Development of Sequence Characterized Amplified Region (SCAR) Marker for the Authentication of Bacopa monnieri (L.) Wettst

Aims: To develop Sequence Characterized Amplified Region (SCAR) marker for identification of Bacopa monnieri (L.) Wettst.
Study design: Molecular biology tools for authentic identification of Bacopa monnieri.
Methodology: RAPD-based SCAR marker was developed to identify Bacopa monnieri from its adulterant candidates namely Centella asiatica, Eclipta alba and Malva rotundifolia. 50 random primers were used for initial screening of different accessions of Bacopa monnieri, Eclipta alba and Malva rotundifolia. A putative 589 bp marker specific to Bacopa monnieri was identified using RAPD technique. This RAPD-amplicon was then sequenced and cloned. Based on the information of cloned sequences a pair of SCAR primers was designed. SCAR primers were then used for authentication of DNA samples of Bacopa monnieri and its adulterants. Market samples of Bacopa monnieri and Centella asiatica collected under the name of Brahmi was put to test with these primers.
Results: Out of 50 random primers, only 14 primers were able to amplify the above plants. A 589 bp polymorphic band obtained with OPAA-3 primer which was specific to Bacopa monnieri accessions and not found in other adulterant candidates was selected. This band was eluted, cloned and further sequenced. A pair of SCAR primers (Bac F & Bac R) between 406 bp of 589 bp sequence of RAPD amplicon was designed. A single, bright, distinct band was obtained in Bacopa monnieri and not in the adulterants. Further validation was also done in the market samples.
Conclusion: In essence, the study was to develop a RAPD-based SCAR marker for authentication of Bacopa monnieri. The SCAR marker was found to be useful for preventing the adulteration of other plants in Brahmi and also for screening of crude drug samples intended for export and domestic uses.