraction of crude methanol extract exhibited the best antimicrobial activity.

Diversity, Chemical Constituents, and Biological Activities of Endophytic Fungi Isolated From Ligusticum chuanxiong Hort

The objective of this study was to evaluate the diversity of endophytic fungi of different parts of Ligusticum chuanxiong Hort (CX) and further characterize their biological activities and identify chemical compounds produced by these endophytic fungi. A total of 21 endophytic fungi were isolated and identified from CX. Penicillium oxalicum, Simplicillium sp., and Colletotrichum sp. were identified as promising strains by the color reaction. Comparing different organic extracts of the three strains, it was observed that the ethyl acetate extract of Penicillium oxalicum and Simplicillium sp. and the n-butanol extract of Colletotrichum sp. showed significant antioxidant and antibacterial activities. The ethyl acetate extracts of Penicillium oxalicum had outstanding antioxidant and antibacterial effects, and its radical scavenging rates for ABTS and DPPH were 98.43 ± 0.006% and 90.11 ± 0.032%, respectively. At the same time, their IC₅₀ values were only 0.18 ± 0.02 mg/mL and 0.04 ± 0.003 mg/mL. The ethyl acetate extract of Penicillium oxalicum showed MIC value of only 0.5 mg/mL against Escherichia coli and Staphylococcus aureus. By liquid chromatography-mass spectrometry (LC-MS), we found that Penicillium oxalicum could produce many high-value polyphenols, such as hesperidin (36.06 μmol/g), ferulic acid (1.17 μmol/g), and alternariol (12.64 μmol/g), which can be a potential resource for the pharmaceutical industry. In conclusion, these results increase the diversity of CX endophytic fungi and the antioxidant and antibacterial activities of their secondary metabolites.

Antibacterial and antibiofilm activities of Mayan medicinal plants against Methicillin-susceptible and -resistant strains of Staphylococcus aureus

ETHNOPHARMACOLOGICAL RELEVANCE

Several medicinal plants are used in Mayan Traditional Medicine to treat skin, urinary, respiratory, and gastrointestinal infectious diseases. However, scientific studies that have supported the bioactivity of these Mayan medicinal plants are limited.

AIM OF THE STUDY

To assess the in-vitro anti-Staphylococcus aureus growth and biofilm-formation activities of 15 Mayan medicinal plants that were selected based on their traditional uses for the treatment of infectious diseases.

MATERIALS AND METHODS

Mayan medicinal plants used traditionally to treat infectious diseases were preselected. For each part of the plants, four extracts were prepared with different solvents (water, n-hexane, ethyl acetate, and methanol). These were tested against two reference strains: a Methicillin-susceptible and -resistant S. aureus, and two clinical isolates, including a susceptible and multidrug-resistant S. aureus using a Resazurin Microtiter Assay. In addition, the plant extracts were evaluated in biofilm-formation inhibition on S. aureus by means of the Crystal Violet method.

RESULTS

A total of 120 extracts from 15 Mayan medicinal plant species belonging to 12 different families were selected according their ethnopharmacological uses to treat infectious diseases. Among the selected plant species, 26 extracts obtained from eight medicinal Mayan plants exhibited significant anti-S. aureus against the four strains tested. The most active extracts were the Aq (aqueous) leaf extract of Krugiodendron ferreum (Minimal Inhibitory Concentration [MIC] = 125-250 μg/mL), the MeOH bark extracts of Matayba oppositifolia, Clusia flava, Gymnopodium floribundum, the MeOH leaf extract of Spondias purpurea with MIC values of 250 μg/mL, and the MeOH leaf and Aq bark extracts of K. ferreum (MIC = 250-500 μg/mL). Among the active extracts, 12 exhibited a bactericidal effect on S. aureus strains (Minimal Bactericidal Concentration [MBC] = 250-1000 μg/mL). Forty extracts from 13 plants have an effect on the anti-formation of biofilm, the most active were the MeOH leaf extract of M. oppositifolia (one-half Inhibitory Concentration [IC₅₀] = 10.4 μg/mL) and the MeOH (IC₅₀ = 17.7 μg/mL) and Hex (18.2 μg/mL) leaf extracts from S. purpurea.

