3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P49 EVALuATION OF ANTIOxIDANT AND
ANTIMICRObIAL ACTIVITIES OF NATuRAL
hONEyS
MIROSLAVA KAČánIOVá, MARTInA FIKSELOVá,
SOňA FELŠÖCIOVá, VLADIMíRA KňAZOVICKá,
KATARínA FATRCOVá-ŠRAMKOVá, JAnKA
nôŽKOVá and IVETA UBREŽIOVá
Faculty of Biotechnology and Food Sciences, Slovak University
of Agriculture, Tr. A.Hlinku 2, Nitra, 949 76 Slovakia,
miroslava.kacaniova@uniag.sk
Introduction
In general, the antioxidant capacity of honey appeared to
be a result of the compounds including phenolics, peptides,
organic acids, enzymes and other phytochemicals (Gheldof et
al., 2002). The phenolic compounds contribute significantly
to the antioxidant capacity in many studies. Reports on honey
as antifungal agent were comprehensively reviewed by Molan
(1992). The “inhibine number” is the degree of dilution to
which a honey retains its antibacterial activity, representing a
sequential dilution of honey in steps of 5 %, from 25 to 5 %.
Allen et al., (1991) found many honeys with low activity and
36 % of samples with activity near or below detectable levels.
In this study, antioxidant effects (by DPPH method) as well
as the antifungal effects of natural honeys on five species of
fungi collected, were tested.
Experimental
Honey was extracted from the hives of bees and kept at
4 °C away from direct light before use. Samples were derived
from different plant species of Acacia (2 samples), Brassica
(1 sample), Thyme (1 sample) and the rest of samples (5 samples)
were of floral origin. Samples originated from different
places of Slovakia and one sample came from Rodos
A n t i o x i d a n t A c t i v i t y
A method was adapted according to Sanches Moreno
et al. (1998) and Brand-Wiliams et al. (1995). Honey (10 g)
was dissolved in 100 ml of ethanol (90%), and 0.1 ml of
solution was taken to 3.9 ml of DPPH methanolic solution
(25 mg dm −3 ) and mixed. Absorbance at 515 nm was measured
at different time intervals. The blank reference cuvette
contained DPPH methanolic solution. Results were expressed
as % inhibition.
A n t i f u g a l A c t i v i t y
All samples were prepared aseptically and handled protected
from direct sunlight. Honey solutions were prepared in
three fractions: 50, 25 and 10 % (by mass per volume). Five
species of fungi were isolated from wheat samples collected
from different locations in Slovakia: Penicillium crustosum,
P. expansum, P. griseofulvum P. raistrickii and P. verrucosum
by the agar well diffusion method. All fungal isolates were
identified microscopically, and samples of each fungus were
deposited in the fungal collection bank. The strains of fungi
s680
were maintained on Czapek yeast extract agar (CYA, HiMedia).
All plates were incubated at 25 °C in the dark and inhibition
zones were measured after 3 days. The statistical processing
of the data obtained was implemented by means with
SAS software.
Results
In term of antioxidant activity of honeys the best results
were found at thyme honey from Rodos (11.84 %) and floral
honeys from different places of Lučenec (10.09 %, 10.19 %).
The lowest antiradical activity was determined at Acacia
honey (7.615 %). Kücük et al. (2007) studied three different
Turkish honeys and found high levels of polyphenolics and
high antioxidant activity in three antioxidant assays. Radical
scavenging assay was the highest at chestnut honey, then followed
heterofloral honey and the least at rododendron one.
Table I
Antioxidant activity [%] of honey samples
Honey/Place of origin Inhibition [%] ± SD
Acacia/nitra 8.53 ± 0.08
Brassica/nitra 9.89 ± 0.33
Floral/Smrečany 8.39 ± 0.11
Thyme/Rodos 11.84 ± 0.35
Floral/nitra 8.98 ± 0.24
Floral/Hlohovec 9.96 ± 0.40
Floral/Lučenec 10.19 ± 0.53
Acacia/Lučenec 7.62 ± 0.56
Floral/Lučenec 10.09 ± 0.34
All 9.50 ± 1.25
Al-Mamary et al. (2002) showed a linear positive relationship
with the extract concentration. The antioxidant activity
of diluted honey samples increased with increasing the
levels (50 μl, 100 μl, 200 μl) of honey samples. The total
antioxidant activities of diluted samples varied from −6.48 %
(prooxidant activity) to 65.44 % inhibition. In our case determined
antioxidant activity (Table I) was low, varied from
7.62 % (Acacia/Lučenec) to 11.84 % (Thyme/Rodos).
The results obtained characterize honey samples as
a product with a broad antimicrobial effect. The strongest
antifungal effect was shown by honey samples of 50 % concentration
against Penicillium raistricki strains. The least
antifungal effect was shown by honey samples of 10 % concentration
against to Penicillium expansum strains. no inhibitory
activity was detected with any of the seven species
with the pasture honey at any concentration up to the highest
tested 50 % (v/v). Maughrabi (2003) found that wild honey
was effective against Alternaria solani and Phytophthora
infestanns, also against Rhizoctonia solani and Fusarium
oxysporum, and to a less extent against Stemphylium solani
and Colletotrichum sp.