The in vitro antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts were studied against selected pathogenic fungi and bacteria, following broth dilution assay. Leaves and calli were extracted using absolute alcohol, benzene, chloroform, methanol and petroleum ether. Among the five solvents used, leaf and callus extracted in chloroform of both the plants were found to be more effective against pathogenic bacteria and fungi, where the minimum inhibitory concentration (MIC) ranged between 0.25 to 6 mg/ml. Absolute alcohol extracts showed MIC of 0.25 to 4 mg/ml for bacteria, whereas for fungi it ranged from 0.25 to 100 mg/ml. Extracts of benzene and petroleum ether were ineffective in inhibiting the bacterial and fungal growth or showed poor inhibition. Methanol extract showed MIC of 0.25 to 100 mg/ml against bacterial pathogens and 0.5 to 100 mg/ml against fungal pathogens. The antimicrobial activities of these two indigenous medicinal plants were discussed in the present paper.

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Antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts

Introduction and objective: Dental caries is a common oral bacterial pathology that has been associated with Streptococcus spp., mainly Streptococcus mutans and Lactobacillus spp. Antibacterial activities of Terminalia chebula extracts against several bacterial strains have been reported. The aim of this study was to evaluate the possible antimicrobial potential of T. chebula fruit extracts (acetone, ethanol, methanol, cold and hot aqueous) against five dental caries causing microorganisms. Materials and methods: For this purpose, three bacteria S. mutans, Staphylococcus aureus, Lactobacillus acidophilus and two yeasts Candida albicans and Saccharomyces cerevisiae were tested. Antimicrobial activity was tested using agar well diffusion method. All the tested extracts showed antibacterial activity against two bacteria S. mutans and S. aureus but no antimicrobial activity was observed against L. acidophilus, C. albicans and S. cerevisiae. Results: The highest activity was shown by the acetonic extract with a mean diameter of inhibition zone being 25.32mm and a minimum inhibitory concentration (MIC) of 25mg/ml against S. mutans and a mean diameter of 32.97mm and a MIC of 12.5mg/ml against S. aureus followed by ethanolic, hot aqueous, cold aqueous and methanolic extracts. Conclusion: These promising findings suggest the presence of antibacterial activity in the tested plant material, exhibited by its bioactive compounds, and serving them as an alternative antimicrobial agent against dental caries causing microorganisms.

https://jjm.ajums.ac.ir/_jjm/documents/Joshi105-11.pdf

Evaluation of antimicrobial properties of fruit extracts of Terminalia chebula against dental caries pathogens

The in vitro antimicrobial activity of Amomum subulatum and Elettaria cardamomum fruit extracts were studied against Streptococcus mutans, Staphylococcus aureus, Lactobacillus acidophilus, Candida albicans and Saccharomyces cerevisiae. The acetone, ethanol and methanol extracts of the selected plants exhibited antimicrobial activity against all tested microorganism except L. acidophilus. The most susceptible microorganism was S.aureus followed by S.mutans, S.cerevisiae and C.albicans in case of Amomum subulatum while in the case of Elettaria cardamomum; S.aureus was followed by C.albicans, S. cerevisiae and S.mutans. The largest mean zone of inhibition was obtained with the ethanolic extract of A. subulatum and acetonic extract of E.cardamomum against Staphylococcus aureus (16.32mm and 20.96mm respectively). Minimum inhibitory concentrations (MIC) of the extracts were also determined against the four selected microorganisms showing zones of inhibition ≥10mm. This study depicts that ethanol and acetone extracts of fruits of Amomum subulatum and Elettaria cardamomum can be used as a potential source of novel antimicrobial agents used to cure dental caries.

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Antimicrobial Activity of Amomum subulatum and Elettaria cardamomum Against Dental Caries Causing Microorganisms

The present work was designed to assess the antibacterial properties of the methanol extracts of some Cameroonian medicinal plants and the effect of their associations with currently used antibiotics on multidrug resistant (MDR) Gram-negative bacteria overexpressing active efflux pumps. The antibacterial activities of twelve methanol extracts of medicinal plants were evaluated using broth microdilution. The results of this test showed that three extracts Garcinia lucida with the minimal inhibitory concentrations (MIC) varying from 128 to 512 g/mL, Garcinia kola (MIC of 256 to 1024 g/mL), and Picralima nitida (MIC of 128 to 1024 g/mL) were active on all the twenty-nine studied bacteria including MDR phenotypes. The association of phenylalanine arginine -naphthylamide (PAN or efflux pumps inhibitor) to different extracts did not modify their activities. At the concentration of MIC/2 and MIC/5, the extracts of P. nitida and G. kola improved the antibacterial activities of some commonly used antibiotics suggesting their synergistic effects with the tested antibiotics. The results of this study suggest that the tested plant extracts and mostly those from P. nitida, G. lucida and G. kola could be used alone or in association with common antibiotics in the fight of bacterial infections involving MDR strains.

https://downloads.hindawi.com/journals/ecam/2012/623723.pdf

Antibacterial Activities of Selected Cameroonian Plants and Their Synergistic Effects with Antibiotics against Bacteria Expressing MDR Phenotypes

Medicinal uses, phytochemistry and pharmacology of Picralima nitida (Apocynaceae) in tropical diseases: a review.

Ethanol, benzene, chloroform and aqueous (cold and hot) extracts of Picralima nitida (seed, stembark and root) were tested against five bacterial strians using the agar-well diffusion method. The ethanol extracts of the root and stembark (Er and Esb) were active against 100% of the test organisms, repectively. The benzene and chloroform extracts exhibited no activity. Of the fifteen extracts teated, 40.0% were active against Staphylococcus aureus ATCC 12600, 20.0% each against Pseudomonas aeruginosa ATCC 10145 and Escherichia coli ATCC 11775, 33.3% against Bacillus subtilis ATCC 6051 and 13.3% against Salmonella kintambo Human 1,13,23:mt: -. The MIC values for the ethanol extracts range from 6.25 to 50 mg/ml, while the MIC values for the cold water seed extract (CWs) was 50 mg/ml. The results provide a rationalization for the traditional use of P. nitida for the treatment of various diseases. African Journal of Biotechnology Vol. 4 (6), pp. 522-526, 2005

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C U Iroegbu

Papers

Antibacterial screening of the root, seed and stembark extracts of Picralima nitida