EFFECT OF THE EXTRACTION ETHANOL AND MACERATION TIME ON

Effect of the extraction ethanol and maceration time on phenolics of Finnish propolis Anneli Salonen, Anu Lavola and Riitta Julkunen-Tiitto, Natural Product Research Laboratories, University of Eastern Finland

 

Background

 

• Propolis, the bee glue collected by honeybees, contains a large variety of phenolic compounds and thus is used in apitherapy and traditional medicine • Different concentrations of ethanol and maceration times are suggested for the preparation of ethanolic extract of propolis (EEP) (1,2) • The purpose of this study was to determine the ethanol concentration for the largest yield of phenolic compounds in the propolis collected in Finland • In order to conclude the optimal maceration time for EEP the amount of the phenolic compounds was followed over the maceration time of 12 months

Materials and methods

B

C

© SML ry/ Tarja Ollikka

© SML ry/ Tarja Ollikka

A

© SML ry/ Tarja Ollikka

• The ethanol concentrations used were 20, 40, 60, 70, 80 and 96% • The amount of phenolic compounds in EEPs was analyzed after 0.5, 1, 2, 3, 4, 6, 9 and 12 months using HPLC-DAD (3) • The antioxidant capacity of the samples was determined using DPPH method (4) after 12 months

D

E

F

Fig. 1. Honeybees carry propolis pellets to the hive in their legs (A). Sample 1 was collected from the propolis trap (B) and sample 2 from the wooden frames of the hive (C). Raw propolis (D) was cleaned, frozen and grounded (E) into the powder. A 0.1 g amount of propolis was mixed with 10 ml of ethanol for EEPs (F).

Results Sample 1 Sample 1

Sample 2 Sample 2

Fig. 2. The highest amount of the phenolic compounds was obtained with 70 and 80% ethanol consentration

Fig. 3. The highest amount of phenolic compounds was obtained after maceration time of two months Sample 1

Sample 1

Sample 2

Fig. 4. Flavonoids, cinnamic acids and other phenolic compounds found in 70% EEP during the maceration time

Fig. 6. EEPs of 40-95% concentration had the same antioxidant capacity

References

Fig. 5. Changhes in the amounts of cinnamic acids during the maceration time

Conclusions • The largest yields of phenolic compounds for the EEP were obtained with 70 or 80% ethanol concentration • Highest total amount of phenolic compounds was obtained within two months • There are differences in the optimal maceration time for the solubility of individual phenolic compounds • EEPs of 40-95% ethanolic concentration had high antioxidant capacity • These results indicate that the optimal maceration time for Finnish propolis is no more than two months • With shorter maceration time the best-before date of the EEP products can be set longer

1. Silva Cunha I B, Tiveron Rodrigues M L, Meurer E D, Bankova V S, Marcucci M C, Eberlin M N, & Frankland Sawaya A C H 2006. Effect of the maceration time on chemical composition of extracts of Brazilian propolis. Journal of Apicultural Research. 45: 137-144. 2. Park Y K & Ikegaki M 1998. Preparation of water and ethanolic extracts of propolis and evaluation of the preparations. Biosci. Biotechnol. Biochem. 62: 2230-2232. 3. Salonen A, Saarnio S & Julkunen-Tiitto R 2012. Phenolic compounds of propolIs from the boreal coniferous zone. Journal of Apicultural Science. 56: 13-22. 4. Tabart J, Kevers C, Pincemail J, Defraigne J-O & Dommes J 2006. Antioxidant capacity of black currant varies with organ, season and cultivar. J. Agric. Food Chem. 54: 6271-6276.