BackgroundPropolis is the bee product noted for multiple biological effects, and therefore it is widely used for the prevention and treatment of a variety of diseases. The active substances of propolis are easily soluble in ethanol. However ethanolic extracts cannot be used in treatment of certain diseases encountered in ophthalmology, pediatrics, etc. Unfortunately, the main biologically active substances of propolis are scarcely soluble in water, oil and other solvents usually used in pharmaceutical industry. The aim of this study was to investigate chemical composition, radical scavenging and antimicrobial activity of propolis extracts differently made in nonethanolic solvents.MethodsTotal content of phenolic compounds in extracts was determined using Folin-Ciocalteu method. Chemical composition and radical scavenging activity of extracts were determined using HPLC system with free radical reaction detector. Antimicrobial activity of examined preparations was evaluated using the agar-well diffusion assay.ResultsTotal amount of phenolic compounds in extracts made in polyethylene glycol 400 (PEG) and water mixture or in PEG, olive oil and water mixture at 70 °C was comparable to that of ethanolic extract. Predominantly identified compounds were phenolic acids, which contribute ca. 40 % of total radical scavenging activity.Investigated nonethanolic extracts inhibited the growth and reproduction of all tested microrganisms. Antimicrobial activity of some extracts was equal or exceeded the antimicrobial effect of ethanolic extract. Extracts made in pure water or oil only at room temperature, contained more than 5 – 10-fold lower amount of phenolic compounds, and demonstrated no antimicrobial activity.ConclusionsNonethanolic solvent complex and the effect of higher temperature allows more effective extraction of active compounds from propolis. Concentration of total phenolic compounds in these extracts does not differ significantly from the concentration found in ethanolic extract. Propolis nonethanolic extracts have radical scavenging and antimicrobial activity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-015-0677-5) contains supplementary material, which is available to authorized users.
Background
Avian infectious bronchitis (IB) is a disease that can result in huge economic losses in the poultry industry. The high level of mutations of the IB virus (IBV) leads to the emergence of new serotypes and genotypes, and limits the efficacy of routine prevention. Medicinal plants, or substances derived from them, are being tested as options in the prevention of infectious diseases such as IB in many countries.
The objective of this study was to investigate extracts of 15 selected medicinal plants for anti-IBV activity.
Results
Extracts of
S. montana
,
O. vulgare
,
M. piperita
,
M. officinalis
,
T. vulgaris
,
H. officinalis
,
S. officinalis
and
D. canadense
showed anti-IBV activity prior to and during infection, while
S. montana
showed activity prior to and after infection.
M. piperita
,
O. vulgare
and
T. vulgaris
extracts had > 60 SI. In further studies no virus plaques (plaque reduction rate 100%) or cytopathogenic effect (decrease of TCID
50
from 2.0 to 5.0 log
10
) were detected after IBV treatment with extracts of
M. piperita
,
D. canadense
and
T. vulgaris
at concentrations of extracts ≥0.25 cytotoxic concentration (CC
50
) (
P
< 0.05). Both PFU number and TCID
50
increased after the use of
M. piperita
,
D. canadense
,
T. vulgaris
and
M. officinalis
extracts, the concentrations of which were 0.125 CC
50
and 0.25 CC
50
(
P
< 0.05). Real-time PCR detected IBV RNA after treatment with all plant extracts using concentrations of 1:2 CC
50
, 1:4 CC
50
and 1:8 CC
50
. Delta cycle threshold (Ct) values decreased significantly comparing Ct values of 1:2 CC
50
and 1:8 CC
50
dilutions (
P
< 0.05).
Conclusions
Many extracts of plants acted against IBV prior to and during infection, but the most effective were those of
M. piperita
,
T. vulgaris
and
D. canadense
.
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