Antibacterial Activity Of Plant Extracts Research Articles

Antibacterial activity of plant extracts against Streptococcus equi subsp. zooepidemicus isolates from guinea pigs with lymphadenitis in Ecuador

Lymphadenitis is a commonly occurring and contagious disease in guinea pigs caused by different pathogens, including Streptococcus sp., Staphylococcus sp., and Corynebacterium sp. This study aimed to characterize the bacteria isolated from pus extracted from abscessed mandibular lymph nodes of diseased guinea pigs in Ecuador in 2019 and evaluate the in vitro antibacterial activity of the total extracts of three plant species. Isolates were recovered from three diseased guinea pigs with Lymphadenitis on a farm in Imbabura, Ecuador province. The bacteria were characterized through microbiological, biochemical, and molecular tests as Streptococcus equi subsp. zooepidemicus. Furthermore, the susceptibility of S. equi subsp. zooepidemicus to three plant extracts belonging to the Asteraceae family, Acmella ciliata, Bidens andicola, and Gazania splendens collected in Ecuador, were assessed in vitro by the microdilution method. Our data indicate that all the evaluated extracts showed activity, with a Minimum Inhibitory Concentration (MIC) of 22.50 mg/mL for Acmella ciliata, 11.25 mg/mL for Bidens andicola, and 5.60 mg/mL for Gazania splendens. Bidens andicola extract showed the highest efficacy with a % inhibition of 63.90 at the highest tested concentration (45 mg/mL). This is the first report on the bioactivity of these plant species against S. equi subsp. zooepidemicus.

Probing Antibacterial and Anticancer Potential of Selenicereus undatus, Pistacia vera L. and Olea europaea L. against Uropathogens, MCF-7 and A2780 Cancer Cells.

Urinary tract infection is an infectious disease that requires immediate treatment. It can occur in any age group and involves both genders equally. The present study was to check the resistance of some antibiotics and to assess the antibacterial potential of three extracts of three plants against notorious bacteria involved in urinary tract infections. Along with assessing the antibacterial activity of plant extracts, we checked for the anticancer potential of these extracts against the cancer cell lines MCF-7 and A2780. Cancer is the leading cause of mortality in developed countries. Determinations of total flavonoid content, total phenolic content, total alkaloid content, total tannin content, total carotenoid content, and total steroid content were performed. The disk diffusion method was used to analyze the antibacterial activity of plant extracts. Ethanolic extract of Selenicereus undatus showed sensitivity (25-28 mm) against bacteria, whereas chloroform and hexane extracts showed resistance against all bacteria except Staphylococcus (25 mm). Ethanolic extract of Pistacia vera L. showed sensitivity (22-25 mm) against bacteria, whereas chloroform and hexane extracts showed resistance. Ethanolic extract of Olea europaea L. showed sensitivity (8-16 mm) against all bacteria except Staphylococcus, whereas chloroform and hexane extracts showed resistance. Positive controls showed variable zones of inhibition (2-60 mm), and negative control showed 0-1 mm. The antibiotic resistance was much more prominent in the case of hexane and chloroform extracts of all plants, whereas ethanolic extract showed a sensitivity of bacteria against extracts. Both cell lines, MCF-7 and A2780, displayed decreased live cells when treated with plant extracts.

Psidium guajava, Phalaenopsis sp., Syzygium aromaticum e Cinnamomum verum como inibidores naturais do crescimento de Streptococcus mutans

Currently, an increase on research on plant extracts seeking therapeutic action in the control of diseases of the oral cavity are observed, especially dental caries. Several plant extracts are already incorporated into toothpastes and mouthwashes. The objective of this study was to evaluate in vitro the antibacterial action of Psidium guajava (guava), Phalaenopsis sp. (orchid), Syzygium aromaticum (clove) and Cinnamomum verum (Ceylon cinnamon) extracts. The tests were carried out with the oral cavity bacteria Streptococcus mutans. The antibacterial activity of plant extracts was evaluated by the disk diffusion method in agar and by minimal inhibitory concentration (MIC). The tests showed the effectiveness of the extracts through inhibition zones of bacterial growth (from 5 to 20 mm in diameter) and MIC of 100 mg. mL-1 Phalaenopsis sp. extract and 50 mg. mL-1 P. guajava extract. Complementary studies will be needed to evaluate other pharmacological actions in order to use these plant extracts in different dental specialties and mainly in the treatment and prophylaxis of dental caries.