CONCLUSION

Aqueous and organic extracts from Mayan medicinal plants showed bactericidal and anti-biofilm activities even against drug-resistant S. aureus strains. The present study supports the traditional usage of some plants employed in Mayan medicine for illnesses such as skin, gastrointestinal, and urinary infections and suggest that these plants could be a good source of antibacterial phytochemicals.

Evaluation of the Antimicrobial Activity of Leaf Extracts of Acokanthera schimperi against Various Disease-Causing Bacteria

Background

In traditional medicine of Ethiopia, Acokanthera schimperi is the one used to treat different infectious diseases. Hence, this study was conducted with the main aim of determining active compounds in the leaves of A. schimperi.

Methods

The antimicrobial activities of using disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) and acute oral toxicity of the fraction.

Results

The average bacterial zone of inhibition of the dichloromethane (DCM), chloroform (TCM), petroleum ether (PE) and ethyl acetate (EA) fractions ranged from 7.67 mm to 18.12 mm. The average values of MIC of the DCM, TCM, PE and EA fractions ranged from 4.17 mg/mL to 33.34 mg/mL. The most susceptible bacterium at 200 mg/mL was S. typhi, (18.12mm), while the less susceptible bacterium was C. freundii (14.33mm).

Conclusion

The solvent fractions demonstrated significant antibacterial activities with varying spectrum and safe up to 2000mg/kg.

Antioxidant and Antimicrobial Activity of Solvent Fractions of Calpurnia aurea (Ait.) Benth. (Fabaceae)

Background

Calpurnia aurea (Ait.) Benth. leaves are used to treat different diseases like ectoparasite infestation, diarrhea, sores, anthrax, fevers, pain, and snake venom. The leaves of Calpurnia aurea were first extracted by methanol and further fractionated with the help of n-hexane, dichloromethane and ethyl acetate with increasing polarity.

Methods

The antibacterial activities of the fractions were evaluated against disease causing bacteria using agar well diffusion. The minimum inhibitory concentrations (MIC) of the fractions were determined by the micro-broth dilution method using tetrazolium salt colorimetric assay. The antioxidant activities of the solvent fractions were determined by phospho-molbedum reduction assay, reducing power assay and hydroxyl radical scavenging activity.

Results

The average MIC value of C. aurea fractions ranged from 1.95mg/mL to 31.25mg/mL, 7.81mg/mL to 31.25mg/mL and 13.02mg/mL to 62.5mg/mL, for ethyl acetate, dichloromethane and n-hexane fractions, respectively. The leaf extracts have a higher antioxidant effect, as shown in the phospho-molbedum reduction assay, reducing power and hydroxyl radical scavenging assay.

Conclusion

The ethyl acetate and dichloromethane fractions revealed significant antibacterial effects against the growth of pathogenic bacteria. However, the n-hexane fraction showed the least antibacterial effect against all of the test bacteria. Furthermore, the n-hexane fractions of C. aurea showed higher antioxidant activity.

Antibacterial Activity of Ritchiea albersii Gilg and Cynoglossum amplifolium Leaves Extracts against Selected Bacteria

Background

The increase in antimicrobial resistance worldwide has necessitated the search for alternative therapeutic agents. The leaf extracts of Ritchiea albersii and Cynoglossum amplifolium have been used as traditional medicine for the management of eye, ear and wound infections in Ethiopia.

Objective

The objective of the study was to evaluate the antibacterial activity of R. albersii and C. amplifolium against three common bacteria.

