Iridoids from Scutellaria albida ssp. albida Chrysoula Gousiadou a , Anastasia Karioti a , Jo ¨ rg Heilmann b , Helen Skaltsa a, * a Department of Pharmacognosy and Chemistry of Natural Products, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, 15771 Athens, Greece b Institute of Pharmacy, Department of Pharmaceutical Biology, University of Regensburg, Universita ¨ tsstrasse 31, D-93053 Regensburg, Germany Received 20 February 2007; received in revised form 16 April 2007 Available online 29 May 2007 Abstract Three iridoid glycosides, 6 0 -O-E-p-coumaroylgardoside (1), 6 0 -O-p-E-coumaroyl-8-epi-loganic acid (2) and scutelloside (3) were iso- lated from the aerial parts of Scutellaria albida subsp. albida, in addition to an anomeric mixture in equilibrium of one iridoid aglycone (4, 4a), nine iridoid glycosides (5–13), four known phenylethanoid glycosides (14–17), and six known phenolic derivatives (18–23). Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Scutellaria albida subsp. albida; Lamiaceae; Iridoids; Phenylethanoid glycosides; Phenolic derivatives 1. Introduction Scutellaria albida L. ssp. albida (Lamiaceae) is an herba- ceous perennial plant, often somewhat woody at the base. The plant has a general distribution from N. Italy to the Balkan peninsula and Crimea (Bothmer, 1985). Several species of the genus Scutellaria present antispasmodic, dia- phoretic and febrifuge properties and are used in folk med- icine (Duke, 1986). In previous research into S. albida L. ssp. albida, apige- nin, hispidulin and luteolin glycosides have been isolated (Skaltsa et al., 1996). In further study, the essential oil of the plant has been investigated (Skaltsa et al., 2000). In this paper, we report on the isolation and structural elucidation of three new iridoid glycosides, 6 0 -O-E-p-coumaroylgardo- side (1), 6 0 -O-p-E-coumaroyl-8-epi-loganic acid (2) and scu- telloside (3) in addition to 10 known iridoid aglycones and glycosides (4–13), four known phenylethanoid glycosides (14–17), and six simple phenolic derivatives (18–23). 2. Results and discussion The methanolic extract of the aerial parts of S. albida ssp. albida after being successively chromatographed on sil- ica gel columns and RP-HPLC, yielded along with the three new iridoid glycosides, an anomeric mixture in equi- librium of one iridoid aglycone (4, 4a), namely dihydroca- talpogenine (C-1) a-epimer (4)/b-epimer (4a)(Gao et al., 1997), nine known iridoid glycosides, catalpol (5)(C ¸ alis et al., 1993a; Chaudhuri and Sticher, 1981), albidoside (6) (C ¸ alis et al., 1993a), picroside III (7)(Weinges and Ku ¨ns- tler, 1977), dihydrocatalpol (8)(Huang et al., 2006), 10-des- cinnamoylglobularinin (9) (Chaudhuri et al., 1979), globularin (10) (Foderaro and Stermitz, 1992), (C ¸ alis et al., 2002), gardoside (11)(Albach et al., 2004), 8-epi- loganic acid (12)(Damtoft et al., 1984), macfadyenoside (13)(Bianco et al., 1974), four known phenylethanoid gly- cosides, martynoside (14)(Warashina et al., 1992), isomar- tynoside (15)(C ¸ alis et al., 1984), deacyl-martynoside (16) (C ¸ alis et al., 1984, 1993b), acteoside (17)(Andary et al., 1982) and six known phenolic derivatives, E-p-coumaric acid (18)(Harborne, 1984), E-caffeic acid (19)(Harborne, 1984), E-ferulic acid (20) (Harborne, 1984), E-p-cou- maroylglucoside (21)(Harborne, 1984), vanilloloside (22) 0031-9422/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.phytochem.2007.04.014 * Corresponding author. Tel./fax: +30 2107274593. E-mail address: skaltsa@pharm.uoa.gr (H. Skaltsa). www.elsevier.com/locate/phytochem Phytochemistry 68 (2007) 1799–1804 PHYTOCHEMISTRY