Screening of poplar biomass for bio-active compounds: a simple method to assess antioxidant activity.

Poplar bud resinoids are a potential source of natural antioxidants. As poplar culture today involves many hybrids, a simple screening test to assess antioxidant properties was proposed. This method used the second derivative of the UV spectra at 233 nm of the iron induced peroxidienes resulting from linoleic acid peroxidation. Kinetic data showed a lag period followed by a quadratic increase in peroxidienes. These two phases were more clearly separated using the square root of the data. An acceptable linear fitting of the length of the lag phase with antioxidant concentration was observed. Calibrating the experimental test with BHA therefore allowed an antioxidant assessment as "BHA equivalent". First results clustered well with taxonomic data, with typically 0.5, 0.15 and 0.08 "BHA equivalent" for P. nigra, P. X euramericana and P. X interamericana, respectively.