ANTIBACTERIAL ACTIVITY OF MARRUBIUM GLOBOSUM 395 Copyright © 2006 John Wiley & Sons, Ltd. Phytother. Res. 21, 395–397 (2007) DOI: 10.1002/ptr Copyright © 2006 John Wiley & Sons, Ltd. PHYTOTHERAPY RESEARCH Phytother. Res. 21, 395–397 (2007) Published online 21 December 2006 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/ptr.2061 SHORT COMMUNICATION Antibacterial Activity of Flavonoids and Phenylpropanoids from Marrubium globosum ssp. libanoticum Daniela Rigano 1 *, Carmen Formisano 1 , Adriana Basile 2 , Alfredo Lavitola 3 , Felice Senatore 1 , Sergio Rosselli 4 and Maurizio Bruno 4 1 Department of Chemistry of Natural Products, University of Naples ‘Federico II’, Via D. Montesano, 49 – 80131 Naples, Italy 2 Department of Plant Biology, University of Naples ‘Federico II’, Via Foria 223 – 80139 Naples, Italy 3 Department of Cellular and Molecular Biology and Pathology, University of Naples ‘Federico II’, via S. Pansini – 80131 Naples, Italy 4 Department of Organic Chemistry, University of Palermo, Viale delle Scienze, Parco d’Orleans II – 90128 Palermo, Italy Marrubium globosum Montbr. et Auch. ex Benth. ssp. libanoticum Boiss. (Lamiaceae) is a medicinal plant used for the treatment of inflammatory diseases, asthma, coughs and other pulmonary and urinary problems. The goal of our study was to assess the biological activity of M. globosum testing the methanol extract of aerial parts for its antibacterial activity against bacteria known to cause respiratory, gastrointestinal, skin and urinary disorders; the extract showed antibacterial effects against all the strains of bacteria used. A purification of this active extract showed the presence, as main constituents, of verbascoside, isorhamnetin 3-O- β β β -D- rutinoside, quercetin 3-O- β β β -D-rutinoside, naringenin 7-O- β β β -D-glucoside, kaempferol 3-O- β β β -D-rutinoside, isorhamnetin 3-O- β β β -D-glucoside, quercetin 3-O- β β β -D-glucoside, apigenin 7-O-(3″-p-coumaryl)-glucoside, p- methoxy-cinnamic acid, kaempferol 3-O- β β β -D-glucoside and apigenin 7-O- β β β -D-glucoside. The pure compounds were tested for their antibacterial activity; quercetin 3-O- β β β -D-rutinoside, verbascoside and naringenin 7-O- β β β - D-glucoside showed the greatest activity. Copyright © 2006 John Wiley & Sons, Ltd. Keywords: Marrubium globosum ssp. libanoticum; Lamiaceae; flavonoid; phenylpropanoid; antibacterial activity. Received 4 May 2006 Revised 26 October 2006 Accepted 26 October 2006 * Correspondence to: Daniela Rigano, Department of Chemistry of Natural Products, University of Naples ‘Federico II’, Via D. Montesano, 49 – 80131 Naples, Italy. E-mail: drigano@unina.it INTRODUCTION Aqueous and hydroalcohol extracts of flowered aerial parts of different Marrubium sp. are reported in the literature to be used in European folk medicine for treating cough and as a choleretic in digestive and biliary complaints (Wichtl and Anton, 1999; Newall et al., 1996); moreover, they are used in traditional medicine for their neurosedative and antiinflammatory activities (Mascolo et al., 1987; Girre, 2000). Previous studies conducted on a hydroalcohol extract of Marrubium vulgare have demonstrated that it exerts a significant and non- specific antispasmodic effect on isolated smooth muscle (Schlemper et al., 1996). The same extract exhibited potent and dose-dependent antinociceptive action in several models of pain in mice (De Souza et al., 1998). Treatment with an aqueous extract of the aerial parts of M. vulgare significantly lowered the systolic blood pressure in spontaneously hypertensive rats (SHR), related to a vasodilatory effect exhibited by the extract ex vivo as well as in vitro (El Bardai et al., 2001). Aque- ous or hydroalcohol extracts of flowered aerial parts of M. globosum ssp. libanoticum, called ‘hashiashat el kelb’ in Northern Lebanon, are used in folk medicine. Decoctions or infusions of flowers and leaves are com- monly used as hypoglycaemics (diabetes), febrifuges (malaria), antispasmodics (colics), for urinary tract in- fections and have external applications against snake bites and as cicatrizants of wounds (Wichtl and Anton, 1999). Recently, our research group has thoroughly stud- ied the plant (Grassia et al., 2006; Rigano et al., 2006a, 2006b, 2006c) showing among other things that the acetone extract of this species exerts antiinflammatory effects in rat paw oedema induced by carrageenin (Rigano et al., 2006b). Some of the illnesses and complaints against which Marrubium is traditionally used are due to infectious noxes; antimicrobial properties of the plant were there- fore assumed. Thus, the aim of this study was to in- vestigate the methanol extract of M. globosum ssp. libanoticum and its constituents for their antimicrobial activities, in order to validate the ethnopharmacological uses of the plant. MATERIALS AND METHODS Collection of plant material. M. globosum aerial parts were collected from flowering plants in August 2002 on Col de Cèdres (Lebanon), at 2340 m above sea level. The identification was done by Professor N. A. Arnold, University of Saint Esprit, Lebanon, and confirmed by Professor T. Raus, Botanischer Garten, Berlin. A voucher specimen (NAP # 23) is deposited at the Herbarium Neapolitanum (NAP), Dipartimento