Activity of Bulgarian propolis against 94 Helicobacter pylori strains in vitro by agar-well diffusion, agar dilution and disc diffusion methods

Abstract

Propolis exhibits antimicrobial, anti-inflammatory and other biological effects. The aim of this study was to evaluate the activity of 30 % ethanolic extract of Bulgarian propolis against 94 Helicobacter pylori strains by three methods. By the agar-well diffusion method, only 13 . 8 % of the strains exhibited no inhibition by 30 ìl propolis extract (containing 9 mg propolis) and all isolates were inhibited to some extent by 90 ìl of the extract (27 mg propolis) per well. The mean diameters of growth inhibition by 30, 60 or 90 ìl propolis extract or 30 ìl 96 % ethanol per well were 16 . 8, 19 . 2, 27 . 5 and 8 . 3 mm, respectively. The propolis extract was more active than the ethanol (P , 0 . 001). With 90 ìl propolis extract per well, 69 . 4 % of the strains exhibited large diameters of growth inhibition (>20 mm) versus 26 . 6 % with 30 ìl per well (P , 0 . 001). With moist propolis discs, inhibition was detected in more strains (92 . 1 %) than with dried discs (78 . 2 %, P , 0 . 05), with mean inhibitory diameters of 18 . 7 and 13 . 8 mm, respectively. By the agar dilution method, 100 and 300 ìg propolis ml À1 inhibited the growth of 57 . 1 % and 76 . 2 %, respectively, of the 21 strains tested. In conclusion, Bulgarian propolis had a strong and dose-dependent activity against most of the H. pylori strains tested. Although the effect of propolis on H. pylori in vitro is promising, further microbiological, pharmacological and clinical trials are required.

Comparative study of the antibacterial activity of propolis from different geographical and climatic zones

“…Most investigations on the antimicrobial activity of propolis carried out so far have used Petri dish methods (i.e. well or disk diffusion and agar dilution) (Fernandes Jr et al, 1995;Bosio et al, 2000;Sawaya et al, 2002;Popova et al, 2005;Boyanova et al, 2005). The main limitation of diffusion and dilution methods, however, is that they are laborious, requiring the preparation of many agar plates.…”

Peliminary examination of herbal extracts on the inhibition of <i>Helicobacter Pylori</i>

“…For the agar well diffusion method antimicrobial susceptibility was tested on solid media in petri dishes as previously reported (Boyanova et al, 2005). Briefly, H. pylori inocula prepared at McFarland's turbidity standard 2 was plated onto Mueller-Hinton agar (CM0337, Oxoid, England).…”

Synthesis and biological evaluation of some novel pyrazolopyrimidines incorporating a benzothiazole ring system

“…In vitro antimicrobial activity of synthesized compounds by the cup plate method (14) was first tested at 50 µg mL -1 concentration, but all compounds failed to produce the antimicrobial effect against the tested microorganisms. However, at 100 µg mL -1 , tested compounds 3a, 3d, 3h-j and 3l displayed significant inhibitory activity (inhibition zone 22-27 mm, Table III) against Pseudomonas aeruginosa, whereas the other compounds showed moderate activity (inhibition zone 18-22 mm) against the same organism.…”

“…-Standard strains were procured from the National Collection of Industrial Microorganism, National Chemical Laboratory, India. Synthesized compounds 3a-l were tested [50 and 100 µg mL -1 in sterile dimethyl sulfoxide (DMSO)] for their in vitro antimicrobial activity by the cup plate diffusion method (14). The antibacterial activity was evaluated on nutrient agar (Hi-media) plates (37°C, 24 h) against Gram-positive bacteria Staphylococcus aureus NCIM 2079, Bacillus megaterium NCIM 2187, Gram-negative bacteria Escherichia coli NCIM 2567 and Pseudomonas aeruginosa NCIM 2036.…”