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Chemical Investigation of Different Extracts and Essential Oil from the Tubers of (Tunisian) Cyperus Rotundus

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Chemical Investigation of Different Extracts and Essential Oil from the Tubers of (Tunisian) Cyperus Rotundus Annals of Microbiology, 57 (4) 657-664 (2007) Chemical investigation of different extracts and essential oil from the tubers of (Tunisian) Cyperus rotundus. Correlation with their antiradical and antimutagenic properties Soumaya KILANI1, Ines BOUHLEL1, Ribai BEN AMMAR2, Mohamed BEN SGHAIR1, Ines SKANDRANI1, Jihed BOUBAKER1, Amor MAHMOUD1, Marie-Geneviève DIJOUX-FRANCA3, Kamel GHEDIRA1, Leila CHEKIR-GHEDIRA1,2* 1Unité de Pharmacognosie/Biologie Moléculaire 99/UR07-03, Faculté de Pharmacie de Monastir, Tunisie; 2Laboratoire de Biologie Cellulaire et Moléculaire, Faculté de Médecine Dentaire de Monastir, Rue Avicenne 5019 Monastir, Tunisie; 3Laboratoire de pharma- cognosie Botanique et Phytothérapie, Faculté de Pharmacie, Université Claude Bernard Lyon 1, France Received 26 June 2007 / Accepted 26 September 2007 Abstract - The mutagenic potential of aqueous, Total Oligomers Flavonoids (TOF), ethyl acetate, and methanol extracts as well as essential oil (EO) obtained from tubers of Cyperus rotundus L. was assessed by “Ames assay”, using Salmonella tester strains TA98 and TA100, and “SOS chromotest” using Escherichia coli PQ37 strain with and without an exogenous metabolic activation system (S9). None of the different extracts showed a mutagenic effect. Likewise, the antimutagenicity of the same extracts was tested using the “Ames test” and the “SOS chromotest”. Our results showed that C. rotundus extracts have antimutagenic effects with Salmonella typhimurium TA98 and TA100 strains towards the mutagen Aflatoxin B1 (AFB1), as well as with E. coli PQ37 strain against AFB1 and nifuroxazide mutagens. A free radical scavenging test was used in order to explore the antioxidant capacity of the extracts obtained from the tubers of C. rotundus. TOF, ethyl acetate and methanol extracts showed an important free radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. These extracts showed IC50 values of respectively 5, 20 and 65 µg/ml. The beneficial effects of TOF, ethyl acetate, methanol and essential oil extracts of C. rotundus have been assessed by antioxidant and antimutagenic activities. Key words: Cyperus rotundus tubers, essential oil, extracts, mutagenicity, antimutagenicity, free radical scavenging activity. EINTRODUCTION ageing postulates that ageing is caused by excessive reac- tion of free radicals called reactive oxygen species (ROS). Since ancient times, several diseases have been treated by Therefore, researchers have made numerous efforts to find administration of plant extracts based on traditional medi- antioxidants. In view of several drawbacks of synthetic cine. Investigation of traditionally used medicinal plants is compounds for the human organism, examination of thus valuable on two levels, firstly, as a source of potential preparations of plant origin for this purpose has received chemotherapeutic drugs, and secondly, as a measure of more attention. safety for the continued use of medicinal plants. Plants and Cyperus rotundus (Cyperaceae) is a traditional herbal micro-organisms provide the pharmaceutical industry with medicine used widely as analgesic, sedative, antispasmod- some of the most important sources of components for the ic and to relieve diarrhoea (Thebtaranonth et al., 1995; research of new medications. Zhu et al., 1997). This plant, which grows naturally in trop- In recent years there has been increasing interest in ical, subtropical and temperate regions, is widespread in antimutagenesis (Calomme et al., 1996) and antioxidant North-East, Centre and South of Tunisia (Cuénod, 1954). activity (Vaya et al., 2002) of plant origin compounds. Such The tuber part of C. rotundus is one of the oldest known compounds may be useful in preventing from cancer and medicinal plants used for the treatment of dysmenorrheal other mutation-related diseases that can be pursued by and menstrual irregularities (Bhattarai, 1993). Previous avoiding exposures to recognised mutagens-carcinogens, phytochemical studies showed that the major chemical by fortifying physiological defence mechanisms, or by components of this herb were essential oil, terpenoids, favouring the intake of protective factors (De Flora, 1998). mono and sesquiterpenes (Ohira et al., 1998; Sonwa et al., In fact according to Lee et al. (2003), free radical theory of 2001; Kilani et al., 2005a). In this study, we reported mutagenic, antimutagenic * Corresponding author. Phone: + 216 97316282; and an antioxydant properties of several extracts from C. Fax: + 216 73461150; E mail: [email protected] rotundus tubers. 