Determination and biosynthesis of multiple salvianolic acids in hairy roots of Salvia miltiorrhiza

Danshen (Salvia miltiorrhiza Bunge) hairy roots were obtained by infecting Danshen leaves with Agrobacterium rhizogenes 9402.  Besides rosmarinic acid (RA) and salvianolic acid B (SAB), the hairy root could also produce salvianolic acid K (SAK), salvianolic acid L, ethyl salvianolic acid B (ESAB), methyl salvianolic acid B (MSAB), and a compound with a molecular weight of 538 (compound 538) identified by using LC-MS.  Effects of methyl jasmonate (MeJA) and yeast elicitor (YE) on the accumulation of these compounds had been investigated.  MeJA increased the accumulation of SAB, RA, SAK, and compound 538 from 4.21%, 2.48%, 0.29%, and 0.01% of dry weight to 7.11%, 3.38%, 0.68%, and 0.04%, respectively.  YE stimulated the biosynthesis of RA from 2.83% to 5.71%, but depressed the synthesis of SAB, SAK and compound 538.  It was indicated in all the results that these Danshen hairy roots could be used as alternative resources to produce salvianolic acids.  Analysis of the content variation of these compounds after elicitation suggested that SAK and compound 538 might be the intermediates in the biosynthesis from RA to SAB in Danshen hairy roots.