Turk J Pharm Sci 11(1), 101-106, 2014
Original article
Cytotoxic and Antibacterial Activities of Centaurea cadmea Boiss.
Kaveh Alizadeh ASTARİ1, Şura BAYKAN EREL1, Fadime AYDIN KÖSE2, £inel KÖKSAL3, Canan KARAALP1*
'Ege University, Faculty of Pharmacy, Department of Pharmaceutical Botany, 35100 Bornova, İzmir, TURKEY, 2Ege University, Faculty of Pharmacy, Department of Biochemistry, 35100 Bornova, İzmir, TURKEY, 3Ege University, Faculty of Science, Department of Biology, 35100
Bornova, İzmir, TURKEY
The cytotoxic activity of the extracts obtained from roots and the aerial parts of Centaurea cadmea Boiss.
(Asteraceae) were analyzed by cell proliferation assay using WST-1 reagent against three human cancer cell lines; HeLa, A549 and U20S and one non-cancer cell line; 293HEK. The chloroform extract of the aerial parts of the plant exhibited inhibitory activities against all cell lines (IC50: 14.24-43.10 μg/mL). The antibacterial activity of the extracts were tested against four gram negative (Escherichia coli ATCC 23999, Pseudomonas aeruginosa ATCC 27853, Salmonella typhimurium CCM 5445 and Klebsiella pneumoniae CCM 2318 and four gram positive (Staphylococcus aureus ATCC 6538/P, S. epidermidis ATCC 12228, Enterococcus faecalis ATCC 29212 and Bacillus cereus ATCC 7064) bacteria strains by broth dilution method. The chloroform extract of the aerial parts of the plant showed strong activity on E. faecalis (8 μg/
mL) and B. cereus (16 μg/mL).
Key words: Centaurea cadmea, Antibacterial activity, Cytotoxic activity.
Centaurea cadmea Boiss.’in Sitotoksik ve Antibakteriyal Aktiviteleri
Centaurea cadmea Boiss. (Asteraceae) kök ve topraküstü kısımlarından elde edilen ekstrelerin sitotoksik aktiviteleri, WST-1 reaktif kullanılarak üç insan kanser hücre hattı; HeLa, A549 ve U20S ve bir kanser olmayan hücre hattı; 293HEK üzerinde, hücre proliferasyon testi ile analiz edilmiştir. Topraküstü kısımların kloroform ekstresi tüm hücre hatlarında aktif bulunmuştur (IC50: 14.24-43.10 μg/mL). Ekstrelerin antibakteriyel aktivitesi dört gram negatif (Escherichia coli ATCC 23999, Pseudomonas aeruginosa ATCC 27853, Salmonella typhimurium CCM 5445 ve Klebsiella pneumoniae CCM 2318) ve dört gram pozitif (Staphylococcus aureus ATCC 6538/P, S. epidermidis ATCC 12228, Enterococcus faecalis ATCC 29212 ve Bacillus cereus ATCC 7064) bakteri üzerinde broth dilüsyon metodu ile test edilmiştir. Toprak üstü kısımların kloroform ekstresi, E. faecalis (8 μg/mL) ve B. cereus (16 μg/mL) üzerinde güçlü etki göstermiştir.
Anahtar kelimeler: Centaurea cadmea, Antibakteriyal aktivite, Sitotoksik aktivite.
*Correspondence: E-mail: canan.karaalp@ege.edu.tr, Tel: +90 232 3114084
101
INTRODUCTION
The genus Centaurea L. (Asteraceae) is represented by 199 taxons in Turkish fora and 61.1% of them are endemic (1-10). Various species of Centaurea are used as herbal remedies for their digestive, tonic, expectorant, antipyretic and antidiarrheal effects in traditional medicine (11). Pharmacological studies on some Centaurea species have reported anti-infammatory, antimicrobial, antipyretic, cytotoxic and immunological activities (12).
Centaurea cadmea Boiss. belonging to section Phalolepis (Cass.) DC. (Asteraceae) with purple forets is an endemic taxon for Anatolia, growing wild in N, W & SW of Turkey (1). Phytochemical studies revealed the presence of a sesquiterpene lactone, ivalin, together with eupatorin, 5-hydroxy- 3’,4’,6,7-tetramethoxyfavone, β-sitosterol and β-sitosterol-3-O-β-D-glucopyranoside from the CHCl3 and MeOH extracts of aerial parts of C.
cadmea (13). Essential oil analysis was also reported for the plant (14).
In vitro anti-infammatory, antioxidant, antiprotozoal and antifungal activities of the aerial parts of C. cadmea extracts have been previously studied (15, 16). Formerly, we have reported the cytotoxic and antibacterial efects of the roots of C. cadmea as a poster presentation (17). As a continuation of this study, aerial parts of the plant was planned to be searched for the same activities. So, the present study aims to investigate the cytotoxic and antibacterial activities of extracts obtained from roots and the aerial parts of C. cadmea. Cytotoxic activity was performed by cell proliferation assay using WST-1 reagent against three human cancer cell lines; U2OS (human osteocarcinoma), (adenocarcinoma), HeLa (human cervical carcinoma) and one non-cancer cell line;
293HEK (human embryonic kidney). T e antibacterial activity of the extracts were tested against four gram negative (Escherichia coli ATCC 23999, Pseudomonas aeruginosa ATCC 27853, Salmonella typhimurium CCM 5445 and Klebsiella pneumoniae CCM 2318) and four gram positive (Staphylococcus aureus ATCC 6538/P, S. epidermidis ATCC 12228, Enterococcus faecalis ATCC 29212 and Bacillus cereus ATCC 7064) bacteria strains by broth dilution method.
102
EXPERIMENTAL Plant material
Centaurea cadmea Boiss. was collected from Denizli, Evrantepe, 1512 m, in June 2004 (37o
41’ 18.6’’N; 29o 00’ 07’E) and identifed by Prof.
Dr. Ozcan Secmen, from Section of Botany, Department of Biology, Faculty of Science, Ege University, Izmir, Turkey and a voucher specimens were deposited in the Herbarium of Ege University, Faculty of Pharmacy, Izmir, Turkey (IZEF 5670).
Extraction and isolation
Dried and powdered roots (200 g) were extracted sequentially with chloroform and methanol and the aerial parts (600 g) were extracted also sequentially with n-hexane, chloroform and methanol (3x10 mL/g, for each), sonicated at room temperature for 24h, and then fltered. All solvents were analytical grade and obtained from Sigma Aldrich. The combined extracts were evaporated under reduced pressure to dryness at 40 0C.
Cytotoxic activity
The cytotoxic activity was analyzed by cell proliferation assay. U2OS (human osteocarcinoma), A549 (human lung adenocarcinoma), HeLa (human cervical carcinoma) and non-tumoral 293HEK (human embryonic kidney) cell lines were cultured in DMEM supplemented with L-glutamine (2 mmol/L), 100 U/mL penicillin, 100 μg/mL streptomycin and 10% fetal bovine serum. In order to perform cytotoxicity assay, 5.000 cells were seed in 96 well dishes and 24 hours later samples were added in various concentrations (500, 250, 100, 50 mg/mL). Forty-eight hours after drug exposure, cell viability was measured using WST-1 cell proliferation reagent (Roche) according to the manufacturer instructions (18).
All measurements were performed in triplets.
Antibacterial activity
Antibacterial acitivity tests of C. cadmea extracts were evaluated by using Minimum Inhibitory Concentration (MIC) measurements (19, 20). The MIC values were determined for eight bacterial strains [Escherichia coli (ATCC 23999), Pseudomonas aeruginosa (ATCC 27853), Salmonella thyphimurium (CCM 5445), Klebsiella pneumoniae (CCM 2318), Staphylococcus aureus (ATCC 6538- P), Staphylococcus epidermidis (ATCC 12228), Bacillus cereus (ATCC 7064), and Enterococcus faecalis (ATCC 29212)].
