Essential oils of four Rwandese hepatoprotective herbs: Gas chromatography–mass spectrometry analysis and antioxidant activities Marie-Jeanne Mukazayire a,b,⇑ , Jean C. Tomani b , Caroline Stévigny a , Jean C. Chalchat c , Filomena Conforti d , Francesco Menichini d , Pierre Duez a,e a Université Libre de Bruxelles (ULB), Laboratory of Pharmacognosy, Bromatology and Human Nutrition, CP 205/9, B-1050 Brussels, Belgium b Institute of Research Science and Technology (IRST), Center of Research in Phytomedecine and Life Science, B.P. 227 Butare, Rwanda c Laboratory of Photochemistry Molecular and Macromolecular, Chemistry of Essential Oils, Blaise Pascal Clermont University, 63177 Aubière Cédex, France d Department of Pharmaceutical Sciences, University of Calabria, Italy e Université de Mons (UMONS), Service of Therapeutic Chemistry and Pharmacognosy, Bât. Mendeleiev, Av. Maistriau, 7000 Mons, Belgium article info Article history: Received 13 December 2010 Received in revised form 20 March 2011 Accepted 3 May 2011 Available online 8 May 2011 Keywords: Essential oils Chemical composition Antioxidant Ocimum lamiifolium Crassocephalum vitellinum Guizotia scabra Microglossa pyrifolia Lamiaceae Asteraceae abstract Following an ethnobotanical survey in Southern Rwanda for hepatoprotective remedies, four food and medicinal plants, Crassocephalum vitellinum, Guizotia scabra, Microglossa pyrifolia and Ocimum lamiifolium, were selected for pharmacological and chemical investigations aiming to validate their reported proper- ties. The chemical compositions of essential oils obtained from leaves were investigated by GC–MS; essential oils and methanolic extracts were evaluated for antioxidant activity by 1,1-diphenyl-2-pic- ryhydrazyl (DPPH) and linoleic acid peroxidation assays. C. vitellinum [limonene (34.8%), (E)-b-ocimene (21.8%), b-pinene (8.5%), a-pinene (6.6%), myrcene (6.3%)], G. scabra [germacrene-D (25.5%), limonene (9.7%), (E)-b-ocimene (6.6%)], M. pyrifolia [germacrene-D (58.3%)] and O. lamiifolium [sabinene (12.2%), alpha phellandrene (11.6%)] volatile oils scavenge DPPH (10%, 39%, 27%, and 11% quercetin equivalents) and inhibit linoleic acid peroxidation (13%, 23%, 20%, and 13% Trolox Ò equivalents). The four methanolic extracts were quite active on the lipid peroxidation model (93%, 93%, 70%, and 67% Trolox equivalents) with modest activity on DPPH (5%, 10%, 8%, and 11% quercetin equivalents). These properties most prob- ably participate in the four plants hepatoprotective activities reported in ethnopharmacological and/or pharmacological studies. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Reactive oxygen species (ROS), highly reactive and toxic mole- cules generated in cells under normal metabolic activities, are practically counter-balanced by a remarkable series of antioxidant defence lines. However, under the influence of external stresses, including tobacco smoke, pollutants, ionising and UV radiations, alcohol, synthetic pesticides and some solvents, ROS production in- creases, leading to an imbalance status known as ‘‘oxidative stress’’ (Halliwell, 1997). ROS can cause oxidative damage to biomolecules, proteins, lipids and nucleic acids, which are markedly linked to many diseases pathogenesis (Halliwell & Gutteridge, 1999). With ageing, scavenging mechanisms become less efficient and dietary supplementation of synthetic antioxidants would ideally be required. Antioxidants are also increasingly important in food processing and preservation, inhibiting the development of oxida- tive rancidity in fat-based foods, particularly meat and dairy prod- ucts, and fried foods. Given increasing concerns about the safety and potential adverse effects of synthetic chemicals used for food preservation and in diet (Namiki, 1990), many research groups have been interested in the functional role of natural additives, especially plant extracts, as potentially non-toxic antioxidants (Baratta et al., 1998; Pale, Kouda-Bonafos, Nacro, Vanhaelen, & Vanhaelen-Fastre, 2003; Tomaino et al., 2005). In this context of natural substances possibly used for both dietary supplementation and food preservation, aromatic plants and their essential oils are being actively evaluated for antioxidant activity (Bozin, Mimica- Dukic, Simin, & Anackov, 2006; Vagionas et al., 2007; Wei & Shibamoto, 2007). Essential oils, extracted by steam distillation from aromatic and medicinal plants, are well-known for spasmo- lytic, carminative, antiviral, anticarcinogenic or hepatoprotective properties (Baratta et al., 1998; Bozin et al., 2006; Politeo, Jukic, & Milos, 2007; Özbek et al., 2004) and find extensive use in the food and beverage industry for their bioactive efficacy as antibac- terials, bacteriostatics, fungicides and/or antioxidants (Boudid et al., 2006; Peschel et al., 2006). 0308-8146/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2011.05.016 ⇑ Corresponding author. Address: Laboratoire de Pharmacognosie, de Bromatol- ogie et de Nutrition humaine, Université Libre de Bruxelles (ULB), Campus de la Plaine – CP 205/9, Bd du Triomphe, B-1050 Bruxelles, Belgium. Tel.: +32 2 650 5283; fax: +32 2 650 5430. E-mail addresses: pduez@ulb.ac.be, mmukazay@ulb.ac.be (M.-J. Mukazayire). Food Chemistry 129 (2011) 753–760 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem