Triterpenoids with Rare Carbon Skeletons from Salvia hydrangea: Antiprotozoal Activity and Absolute Configurations M. Moridi Farimani,* ,† M. Babak Bahadori, † Salman Taheri, ‡ Samad N. Ebrahimi, †,‡ Stefanie Zimmermann, ‡,§ Reto Brun, § Gholamreza Amin, ∥ and Matthias Hamburger ‡ † Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, G. C., Evin, Tehran, Iran ‡ Chemistry and Chemical Engineering Research Center of Iran, Tehran, Iran ‡ Division of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland § Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4002 Basel, Switzerland ∥ Department of Pharmacognosy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran * S Supporting Information ABSTRACT: Salvadione C (1) and perovskone B (2), two new triterpenoids with rare carbon skeletons, were isolated from an antiplasmodial n-hexane extract of Salvia hydrangea. The absolute configuration was determined by comparison of experimental and calculated electronic circular dichroism (ECD) spectra. In vitro activity against Plasmodium falciparum K1 strain, Trypanosoma brucei rhodesiense STIB 900 strain, and cytotoxicity in rat myoblast (L6) cells were determined. Compounds 1 and 2 showed in vitro antiplasmodial activity, with IC 50 values of 1.43 and 0.18 μM and selectivity indices (SI) of 86.2 and 69.6, respectively. IC 50 values against T. brucei rhodesiense were found to be 4.33 and 15.92 μM, respectively. T he genus Salvia comprises over 1000 species, being the largest genus of the Lamiaceae family. Several Salvia species, such as S. officinalis, S. triloba, S. miltiorrhiza, S. hispanica, and S. sclarea, are cultivated as medicinal plants, spices, and sources of essential oils for the perfume industry. 1 From a phytochemical viewpoint, the genus is characterized by the widespread occurrence of diterpenoids and triterpenoids. Rare classes of terpenoids in Salvia include sesterterpenoids 2,3 and some di- and triterpenoids with highly unusual carbon skeletons. 4−7 In Iran, the genus Salvia consists of 58 annual and perennial species, 17 of which are endemic. 8 S. hydrangea DC. ex Benth. is a conspicuous aromatic plant that grows widely in Iran, Anatolia, and Transcaucasia. 8 Its common name in Persian is “Gol-e Arooneh”, and the aerial parts of the plant have been used in Iranian folk medicine as anti-inflammatory, antispas- modic, carminative, and sedative compounds. 9 Infusions prepared from flowers serve as an anthelmintic and antileishmanial, especially in the Pars province of Iran. 10 Abietane-type diterpenoids have been reported from the roots of the plant. A moderate in vitro antiplasmodial effect of the flower extracts was attributed to a high content in pentacyclic triterpenes, mainly oleanolic acid. 11 S. hydrangea is taxonomi- cally close to S. bucharica, 8 from which triterpenoids with novel carbon skeletons have been discovered. 6,7,12,13 This prompted us to investigate S. hydrangea. As part of an ongoing screening for new antiparasitic natural products, 14−17 an n-hexane extract of S. hydrangea was found active against P. falciparum and T. b. rhodesiense, with IC 50 values of 3.2 and 18 μg/mL, respectively. Herein, we report the isolation and structure elucidation of two active compounds, salvadione C (1) and perovskone B (2), including the determination of their absolute configuration by chiroptical methods. Received: June 29, 2011 Published: October 3, 2011 Article pubs.acs.org/jnp © 2011 American Chemical Society and American Society of Pharmacognosy 2200 dx.doi.org/10.1021/np200559c | J. Nat. Prod. 2011, 74, 2200−2205