Turk J Pharm Sci 11(1), 101-106, 2014
Those strains were inoculated on Mueller- Hinton broth (Difco) and incubated at 37
± 0.1oC for 24 h. The inoculated strains were prepared from 24 h broth cultures and suspensions were adjusted to 0.5 McFarland standard turbidity and diluted 1:100 (v/v) in Mueller-Hinton broth. Dilution series of the compounds were prepared in test tubes and transferred to the broth in 96-well micro titer plates. Final concentrations were 256 to 0.25 µg/mL in the medium. The last well contained 100 mL of nutrient broth without compounds and 10 mL of the inoculums on each strip was used as a negative control and Gentamycin (Sigma Aldrich) was used as a positive control.
All plates were covered with a sterile plate sealer and incubated at 37oC for 24 h.
After incubation, MIC values were detected Those strains were inoculated on Mueller- by adding 50 mL of 0.5% triphenyl tetrazolium Hinton broth (Difco) and incubated at 37 ± chlooride (TTC, Fluca) aqueous solution and 0.1 C for 24 h. The inoculated strains were they were defned as the lowest conce tration
prepared from 24 h broth cultures and that inhibited visible growth as indicated by
suspensions were adjusted to 0.5 McFarland the TTC reduction. In the presence of bacterial gsrtoawndtha rbdy turrebdiudcityiona nrde adcitliuotnesd, T1 :T1C00 c (hva/nvg) e idn t hMe uceolleor- Ho fi nmtoincrobor rogthan. iDsmilsutfiroonm s ce roileosrleosfs t thoe recdo.m Tphoiusndpsro wviedreed pcrlepaarlrye ddeinfnteds t a tnudb eesa sainlyd retraadnasbfeler r eedndtopotihnetsb. r oAt lhl inof 96th-we eallssmayicsr ow tei trer ppelraftoersm. eFdi n ianl t rciopnl icceantetr.ations w e r e 2 5 6 t o 0 . 2 5
µg/mL in the medium. The last well contained RESU TS AND DISCUSSION
100 µL of nutrient broth without compounds aYndiel1d0s µLofof nt -hhee ixnaonceu, lumCHs Co nl3 eanchd stMripeOwHas euxstreadctas so batanineegda tfirvoem c ro nottrso al nadn tdheG aernit alm pyacrtisn o(fS Cig. mcadmAelad risic shh)owwn a isn Tuasbelde 1 a. sExatracptos stiht ievne wceornet rotels. tAedl l fpol ra tethse wi r e rpeo tceonvteiarledcywtoitthoxaics t earnidle apnltaibteacsteearliearl ancdtivinitcieusb.ated a t 3 7oC f o r 2 4 h .
TAhfet ecry itnoctouxbiact ioanc,tivMi tIyC rveasulultess awr e reprdeesetenct teedd inby Taabdledin2g. T5h0e nµ-hLexaonfe a0n.5d% chltorripohfoernmy l etxettracztos l oiufm t h ec ahel roiraild pear(tTs oT fC t,heF pl luacnat) e xahqiubeitoeuds inhibit ry activities against all cell lines. The solution and they were defined as the lowest
strongest activity was observed on HeLa (IC50: 14.24 µg/mL) by chloroform extract of aerial parts. But it is also active against non-cancerous cell line 293 HEK, which is used for detecting selectivity. Hexane extract had weak activity on U2OS and showed moderate effect on the other cell lines (43.05 to 79.03 µg/mL). MeOH extract of aerial parts and the extracts of roots were not exhibited cytotoxic activity.
In a previous report we have evaluated in vitro cytotoxic properties of extracts of fve Centaurea species and the strongest effect has been determined on chloroform extract of C.
polyclada on KB (human epidermal carcinoma, oral) and BT-549 (breast ductal carcinoma) cell lines (33 and 30 µg/mL, respectively) (21).
