Antimicrobial Activity of Rhaponticum Acaule and Scorzonera Undulata Growing Wild in Tunisia

African Journal of Microbiology Research Vol. 4(19) pp. 1954-1958, 4 October, 2010 Available online http://www.academicjournals.org/ajmr ISSN 1996-0808 ©2010 Academic Journals Full Length Research Paper Antimicrobial activity of Rhaponticum acaule and Scorzonera undulata growing wild in Tunisia Houda Ben Abdelkader1*, Karima Bel Haj Salah2, Kaouthar Liouane1, Olfa Boussaada3, Karima Gafsi1, Mohamed Ali Mahjoub1, Mahjoub Aouni2, Ahmed Nourreddine Hellal3 and Zine Mighri1 1Laboratory of Natural Substances, Chemistry and Organic Synthesis, Faculty of Science, 5000 Monastir, Tunisia (99/UR/12-26). 2Laboratory of Transmissible Diseases and Biologically Active Substances, Faculty of Pharmacy, 5000 Monastir, Tunisia. 3Laboratory of Conservation and Valorisation of Plant Resources, Faculty of Pharmacy, 5000 Monastir, Tunisia. Accepted 3 August, 2010 This study examined the in vitro antibacterial and antifungal activities of the extracts (butanolic, ethyl acetate, petroleum ether and the product H2) of 2 plants belonging to the Asteraceae family: Rhaponticum acaule L. and Scorzonera undulata L. Butanolic and ethyl acetate extracts of the Rhaponticum acaule plant showed a moderate antibacterial activity against 3 of the tested strains; Staphylococcus aureus, Escherichia coli and Enterococcus fecalis while Proteus mirabilis, Pseudomonas aeruginosa and Citrobacter freundeï were resistant to the extracts. The product H2 showed an antibacterial activity against S. aureus, C. freundeï and E. fecalis. From the results of the antifungal activity, we observed that butanolic and ethyl acetate extracts of R. acaule showed a strong inhibition against Trichophyton rubrum with inhibition percentage of 56.25 and 78.75%, respectively. Butanolic extract showed a moderate inhibition of Microsporum canis, Scopulariopsis brevicaulis and Aspergillus fumigatus while ethyl acetate extract showed low inhibition. The aerial part ethyl acetate extract of S. undulata seemed to be more active than the petroleum one. It showed an antibacterial activity against all bacteria strains tested except for E. coli. For antifungal activity, the petroleum ether and ethyl acetate extracts of the aerial part inhibited strongly all tested fungi. The roots extracts from S.undulata show weak antimicrobial activities compared with the aerial parts extracts of the same plant. Key words: Rhaponticum acaule L, Scorzonera undulata L, Asteraceae, antibacterial activity, antifungal activity, Tunisia. INTRODUCTION This present study is another contribution to the from March to May . It grows wild in rosette on the slopes valorization of Tunisian National Patrimony (Boussaada of hills, fields and in sandy pastures. It is a mono specific et al., 2008; Braham et al., 2001; Boukamcha et al., genus belonging to the Asteracea family. It is a North 2004; Bel haj salah et al., 2006; Oueslati et al., 2004; African endemic species distributed in the north and Hichri et al., 2003; Nacef et al., 2003; Hichri et al., 2005). central area of Tunisia (Pottier- Alapetite, 1981). R. Rhaponticum acaule also known as Lenzea acaulis L. or acaule is a fragrant and perennial herb with yellow flower, Centraurea chamaerhaponticum Ball., is one of the most large and pinnatisect leaves. The capitula are big with fleshy conspicuous aromatic plants of early spring flowering and hairy receptacles. Le Floc’h (1983) did not report about its possible use in popular medicine in Tunisia. However, many species of the genus Rhapanticum have long been used in *Corresponding author. E-mail: [email protected]. traditional medicine. Indeed, the root of Rhaponticum Abdelkader et al. 1955 uniflorum has been used against intoxication and for the in the area of Amira (North east Tunisia). A voucher specimen, treatment of fever. It has been demonstrated that this Rhap 1170 and SCR 1171 were respectively deposited in the species inhibits peroxydation of membrane lipids and Laboratory of Natural substances chemistry and organic synthesis, Faculty of sciences, Monastir, Tunisia. possesses antiatherotic activity (Zhang et al., 2002). The plant samples were air-dried for several weeks. Powdered Chemical composition and antimicrobial activity of plant tissues were extracted 3 times by maceration with methanol, volatile components from capitula and aerial parts of R. the resultant extract was concentrated under reduced pressure. acaule has been described in one study of Mighri et al. The methanol extract was extracted successively with equal volume (2008). From the 57 identified constituents, representing of 3 organic solvents of increasing polarity (petroleum ether, chloroform and ethyl acetate). Each fraction was taken to dryness 95.5 and 96.3% of two oils, respectively, methyl eugenol, under