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Influence of seasonality and production method on the antibacterial activity of propolis/Influencia da sazonalidade e metodo de producao na atividade antibacteriana da propolis.

Introduction

Propolis is a natural resinous mixture produced by Apis mellifera L. from leaf, buds and bark, representing a complex set of substances (55% resins and balsams; 30% waxes; 10% volatile oils; about 5% pollen) and mechanical impurities (SALATINO et al., 2011; KUROPATNICKI et al., 2013).

Flavonoids were the principal group of compounds isolated from propolis, but other substances, such as aromatic acids, phenolic compounds, organics acids, minerals, vitamins and amino acids, were also found (SEIDEL et al., 2008; KUROPATNICKI et al., 2013). However, the chemical composition and biological activities of propolis vary and depend on the diversity of plants and geographical locations from which bees collect it (SALATINO et al., 2011).

Propolis production is an inborn trait of honeybees. Several factors, such as seasonality, production method and others, are involved in this process, which must be taken into account when productivity increase is desired (BANKOVA et al., 1998; DAUGSCH et al., 2008; TEIXEIRA et al., 2008).

Propolis has a broad spectrum of biological properties including antifungal, anti-inflammatory, anti-tumoral and antibacterial activities (ARAUJO et al., 2012; MANNANI et al., 2012; KUROPATNICKI et al., 2013). Several authors have reported that the susceptibility of a range of Gram-positive bacteria to ethanol extracts of propolis may vary according to the site of the propolis collected (GONSALES et al., 2006; MULI et al., 2008).

Current study investigated the microbiological activity of propolis produced by different methods of collection (Intelligent Collector of Propolis, plastic screen and scraping) and in different seasons, on the standard Staphylococcos aureus and Escherichia coli.

Material and methods

Propolis samples were collected at Nucleus of Education, Sciences and Technology in Rational Beekeeping (NECTAR) in the apiary of Animal Production Department--College of Medicine Veterinary and Animal Sciences--Sao Paulo State University (UNESP) in Botucatu, Sao Paulo State, Brazil.

Africanized A. melifera were allocated in fifteen Langstroth beehives (five per collector), distributed randomly and managed only for the production of propolis. The collectors comprised plastic screen (PS), 'intelligent' collector of propolis (ICP) and scraping collector (SC).

The climatic data for spring were: temperature 19.5 [+ or -] 2.8[degrees]C; humidity 50.7 [+ or -] 8.4%; insolation 6.0 [+ or -] 3.6 hours; rainfall 3.1 [+ or -] 8.3 mm; wind speed 118.9 [+ or -] 59.4 km [h.sup.-1]; for summer: temperature 21.3 [+ or -] 2.3[degrees]C; humidity 55.7 [+ or -] 8.5%; insolation 5.8 [+ or -] 3.7 hours; rainfall 6.9 [+ or -] 13.1 mm; wind speed 91.4 [+ or -] 52.5 km [h.sup.-1]; for autumn: temperature 18.9 [+ or -] 2.9[degrees]C; humidity 56.1 [+ or -] 6.2%; insolation 7.5 [+ or -] 3.6 hours; rainfall 3.9 [+ or -] 8.1 mm; wind speed 73.5 [+ or -] 38.1 km [h.sup.-1]; for winter: temperature 17.9 [+ or -] 2.9[degrees]C; humidity 53.0 [+ or -] 8.4%; insolation 6.9 [+ or -] 3.3 hours; rainfall 1.3 [+ or -] 5.0 mm; wind speed 89.7 [+ or -] 47.1 km [h.sup.-1].

Extract was prepared by the mixing of the monthly propolis produced from the same technique of collection. The ethanol extract of propolis (EEP) was prepared in the ratio of 30% (30 g of propolis, completing the 100 mL volume, with ethanol 70%). After a week, extracts were filtered and EEP obtained (ORSI et al., 2000).

To determine dry weight (DW; mg [mL.sup.-1]) in each sample, 2 mL of EEP were weighed and kept at 105[degrees]C during two hours for the evaporation of the volatile phase. Contents were weighed again and DW was obtained by the difference between the initial and final weights.