Most of the studies involved the activities of pure compounds isolated from various extracts concentration that inhibited visible growth as of C aurea species. Especial y isolated indicated by the TTC reduction. In the sesquiterpenes and favonoids were found to be
presence of bacterial growth by reduction responsible for cytotoxic p perties (22-26). reactions, TTC changed the color of In our earlier study, we hav isolated a
microorganisms from colorless to red. This sesquite pe e lactone, ivalin, from the CHCl3
provided clearly defined and easily readable extract of aeri l parts of C. cadmea (13). The aecntidvpitoyi notfs .c hAl lol r o f othrme aesxstaryasctw oefr ea epreiarfl opr amr tesd o ifn thtrei pplliacnatem. a y b e d u e t o t h e p r e s e n c e o f i v a l i n that is known as a potent cytotoxic compound on several tumor cell lines (27).
RAEntSimUiLcrTobSiaAl NacDtivDitIieSsC wUeSreS ItOesNted against 8 bacteria strains by using NCCLS method.
ReYsuiletlsd as r eo sfhonw-hne ixna nTea,bleC 3H . CTl h3 e acnhdlorMofoeOrmH eexxtrtaracct t os f othbeta ianeerdial fproamrts roofoths e apnldanth seh oawe rei da l strong activity on E. f ecali (8 mg/mL) nd B. parts of C. cadmea is shown in Table 1.
cereus (16 mg/mL) with concen rations more Extracts then were tested for their potential or equal to the standart antibiotic gentamycin. cytotoxic and antibacterial activities.
MeOH extract also had a strong effect on these strains (16 mg/mL, both). Hexane extract of the aerial parts and MeOH extract of the roots have weak activity against all tested microorganisms (64-256 mg/mL).
Table 1. Yields of various extracts of C. cadmea.
Obtained extracts (g) Yield of extracts (% of dry weight)
Root CHCl3 1.5 0.75
Root MeOH 5.36 2.68
Aerial parts n-hexane 7.8 1.3
Aerial parts CHCl3 23.58 3.93
Aerial parts MeOH 53.51 8.91
The cytotoxic activity results are presented in Table 2. The n-hexane and chloroform extracts of the aerial parts of the plant exhibited inhibitory activities against all cell lines. The strongest activity was observed on
been determined on chloroform extract of C.
polyclada on KB (human epidermal carcinoma, oral) and BT-549 (breast ductal carcinoma) cell lines (33 and 30 µg/mL, 103 respectively) (21). Most of the studies
Kaveh Alizad e h ASTARl, §ura BAYKAN EREL, Fa dime AYDIN ROSE, Qinel KOKS AL, Canan Karaalp
Antimicrobial activities were tested against extra ct of the aerial part s of the plant showed 8 bacteria strains by using NCCLS method, strong activity on E. faecalis (8 mg/mL) and B.
Results are shown in Table 3. T he chloroform cereus ( 16 mg /mL) with conce ntrations more
Table 2. Cytotoxic activities of C. cadmea extracts (IC50, |lg/mL).
U 2 0 S A549 HeLa 293HEK
Root CHCl3 NA NA HeLa NT NA
Root CHCl3
Root MeOH >100 NA NT
NT NA
Root MeOH Aerial parts n-
hAeexraianle parts n- >100 79.03
NT
50.25 43.05
hexane Aerial parts CAHerCiall3 p a r t s C H C l3
A e r i a l p a r t s MA eerOi aHl p a r t s
43.10
N A
35.00
N A
14.24
N A
23.50
N A
N T : Not tested, N A : Not active at 500 µg/mL concentration.
