Comparison of rDNA ITS sequences and tanshinones between Salvia miltiorrhiza populations and Salvia species

Danshen is one of the well-known herbs classified as "blood- invigorating" in traditional Chinese herbal medicine. Although Salvia miltiorrhiza is listed as the only botanical source of Danshen in the Chinese Pharmacopoeia, more than 20 other Salvia species are also used as Danshen in China while about 10 Salvia species are employed as non-Danshen. In order to identify S. miltiorrhiza and related Salvia species, and evaluate their quality, the rDNA ITS regions of ten Salvia species and twelve S. miltiorrhiza populations were sequenced and compared, and tanshinones (including cryptotanshinone, tanshinone I and tanshinone IIA) were quantitatively determined using the HPLC method. The nucleotide sequences of Salvia samples showed obvious diversity, and each Salvia species and S. miltiorrhiza population were found to have a unique sequence in the ITS region, so that they could be distinguished at the DNA level. Cluster analysis divided the Salvia species into two main groups. Salvia miltiorrhiza and six other Danshen species had a closer phylogenetic relationship and were differentiated from the non-Danshen species, results which corresponded with their medicinal requirements. The HPLC data showed that tanshinones were present mainly in the roots of S. miltiorrhiza and eight other Salvia species, including six Danshen species, and the contents were significantly different in each of them. However tanshinones were not detected in the non-Danshen-S. deserta, and this chemical variation can distinguish Danshen and non-Danshen species from each other. Although no direct cluster analysis correlation between chemical and DNA data appeared, both types of analysis are important for the quality evaluation of S. miltiorrhiza and related Salvia species.