For the evaluation of the biological activity EEP, two standard microorganisms (American Type Culture Collection), namely, Gram positive (S. aureus--ATCC 25923) and Gram negative (E. coli --ATCC 25922) bacteria were used. The microorganisms had been tested by the methodology of diffusion in agar using paper discs filter. Three antibiotics were used as control: ampicillin, cephalexin and penicillin. A disc containing only alcohol (propolis solvent) was also used as control.

Filter paper discs (8 mm in diameter) saturated with 15 [micro]L of each EEP (one extract to each month) were placed on Mueller Hinton agar plates, which were inoculated with test organisms (106 UFC [mL.sup.-1]), following standard protocol described by the National Committee of Clinical Laboratory Standards (NCCLS, 2005).

The antibacterial activity was determined by reading the formation of the inhibitory halo around the discs after 24 hours incubation, at 37[degrees]C. Each assay was performed in triplicate.

Results were compared by ANOVA, followed by Tukey's test to verify differences between averages, at statistical significance p < 0.05. The results are also evaluated by Correlation of Pearson to verify the existence of relations between the variables analyzed for each extract (ZAR, 1996).

Results

No correlations between climatic variables and propolis production were observed. Seasonality affected the antibacterial activity of EEP against S. aureus. It may be observed that in the winter the ICP and SC methods showed an inhibition halo significantly greater than that in the other seasons. Similarly, the collector also influenced the antibacterial activity against S. aureus, since ICP and SC showed an inhibition halo significantly greater when compared with that of PC (Table 1).

The season affected the antibacterial activity of EEP on E. coli. The propolis produced by ICP in the winter showed an inhibition halo which was significantly greater than that for spring and summer. In the case of SC, the inhibition halo was significantly greater in the winter than in spring, summer and autumn. Collector did not affect the antibacterial activity of EEP on E. coli (Table 2).

There was no statistical significance between the dry weight (DW) of EEP produced in the different seasons and that by collectors, for the two bacteria (Tables 1 and 2).

The antibiotics amoxicillin and cephalexin showed antibacterial activity on S. aureus and E. coli. Penicillin showed antibacterial activity on S. aureus. Ethanol 70% failed to influence the two bacteria (Tables 1 and 2).

Discussion

Several researchers have studied the antibacterial properties of propolis and evidenced its efficient activities against Gram positive and its limited activity against Gram negative bacteria (TOSI et al., 2007; PROBST et al., 2011). Current assay showed that EEP had a greater activity against Gram positive bacteria and less activity against Gram negative bacteria. Above differences might be due to the bacterial wall cell constitution. In fact, gram positive bacteria have a less complex wall cell and lower lipid contents (LOGUERCIO et al., 2005) and thus might have a higher susceptibility to the propolis's chemical constituents.

Other evidences also suggest that propolis composition may be altered as a function of bioactive complex compounds in vegetal sources. Analyzing the possible vegetal sources of the propolis produced in Botucatu, Sao Paulo State, Brazil, Bankova et al. (1999) observed that the propolis was usually derived from Baccharis dracunculifolia, popularly known as 'vassourinha', Araucaria angustifolia (Parana pine tree) and Eucalyptus citriodora, even though other secondary vegetal resinous sources may occur around the apiary.

Trusheva et al. (2011) reported that propolis produced in different Brazilian states showed activities against S. aureus and verified a positive co-relationship between the antibacterial activity and total flavonoid contents. Other researchers underscored a relationship between the flavonoid concentration and the propolis's antibacterial activity (BARBARIC et al., 2011; ISLA et al., 2012). However, Souza et al. (2010) researched flavonoid contents in the propolis produced in the same region as current research and failed to observe any difference due to seasonality and production method. They suggested that other substances could have caused the antibacterial activity observed, which may vary according to seasons.

In a study on Brazilian propolis, seasonality affected the antibacterial activity of the propolis produced in the northeastern and southeastern regions of Brazil (CASTRO et al., 2007). The authors suggested that propolis composition may alter as a function of bioactive complex compounds in vegetal sources and may vary over the year (EREMIA; DABIJA, 2007).

