In vitro anti-melanoma effect of polyphenolic compounds

Objective: To evaluate the effects of phenolic acids (caffeic, ferulic, and coumaric acids) and flavones (luteolin and apigenin) on the proliferation and melanogenesis in murine melanoma B16-F10 cells. Methods: Cell proliferation was determined after 24 and 48 hours of incubation using MTT assay. The effects of these tested compounds on cell cycle progression were analyzed by flow cytometry. Moreover, the melanin content and tyrosinase activity were measured spectrophotometrically at 475 nm. Results: Luteolin and apigenin exhibited significant anti-proliferative activity against B16-F10 cells, while caffeic, ferulic, and coumaric acids induced slight inhibition after 24 and 48 hours of incubation. The tested compounds disturbed cell cycle progression of B16-F10, by a subsequent decrease in G

Anti-melanogenesis and antigenotoxic activities of eriodictyol in murine melanoma (B16-F10) and primary human keratinocyte cells.

AIMS: The objective of this study was to examine the effect of eriodictyol on melanogenesis in cultured murine melanoma cells (B16-F10) and its antigenotoxic and antioxidant potentials on primary human keratinocyte (PHK) cells. MAIN METHODS: Anti-melanogenic effect was performed via the determination of melanin content and tyrosinase activity. Antigenotoxicity and antioxidant potentials were assessed by comet and cellular antioxidant assays, respectively. KEY FINDINGS: Eriodictyol reduced melanogenesis by inhibiting the tyrosinase activity of B16-F10 cells in a dose dependent manner. Its eventual genotoxicity was investigated by evaluating its capacity to induce DNA degradation of treated cell nuclei. As no genotoxicity was detected at the different tested concentrations, its ability to protect cell DNA against hydrogen peroxide (H2O2) oxidative effect in PHK cells was investigated using the "comet assay. It appears that 50 µM of eriodictyol solution suppressed H2O2 induced genotoxicity. In addition, this molecule revealed a significant cellular antioxidant capacity against reactive oxygen species formation in B16-F10 and PHK cells. SIGNIFICANCE: Thus, eriodictyol could be introduced as a natural skin depigmenting agent in skin care products.

Pharmacological, antioxidant, genotoxic studies and modulation of rat splenocyte functions by Cyperus rotundus extracts.

BACKGROUND: Cyperus rotundus Linn. (Cyperaceae) is a Tunisian medicinal plant used in folkloric (traditional) medicine to treat stomach disorders and inflammatory diseases. The present study explored the analgesic, anti-inflammatory and genotoxic activities of extracts from the aerial parts of C. rotundus. The antioxidant capacity and the modulation of splenocyte functions by these extracts were also investigated in mice. The phytochemical analysis was carried out using standard methods. METHODS: Aqueous, ethyl acetate, methanol and TOF-enriched extracts (300, 150, and 50 µg/ml) were evaluated for their analgesic and anti-inflammatory activities. 4, 2, and 1 mg/ml of each extract were tested to investigate their effect on lipid peroxidation. The genotoxic study was monitored by measuring the structural chromosome aberrations of mice treated with 300 mg/kg of extract. The proliferation of lymphocytes in the absence and presence of mitogens was assessed at a concentration range 1-1000 µg/ml. RESULTS: The tested extracts were able to decrease the mouse ear oedema induced by xylene. Furthermore, it was shown that the same extracts reduced the number of abdominal contractions caused by acetic acid in mice, revealing the peripheral analgesic activity of these extracts. It is worth noting that mice treated with doses up to 300 mg/kg b.w. of Cyperus rotundus extracts did not exhibit any toxicity. The tested extracts significantly enhance lymphocyte proliferation at 1 mg/ml. CONCLUSIONS: It appears that C. rotundus extracts contain potent components such as flavonoids that may potentially be useful for modulating the immune cell functions, provoking analgesic, anti-inflammatory and antioxidant effects.

In vitro antioxidant and antigenotoxic potentials of 3,5-O-di-galloylquinic acid extracted from Myrtus communis leaves and modulation of cell gene expression by H2O2.

3,5-O-di-galloylquinic acid (DGQA) purified from leaves of Myrtus communis was investigated for its antioxidative, antiproliferative and antigenotoxic activities. Antioxidant activity was determined by the ability of the compound to inhibit lipid peroxidation induced by H(2)O(2) in the K562 cell line. The pure molecule displayed an important malondialdehyde formation inhibition percentage (82.2%). Moreover, this compound exhibited an inhibitory effect against H(2)O(2)-induced genotoxicity, using the comet assay. A protective effect of the same molecule was also revealed when assessing the gene expression of the chronic myelogenous leukemia cell line (K562), stressed with H(2)O(2). For this purpose, we used a cDNA-microarray containing 82 genes related to cell defense, essentially represented by antioxidant and DNA repair proteins. We found that DGQA increase the activity of antioxidant enzymes family and the activity of DNA repair enzymes. Taken together, these observations provide evidence that the DGQA is able to protect cells against oxidative stress.

Assessment of isorhamnetin 3-O-neohesperidoside from Acacia salicina: protective effects toward oxidation damage and genotoxicity induced by aflatoxin B1 and nifuroxazide.

Antioxidant activity of isorhamnetin 3-O-neohesperidoside, isolated from the leaves of Acacia salicina, was determined by the ability of this compound to inhibit xanthine oxidase activity and to scavenge the free radical 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(.-)) diammonium salt. Antigenotoxic activity was assessed using the SOS chromotest assay. This compound has the ability to scavenge the ABTS(.+) radical by a hydrogen donating mechanism. We also envisaged the study of the antioxidant effect of this compound by the enzymatic xanthine/xanthine oxidase (X/XOD) assay. Results indicated that isorhamnetin 3-O-neohesperidoside was a potent inhibitor of xanthine oxidase and superoxide anion scavengers. Moreover, this compound induced an inhibitory activity against nifuroxazide and aflatoxine B1 (AFB1) induced genotoxicity. Taken together, these observations provide evidence that isorhamnetin 3-O-neohesperidoside isolated from the leaves of A. salicina is able to protect cells against the consequences of oxidative stress.