The Influence of Phytohormones on Antioxidative and Antibacterial Activities in Callus Cultures of Hypericum perforatum L.

Natural extracts of Hypericum perforatum L. are widely used in the pharmaceutical industry due to their antiviral, antioxidant, antibacterial, antidiabetic, and antidepressant activities. Plant biotechnological methods are gaining more attention as efficient and biosustainable approaches for the production of high value compounds by using plant callus cultures in vitro. The aim of this research was to evaluate the influence of phytohormones on the formation of Hypericum perforatum L. callus culture, to explore antioxidant and antibacterial activities, and to determine the amounts of phytochemicals in the analyzed extracts. Callus cultures were induced on Murashige and Skoog basal medium supplemented with phytohormones (auxins, cytokinins, and salicylic acid), and containing newly synthesized compound N-(1,3-dioxoisoindolin-2-yl)-3-((4-methoxyphenyl)amino)propanamide. The antioxidant activities of callus cultures were evaluated using DPPH and FRAP assays and the enzyme antioxidants (superoxide dismutase, catalase, and ascorbate peroxidase) were evaluated. The antibacterial activity of plant extracts was screened against Escherichia coli and Bacillus subtilis bacteria by the diffusion agar method. There was a significant positive correlation between total phenolic content and high antioxidant efficiency in Hypericum perforatum L. callus cultures, which were formed on Murashige and Skoog medium supplemented with auxin, cytokinin, and salicylic acid (100 µM). Our results have demonstrated that callus cultures generated on MS medium supplemented with N-(1,3-dioxoisoindolin-2-yl)-3-((4-methoxyphenyl)amino)propanamide and cytokinin BAP (0.5 mg L−1) exhibited improved antioxidant activities for the first time.

Botanicals from Aframomum letestuanum Gagnep. (Zingiberaceae) can overcome the multidrug resistance of Klebsiella species overexpressing AcrAB-TolC efflux pumps

Background: Bacteria belonging to the genus Klebsiella have developed resistance mechanisms to clinically used antibiotics, leading to their loss of efficacy. In the present study, the in vitro antibacterial activity of methanol extracts from Aframomum letestuanum, as well as their modes of action against a panel of 14 bacterial species belonging to the genus Klebsiella including multidrug-resistant (MDR) phenotypes overexpressing efflux pumps were evaluated. Methods: The broth microdilution method was used to assess the antibacterial activities of plant extracts (botanicals), while standard experimental protocols were used to study modes of action. Harborne's qualitative reference methods were used to identify the major groups of secondary metabolites present in the botanicals. Results: Phytochemical screening revealed that botanicals contain alkaloids, terpenoids, phenols, flavonoids, tannins, saponins, and anthocyanins. Botanicals from A. letestuanum seed pulp and seed inhibited the growth of all the bacteria tested, with MICs ranging from 16 to 512 μg/mL (pulp) and 64 to 2048 μg/mL (seed). The pulp extract had excellent activity, with MIC values of 16 μg/mL against K2, 32 μg/mL against Kp 80, and Kp 126, and 64 μg/mL against Kp55, Kp63, and ATCC11296. The seed extract displayed a MIC of 64 μg/mL against Kp58 and Kp2. A. letestuanum seed pulp extract inhibited bacterial growth in the exponential phase and induced inhibition of ATPase-H+-dependent proton pumps in K. pneumoniae ATCC11296. Conclusion: Botanicals from A. letestuanum are potential phytomedicines that deserve further investigation to develop novel drugs to overcome the multidrug resistance of Klebsiella species. Keywords: Aframomum letestuanum; antibacterial; antibiotics; efflux pumps; multidrug resistance; Klebsiella species.

Phytochemical Diversity, Classification and Antibacterial Activity of Some Medicinal Plant Species from Tabuk (Saudi Arabia).