Materials and Methods

In this experimental study, the antimicrobial properties of 80% methanol, chloroform and acetone extracts of R. albersii and C. amplifolium were evaluated against two Gram-positive bacteria (Staphylococcus aureus ATCC 25923 and Streptococcus pneumoniae ATCC 49619) and one Gram-negative bacterium (Escherichia coli ATCC 25922) using the agar-well diffusion method. Ciprofloxacin 0.05 mg/disc was used as a positive control. Furthermore, a preliminary phytochemical study was carried out.

Results

The zones of inhibition shown by all extracts of the two plants against the tested bacteria were significantly lesser (P < 0.05) than the standard drug. E. coli and S. aureus were the most susceptible strains for most extracts studied. The acetone extract of R. albersii exhibited a higher inhibitory effect (P < 0.05) against S. pneumoniae (16 mm) and E. coli (19 mm) compared with its methanol extract. The chloroform extract of R. albersii was more effective than its methanol extract (P < 0.05) against all tested bacteria. The acetone extract of C. amplifolium displayed a higher inhibitory effect (20 mm) against E. coli than its methanol and chloroform extracts.

Conclusions

The leaf extracts of R. albersii and C. amplifolium exhibited broad-spectrum antimicrobial activity, highlighting their potential as phytotherapeutic drugs in preventing and treating infections caused by S. aureus, S. pneumoniae and E. coli. Further investigations for isolating specific compounds and elucidating mechanisms are required to address the need for novel antibacterial drugs.

Evaluation of in-vivo antidiarrhoeal and in-vitro antibacterial activities of the root extract of Brucea antidysenterica J. F. Mill (Simaroubaceae)

BACKGROUND

Diarrhoea has been the major cause of death especially in children of developing countries. Brucea antidysenterica is one of the several medicinal plants used traditionally for the treatment of diarrhoea in Ethiopia. Hence, the present study was undertaken to investigate the antidiarrhoeal and antibacterial activities of the root extract of B. antidysenterica.

METHODS

Plant material was extracted by maceration technique using 80% methanol. The antidiarrhoeal activity was tested using castor oil-induced diarrhoea, castor oil-induced charcoal meal test, and castor oil-induced enteropooling models in mice. Whilst, the antibacterial activity of the crude extract was evaluated using agar well diffusion and broth microdilution methods.

RESULTS

The 80% methanolic crude extract significantly delayed the diarrhoeal onset at the two higher doses (p < 0.001) and it has also inhibited the number and weight of faecal output at all tested doses as compared with the negative control. Moreover, it showed a significant anti-motility effect (p < 0.001) at all tested doses. Whereas it displayed a significant reduction in the weight and volume of intestinal contents at the doses of 200 and 400 mg/kg (p < 0.01). The highest concentration (800 mg/mL) of test extract showed maximum zone of inhibition in all tested standard strains of bacteria (18.3 mm-22 mm). While MIC and MBC values (0.39 mg/mL and 1.56 mg/mL) showed that S. flexneri was the most susceptible pathogen for test extract.

CONCLUSION

The study revealed that the root extract of B. antidysenterica has antidiarrhoeal and antibacterial activities.

Diversity, Chemical Constituents and Biological Activities of Endophytic Fungi Isolated from Schinus terebinthifolius Raddi

Schinus terebinthifolius Raddi is a medicinal plant widely used for the treatment of various diseases. The secondary metabolites responsible for the pharmacological properties can be produced directly by the plant or by endophytic fungi. The objective of this study was to evaluate the diversity of endophytic fungi of different parts of S. terebinthifolius and to identify chemical compounds produced by endophytes and their antioxidant and antibacterial activities. For this, fruits, stem bark and roots were dried, ground and placed in fungal growth medium. The selected endophytes were grown and subjected to extraction with ethyl acetate. DPPH, FRAP, β-carotene bleaching and antimicrobial assays were performed. The phylogenetic tree was elaborated, encompassing 15 different species. The fungal extracts showed hydroxybenzoic acids and 1-dodecanol as predominant compounds. All fungal extracts exhibited antioxidant activity. The fungal extracts exhibited bactericidal and bacteriostatic activities against Gram-positive and Gram-negative bacterial ATCC strains and against methicillin-resistant nosocomial bacteria. Among the 10 endophytic fungi evaluated, the extract of the fungus Ochrocladosporium elatum showed higher phenolic content and exhibited higher antioxidant and antibacterial activities in all tests. Together, the results increase the known diversity of S. terebinthifolius endophytic fungi, secondary metabolites produced and their antioxidant and antibacterial activities.

