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.

Evaluation of in vitro antioxidant and apoptotic activities of Cyperus rotundus.

OBJECTIVE: To evaluate in vitro antioxidant and apoptotic activities of Cyperus rotundus (C. rotundus). METHODS: The phytochemical study and the antioxidant activities of both methanol and aqueous extracts from C. rotundus aerial part were determined. In addition, these extracts were also investigated for their cytotoxic and apoptotic activities. The major compound of the methanol extract was isolated. Both methanol and aqueous extracts (300, 150, and 50 µg/mL) were evaluated for their antioxidant activity by the xanthine/xanthine oxidase assay system. However, 16, 8, and 4 mg/mL of each extract were tested to investigate their OH. formation scavenging potential. Aqueous extract (800, 400, and 200 µg/mL) and methanol extract (350, 175, and 88 µg/mL) were tested against lipid peroxidation, induced by 75 µM H2O2. The cytotoxicity (by MTT assay) and cell DNA fragmentation of both extracts were evaluated towards K562 and L1210 cell lines. The major compound was obtained from the butanol fraction of methanol extract and its structure was determined by RMN spectroscopic analysis. RESULTS: The methanol and aqueous extracts showed respectively, 88% and 19% inhibition of xanthine oxidase activity. Yet, the same extracts inhibited lipid peroxidation by 61.5% and 42.0%, respectively. Both extracts inhibited OH. formation by 27.1% and 25.3%, respectively. Only methanol extract induced DNA degradation. Orientin was determined as the major compound isolated from the butanol fraction of methanol extract. CONCLUSIONS: It appears that C. rotundus extracts exhibit a potential use as a natural antioxidant and an apoptosis inducer.

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.