The main objectives of this study were to investigate the intra-specific and inter-specific phytochemical diversity and classification of nine important medicinal plant species from Tabuk region (KSA), namely (Pulicaria undulata L., Pulicaria incisa Lam., Artemisia herba-alba Asso., Artemisia monosperma Delile, Artemisia judaica L. and Achillea fragrantissima Forssk. from Asteraceae family, Ducrosia flabellifolia Boiss. from Apiaceae family, Thymus vulgaris L. and Lavandula coronopifolia Poir. from Lamiaceae family); to evaluate the antibacterial potentials of the plant extracts, and to inspect the possible associations between phytochemical diversity and contents of different phytochemical classes with the antibacterial activities of plant extracts. GC/MS technique was used to identify phytochemicals in the plant extracts. The standard disk diffusion technique was used to conduct the antibiotic susceptibility against four pathogenic bacterial species (two Gram positive: Staphylococcus aureus and Bacillus subtilis and two Gram negative species: Pseudomonas aeruginosa and Escherichia coli. A total of 160 different phytochemicals belonging to 30 compound classes were separated and identified. A. fragrantissima had the highest phytochemical diversity and P. incisa had the lowest one. Phytochemical beta diversity was 6.2362. Ethanol outperformed other extraction solvents in terms of antibacterial activity, while Pulicaria undulata and T. vulgaris ranked highest among plants in this regard. Gram positive bacterial species were more sensitive to plant extracts compared to Gram negative species. Phytochemical diversity and antibacterial activity of plant extracts against E. coli and P. aeruginosa were positively correlative, terpenoid and benzene & substituted derivative contents exhibited significant (p<0.05) positive correlations with the antibacterial activity against E. coli, terpenoid contents also showed positive correlation with activity against P. aeruginosa; benzene & derivative showed positive correlation with activity against the rest of bacterial species.

Antibacterial Activity of Selected Medicinal Plants and Therapeutic Potential of Bridelia micrantha on Excision Wound Infected with Pseudomonas aeruginosa in Rat

Bridelia micrantha (Hochst.) Baill (Euphorbiaceae) and Smilax krausiana Meisn. (Smilaceae) are traditionally used in tropical Africa to treat various diseases including infectious diseases, stomach pains, skin diseases and wounds. The study aimed to evaluate the antibacterial activity of Bridelia micrantha (Hochst.) Baill (Euphorbiaceae) and Smilax krausiana Meisn. (Smilaceae) extracts and the healing potential of the most active extract in a rat excision wound model infected by Pseudomanas aeruginosa. The crude extracts were prepared by maceration in ethanol. Phytochemical analysis was performed using standard methods. Antibacterial activities of extracts alone and the combinations of extracts with amoxicillin as well as the effect of osmotic stress on their activities were determined by the broth microdilution method against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. The therapeutic effect of the B. micrantha extract ointment was evaluated in a rat excision wound model infected by P. aeruginosa. Skin and eye toxicity tests were performed using the Draize method. The ethanol extract of B. micrantha (MIC = 512 - 1024 µg/ml) displayed the largest antibacterial activity compared with that of S. krausiana (MIC = 512 - 2048 µg/ml). The antibacterial activities of plant extracts and amoxicillin increased under osmotic stress conditions ((2.5% and 5% NaCl). B. micrantha extract showed indifference and antagonism effects with amoxicillin against the tested bacteria. The B. micrantha extract ointment yielded the shortest epithelization times, highest wound contraction rates and lowest numbers of colony forming units of P. aeruginosa at the infection site as compared with the standard drug (Baneocin) and blank (palm kernel oil). The antibacterial and wound healing effects observed may be attributed to the presence of polyphenols, flavonoids, anthocyanins, alkaloids, triterpenes, saponines and tannins found in the test plants. The results of this study clearly demonstrate the antibacterial activity of B. micrantha and S. krausiana as well as the wound healing potential of B. micrantha.

Antibacterial and Wound Healing Properties of Selected Cameroonian Medicinal Plants

Emilia coccinea (Sims.) G. Don. (Asteraceae), Erigeron floribundus (Kunth) Sch. Bip. (Asteraceae) and Hibiscus asper Hook.f. (Malvaceae) are used ethnomedicinally in tropical region of Africa to treat various diseases including infectious diseases, abscesses, skin diseases and wounds. The study aimed to evaluate the antibacterial activity of E. coccinea, H. asper and E. floribundus extracts and the healing efficiency of the most active extract in a rat excision wound model infected by Staphylococcus aureus. The plant extracts were prepared by maceration in ethanol. Secondary metabolites were detected in the extracts by using standard methods. Antibacterial activities of extracts alone and the combinations of extracts with amoxicillin as well as the effect of osmotic stress on their activities were determined against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus by using broth micro dilution method. The therapeutic effect of the E. coccinea extract was evaluated in a rat excision wound model infected by S. aureus. E. coccinea extract (MIC = 256 - 512 µg/ml) displayed the largest antibacterial activities followed in decreasing order by the extracts of E. floribundus flowers and leaves (MIC = 256 - 1024 µg/ml), E. floribundus roots (MIC = 512 - 1024 µg/ml) and H. asper (MIC = 1024 µg/ml). The antibacterial activities of plant extracts and amoxicillin increased under osmotic stress conditions. E. coccinea extract showed additive effect with amoxicillin against pathogenic bacteria among which multidrug resistant strains. E. coccinea extract ointment yielded the shortest epithelization times, highest wound contraction rates and lowest numbers of colony forming units of S. aureus at the infection site as compared with the standard drug (Baneocin). Interestingly, this extract ointment is non-irritating to the skin and eyes. The observed biological activities may be attributed to the presence of groups of phytochemical compounds found in the test plants. The results of the present study demonstrate the antibacterial activity of the test plants as well as the healing efficiency of the E. coccinea extract ointment. E. coccinea can be used for the development of phytomedicines to treat wounds and infectious diseases particularly those caused by the tested bacteria. So, further studies are warranted.