o r Ae qnut iaml itcor ot hbei a sl t ancdtiavritt iaens t iwb ieor teict egsetnetdamagyaciin s. t
M8 e AOb naHtcit m e xriictar aoscbtriali sn oas c htbiavydituai e ssitn r wgo neNgr e Ce ftCfe eLsctSet do m na egthtahei ons des .t s tR8raebisnauscl t(se1 r6ai ra me sgsth/r maoiwLn sn, b ibonyt h Tu)a.s bHi lneg x 3aN. nTCe h CeexL tcSrhalcomt reotfh ot ohr mde . a eRxreitasr ula clpttas roat fsr e at hns edh oaMwe reni Oa il Hn p Tae rxatbtsr l aeoc f t3 to. hfTe th pe l acr nohtol otssrho hof awovremed wseetxratokr na agc ct taoi cvfti itvyh i eat y ga aeoirniastEl a.plalfarttessc toaefld i s tmh(ei8 cp r µol aognr/ tmg asLhn )oi swma nesd (6Bs t4.r -o2cn5eg6r eamucsgti/vm(i1tLy6 ).oµng E/m. Lfa)ecwailtihs (8co µncge/mntLra)t iaonds
B. cereus (16 µg/mL) with concentrations Antibacterial activities of
Table 3. Antibacterial activities of C. cadmea extracts (ug/mL).
mThoerere oa r e esqeuvaelralt or e pt hoer t s s toa n d anr t imainctriobbioiatilc
a cgmteionvrtieat i me soy rco ifn e.dq i Muf fael r Oe Hnt ot eCxtehtnreatactus traelnas do as phr tea cd ia eans t isfbtriomntigc T eguferfkneetcayt m . oy Vcn ai nr it. oh MueseO e sHxttr raeixcntsr a c(ot1 f 6a lsµoi x g h/ maCdLena,tasbut orrotehna)g . t aHexf eof exn castn e(o Cen.x t rtphasceetsu eod fo sstchraeib naisoe sria(a1 l 6sp uabµr stgsp/ .ma nLgdl, eMcbheonOtihiH,) . CeH. xetsxrpaicn tae o taef, x tthrCea. c rtog olaft s t thifeaov laieae rw, i aeCla .kp asaractlstoi vnaint ydanaMag,ae iOCn Hs. t bae lxlst art eamscitetaod f am nt hdi ce Cr or.o boregt sha enhnias)vm he asw d( 6eba4ek-e2 na5 ce6tviµva ilgtu/yam taeLgd)a .fionrst
all tested microorganisms (64-256 µg/mL).
extracts (µg/mL).
Microorganisms Microorganisms
Aerial Root Root
CHC13 MeOH
AEsTcCheCr i2c3h9ia99coli
SAtTapChCy l2o3c9o9cc9us aureus AStTapChCy l6o5c3o8cc/Pus aureus SA.T eCpiCde6r5m3i8d/iPs AS.T eCpiCde1r2m2i2d8is SAaTlmCoCn 1e2ll2a2 t8yphimurium CSaClmMo 5n4e4ll5a typhimurium BCaCcMill u5s44ce5reus ABaTcCilClu s70c6e4reus
KAlTeCbsCie 7ll0a6 p4neumoniae CKCleMbs i2e3ll1a8 pneumoniae ECnCtMero 2c3o1c8cus faecalis AEnTtCerCo c2o9c2c1u2s faecalis PAsTeCudCo 2m9o2n1a2s aeruginosa APsTeCudCo 2m7o8n5a3s aeruginosa ATCC 27853
> 256
> 256
> 256
> 256
> 256
>256
> 256
> 256
128 256 256 64
128 128 128 64
thaecTitrih v eai rtniete i sma roi ecf r dos eibfvifaelr aealn cttr ieCvpietoni rettas u broyen a dasi nspctei cmdieifcs ur osf riboinma l mTa ecut hri kvoeidtyi. e . sE Vtohaf a r ndioifulf se a rnednx tt erCat hceytnslt aaoucfr etasitxes p eCxceit enr astac ftur roemfa CT. urgkleayst.ifoVliaar iohuasv e xstrhaocwtsedo f s tsrioxn gC eancttaivuirteya
on Staphylococcus epidermidis and Proteus mirabilis when compared with ciprofoxacin (28). In another report, water extract of C.