Activity mechanism of propolis compounds is complex and may be attributed to the synergy among some of its components. Takaisi-Kikuni and Schilder (1994) verified that the ethanol extract propolis interfered on the growth of Streptococcos agalactie by inhibiting protein synthesis. Koo et al. (2002) suggested that propolis and its components may interfere with the enzymatic activity of some bacteria such as Streptococcos mutans and Streptococcos sangui. A significant synergy may be verified between clinical antibiotics and propolis from two geographical sources against Salmonella typhi (ORSI et al., 2006, 2012a and b).

S. aureus and E. coli were sensitive to the antibiotics amoxicillin, cephalexin and penicillin. Since the alcohol used as solvent for EEP preparation did not present antibacterial activity, the activity against S. aureus was due to compounds present in the propolis, as has been reported by other researchers (FERNANDES JR. et al., 2006; AYALA et al., 2008; MAIA-ARAUJO et al., 2011).

Conclusion

Propolis showed antibacterial activity against S. aureus and E. coli, influenced by seasonality and the collector method employed.

Doi: 10.4025/actascianimsci.v36i1.21436

Acknowledgements

The authors would like to thank the Sao Paulo Research Foundation--FAPESP (process n. 05/51661-0) for funding.

References

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Received on July 19, 2013.

Accepted on September 12, 2013.

Edison Antonio de Souza (1), Hemily Tiemi Inoue (1), Ary Fernandes Junior (2), Nabor Veiga (1) and Ricardo de Oliveira Orsi (1) *

(1) Nucleo de Ensino, Ciencia e Tecnologia em Apicultura Racional, Departamento de Producao Animal, Faculdade de Medicina Veterinaria e Zootecnia, Universidade Estadual Paulista "Julio de Mesquista Filho", Distrito de Rubiao Jr., s/n, 18618-000, Botucatu, Sao Paulo, Brazil. (2) Departamento de Microbiologia e Imunologia, Instituto de Biociencias, Universidade Estadual Paulista "Julio de Mesquista Filho", Botucatu, Sao Paulo, Brazil. * Author for correspondence. E-mail: orsi@fmvz.unesp.br
Table 1. Antibacterial activity of ethanolic extract of propolis
(EEP) and dry weight (DW in mg [mL.sup.-1]) produced by 'intelligent'
collector of propolis (ICP), scrape (SC) and plastic sreen (PS) in
function of the seasonality, Ethanol 70%, Amoxicillin (AM),
Cephalexin (CEF) and Penicillin (PEN) against Staphylococcos
aureus. The results represent the average and the respective
standard deviation.

                            SPRING

              Inhibition Halo        DW (mg)
               (mm)

ICP          8.7 [+ or -] 0.6aA    3.0 [+ or -] 0.2A
SC           8.3 [+ or -] 0.6aA    3.6 [+ or -] 0.7A
PC           9.0 [+ or -] 0.0aA    2.6 [+ or -] 0.2A
Ethanol      0.0 [+ or -] 0.0             --
AM          14.0 [+ or -] 0.0             --
CEF         24.2 [+ or -] 0.1             --
PEN         15.0 [+ or -] 0.0             --

                            SUMMER

             Inhibition Halo         DW (mg)
              (mm)

ICP          8.7 [+ or -] 0.6 aA    3.0 [+ or -] 0.5A
SC           8.3 [+ or -] 0.6 aA    2.8 [+ or -] 0.5A
PC           8.0 [+ or -] 1.7 aA    2.6 [+ or -] 0.3A
Ethanol      0.0 [+ or -] 0.0              --
AM          14.2 [+ or -] 0.0              --
CEF         24.1 [+ or -] 0.0              --
PEN         15.0 [+ or -] 0.1              --

                             AUTUMN

              Inhibition Halo         DW (mg)
                (mm)