Assessment of Hexavalent Chromium Accumulation of Beta Vulgaris L. Var. Cicla and the Change of Its Antibacterial Activity

ABSTRACT Hexavalent chromium (Cr(VI)) is a frequently encountered heavy metal contaminant in agricultural soil and water sources resulting from industrial and agricultural applications, traffic, and urbanization. It is the most toxic form of chromium (Cr), which causes severe health problems. The accumulation capacity of Swiss chard (Beta vulgaris L. var. cicla) for hexavalent chromium and the effect of heavy metal accumulation on the antibacterial activity of plant extracts were evaluated in a pot experiment. The soil was treated with 10 mg kg−1 hexavalent chromium, 30 days prior to planting Swiss chard seedlings. After the harvest, macro- and micronutrient elements and Cr were measured using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES). Moreover, plant extracts were obtained by maceration in methanol and the extracts were tested against Gram-positive and Gram-negative bacteria. Cr was found to be uptaken and accumulated with a high concentration (54.7 ± 0.23 mg kg−1) in the aerial parts (transfer factor = 74.95). Cr toxicity reduced plant development and the macronutrient elements phosphorus and potassium in Swiss chard. The micronutrient elements iron and boron were found to be significantly increased in plant upon chromium in a synergistic manner with Cr. Additionally, the antibacterial activity of the extract of Swiss chard decreased against Staphylococcus aureus and Enterococcus faecalis around 50%. Moreover, the number of culturable bacteria decreased about 40% in soil after chromium treatment. The results suggested that this plant can accumulate a high amount of Cr in its aerial parts, which may decrease the health effects of the extracts.

Investigation of composition, antioxidant, antimicrobial and cytotoxic characteristics from Juniperus sabina and Ferula communis extracts

Plants have been one the most valuable sources of biologically active compounds. This study investigates the chemical composition, as well as the antioxidant, antimicrobial, and cytotoxic activities of methanolic and ethanolic extracts from Juniperus sabina and Ferula communis leaves, grown in Cyprus. Total phenolic and flavonoids content of methanol and ethanol extracts were quantified. Chemical constituents of the leaf extracts were analysed using gas chromatography/mass spectrometry (GC/MS). Mome inositol was the predominant component in the J. Sabina’s extracts. The most dominant component in F. communis ethanolic extract was phytol, while in FCL methanolic extract 1,3,4,5 tetrahydroxycyclohexanecarboxylic acid. Antioxidant activities were evaluated by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging ability. Antioxidant activity results revealed concentration dependent activity for methanolic and ethanolic extracts from the plant leaves. Antibacterial activity of plant extracts was tested against Gram-negative and Gram-positive bacteria using disk diffusion and minimal inhibitory concentration methods. Cytotoxic activity of plant extracts were evaluated on MCF-7 and MDA-MB-231 breast cancer cell lines, where they demonstrated their potential on the viability of both cell lines. The biological activity revealed by plants is due to the bioactive compounds found in the extracts. These bioactive components could be used as anticancer drug candidates.

