Abstract

Rosemary plant is in high demand due to its application in traditional health care, food flavoring, fragrance and pharmaceutical industries. It contains high level of secondary metabolites which are responsible for its beneficial activities. Application of molecular techniques would facilitate the production of these substances and screening of accessions. The isolation of polymerase chain reaction (PCR) amplifiable genomic DNA is a pre-requisite for taking advantage of these technologies. Even though several DNA isolation protocols for plants with high level of secondary metabolites were developed, they may not permit optimal DNA extraction due to chemotypic variation within species. Extracting DNA from different rosemary accessions is a challenging task due to its high level of secondary metabolites. Therefore, this research is conducted with the aim of optimizing a reliable and rapid method suitable for extracting DNA from rosemary plants. The optimized protocol avoids the use of repeated toxic phenols, liquid nitrogen and large polypropylene tube. It is appropriate for both fresh and dry leaf samples. The quality of the obtained DNA was excellent as evident by A₂₆₀/A₂₈₀ ratio ranging from 1.7 to 1.89 and the concentration ranged from 195.8 to 2184 ng/µl. The success of this protocol indicated its applicability for other plants with high secondary metabolite contents.

Key words: DNA isolation, secondary metabolites, rosemary, gel electrophoresis, polymerase chain reaction (PCR) amplification.