Screening of antifungal and antimycotoxigenic activity of plant phenolic extracts

2008 ◽  
Vol 1 (2) ◽  
pp. 139-146 ◽  
Author(s):  
M. dos Santos Oliveira ◽  
E. Badiale Furlong

The antifungal and antimycotoxigenic activities of extracts from edible plants were tested by the agar dilution method using the growth diameter of Aspergillus flavus as response and the determination of aflatoxins B1 and B2 in the culture medium. On the 7th incubation day, the greatest fungal inhibitions were reached by the extracts from potato peel; rice and wheat; lemon peel and pulp; eggplant peel; orange peel and pulp; and apple pulp. After the 14-day incubation, the extracts from banana (30 µg phenol/ml agar), eggplant (30 µg phenol/ml agar), and potato (50 and 67 µg phenol/ml agar) pulp reduced the production of aflatoxin B1 by 3.2%/µg phenol/ml agar, 2.9%/µg phenol/ml agar, 1.8%/µg phenol/ml agar and 0.85%/µg phenol/ml agar, respectively, in relation to the control. The extracts from the other vegetables fully inhibited the synthesis of the mycotoxin. These results point to the studied plants and their residues as potential sources of phenolic compounds that may have an inhibitory effect on fungal development and the production of mycotoxins in food.

2008 ◽  
Vol 3 (9) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Mehrdad Iranshahi ◽  
Abdolmajid Fata ◽  
Bahareh Emami ◽  
Bibi Mohadeseh Jalalzadeh Shahri ◽  
Bibi Sedigheh Fazly Bazzaz

The increase in dermatophytoses and the fact that some patients do not respond well to therapy make it necessary to find new antifungal agents. As part of our ongoing studies on medicinal plants from Iran, we studied antidermatophytic activities of Ferula latisecta essential oil, which had shown considerable antifungal activity in preliminary antimicrobial screening. Antifungal activity was evaluated by determination of MIC values using the agar dilution method on type strains of Candida albicans and dermatophytes. The composition of the oil was characterized by GC and GC/MS analyses. The essential oil was rich in polysulfides (75.2%) and exhibited good activity against Trichophyton rubrum and T. verrucosom for about three weeks, with a MIC value 96 μg/mL. The oil showed antifungal activity, especially against dermatophytes, and the activity is probably related to the sulfur-containing components of the oil. This study has identified that the polysulfides-rich essential oil of Ferula latisecta fruits has activity against a range of human pathogenic dermatophytes, justifying future clinical trials to validate its use as a therapeutic alternative for dermatophytosis.


Author(s):  
M B Odebisi-Omokanye

Despite the increase in popularity of hand sanitizers (HS) in Nigeria, there is a dearth of literature on the efficacies of these products. This study assessed the efficacies of four popular brands of HS in Nigeria against some clinically important bacterial pathogens. Using the well variant of the agar dilution method to determine antimicrobial susceptibility and the broth dilution method to determine minimum inhibitory concentration, the activities of the HS (HSF, HSM, HDT, and HSK) were evaluated against Staphyl ococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia . Each of the products displayed varying activities against the test organisms. HSM had the highest inhibitory effect against all the test organisms, while HSF was the least effective. S. aureus was the most susceptible organism, with the highest susceptibility to HSM (12.0 mm). P. aeruginosa was the most resistant organism, with the highest resistance to HSM (9.0 mm). Each of the HS was bacteriostatic against all of the test bacteria and none displayed bactericidal activity. HSM and HDT reduced the mean colonyforming unit (cfu) counts of bacteria on the hands of subjects by 72% and 62%, respectively. A onetailed t-test showed that HSM was more effective than HDT in this regard. None of the products could reduce bacterial counts by 99.9%, as the manufacturers claim. Such claims need to be verified to ensure that these products contain the correct quantities of active ingredients, and sellers need to store such products according to the manufacturers’ instructions.


2005 ◽  
Vol 49 (7) ◽  
pp. 2997-3000 ◽  
Author(s):  
K. Van den Bulck ◽  
A. Decostere ◽  
I. Gruntar ◽  
M. Baele ◽  
B. Krt ◽  
...  