Formulation and characterization of polyherbal anti-acne gel containing Citrus aurantifolia and Aloe barbadensis extracts for the management of acne vulgaris

The antibiotic used to treat acne may develop antibiotic resistance and side effects. Meanwhile, treating acne-causing bacteria by applying Citrus aurantifolia juice to the skin immediately is ineffective. Citrus aurantifolia juice was employed in an anti-acne gel formulation to treat acne that was caused by Cutibacterium acnes and Staphylococcus epidermidis has no synergistic therapeutic effect shown. Additionally, polyherbal formulations are currently in high demand in the global market. The herbal industry's global market value has risen dramatically from US$60 billion in 2000 to US$105 billion in 2017. The worldwide market will increase at a rate of 7.6% each year until it reaches $5 trillion in 2050. This study aims to formulate a polyherbal anti-acne gel containing C. aurantifolia and Aloe barbadensis, and to characterize the formulated gel for its physicochemical properties. The phytoconstituents found in plant extracts were also analysed. The antibacterial activity of plant extracts against Staphylococcus aureus was also investigated using an agar well diffusion method. After plant extracts were discovered, gels with varying concentrations of plant extracts, and excipients were prepared along with compatibility studies. Parameters like colour, odour, homogeneity, phase separation, consistency, washability, pH, viscosity, spreadability and antibacterial activity were evaluated. The results showed that the levels of phenol, tannins, and flavonoids in plant extracts varied, the antibacterial activity of plant extracts was studied with a clear inhibition zone demonstrated, and plant extracts were compatible with all excipients. Gel formulations containing C. aurantifolia, A. barbadensis, the excipients Carbopol-940, methylparaben, propyl paraben, propylene glycol-400, triethanolamine and water have been developed. The formulated gels were clear, odourless, uniform, consistent, without lumps, and washable. It was found that pH was closer to the skin, good viscosity and spreadability. The formulated gel, F4 has greater antibacterial activity than plant extracts and other formulations with a larger diameter inhibition zone. It is concluded that the polyherbal anti-acne gel containing C. auranfolia and A. barbadensis can be formulated which has a high potential for halal cosmetics product development. However, more research should be done before it can be commercialised by comparing it to commercially available marketed formulations to treat acne vulgaris.

Inhibitory Effects of Selected Medicinal Plants on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to global public health due to its capacity of tolerate conventional antibiotics. Medicinal plants are traditionally used to treat infectious diseases caused by bacterial pathogens. In the present study, 16 medicinal plants were screened for antibacterial activities to preselect more effective species. Ethanol extracts of selected medicinal plants (Caesalpinia sappan L., Glycyrrhiza uralensis Fisch., Sanguisorba officinalis L., and Uncaria gambir Roxb) were partitioned successively with different solvents (n-hexane, chloroform, ethyl acetate, 1-butanol, and water). Disc diffusion assay and broth microdilution were performed to evaluate the antibacterial activities of plant extracts and fractions against Staphylococcus aureus strains. Furthermore, the cytotoxicity of the extracts and fractions was determined against the human hepatoma (HepG2) and human lung carcinoma (A549) cell lines using a trypan blue exclusion method. A few extracts and fractions showed significant inhibitory effects on the bacterial growth of all tested strains, including multidrug-resistance (MDR) clinical isolates. The ethyl acetate fraction of C. sappan had the most potent effects with minimum inhibitory/bactericidal concentrations (MIC/MBC) of 31.2/62.5 μg/mL and showed low cytotoxicity with over 90% cell viability in both cells. Our results suggest that medicinal plants have considerable potential as alternatives to conventional antibiotics.

Light and scanning electron microscopy of Datura stramonium L. extract and its biological applications.

The study deals with the LM and SEM (light microscopy and scanning electron microscopy) of Datura stramonium L. extract and to evaluate its phytochemical, antimicrobial, and antioxidant activities. The plant sample collected from different Lahore region was dried under shade. The plant extract was prepared using different solvents (n-hexane, chloroform, ethyl acetate, and methanol). Phytochemical screening performed qualitatively for alkaloids, carbohydrates, flavonoids, saponins, and tannins. Radical scavenging potential of plant extracts was estimated and ethyl acetate extract exhibited maximum percentage scavenging ability of 92.2 ± 0.09. Total antioxidant capacity of different extracts was measured by phosphomolybdate method. The ethyl acetate and methanolic extracts showed maximum values of 72.3 ± 0.08% and 79 ± 0.15% with respect to gallic acid. Total phenolic contents were determined through Folin-Ciocalteau method and highest value of 495.2 ± 3.4 was obtained by methanolic extract. DPPH-TLC autography was used for the visual detection of antioxidant compounds in different plant extracts. Antibacterial activity of plant extract was measured by disc diffusion method against microorganisms named Bacillus licheniformis, Bacillus subtilis (Gram positive), and Salmonella typhimurium, and Proteus mirabilis (Gram negative). Because of the vast medicinal importance of D. stramonium L. it would be beneficial to study LM and SEM for correct identification of plant and to determine phytochemicals. RESEARCH HIGHLIGHTS: LM and SEM (light microscopy and scanning electron microscopy) of Datura stramonium L. was studied for the exact identification of plant. To evaluate the biological activities of pharmaceutically important plant. Antioxidant and antimicrobial activity were determined. D. stramonium L. proved to be medicinally important plant.