vacuum and stored at 4°C until tested. epi-13 manool, b-ionone, b-bisabolol, 1-octadecanol, phytol and farnesyl acetate were found to be the main components. Furthermore, the oils were tested against 6 Antifungal activity gram-positive and gram-negative bacteria and four The extracts were individually tested against 5 strains of fungi that phytopathogenic fungi. It was found that oils from both comprised two opportunist pathogenic yeasts (Candida albicans parts of R. acaule, and especially that of capitula, and Cryptococcus neoformans), two dermatophytes (Trichophyton exhibited interesting antibacterial activity, but no anti- rubrum, Microsporum canis) and one hyphamycet (Scopulariopsis fungal activity was observed (Boussaada et al ., 2008) . brevicaulis). The micro-organisms were obtained from the S. undulata is another perennial asteraceae species laboratory of the transmissible diseases and biologically active (D’amato, 2000). It is a diploid and a very polymorphic substances, Faculty of Pharmacy Monastir. Antifungal activity was assayed by the agar incorporation method plant; it grows in the pastures, hills and sandy clay (dilution in a solid medium) including a negative control, as alluvium (Pottier- Alapetite, 1981). described previously (Bel haj salah et al., 2006). Briefly, the test S. undulata is mainly used as food. In Tunisia, the roots was performed in sterile Petri dishes (33 mm) that contained are appreciated for their sweetness; they are either eaten Sabouraud Glucose Agar (SGA). Samples were mixed aseptically raw or cooked in water (Le Floc'h, 1983). They are also with SGA (100 ml) to give stocks with concentrations of 1000 µL/ml. Stocks were dissolved in 10% DMSO(Dimethyl sulfoxide), and this used to prepare a decoction for its benefits as depurative. solvent was used as the negative control. After cooling and The ashes of burned roots would be effective in the solidification, the medium was inoculated with a small amount (5 treatment of burns (Boukef, 1986). mm) of a 7 day old mycelium culture (for dermatophytes), a 3 day The chemical composition and antimicrobial activities of culture suspension adjusted to 105 conidies/ml (Aspergillus and volatile components from capitula and aerial parts of S. Scopulariopsis) or a 3 day culture suspended in sterile distilled water and adjusted to 105 spores/ml (yeasts). The Petri dishes were undulata have been described (Mighri et al., 2008). In then incubated for 7 days at 24°C for dermatophytes, 24 h at 37°C fact 36 constituents were identified in the oils and the for Candida and Aspergillus and 48 h at 37°C for Cryptococcus. 3 main components of them were methyl hexadecanoate replications were carried out for each concentration and for each (30.4%), methyl linolenate (23.9%) and heneicosane micro-organism. (12.2%). The S. undulata sub sp. deliciosa oil exhibited The antifungal activity of the extracts was evaluated using two an interesting antibacterial activity against gram-positive methods: (a) by calculating the percentage inhibition (%I) from the and gram-negative bacteria but no antifungal activity was diameters of the colonies in the control plate (dC) and the colonies in the treated plate (dE); %I= (dC-dE)/dC, according to the method detected. of Singh et al. (1993); (b) by determining the minimal inhibitory Other studies have been made on other species of the concentration (MIC), defined as the lowest concentration which family Asteraceae. In fact Mighri et al. (2001) reported inhibits the visible growth of fungi during the defined incubation that essential oils from Inula graveolens had an period for each species. antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Cardopatium amethystinum, Antibacterial activity another species of the Asteraceae family, showed an antibacterial activity against S. aureus, Escherichia coli The antibacterial activity of extracts was evaluated by paper disc and Salmonella typhimurium (Boukamcha et al., 2004). diffusion and dilution methods against 6 selected gram-positive and This study was focused on the antimicrobial activity of gram-negative species: S. aureus ATCC 25923, E. fecalis ATCC 29212, E. coli ATCC 25922, Pseudomonas aeruginosa ATCC the extracts from the two species and the secondary 27853, C. freundeï and Proteus mirabilis. metabolic compound isolated from R. acaule. Agar diffusion method MATERIALS AND METHODS The qualitative antibacterial assay of the extracts of R. acaule and Plant material and extraction S. undulata was carried out by the disc diffusion method (Marmonier, 1987). All the microorganisms mentioned above were R. acaule was gathered at the flowering stage in May 2005 in the incubated at 37°C for 24 h by inoculation into Mueller-Hinton (M-H) area of Chebba (North east Tunisia) and S. undulata

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