Abstract:The aim of our study was to evaluate the effect of in vitro anticancer and cytotoxic activity of the methanolic extracts of 14 medicinal plants, 8 of which are endemic species in Anatolia, against the human HeLa cervical cancer cell line and to compare to the normal African green monkey kidney epithelial cell line (Vero) using the MTT colorimetric assay. Values for cytotoxicity measured by MTT assay were expressed as the concentration that causes 50% decrease in cell viability (IC50, μg/mL). The degree of selectivity of the compounds can be expressed by its selectivity index (SI) value. High SI value (>2) of a compound gives the selective toxicity against cancer cells (SI = IC50 normal cell/IC50 cancer cell). Dose-dependent studies revealed IC50 of 293 mg/mL and >1000 mg/mL for Cotinus coggygria Scop., IC50 of 265 μg/mL and >1000 mg/mL for Rosa damascena Miller, IC50 of 2 μg/mL and 454 mg/mL for Colchicum sanguicolle K.M. Perss, IC50 of 427 μg/mL and >1000 μg/mL for Centaurea antiochia Boiss. var. praealta (Boiss & Bal) Wagenitz on the HeLa cells and the Vero cells, respectively. Four plants showed significant SI values which were 227 for Colchicum sanguicolle K.M. Perss (endemic species), >3.8 for Rosa damascena Miller, >3.4 for Cotinus coggygria Scop. and >2.3 for Centaurea antiochia Boiss. var. praealta (Boiss & Bal) Wagenitz (endemic species). According to our study, 4 methanolic extracts of 14 tested plants exhibit greater activity on the HeLa cell line and little activity on the Vero cell line, meaning that these plants can be evaluated for potential promising anticancer activity.

Crataegus microphylla C. Koch is one of the 17 species of Crataegus growing in Turkey [H.P.T. Ammon and R. Kaul (1994). Dtsch. Apoth. Ztg., 134, 2433, 2521, 2631.]. This report is part of a series on the chemical investigations of Crataegus species from Turkey. Nine flavonoids have been isolated from the leaves and flowers of C. microphylla C. Koch. The amounts of the flavonoids from the leaves and flowers of the plant were determined.

The aim of our study was to evaluate in vitro antioxidant potential of methanolic extracts (ME) of 14 medicinal plants, 8 of which are endemic species of Anatolia. Scavenging activity was tested by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and the inhibitory effect on lipid peroxidation was examined by the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. The obtained results showed significant differences in the antioxidant potential amongst the tested methanolic plant extracts. Among the plant samples, Crataegus microphylla C. Koch, Salvia hypargeia Fisch. & Mey., Cotinus coggygria Scop., Origanum sipyleum L. and Rosa damascena Miller exhibited the highest DPPH scavenging activity. Five extracts (Centaurea nerimaniaeŞ. K€ ult€ ur, C. coggygria, Scorzonera tomentosa L., R. damascena and Colchicum sanguicolle K.M. Perss) showed strong antioxidant activity in the FTC and TBA tests, with per cent inhibition ranges of 72%À84% and 84%À92%, respectively. The ME of C. coggygria and R. damascena exhibited potent antioxidant activity by the DPPH, FTC and TBA methods.

Crataegus (hawthorn) has long been used as a folk medicine all around the world. Most of the studies with Crataegus species focus on effects on heart failure and cardiovascular disease. The pharmacological effects of Crataegus have been attributed mainly to the content of flavonoids, procyanidin, aromatic acid and cardiotonic amines. The present study investigated the blood pressure and the structure of the coronary arterial wall of L-NAME-induced hypertensive rats given an aqueous leaf extract of C. tanacetifolia (100 mg/kg), for 4 weeks via gavage. It was observed that C. tanacetifolia, especially the hyperoside fraction, prevented L-NAME-induced hypertension in rats and had beneficial effects on the cardiovascular system.