ICP         10.8 [+ or -] 2.5 aA    3.5 [+ or -] 0.8A
SC          11.3 [+ or -] 3.0 aA    3.0 [+ or -] 0.3A
PC          11.2 [+ or -] 2.6 aA    3.0 [+ or -] 0.6A
Ethanol      0.0 [+ or -] 0.0              --
AM          13.8 [+ or -] 0.1              --
CEF         24.0 [+ or -] 0.0              --
PEN         14.8 [+ or -] 0.0              --

                            WINTER

             Inhibition Halo         DW (mg)
              (mm)

ICP         14.3 [+ or -] 0.6bB    3.1 [+ or -] 1.1A
SC          13.8 [+ or -] 0.8bB    3.1 [+ or -] 0.3A
PC          12.0 [+ or -] 0.5 aA   1.9 [+ or -] 0.6A
Ethanol      0.0 [+ or -] 0.0             --
AM          14.0 [+ or -] 0.0             --
CEF         23.7 [+ or -] 0.1             --
PEN         15.2 [+ or -] 0.0             --

Different small letters in the same row and different capital
letters in the same column indicate statistical difference
between the means (p < 0.05).

Table 2. Antibacterial activity of ethanol extract of propolis (EEP)
and dry weight (DW in mg [mL.sup.-1]) produced by 'intelligent'
collector of propolis (ICP), scrape (SC) and plastic screen (PS) as a
function of seasonality, Ethanol 70%, Amoxicillin (AM), Cephalexin
(CEF) and Penicillin (PEN) against Escherichia coli. Results
represent average and the respective standard deviation.

           SPRING

           Inhibition Halo         DW (mg)
           (mm)

ICP         6.0 [+ or -] 0.0 abA    3.0 [+ or -] 0.2A
SC          5.3 [+ or -] 1.1aA      3.6 [+ or -] 0.7A
PC          5.3 [+ or -] 0.6aA      2.6 [+ or -] 0.2A
Ethanol     0.0 [+ or -] 0.0               --
AM         20 [+ or -] 0.0                 --
CEF        15.0 [+ or -] 0.0               --
PEN         0.0 [+ or -] 0.0               --

           SUMMER

           Inhibition Halo       DW (mg)
           (mm)

ICP         4.7 [+ or -] 0.6aA    3.0 [+ or -] 0.5A
SC          4.3 [+ or -] 0.6aA    2.8 [+ or -] 0.5A
PC          5.7 [+ or -] 1.7aA    2.6 [+ or -] 0.3A
Ethanol     0.0 [+ or -] 0.0             --
AM         20.0 [+ or -] 0.0             --
CEF        15.0 [+ or -] 0.1             --
PEN         0.0 [+ or -] 0.0             --

           FALL

           Inhibition Halo          DW (mg)
           (mm)

ICP         6.5 [+ or -] 0.9bA     3.5 [+ or -] 0.8A
SC          6.3 [+ or -] 0.3abA    3.0 [+ or -] 0.3A
PC          7.0 [+ or -] 1.8aA     3.0 [+ or -] 0.6A
Ethanol     0.0 [+ or -] 0.0              --
AM         20.2 [+ or -] 0.1              --
CEF        14.8 [+ or -] 0.0              --
PEN         0.0 [+ or -] 0.0              --

           WINTER

           Inhibition Halo          DW (mg)
           (mm)

ICP         8.2 [+ or -] 0.8bcA    3.1 [+ or -] 1.1A
SC          7.8 [+ or -] 1.0bA     3.1 [+ or -] 0.3A
PC          8.0 [+ or -] 0.9aA     1.9 [+ or -] 0.6A
Ethanol     0.0 [+ or -] 0.0              --
AM         19.8 [+ or -] 0.0              --
CEF        15.2 [+ or -] 0.0              --
PEN         0.0 [+ or -] 0.0              --

Different small letters in the same row and different capital letters
in the same column indicate statistical difference between the means
(p < 0.05).
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Author:de Souza, Edison Antonio; Inoue, Hemily Tiemi; Fernandes, Ary, Jr.; Veiga, Nabor; Orsi, Ricardo de O
Publication:Acta Scientiarum. Animal Sciences (UEM)
Date:Jan 1, 2014
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