658 S. Kilani et al. MATERIALS AND METHODS test strains were checked routinely for their histidine requirement, deep rough (rfa) character, UV sensitivity Chemicals. Dimethylsulfoxide (DMSO), glucose-6-phos- (uvr B mutation) and the presence of the R factor. They phate (G6P), nicotinamide adenine dinucleotide phosphate were stored at –80 °C. (NADP), O-nitrophenyl-β-D-galactopyranoside (ONPG), P- nitrophenyl phosphate (PNPP), the positive mutagens Preliminary phytochemical analysis. Plant materials Aflatoxin B1 (AFB1), nifuroxazide, 1,1-diphenyl-2-picrylhy- were screened for the presence of tannins, flavonoids, drazyl (DPPH) and α-tocopherol were purchased from coumarins and sterols by using the methods previously Sigma-Aldrich, USA. Histidine, biotine, agar, bactotrypton, described by Tona et al. (1998) and Kilani et al. (2005b). yeast extract and nutrient broth N° 2 were purchased from Two milligrams of each extract was separately dissolved in Difco, USA. Aroclor 1254 was purchased from Supelco, USA. 2 ml of the adequate solvent. The identification of major chemical groups was carried out by thin-layer chromatog- Plant material. Tuber parts of C. rotundus L., were har- raphy (TLC) on silica gel 60 F254 Merck (layer thickness vested in the region of Monastir in the Centre of Tunisia, in 0.25 mm) as follows: for flavonoids, TLC was developed in June 2003. Botanical identification was carried out by Prof. n-butanol/acetic acid/water 4:1:5 (top layer), spots were Mohamed Chaieb (Department of Botany, Faculty of visualised with 1% aluminium chloride solution in methanol Sciences, University of Sfax, Tunisia), according to the flora under UV (366 nm). Coumarins were detected under UV of Tunisia (Cuénod, 1954). A voucher specimen (CP-06.03) light (366 nm) thanks to their blue fluorescence which has been deposited in the Laboratory of Pharmacognosy, becomes intense after spraying 10% potassium hydroxide Faculty of Pharmacy of Monastir, Tunisia. solution in ethanol. Steroids were identified with Libermann-Burchard, as reagent using n-hexane/CH2Cl2 Preparation of plant extracts. The tuber parts of C. 1:9 as mobile phase. A range of colours are produced after rotundus, were dried at room temperature and reduced to heating sprayed plates for 10 min at 100 °C. The test for coarse powder. The powdered was extracted with boiling tannins was carried out with FeCl3. Each class of tannins water for 15 to 20 min. After filtration, the extracts were gave a specific coloration. The composition of the oil was lyophilised (aqueous extract). The residues were dissolved investigated by gas chromatography (GC) and GC/MS in water. In order to obtain an extract enriched with TOF, (Kilani et al. 2005a). the powder was macerated in water/acetone mixture (1:2 v/v), during 24 h with continuous stirring. The extract was Activation mixture. The S9 microsome fraction was pre- filtered and the acetone was evaporated under low pres- pared from rats treated with Aroclor 1254 (Maron and sure in order to obtain an aqueous phase. Tannins were Ames, 1983). The composition of the activation mixture for removed by precipitation with an excess of NaCl during 24 the SOS chromotest was the following per 10 ml of S9 mix: h at 5 °C, and the supernatant was recovered. This latter 0.2 ml of salt solution (1.65 M KCl and 0.4 M MgCl2·6H2O); was extracted with ethyl acetate, concentrated and precip- 0.05 ml of 1 M G6P; 0.15 ml of 0.1 M NADP; 2.5 ml of 0.4 itated with an excess of chloroform. The precipitate was M Tris buffer, pH 7.4; 6.1 ml of Luria broth medium; 1 ml separated the TOF extract was yielded. of S9 (Quillardet and Hofnung, 1985). Ethyl acetate and methanol extracts were obtained by The components of S9 mix for the Ames test was 1 ml soxhlet extraction (6 h). The two types of extract, with dif- of salt solution; 0.25 ml of 1 M G6P; 2 ml of 0.1 M NADP; ferent polarities were concentrated to dryness and the 25 ml of 0.2 M sodium phosphate buffer, pH 7.4; 7 ml of residue was kept at 4 °C. These two extracts were resus- S9 and 14.75 ml H2O. The S9 mix was prepared freshly for pended in DMSO. In the present study, four extracts were each assay (Maron and Ames, 1983). investigated. Protein concentration of rat liver S9 was determined The essential oil was extracted by steam distillation of using protein BioRad assay (Bradford, 1976). It was found the tubers part of C. rotundus, using the apparatus to be 12.3 mg/ml. described in the 9th edition of the French Pharmacopoeia cited by Bruneton (1999) and analysed by gas chromatog- SOS chromotest assay. The procedure of SOS chro- raphy-mass spectrometry (GC-MS). motest was performed according to Quillardet and Hofnung (1985). As a measure of anti-genotoxicity, the SOSIP Bacterial strains. Escherichia coli PQ37 and Salmonella (SOS-inducing potency) was calculated from the linear part typhimurium strains TA100 and TA98 were kindly provided of the induction factor dose-response curve. The induction by Prof. Felzen, UERJ, Brazil. The complete genotypes of factor (IF), was calculated as the ratio: Escherichia coli PQ37, as well as strain construction details R / R are described by Quillardet and Hofnung (1985). Frozen C 0 β β permanent copies of the tester strain were prepared and where RC is equal to -galactosidase ( -gal) activity / alca- stored at –80 °C. line phosphatase (AP) activity determined for the test com- β Histidine-dependent strains, S. typhimurium TA100 and pound at concentration c, and R0 is equal to -gal activity / TA98 were maintained as described by Maron and Ames AP activity in the absence of test compound.
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