Synthesis of Silver Nanoparticles from Extracts of Wild Ginger (Zingiber zerumbet) with Antibacterial Activity against Selective Multidrug Resistant Oral Bacteria.

Antibiotic resistance rate is rising worldwide. Silver nanoparticles (AgNPs) are potent for fighting antimicrobial resistance (AMR), independently or synergistically. The purpose of this study was to prepare AgNPs using wild ginger extracts and to evaluate the antibacterial efficacy of these AgNPs against multidrug-resistant (MDR) Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis. AgNPs were synthesized using wild ginger extracts at room temperature through different parameters for optimization, i.e., pH and variable molar concentration. Synthesis of AgNPs was confirmed by UV/visible spectroscopy and further characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy analysis (EDXA), and Fourier-transform infrared spectroscopy (FTIR). Disc and agar well diffusion techniques were utilized to determine the in vitro antibacterial activity of plant extracts and AgNPs. The surface plasmon resonance peaks in absorption spectra for silver suspension showed the absorption maxima in the range of 400–420 nm. Functional biomolecules such as N–H, C–H, O–H, C–O, and C–O–C were present in Zingiber zerumbet (Z. zerumbet) (aqueous and organic extracts) responsible for the AgNP formation characterized by FTIR. The crystalline structure of ZZAE-AgCl-NPs and ZZEE-AgCl-NPs was displayed in the XRD analysis. SEM analysis revealed the surface morphology. The EDXA analysis also confirmed the element of silver. It was revealed that AgNPs were seemingly spherical in morphology. The biosynthesized AgNPs exhibited complete antibacterial activity against the tested MDR bacterial strains. This study indicates that AgNPs of wild ginger extracts exhibit potent antibacterial activity against MDR bacterial strains.

Antibacterial activities of seven ethnomedicinal plants from family Annonaceae.

ABSTRACTSerious threat to human health caused by bacterial infection persists as a global concern. It becomes more serious when the burden of multidrug-resistance bacteria is in the increasing trend. To overcome, researches have been conducted to develop antibacterial agents from plant-derived bioactive compounds. This review article focuses on the antibacterial activities of plant extracts from seven Annonaceae members, namely Annona muricata, Annona reticulata, Annona squamosa, Cananga odorata, Annona hypoglauca, Polyalthia longifolia, and Xylopia aethiopica. First, ethnomedical uses of the aforementioned plants are discussed and followed by the screening results of related phytochemicals. Among many secondary metabolites contained in the extracts of Annonaceae spp., anonaine, nornuciferine, and liriodenine are common and bioactive. The extracts were reported to have bacteriostatic and bactericidal properties against a wide spectrum of bacteria, including multidrug-resistant Escherichia coli, Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, Enterobacter aerogenes, Enterobacter cloacae, Salmonella choleraesuis, Salmonella typhimurium, and Shigella dysenteriae. We conclude that investigation on the extracts from Annonaceae spp. could contribute to the development of antibacterial agents that could be used against multidrug-resistant bacteria.

The Antibacterial Activity of Catunaregam tomentosa Against Selected Gram-Positive and Gram-Negative Bacteria

Catunaregam tomentosa is a plant from Rubiaceae family that is used in traditional medicine for the treatment of stomatitis and ulcers due to bacterial infections. Besides, it also helps in the treatment of oliguria and dysuria. Indiscriminate use of commercial antibacterial medicines had led to the search for novel antibacterial drugs. Since for ages medicinal plants have been used to treat bacterial infection, so they can be excellent sources of the novel antibacterial drug. To evaluate the scientific basis of the use of plant, antibacterial activity leaves extract of C.tomentosa was investigated against selected Gram-positive and Gram-negative bacteria. The study also investigated the effect of pH on its antibacterial activity. Antibacterial activity of the plant extracts was evaluated against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa by using the disc diffusion method at 100mg/mL concentration. Extracts of C. tomentosa inhibit the activity of S. aureus but do not inhibit the activity of Gram-negative bacteria. Minimum inhibitory concentration (MIC) was also determined against S. aureus at concentration 100, 50, 25, 12.5, 6, 3, 1.5, 0.75 and 0.395mg/mL and 3mg/mL were the MIC value. Evaluation on the effect of different pH on antibacterial activity of plant extracts shows that the activity of the plant extracts does not affect when treated with acidic pH but increased at alkaline pH. Based on the present finding, C. tomentosa leaves extract have the potential to be a viable candidate in the discovery of a natural antibacterial agent against S. aureus infections. This study provides scientific knowledge to further determine the antibacterial values of C. tomentosa extracts.

