Received: 12 January, 2010. Accepted: 20 April, 2010. Original Research Paper Functional Plant Science and Biotechnology ©2011 Global Science Books Antimicrobial and Antiproliferative Activities of Extracts and Compounds Isolated from Varthemia (Varthemia iphionoides Bloiss) Maher M. Al-Dabbas * • Ruba Abu-Taleb • Khalid Al-Ismail Department of Nutrition and Food Technology, Faculty of Agriculture, University of Jordan, Amman 11942, Jordan Corresponding author: * m.aldabbas@ju.edu.jo ABSTRACT The present study was designed to evaluate the antimicrobial activity and antiproliferation activity against human leukemia (HL-60) cells in vitro for hexane, ethyl acetate, ethanol and aqueous extracts of aerial parts of Varthemia iphionoides. The ethyl acetate extract showed a pronounced antibacterial activity against four bacterial and three candidal species. Hexane and ethanol extracts showed a pronounced antiproliferation effect on human leukemia (HL-60) cells (P < 0.05), with a 89.0 and 62.3 inhibition percentage, respectively at 200 g/mL. Fractionation of ethyl acetate and ethanol extracts and further purification by columns chromatography afforded sesquiterpene, selina-4, 11(13)-dien-3-on-12-oic acid (1) from ethyl acetate extract and three 3-O-methylated flavones; 5,7,4'-trihydroxy-3,6-dimethoxy- flavone (2), 5,7,4'-trihydroxy-3,5'-dimethoxyflavone (3) and 5,4'-dihydroxy-3,7,5'-trimethoxy-flavone (4) from ethanol extract. Compound (1) showed a pronounced antibacterial activity against studied microorganisms except Listeria monocytogenes and showed almost no inhibitory effect on the proliferation of HL-60 cells. Compound (4) exhibited the highest anticandidal activity and great antiproliferative activity against leukemia (HL-60) cells with inhibition percentage of 66.7 at 200 g/mL. Compounds 2 and 3 inhibited completely the proliferation of human leukemia (HL-60) cells at 200 g/mL and showed low antimicrobial activities. _____________________________________________________________________________________________________________ Keywords: antibacterial, flavones, HL-60 cells, sesquiterpene Abbreviations: ATCC, American type culture collection; CDCl3, deuterated chloroform; CFU; colony-forming unit; FBS, fetal bovine serum; FT/IR, fourier transform infrared spectrometer; HL, human leukemia; IR; infrared, KBr, potassium bromide; MeOH, methanol; MTT, 3-(4,5-dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide; NMR, nuclear magnetic resonance; PSG, penicillin-streptomycin- glutamine; UV, ultraviolet INTRODUCTION Plants produce a high diversity of secondary metabolites for defense and survival in the ecosystem. Secondary meta- bolites have been shown to exhibit numerous biological ac- tivities that promote positive health effects, which justified research on traditional medicine focused on the characteri- zation and isolation of the biologically active compounds from these plants (Newman et al. 2003; Kilani et al. 2008). Furthermore, plant secondary metabolites and their deriva- tives may be used safely and effectively against drug-resis- tant microbial pathogens and they could play an important role in the treatment of many diseases (Newman et al. 2000, 2003; Butler 2004). Wilkins and Board (1989) reported that more than 1,340 plants are known to be potential sources of antimicro- bial compounds but few active compounds were isolated and identified (Saxena and Vyas 1986; Thomann and Baeurmann 1993; Elgayyar et al. 2001). Many diseases such as atherosclerosis, Parkinson, Alz- heimer and cancer are mainly linked to oxidative stress due to free radicals formation in the body (Addis and Warner 1991; Halliwell 1994; Rice-Evans et al. 1997; Lu and Foo 2000; Emerit et al. 2004). Phenolic antioxidants, which are widely distributed in the plant kingdom and present in con- siderable amounts in fruits, vegetables, spices, medicinal herbs and beverages reported to have protective effect against damages in organs caused by free radicals and to have beneficial health effect against many human diseases such as diabetes, cancers, and coronary heart diseases (Middleton and Kandaswami 1993; Broadhurst et al. 2000). These protective effects have been mostly ascribed to their scavenging, metal chelating and antioxidant activities (Kameoka et al. 1999; Al-Dabbas et al. 2006). Thus, pheno- lic compounds in plants may be linked to the lower inci- dence and lower mortality rates of cancer (Rejiya et al. 2009). Varthemia (Varthemia iphionoides) is a perennial, bushy plant, 20-50 cm long, with a woody base and many basal, unbranched stems, hairy to sticky, aromatic. Leaves oblong, simple, entire, sub-sessile, densely hairy, and gray- ish. Heads 2-5 mm in diameter, florets yellow-orange sur- rounded by oblong involucres (Afifi et al. 1991; Al-Dabbas et al. 2005). The aqueous extracts of Varthemia iphionoides are commonly used in local Jordanian folk-medicine for treat- ment of gastrointestinal disorders (Afifi et al. 1991), the treatment of patients with diabetes mellitus (Afifi et al. 1997), have been found to have an antispasmodic effect on the smooth muscles of rabbits (Afifi et al. 1990). Extracts possessed antioxidant (Al-Dabbas et al. 2006a) and anti- microbial activity (Afifi et al. 1991; Al-Dabbas et al. 2005). The aim of this study was to evaluate the antimicrobial and HL-60 cells antitumor activities of extracts and isolated compounds from V. iphionoides aerial parts. MATERIALS AND METHODS Chemicals Silica gel 60 (0.063-0.200 mm, Merck, Germany) was used in silica gel column chromatography; antimicrobial susceptibility test ®