Comparison of methods for isolating high quality DNA from sage (Salvia officinalis)

A number of protocols have been reported for efficient plant DNA isolation. However, many of these methods are often species dependent. Several protocols described for DNA isolation from medicinal herbs and aromatic plants fail to produce good quality DNA. These plants contain exceptionally high amounts of secondary metabolites which interfere with DNA isolation. To address this problem, CTAB-modified protocols were compared for efficient DNA extraction from sage (Salvia officinalis). These protocols are traditional CTAB-based DNA extraction and its modifications. The modifications either involved use of activated charcoal and PVP, column based purification step or copper (II) acetate solution. The highest genomic DNA yield with the best quality was obtained when employing activated charcoal and PVP in the CTAB extraction buffer. In the presence of these compounds, unwanted polysaccharides and polyphenols were removed and this method yielded an average amount of 411 mu g DNA/g of leaf materials with UV absorbance ratios A(260/280) and A(260/230) 1.86 and 1.95, respectively. DNA extracted by this method is also suitable for PCR amplification, indicating the absence of impurities.