Phytochemical and Pharmacological Evaluation of Ziziphus mauritiana, Allium sativum and Brassica nigra

Unrefined methanolic extracts of Ziziphus mauritiana (Ber) leaves, bulbs of Allium sativum (Garlic) and seeds of Brassica nigra (Black Mustard/Sarso) generally utilized in medication were studied for their in vitro phytochemical and pharmacological screening. Phytochemical screening of Z. mauritiana showed the presence of flavonoids, flavones, phenolic compounds, saponins, terpenoids and nonattendance of tannins, steroids, and glycosides. Similarly, unrefined methanolic extract of A. sativum bulbs showed the presence of flavonoids, phenols, tannins, saponins, terpenoids and steroids. Also, B. nigra seeds showed the indicated the presence of flavonoids, phenols, tannins, terpenoids and glycosides. The antibacterial activity of plant extracts was determined by utilizing agar well diffusion technique. The plant extracts demonstrated varied levels of antibacterial activity. In this study five bacterial isolates were utilized (Escherichia coli, Staphylococcus aureus, Pesudomonas aerugenosa, Klebseila pneunomonae, and Proteus). ZM leaves and AS bulbs extracts showed good antibacterial action against P. aeruginosa and Proteus (50% and 60%), while BN seeds showed low inhibition against P. aeruginosa (28%) but showed great restraint effect against E. coli and Proteus (50%and 60%). The antifungal activity was determined by agar slant technique in contradiction of R. stolonifer, A. niger and A. flavus. AS bulbs extract showed good (14%) antifungal activity when contrasted with ZM leaves (14%) and BN seeds (13%) against R. stolonifer. The extract exhibited low activity against A. niger and A. flavus similarly methanolic extract showed low antifungal activity (10% and 11%). Phytotoxic activities show that these plants caused substantial growth inhibition of Lemna minor in all the dilutions.

Reproducibility challenges in the search for antibacterial compounds from nature.

BackgroundReproducibility of reported antibacterial activities of plant extracts has long remained questionable. Although plant-related factors should be well considered in serious pharmacognostic research, they are often not addressed in many research papers. Here we highlight the challenges in reproducing antibacterial activities of plant extracts.MethodsPlants with reported antibacterial activities of interest were obtained from a literature review. Antibacterial activities against Escherichia coli and Klebsiella pneumoniae were tested using extracts’ solutions in 10% DMSO and acetone. Compositions of working solutions from both solvents were established using LC-MS analysis. Moreover, the availability of details likely to affect reproducibility was evaluated in articles which reported antibacterial activities of studied plants.ResultsInhibition of bacterial growth at MIC of 256–1024 μg/mL was observed in only 15.4% of identical plant species. These values were 4–16-fold higher than those reported earlier. Further, 18.2% of related plant species had MICs of 128–256 μg/mL. Besides, 29.2% and 95.8% of the extracts were soluble to sparingly soluble in 10% DMSO and acetone, respectively. Extracts’ solutions in both solvents showed similar qualitative compositions, with differing quantities of corresponding phytochemicals. Details regarding seasons and growth state at collection were missing in 65% and 95% of evaluated articles, respectively. Likewise, solvents used to dissolve the extracts were lacking in 30% of the articles, whereas 40% of them used unidentified bacterial isolates.ConclusionReproducibility of previously reported activities from plants’ extracts is a multi-factorial aspect. Thus, collective approaches are necessary in addressing the highlighted challenges.

