Antiradical activity and polyphenol content of ethanolic extracts of Propolis.

Propolis is a natural substance produced by honeybees from resinous products collected from plants. Its ethanolic extract is currently commercialised in Cameroon under the brand name Promax C. This study investigated the total polyphenols, tannins and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of Promax C (6 samples) compared to the freshly ethanol extracted propolis (15 samples). The results revealed that all Promax C samples tested showed evidence of radical scavenging properties with values ranging from 28 to 70 %. Although the ethanolic samples had lower phenol contents (8.6 – 17.0 g/100 g), their anti-oxidant activities (38.8 - 85.9 %) were systematically higher than those of Promax C. In addition the Promax C manufactured in 2006 systematically exhibited the highest scavenging activity (67.3%) and polyphenol contents (772.8 mg/L) compared to those manufactured in 2004 (mean scavenging activity 43.7 %; mean polyphenol contents, 227.8 mg/L). While there was a linear relationship between the radical scavenging activity and the polyphenols or tannin content in the Promax samples, this was not the case with the fresh ethanolic extract. The Cameroonians propolis exhibited higher scavenging activity which could justify their commercialisation and role in the management of some chronic diseases. However, the activity of Promax tends to decrease with aging, and this needs to be investigated.