ABSTRACT The susceptibilities of Helicobacter felis (15 strains), H. bizzozeronii (7 strains), and H. salomonis (3 strains) to 10 antimicrobial agents were investigated by determination of the MIC using the agar dilution method. No consistent differences were noticed between the different Helicobacter species, which were all highly susceptible to ampicillin, clarithromycin, tetracycline, tylosin, enrofloxacin, gentamicin, and neomycin, as demonstrated by low MICs. Higher MICs were obtained for lincomycin (up to 8 μg/ml) and spectinomycin (up to 4 μg/ml). Two H. felis strains showed a MIC of 16 μg/ml for metronidazole, suggesting acquired resistance to this antimicrobial agent.


2011 ◽  
Vol 6 (6) ◽  
pp. 1036-1043 ◽  
Author(s):  
Magdalena Wegiera ◽  
Urszula Kosikowska ◽  
Anna Malm ◽  
Helena Smolarz

AbstractThis study was designed primarily to investigate the antibacterial and antifungal activity of the extracts from fruits of six Rumex L. species: R. acetosa L., R. acetosella L., R. confertus Willd., R. crispus L., R. hydrolapathum Huds. and R. obtusifolius L. The 7 Grampositive and 7 Gram-negative bacteria strains and 5 fungal ones were tested by agar and broth dilution method. Determination of minimal inhibitory concentration (MIC) revealed that the extracts from R. confertus, R. crispus, R. hydrolapathum and R. obtusifolius exerted differential inhibitory effect on the growth of Gram-positive bacteria — staphylococci (MIC=62.5–125 µg/mL) and Gramnegative bacteria — Escherichia coli ATCC 3521, Proteus mirabilis, Pseudomonas aeruginosa (MIC=125→500 µg/mL); MIC values determined by agar dilution method were somewhat higher. The same extracts inhibited also the growth of fungi — Candida spp. or Trichophyton mentagrophytes ATCC 9533 (MIC=250–500 µg/mL), as found by agar dilution method. The total content of polyphenols (11.66–78.36 mg/g), anthracene derivatives (0.26–12.93 mg/g) and tannins (4.00–11.16%) was also determined.


2021 ◽  
Author(s):  
Po-Wei Tsai ◽  
Pei-Chin Lin ◽  
Ling-Ling Yang ◽  
Ming Shun Wu

Abstract It has been a challenge for many clinicians to treat a complicated extended-spectrum-β-lactamase (ESBL) producing Klebsiella Pneumoniae (Kp) and Escherichia coli (E. coli) infection due to widespread antibiotic abuse with renal damage as one of its common side effects. Therefore, this study aimed to assess the antibacterial activity of extracts from several Taiwanese folk medicinal plants against ESBL- Kp and E. coli. with renal protecting ability against lipid peroxidation (LPO) on mice kidney mitochondria. Preliminary antibacterial activities of ethanol extracts from twenty (20) Taiwanese folk medicinal plants were measured by agar-dilution method against standard ESBL strains of E. coli (ATCC 25922, ATCC 35218) and Kp (ATCC 23856, ATCC 700603). Rhus semialata var. roxburghiana DC. (RSR) exerted the most inhibitory effect and then further extracted with n-hexane, ethyl acetate, acetone, ethanol, and water, respectively. Each extract also evaluated against the four standard ATCC microorganisms. Their MIC50, MIC90, and time kill assay were adapted with detecting the maximum inhibitory activities and the antibacterial spectrum range of each extract was measured against twenty-four (24) kinds of microbes. Which were used including gram-positive, gram-negative bacteria and fungus by agar dilution method. Finally, renal protective ability was detected inhibitory effect of ferrous induced lipid peroxidation on mice mitochondria. Among 20 Taiwanese folk medicinal plants tested, Rhus semialata var. roxburghiana DC. (RSR) exhibited maximum inhibition against clinical ESBL-producing Kp and E. coli strains with acetone extracts showing MIC50/MIC90 values at 1000 µg/mL, the course of antimicrobial action was bacteriostatic and with inhibitions to all 24 kinds of microbial including Gram positive and negative bacteria and fungi. Furthermore, result of thiobarbituric acid reactive substances (TBARS) assay from this extract showed high lipid peroxidative (LPO) protective capability on mice kidney mitochondria (IC50: 29.29 ± 0.35µg/mL). RSR acetone extract, with its maximum activity against clinical isolated ESBL-producing Kp and E. coli, antimicrobial effect against other wide spectral range bacteria and relatively high LPO protective ability on mice kidney mitochondria, is a potential source, albeit further studies have yet to be conducted, to develop an antimicrobial drug against ESBL-Kp and E. coli.


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