An in vitro evaluation of antibacterial activity of various extracts of Achyranthes aspera and Cissus quadrangularis

The antibacterial activity of aqueous and methanol extracts of Achyranthes aspera and Cissus quadrangularis was evaluated. A. aspera and C. quadrangularis plants collected from its natural habitat in and around Tirunelveli, Tamil Nadu, India were shadow dried at room temperature and pulverized into coarse powder. Aqueous extracts were prepared by extracting with distilled water at 100°C for 4h and methanol extracts were prepared by maceration process using methanol for 72h. The aqueous extract yield was 12.1% and 23.5% for A. aspera and C. quadrangularis respectively. Whereas, methanol extract yield was 6% and 4% for A. aspera and C. quadrangularis, respectively. The antibacterial activity of plant extracts against Staphylococcus aureus (MTCC-96) and Escherichia coli (MTCC-443) was evaluated by Agar well diffusion method. The diameters of zone of inhibition ranged from 8mm to 17mm with highest inhibition zone observed against S. aureus by methanol extract of A. aspera (17mm) followed by aqueous extract of C. quadrangularis (13mm) and methanol extract of C. quadrangularis (9mm). Whereas, zone of inhibition (8mm) against Escherichia coli was observed only with methanol extract of C. quadrangularis. The results necessitate further study to isolate the active principles from the plant extracts to exploit the potential antibacterial activity and to find novel pharmacological uses of these plants beyond their racial use.

In vitro antibacterial and antibiotic-potentiation activities of five edible plant extracts and mode of action against several MDR Gram-negative phenotypes

Abstract Background: Bacterial infections involving the multidrug resistant (MDR) strains are among the top leading causes of death throughout the world. Healthcare system across the globe has been suffering from an extra-ordinary burden in terms of looking for the new and more potent antimicrobial compounds. The aim of the present study was to determine the antibacterial activity of some Cameroonian edible plants (Garcinia lucida bark, Phoenix dactylifera pericarps, Theobroma cacao pod, Solanum macrocarpon leaves and Termitomyces titanicus whole plant) and their antibiotics-potentiation effects against some MDR Gram-negative bacteria phenotypes expressing efflux pumps (Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa and Providencia stuartii strains). Methods: The antibacterial activities of plant extract alone and in combination with usual antibiotics were carried out using the micro-dilution method. The effects of the most active plant extract (Garcinia lucida bark) on H+-ATPase-mediated proton pumps and on bacterial growth kinetic were performed using experimental protocols, while qualitative reference methods were used to highligh the major groups of secondary metabolites present in the extracts. Results: Qualitative phytochemical screening of plant extracts indicated that all analysed secondary metabolites were present in Theobroma cacao and Termitomyces titanicus while one (saponins) of them was absent in Garcinia lucida and Solanum macrocarpon. Only three of them (polyphenols, flavonoids and saponins) were detected in Phoenix dactylifera. Antibacterial essays showed that G. lucida was the most active plant as it inhibited the growth of all studied bacteria with strong activity (MIC&lt;100 µg/mL) against E. coli ATCC8739, significant activity (100≤MIC≤512 µg/mL) against 80% of bacteria and moderate activity (512&lt;MIC≤2048 µg/mL) against E. coli AG100A and E. aerogenes (EA289 and CM64). It was followed by T. cacao and S. macrocarpon extracts which exhibited an antibacterial potential against 95% and 80% of bacterial strains, respectively. These three extracts exhibited a bactericidal effect on a few bacteria. Extracts from T. titanicus and P. dactylifera were less active as they moderately (512&lt;MIC≤2048 µg/mL) inhibited the growth of 35% and 10% of bacteria. All extracts selectively potentiated the activities of all antibiotics with improvement activity factors (IAF) ranging from 2 to 256. G. lucida, T. cacao and S. macrocarpon potentiated the activities of 100%, 89% and 67% of antibiotics respectively against more than 70%, suggesting that they contain bioactive compounds which could be considered as efflux pumps inhibitors. Whereas T. titanicus and P. dactylifera improved the activities of almost 40% and 20% of antibiotics, respectively. This increase of activities also characterizes synergistic effects between antibiotics and these bioactive compounds. G. lucida extract at all tested concentrations, strongly inhibited the growth of bacterial strain E. coli ATCC8739 and exhibited an inhibitory effect on this bacterial H+-ATPase-mediated proton pumps increasing the pH of the medium. Conclusion: The overall results indicated that food plants among which G. lucida, T. cacao and S. macrocarpon could have a benefit interest in combatting resistant types of bacteria. Keywords: Food plants; infectious diseases; MDR bacteria; efflux pumps; antibiotics; secondary metabolites.