Antioxidant, Anti-inflammatory Activities and Polyphenol Profile of Rhamnus prinoides

Rhamnus prinoides L’Herit (R. prinoides) has long been widely consumed as folk medicine in Kenya and other Africa countries. Previous studies indicated that polyphenols were abundant in genus Rhamnus and exhibited outstanding antioxidant and anti-inflammatory activities. However, there are very few studies on such pharmacological activities and the polyphenol profile of this plant up to now. In the present study, the antioxidant activities of the crude R. prinoides extracts (CRE) and the semi-purified R. prinoides extracts (SPRE) of polyphenol enriched fractions were evaluated to show the strong radical scavenging effects against 1,1-diphenyl-2- picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) (0.510 ± 0.046 and 0.204 ± 0.005, mg/mL), and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) (0.596 ± 0.005 and 0.096 ± 0.004, mg/mL), respectively. Later, the SPRE with higher contents of polyphenols and flavonoids displayed obvious anti-inflammatory activities through reducing the NO production at the dosage of 11.11 − 100 μg/mL, and the COX-2 inhibitory activity with an IC₅₀ value at 20.61 ± 0.13 μg/mL. Meanwhile, the HPLC-UV/ESI-MS/MS analysis of polyphenol profile of R. prinoides revealed that flavonoids and their glycosides were the major ingredients, and potentially responsible for its strong antioxidant and anti-inflammatory activities. For the first time, the present study comprehensively demonstrated the chemical profile of R. prinoides, as well as noteworthy antioxidant and anti-inflammatory activities, which confirmed that R. prinoides is a good natural source of polyphenols and flavonoids, and provided valuable information on this medicinal plant as folk medicine and with good potential for future healthcare practice.

Rhamnus prinoides (gesho): A source of diverse anti-biofilm activity

ETHNOPHARMACOLOGICAL RELEVANCE

Rhamnus prinoides (gesho) is an evergreen shrub from East Africa traditionally used for the treatment of illnesses including atopic dermatitis, ear, nose and throat infections, pneumonia, arthritis, brucellosis, flu, indigestion and fatigue.

AIM OF THE STUDY

Several of the conditions for which gesho is traditionally used are associated with communities of surface-attached microorganisms, or biofilms. We hypothesized that gesho has anti-biofilm activity. The principal aim of this study was to evaluate gesho-associated anti-biofilm activity and identify active compounds.

MATERIALS AND METHODS

Lyophilized ethanol and aqueous extracts were prepared from dried Rhamnus prinoides stems and leaves. Biofilm inhibition was measured by crystal violet staining and subsequent viability assays were conducted on growth agar. Chemical fractionation, chemical testing, Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) were used to isolate and identify active compounds.

RESULTS

Leaf and stem ethanol extracts significantly inhibited Staphylococcus aureus, Bacillus subtilis and Streptococcus mutans biofilm formation up to 99.9% and reduced planktonic cell growth up to 10 log units relative to untreated controls. The anti-biofilm activity of the ethanol stem extracts was due to a biocidal or bacteriostatic mechanism while bacteriostatic or anti-pathogenic mechanisms were attributed to the leaf ethanol extract. Gesho extracts showed activity against all three species tested but the treatment efficacy and mechanism were species dependent. Chemical fractionation and activity screens of the leaf ethanol extract identified ethyl 4-ethoxybenzoate and 4-hydroxy 4-methyl pentanone to be compounds with anti-biofilm activity. Ethyl 4-ethoxybenzoate activity was potentiated by DMSO. Notably, concentrations of both compounds were identified where biofilm formation was prevented without inhibition of cell growth; i.e. anti-pathogenic characteristics were evident.