pAa retrsi anl- phaerxt as nne- hexane 128 128 256 256 128 128 128 128 64 64 128 128 64 64 128 128
Aerial parts CHCI3
Aerial parts M e O H 128
128 128 128
16 128
8 128
128 128 128 128
16 128
16 128
Gentamycin
1.0 1.0 1.0 1.0 4.0
4.0 16.0
2.0
hsteaplxei ncoaontisad ,(e Cs .C ph. saedgu l dasoshtsoi cfwoa lbni ia o, s toaC s.uh ba vsapel. o gsnliegt acnhni fna ic,i a, nCt . e fbsfpaeilcsta t ma i,a tag Ca ai.n sdtg l Ca .s Bt bi rf eao hnl iehana,) m hCeal.ld a sbaeleconan tieat avr nrahal ua, alitseC,d . S bt aapl hs ay mloict ao cacnuds a Cu.r ebues h aend) Hhaedlicboebeanctevr aplyulaotreid
(29).
E. faecalis can cause life threatening gastrointestinal infections in humans which
104
Turk J Pharm Sci 11(1), 101-106, 2014
has high levels of antibiotic resistance and B. cereus is responsible for a minority of foodborne illnesses, causing severe nausea, vomiting and diarrhea (30). C. cadmea may be a potential natural source for discovering new anti bacterial agents due to its remarkable activity on these pathogens.
ACKNOWLEDGEMENT
Authors are appreciated to U. Karabay- Yavasoğlu, Ph.D. and P. Ballar, Ph.D. for their scientifc contribution.
REFERENCES
1. Wagenitz G. Centaurea L. In: Davis PH ed.
Flora of Turkey and the East Aegean Islands, Vo l 5, pp.582, Edinburgh University Press, Edinburgh, 1975.
2. Uysal T, Demirelma H, Ertugrul K, Garcia-Jacas N, Alfonso S, Centaurea glabro-auriculata (Asteraceae), a new species from Turkey, Ann Bot Fennici 44, 219-222, 2007.
3. Uysal T, Centaurea ertugruliana (Asteraceae), a new species from Turkey. Ann Bot Fennici 45, 137-140, 2008.
4. Dinc M., Dogu S, Centaurea dumanii Comb. &
Stat. nov. (Asteraceae), Ann Bot Fenn 49(1-2), 87-90, 2012.
5. Kultur S, Centaurea nerimaniae sp. nov.
(Asteraceae) from south Anatolia, Turkey, Nord J Bot 28(5), 613-616, 2010.
6. Daskin R., Yilmaz O, Centaurea kaynakiae (Asteraceae), a new species from Turkey, Ann Bot Fenn 46(5), 474-478, 2009.
7. Hamzaoglu E., Budak U, Centaurea aksoyi sp nov (Asteraceae: Cardueae) from Turkey and a contribution to the sectional taxonomy, Nord J Bot 27(1), 16-20, 2009.
8. Dogan B. Duran A, Centaurea serpentinica sp nov (Asteraceae) from the central and south Anatolia transition zone, Turkey, Nord J Bot 27(4), 319-32, 2009.
9. Uysal T, Köse YB, Turkish J Bot 33(1), 41-46, 2009.
10. Aksoy ND, Duman H, Efe, A, Centaurea yaltirikii sp nov (Asteraceae, C. sect.
Pseudoseridia) from Turkey, Nord J Bot 26(1- 2), 53-56, 2008.
11. Baytop T, Türkiye’de Bitkiler ile Tedavi, Istanbul, Nobel Tıp Kitabevleri, 316. 1999.
12. Arif, R, Küpeli E, Ergun F, The biological
activity of Centaurea L. species, G U J Sci 17(4), 149-164, 2004.
13. Karamenderes C, Bedir E, Abou-Gazar H, Khan IA, Chemical constiuents of Centaurea cadmea, Chem Nat Comp 43(6), 694-695, 2007.
