Bioactivity screening of Pinus brutia bark extracts: superoxide dismutase-like and nitric oxide scavenging effects

In the Eastern Mediterranean region the wood of Pinus brutia Ten. is used as building material, the bark being the main waste of the wood production processes. A study was designed to explore possible medicinal applications for the bark waste. This paper reports on the superoxide dismutase-like and NO scavenging effects of bark extracts.

Bark extracts (a raw hydromethanolic extract and its fractions) were initially screened regarding their ability to scavenge DPPH radical. The superoxide dismutase-like and NO scavenging effects were further evaluated. Catechin and quercetin were the positive controls in all antioxidant assays.

According to the EC50 values, all extracts (11.8 +/- 0.1 - 21.10 +/- 0.05 microg/ml) efficiently scavenged DPPH radical in comparison to quercetin (3.13 +/- 0.05 microg/ml) and catechin (6.36 +/- 0.05 microg/ml). The raw extract, diethyl ether and ethyl acetate fractions (449.46 +/- 1.75, 115.43 +/- 0.25 and 278.3 +/- 2.3 microg/ml, respectively) exhibited higher superoxide dismutase-like effects in comparison to catechin (> 645.1 microg/ml). In NO scavenging assay, the raw extract, ethyl acetate and aqueous fractions (160.63 +/- 0.85, 162.96 +/- 0.52 and 160.23 +/- 2.35 microg/ml, respectively) showed a scavenging ability similar to that of quercetin (156.76 +/- 5.05 microg/ml) and higher than the one developed by catechin (242.66 +/- 7.65 microg/ml).

As superoxide anion and NO are important mediators in inflammation, our results support a possible use of Pinus brutia bark waste to develop nutraceuticals with efficiency in disorders involving oxidative and inflammatory stress.