Chrysin, a natural and biologically active flavonoid suppresses tumor growth of mouse B16F10 melanoma cells: In vitro and In vivo study.

Chrysin (5,7-dihydroxyflavone) is a natural and biologically active compound which has many biological activities as an anticancer agent. The current report is aimed at finding out whether the antitumor potential of chrysin, evidenced in vitro and in vivo, is linked or not to its effect on immunological mechanisms of melanoma-bearing mice. Chrysin-treated B16F10 cells were analyzed for their metabolic rate and apoptotic potentials. In vivo, BALB/c mice received a subcutaneous injection of B16F10 melanoma cells prior to antitumor treatments with chrysin (50 mg/kg b.w) for 14 days and 21 days. The results showed that chrysin inhibited cancer cell growth at a dose-dependent manner by inducing apoptosis and cell cycle arrest at G2/M phase. Moreover, chrysin suppressed melanoma tumor growth at an average of 60% (after 14 days of treatment) and 71% (after 21 days of treatment) compared to the tumor-bearing group. Furthermore, chrysin treatment increased the cytotoxic activity of NK, CTL and macrophages. The findings showed that chrysin antitumor action on the murine melanoma model was very promising, suggesting that chrysin could be a potentially good candidate for future use in alternative anti-melanoma treatments.

Effect of heated naringenin on immunomodulatory properties and cellular antioxidant activity.

Naringenin is one of the most popular flavonoids derived from citrus. It has been reported to be an effective anti-inflammatory compound. Citrus fruit may be used raw, cooked, stewed, or boiled. The present study was conducted to investigate the effect of thermal processes on naringenin in its immunomodulatory and cellular antioxidant activities. The effects of flavonoids on B and T cell proliferation were assessed on splenocytes stimulated or not with mitogens. However, their effects on cytotoxic T lymphocyte (CTL) and natural killer (NK) activities were assessed in splenocytes co-incubated with target cells. The amount of nitric oxide production and the lysosomal enzyme activity were evaluated in vitro on mouse peritoneal macrophages. Cellular antioxidant activity in splenocytes and macrophages was determined by measuring the fluorescence of the dichlorofluorescin (DCF). Our findings revealed that naringenin induces B cell proliferation and enhances NK activity. The highest concentration of native naringenin exhibits a significant proliferation of T cells, induces CTL activity, and inhibits cellular oxidation in macrophages. Conversely, it was observed that when heat-processed, naringenin improves the cellular antioxidant activity in splenocytes, increases the cytotoxic activity of NK cells, and suppresses the cytotoxicity of T cells. However, heat treatment maintains the anti-inflammatory potency of naringenin.

Compounds isolated from the aerial part of Crataegus azarolus inhibit growth of B16F10 melanoma cells and exert a potent inhibition of the melanin synthesis.

Poor therapeutic results have been reported for treatment of malignant melanoma; therefore in this study, we have investigated inhibitory capacity of vitexin-2''-O-rhamnoside as well as the extract from which it was isolated, i.e. the ethyl acetate extract obtained from the leaves of Crataegus azarolus, on mouse melanoma (B16F10) proliferation. Cell viability was determined using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. In addition, amounts of melanin and tyrosinase were measured spectrophotometrically at 475nm. Ethyl acetate extract and vitexin-2''-O-rhamnoside exhibited significant anti-proliferative activity against B16F10 melanoma cells after incubation for 48hours with IC50s of 50µg/mL and 20µM, respectively. Furthermore, these two compounds have the ability to reduce the melanin content by inhibiting the tyrosinase activity of B16F10 cells. Thus, further investigations are merited to ascertain their potential application in treating hyperpigmentation disorders.

Aqueous extract of Crataegus azarolus protects against DNA damage in human lymphoblast Cell K562 and enhances antioxidant activity.

The present study was carried out to characterize the cellular antioxidant effect of the aqueous extract of Crataegus azarolus and its antigenotoxic potential using human myelogenous cells, K562. The antioxidant capacity of this extract was evaluated by determining its cellular antioxidant activity (CAA) in K562 cells. Also, preceding antigenotoxicity assessment, its eventual genotoxicity property was investigated by evaluating its capacity to induce the DNA degradation of treated cell nuclei. As no genotoxicity was detected at different exposure times, its ability to protect cell DNA against H2O2 oxidative effect was investigated, using the "comet assay." It appears that 800 µg/mL of extract inhibited the genotoxicity induced by H2O2 with a rate of 41.30 %, after 4 h of incubation. In addition, this extract revealed a significant cellular antioxidant capacity against the reactive oxygen species in K562 cells.