Katsumichi Matsushige

Cytotoxic, hepatoprotective and free radical scavenging effects of propolis from Brazil, Peru, the Netherlands and China.

Propolis is a resinous hive product collected by honeybees from various plant sources. The composition of the propolis depends upon the time, vegetation and the area of collection. Thus, quality evaluation of the propolis is important, before use in food and beverages. For this propose three different biological activities were carried out, i.e. 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, cytotoxicity and hepatoprotective activity, of MeOH and water extracts of nine different propolis from Brazil, Peru, the Netherlands and China. The results showed that water extracts of six Brazilian and a Chinese propolis possessed stronger DPPH free radical scavenging activity than the corresponding MeOH extract, whereas in the case of Netherlands and Peruvian propolis MeOH extract exhibited stronger DPPH free radical scavenging activity. The MeOH extracts of all propolis possessed stronger cytotoxicity than the corresponding water extract towards murine colon 26-L5 carcinoma and human HT-1080 fibrosarcoma cells. The result of hepatoprotective activity of Brazilian propolis on D-galactosamine (D-GalN)/tumor necrosis factor-alpha (TNF-alpha)-induced cell death in primary cultured mouse hepatocytes were found in accordance with the grade set up by beekeepers in Brazil.

Antiproliferative activity of the Netherlands propolis and its active principles in cancer cell lines

The MeOH extract of the Netherlands propolis showed promising antiproliferative activity toward highly liver-metastatic murine colon 26-L5 carcinoma with an EC(50) value of 3.5 microg/ml. Further, antiproliferative activity-guided purification of the MeOH extract led us to isolate four flavonoids (1-4), seven cinnamic acid derivatives (5-11) and two new glycerol derivatives (12, 13), whose structures were elucidated on the basis of spectral analysis. The isolated compounds were tested for their antiproliferative activity against murine colon 26-L5, murine B16-BL6 melanoma, human HT-1080 fibrosarcoma and human lung A549 adenocarcinoma cell lines. The benzyl (9), phenethyl (10) and cinnamyl caffeates (11) possessed potent antiproliferative activities with EC(50) values of 0.288, 1.76 and 0.114 microM, respectively, toward colon 26-L5 carcinoma. These caffeates were considered to be active constituents of the Netherlands propolis in their antiproliferative activity. The antioxidative activity of these caffeates may play an important role in their antiproliferative activities.