14. Karamenderes C, Demirci B, Baser KHC, Composition of essential oils of ten Centaurea L. taxa from Turkey, J Ess Oil Res 20, 342-349, 2008.
15. Karamenderes C, Konyalioglu S, Khan S, Khan IA, Total phenolic contents, free radical scavenging activities and inhibitory effects on the activation of NF-kappa B of eight Centaurea L. Species, Phytoterapy Res 21(5), 488-491, 2007.
16. Karamenderes C, Khan S, Tekwani BL. Jacob MR, Khan IA, Antiprotozoal and antimicrobial activities of Centaurea L. species growing in Turkey, Pharm Biol 44(7), 534-539, 2006.
17. Alizadeh AK, Baykan Erel S, Köksal Ç, Aydın Kose F, Karaalp C, Antimicrobial and cytotoxic activities of roots of Centaurea cadmea Boiss., Planta Med 77(12), 1437-1438, 2011.
18. Li Y, Backesjo CM, Haldosen LA, Lindgren U, Resveratrol inhibits proliferation and promotes apoptosis of osteosarcoma cells, European J Pharm, 609(1–3), 13-18, 2009.
19. National Committee for Clinical Laboratory Standards: Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically; Approved Standard-Eighth edition, NCCLS document M7-A6. NCCLS, Wayne, Pennsylvania, USA, 2003.
20. Atlas RM, Parks LC, Brown AE, Laboratory Manual of Experimental Microbiology, St.
Louis, Mosby-Year Books, 341, 1995.
21. Baykan Erel S, Demir S, Nalbantsoy A, Ballar P, Khan S, Karaalp C, Karabay Yavasoglu U, Cytotoxic, antioxidant, antiinfammatory capacities of fve Centaurea L. species and in vivo antiinfammatory evaluation of Centaurea athoa, 10th International Symposium on Pharmaceutical Sciences, June 26-29, Ankara, 2012
22. Csapi B, Hajdú Z, Zupkó I, Berényi A, Forgo P, Szabó P, Hohmann J, Bioactivity-guided Isolation of antiproliferative compounds from Centaurea arenaria, Phytother Res 24, 1664–
1669, 2010.
23. Seghiri R, Boumaza Q, Mekkiou R, Benayache S, Mosset P, Quintana J, Este´vez F, Leo´n F, Bermejo J, Benayache F, A favonoid with
105
cytotoxic activity and other constituents from Centaurea africana, Phytochem Lett 2(3),114- 118, 2009.
24. Ulubelen A, Öksüz S, Cytotoxic favones from Centaurea urvillei, J Nat Prod 45, 373, 1982.
25. Saroglou V, Karioti A, Demetzos C, Dimas K, Skaltsa H, Sesquiterpene lactones from Centaurea spinosa and their antibacterial and cytotoxic activities, J Nat Prod 68(9), 1404- 1407, 2005.
26. Erel SB, Karaalp C, Bedir E, Kaehlig H, Glasl S, Khan S, Krenn L, Secondary metabolites of Centaurea calolepis and evaluation of cnicin for anti-infammatory, antioxidant, and cytotoxic activities, Pharm Biol 49, 840-849, 2011.
27. Lee J, Min B, Lee S, Na M, Kwon B, Kim Y, Bae K, Cytotoxic sesquiterpene lactones from Carpesium abrotanoides, Planta Med 68, 745, 2002.
28. Uysal İ, Çelik S, Oldaçay M, Antibacterial activity of Centaurea species having ethnobotanical features, Pakistan J Bio Sci 8(12), 1812-1813, 2005.
29. Buruk K, Sökmen A, Aydın F, Ertürk M, Antimicrobial activity of some endemic plants growing in the Eastern Black Sea Region, Turkey, Fitoterapia 77, 388-391, 2006.
30. Ryan KJ, Ray CG (eds.) Sherris Medical Microbiology (4th ed.). pp. 294, McGraw Hill, 2004.
Received: 28.03.2013 Accepted: 02.05.2013
106
