DNA Barcoding of Philippine Herbal Medicinal Products

The Philippine government established the Traditional and Alternative Medicine Act in 1997 to promote traditionally used herbal products and to provide an effective yet affordable alternative to conventional medicines. However, government regulation of herbal medicinal products (HMPs) is not stringent, relying only on submitted quality data from the manufacturer. In this study we validated the taxonomic identity of 26 plant samples contained within 22 HMPs, each produced by different local manufacturers, through DNA barcoding of the nuclear internal transcribed spacer-2 (ITS2) region. We recovered 19 ITS2 barcodes from 26 samples. These were compared to sequences in GenBank using MEGABLAST, but ambiguous results (similar max scores for different species) were phylogenetically analyzed. Twelve of the 19 samples matched the indicated species on the product label, three were equivocal in specific identity but were placed in the expected genus, and four other samples from three manufacturers contained contamination and/or substitution. GenBank's reference database was at times problematic because some sequences were lacking or were misidentified, but the database was still useful. Overall, ITS2 barcoding was successful in authenticating the HMPs, and it is recommended during the premarket evaluation process so as to obtain a certificate of registration from the government. The government should also develop a comprehensive database of barcodes for Philippine plants, and should prioritize the development of the traditional pharmacopeia because many locally produced HMPs are not indigenous.