Salpratlactones A and B: A Pair of cis–trans Tautomeric Abietanes as Cav3.1 T-Type Calcium Channel Agonists from Salvia prattii

Salpratlactones A ( 1 ) and B ( 2 ), a pair of abietane cis – trans tautomers from Salvia prattii, were identified as the first naturally occurring agonists of T-type calcium channel (TTCC). Structurally, 1 and 2 were featured by unique 6/5 carbocyclic rings bearing a γ-lactone ring through an exocyclic double bond. Moreover, both compounds and their mixture at 10 μM potently and equally increased Ca v 3.1 TTCC peak currents, and 1 had an EC 50 value of 12.48 μM.