CONCLUSION

Gesho leaf ethanol extract contains chemicals with anti-biofilm and bactericidal activities. This work lends support to the traditional use of gesho for treating topical infections and warrants further investigation into Rhamnus prinoides as a source of antibacterial and anti-biofilm agents.

Investigating In Vitro Antibacterial Activities of Medicinal Plants Having Folkloric Repute in Ethiopian Traditional Medicine

Medicinal plants are targeted in the search for new antimicrobial agents. Nowadays, there is an alarmingly increasing antimicrobial resistance to available agents with a very slow development of new antimicrobials. It is, therefore, necessary to extensively search for new agents based on the traditional use of herbal medicines as potential source. The antibacterial activity of 80% methanol extracts of the leaves of Verbena officinalis (Vo-80ME), Myrtus communis (Mc-80ME), and Melilotus elegans (Me-80ME) was tested against 6 bacterial isolates using agar well diffusion technique. In each extract, 3 concentrations of 10, 20, and 40 mg/well were tested for each bacterium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined. Vo-80ME and Mc-80ME exhibited promising antibacterial activity against Staphylococcus aureus with the highest zone of inhibition being 18.67 and 26.16 mm, respectively at concentration of 40 mg/well. Regarding gram-negative bacteria, Vo-80ME exhibited an appreciable activity against Escherichia coli and Salmonella typhi. Mc-80ME displayed remarkable activity against all isolates including Pseudomonas aeruginosa with the maximum zone of inhibition being 22.83 mm. Me-80ME exhibited better antibacterial activity against E coli, but its secondary metabolites had little or no activity against other gram-negative isolates. The MIC values of Vo-80ME ranged from 0.16 to 4.00 mg/mL. The lowest MIC was observed in Mc-80ME, with the value being 0.032 mg/mL. Mc-80ME had bactericidal activity against all tested bacterial isolates. Mc-80ME showed remarkable zone of inhibitions in all tested bacterial isolates. Besides, Vo-80ME showed good antibacterial activity against S aureus, E coli, and S typhi. Conversely, Me-80ME has shown good activity against E coli only. Generally, M communis L and V officinalis have good MIC and MBC results.

In Vitro Antibacterial Activity of Selected Medicinal Plants in the Traditional Treatment of Skin and Wound Infections in Eastern Ethiopia

Background

External infections involving the skin and wound are the most frequent complications affecting humans and animals. Medicinal plants play great roles in the treatment of skin and wound infections. This study was aimed to evaluate the in vitro antibacterial activity of crude methanolic extracts of nine medicinal plants.

Methods

Agar well diffusion and broth dilution methods were used to determine the antibacterial activity of nine Ethiopian plants against four bacterial species including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae.

Results

Among the tested plants, seven (Cissus quadrangularis, Commelina benghalensis, Euphorbia heterophylla, Euphorbia prostrate, Momordica schimperiana, Trianthema spp., and Solanum incanum) were found to exhibit considerable antibacterial activity against at least one of the test bacteria. The extracts of C. quadrangularis, E. heterophylla, and E. prostrata had a wide spectrum of antibacterial activities against test bacterial strains while the extracts of Grewia villosa and Schinus molle did not show any inhibitory activity. Clinical isolate and laboratory strain of S. aureus showed the highest susceptibility to highest concentration (780 mg/mL) of E. prostrata with a zone of inhibition of 21.0mm and 22.3mm, respectively.

Conclusion

This study indicates clear evidence supporting the traditional use of seven plants in treating skin and wound infections related to bacteria.