Polyphenol-rich extract from Pinus sylvestris L. bark--chemical and antitumor studies

Pinus sylvestris L. is a very important timber tree in Romania, the bark being the main waste from the wood processing. The aim of this study was to investigate the chemical composition and antitumor effects against HeLa cells of a polyphenol-rich extract from Pinus sylvestris L. bark. The polyphenolic content and profile were analyzed by means of spectrophotometry and RP-HPLC-UV/ESI-MS in the negative ion mode. The antitumor activity was investigated using two in vitro assays: MTT and flow cytometric apoptosis assays. Pine bark extract contained a high total phenolic content (48.16 +/- 0.29%). RP-HPLC-UV/ESI-MS analysis allowed the identification of taxifolin, a taxifolin-hexoside and several procyanidins (two monomers, three dimers and three trimers). At 200 microg/mL, pine bark extract exhibited a high cytotoxicity against HeLa cells (82.10 +/- 1.95%). Flow cytometry revealed the ability of pine bark extract to induce apoptosis: 71.97 +/- 0.96% apoptotic cells were determined in HeLa cells after a 48 h incubation with pine bark extract (200 microg/mL). The ability of pine bark extract to reduce viability and induce apoptosis in HeLa cells suggests the presence of compounds with antitumor properties and encourages further studies for their isolation and characterization.