Rosa sempervirens L. (Rosaceae) growing wildly in Turkey is used in folk medicine for various indications. Here, we report the isolation of four flavonoids and determination of the total phenolic and flavonoid contents and the antimicrobial and antioxidant activities of various extracts from R. sempervirens leaves. Antioxidant activity was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The total phenolic and flavonoid contents were determined using the Folin-Ciocalteu and AlCl 3 methods, respectively. The antimicrobial activity was evaluated by the broth microdilution method against seven microbial species. The ethyl acetate extract (E) had significant antioxidant activity with half maximal inhibitory concentration (IC 50 ) values of 3.96 in the DPPH and 2.92 mg/mL in the ABTS assay. The total phenolic (203.8 mg gallic acid equivalents/g extract) and total flavonoid (95.81 mg catechin equivalents/g extract) contents of the E extract were significantly higher as compared to other extracts. The E extract exhibited strong antimicrobial activity against Candida albicans with a minimum inhibitory concentration of 39 mg/mL. Quercetin 3-xyloside, quercitrin and hyperoside were isolated from the E extract and quercetin, from the chloroform extract, and quercetin and hyperoside were identified for the first time in this species. Quercitrin was found to be a major compound in the E extract. Antimicrobial activity of R. sempervirens was also reported for the first time. These results indicate that the E extract has significant antioxidant and antimicrobial activity, probably due to flavonoids as well as other phenolic compounds in the E extract, acting individually or in combination.

The antioxidant, anti-inflammatory, acetylcholinesterase (AChE) inhibitory and antimicrobial activities of extract from the Centaurea antiochia Boiss. var. praealta (Boiss. & Bal.) Wagenitz, an endemic plant species from Turkey, were investigated. The results indicated that the extract inhibits FeCl3/ascorbic acid-induced phosphatidylcholine liposome oxidation, scavenges stable 2,2-diphenyl-1picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radicals, and reduces Fe 3+ to Fe 2+ in the ferric-reducing antioxidant power (FRAP) assay. The extract inhibited AChE and both cyclooxygenase (COX)-1 and COX-2, which suggests this species might be a potential source of plant-derived anti-inflammatory and anti-AChE substances. The extract may also act as an antimicrobial agent because it inhibited the growth of Gram-positive and Gram-negative bacteria as well as yeast. These findings may scientifically explain some uses of this species in Turkish folk medicine as an antimicrobial, antiinflammatory and wound healing agent.

Background:Flavonoids are natural compounds with antioxidant, anticarcinogenic, and anti-inflammatory effects.Aims:To determine the cytotoxic effects of flavonoids and drug resistance related to P-gp on K562 human chronic myeloid leukemia cells. We also aimed to evaluate the therapeutic potential of imatinib and flavonoid combinations.Study Design:Cell culture study.Methods:In this study, K562 cells were treated with apigenin, luteolin, 5-desmethyl sinensetin and the anticancer drug imatinib mesylate. The effect of flavonoids on K562 cell proliferation was detected using the 3-(4,5-dimethylthiazolyl)2,5‑diphenyl‑tetrazolium bromide assay. Concentrations of apigenin, luteolin, and 5-desmethyl sinensetin ranging from 25 to 200 μM and of imatinib from 5 to 50 μM administered for 72 h were studied. Apoptosis/necrosis and P-gp activity were measured using flow cytometry. The combined effects of different concentrations of flavonoids with imatinib were evaluated according to combination index values calculated using CompuSyn software.Results:In our study, the IC50 values for apigenin, luteolin, and 5-desmethyl sinensetin were found to be 140 μM, 100 μM, and >200 μM, respectively. Luteolin (100 μM) had the highest cytotoxic activity of these flavonoids. These results were statistically significant (p<0.05). Among the flavonoids studied, the combination of luteolin and imatinib was the most effective and is therefore recommended for its cytotoxic activity in the K562 cell line. After 72 h of incubation at their respective IC50 concentrations, all flavonoids were associated with an apoptosis rate of approximately 50%. P-glycoprotein activity was increased in all groups. Combination treatment may provide better outcomes in terms of cytotoxicity and thus reduce the dosages of imatinib used.Conclusion:The combination of some flavonoids and imatinib mesylate may increase the cytotoxic effect; However, the antagonistic effect should be considered in combined use on k562 cells.

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