Synergistic Effect of Apigenin and Curcumin on Apoptosis, Paraptosis and Autophagy-related Cell Death in HeLa Cells.

BACKGROUND/AIM: We aimed to investigate the synergistic effects of apigenin and curcumin on the cross-talk between apoptosis and autophagic cell death, as well as on paraptosis in HeLa cells. MATERIALS AND METHODS: Cell viability was measured using the MTT assay. Synergistic effects were measured using the Bliss independence model. qRT-PCR was used to study the expression of genes related to apoptosis, autophagic cell death, and cross-talk. GRP78/BiP immunostaining was used to identify endoplasmic reticulum (ER) stress. RESULTS: Treatment with a combination of apigenin and curcumin increased the expression levels of genes related to cell death in HeLa cells 1.29- to 27.6-fold. The combination of curcumin and apigenin showed a synergistic anti-tumor effect via cross-talk between processes leading to apoptosis and autophagic cell death, as well as ER stress-associated paraptosis. GRP78 expression was down-regulated, and massive cytoplasmic vacuolization was observed in HeLa cells. CONCLUSION: The combination of curcumin and apigenin is an effective potential therapeutic for cervical cancers.

Cytotoxic Effects of Some Flavonoids and Imatinib on the K562 Chronic Myeloid Leukemia Cell Line: Data Analysis Using the Combination Index Method

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)2,5­diphenyl­tetrazolium 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.

In vitro anticancer and cytotoxic activities of some plant extracts on HeLa and Vero cell lines.

PURPOSE: 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. METHODS: 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). RESULTS: 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). CONCLUSION: 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.

Screening for antitumor activity of various plant extracts on HeLa and C 4-I cell lines.

PURPOSE: Cancer is a long process that leads the organism to death and is associated with the normal cells acquiring the ability to divide permanently. Nowadays, the use of natural products in cancer therapy has a great importance. In addition, working with plants that are endemic to Turkey and determining the biological activities of these plant extracts, is extremely important due to the potential for new drug development. There is no comparative study available in the literature on the antitumor effects of Colchicum sanguicolle, a new found species of the genus Colchicum in Turkey, Crateagus microphylla, of the genus Crateagus and Centaurea antiochia of the genus Centaurea. In this study, we tried to demonstrate the antitumor effect of these plant extracts on HeLa and C 4-1 cells. METHODS: Five different doses (0.001, 0.01, 0.05, 0.25 and 0.5 mg/ml) of the three plant types were prepared and applied for 24, 48 and 72 hrs on the cervical cancer derived cell lines. Subsequently, the growth rate was evaluated with the mitochondrial dehydrogenase enzyme method. RESULTS: Colchicum sanguicolle extracts showed the most effective antitumor activity. For the Colchicum sanguicolle extract, the IC50 dose for HeLa cells was 0.01 mg/ml at 48 hrs, while for the C-4 I cells it was 0.001 mg/ml at 48 hrs. These results showed that C-4 I cells were more sensitive to the Colchicum sanguicolle extracts. Conclus?on: The results of from this study regarding the antitumor effect of plant extracts of endemic varieties of Turkey may have an important place in design and development of anticancer drugs and would make contributions to other studies to be conducted in this area.

Effects of Crataegus microphylla on vascular dysfunction in streptozotocin-induced diabetic rats.

Vascular dysfunction plays a key role in the pathogenesis of diabetic vascular disease. In this study, we aimed to investigate whether chronic in vivo treatment of Crataegus microphylla (CM) extract in diabetic rats induced with streptozotocin (STZ, intraperitoneal, 65 mg/kg) preserves vascular function and to evaluate whether the reduction of inducible nitric oxide synthase (iNOS), proinflammatory cytokines, and lipid peroxidation mediates its mechanisms of action. Starting at 4 weeks of diabetes, CM extract (100 mg/kg) was administrated to diabetic rats for 4 weeks. In aortic rings, relaxation to acetylcholine and vasoreactivity to noradrenaline were impaired, whereas aortic iNOS expression and plasma tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), total nitrite-nitrate, and malondialdehite levels were increased in diabetic rats compared with controls. Chronic CM treatment significantly corrected all the above abnormalities in diabetic rats. In comparison, pretreatment of the aorta of diabetic rats with N-[3(aminomethyl) benzyl]-acetamidine, dihydrochloride (10(-5) M), a selective inhibitor of iNOS, produced a similar recovery in vascular reactivity. These results suggest that chronic in vivo treatment of CM preserves endothelium-dependent relaxation and vascular contraction in STZ-induced diabetes, possibly by reducing iNOS expression in the aorta and by decreasing plasma levels of TNF-α and IL-6 and by preventing lipid peroxidation.

Diterpenoid alkaloids of Aconitum vulparia Rchb.

From the roots of Aconitum vulparia Rchb., collected in Prüm (Germany), a new norditerpenoid alkaloid, named alexhumboldtine, has been isolated along with the known norditerpenoid alkaloids lappaconitine, anthranoyllycoctonine, lycoctonine, puberaconitine, ajacine, and septentriodine. The structure of alexhumboldtine was established on the basis of 1H, 13C, DEPT, homonuclear 1H COSY, NOESY, HSQC, and HMBC NMR studies. From the aerial parts of the plant another norditerpenoid alkaloid, aconorine, has been isolated.

Flavonoids and antioxidant activity of Rosa agrestis leaves.

In this work we report the isolation and characterisation of seven flavonoids, the levels of total phenolics, flavonoids and proanthocyanidins, and the antioxidant activity of the leaf extract of Rosa agrestis Savi (Rosaceae). The results showed that the R. agrestis leaf extract exhibited significant antioxidative activity as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) (EC(50) = 47.4 microg mL(-1)), inhibited both beta-carotene bleaching and deoxyribose degradation, quenched a chemically generated superoxide anion in vitro and showed high ferrous ion chelating activity. Reactivity towards 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical cation and ferric-reducing antioxidant power (FRAP) values were equivalent to 2.30 mM L(-1) Trolox, the water soluble alpha-tocopherol analogue, and 1.91 mM L(-1) Fe(2+), respectively. The high antioxidant activity of the extract appeared to be attributed to its high content of total phenolics, flavonoids and proanthocyanidins. The flavonoids isolated from R. agrestis leaves were diosmetin, kaempherol, quercetin, kaempherol 3-glucoside (astragalin), quercetin 3-rhamnoside (quercitrin), quercetin 3-xyloside and quercetin 3-galactoside (hyperoside). Diosmetin (5,7,3'-trihydroxy-4'-methoxyflavone) was isolated for the first time from Rosa species.

Flavonoids of Artemisia araratica.

Artemisia araratica Krasch. is one of the 22 species growing in J. Cullen. In Flora of Turkey and the East Aegean Islands, P.H. Davis (Ed.), Vol. 5, University Press, Edinburgh (1975). In this report we have isolated seven flavonoids from the aerial parts of A. araratica.

Flavonoids of Crataegus microphylla.

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.