Beta-ionone-inhibited proliferation of breast cancer cells by inhibited COX-2 activity.

As one of the isoprenoids and widely derived from many fruits and vegetables, ß-ionone (BI) has a potent inhibitory proliferation of cancer cells in vitro and in vivo. However, its exact mechanism is still uncompleted understood and needs to be further verified. Cyclooxygenase-2 (COX-2), as a potential target of cancer chemoprevention, has been played pivotal roles in proliferation of tumor cells and carcinogenesis. Thus, the objective of present study was to determine that BI inhibited the activity of COX-2 in breast cancer and related to cancer cell models. Cell proliferation, DNA synthesis, the distribution of cell cycle, apoptosis induction and the expression of P38-MAPK protein were determined in MCF-7 cells by methylene blue, 3H-thymidine (TdR) incorporation, flow cytometry, TUNEL and Western blotting assays. Quinone reductase (QR) activity was determined in murine hepatoma Hepa1c1c7 cells by enzyme-linked immunosorbent assay (ELISA). The expression of COX-2 in a phorbol-12-myristate-13-acetate (PMA)-induced cell model and mammary tumor tissues was examined by Western blotting and immunohistochemistry. The results showed that BI significantly inhibited cell proliferation and DNA synthesis, arrested the distribution of cell cycle at the S phase or decreased proteins related to cell cycle such as cyclin D1 and CDK4, induced apoptosis and increased the expression of p-P38 in MCF-7 cells. BI at low doses (< 50 µmol/L) significantly increased QR activity, decreased the expression of COX-2 protein and prostaglandin E2 (PEG2) release in cell models. In addition, BI also significantly decreased the expression of COX-2 protein in rat mammary tumor tissues. Therefore, our findings indicate that BI possesses inhibitory proliferation of breast cancer cells through down-regulation of COX-2 activity.

Study on the developmental toxicity of ß-ionone in the rat.

ß-ionone (BIO) is used in fragrances, toiletries and non-cosmetic products, and as a flavor food additive. Notwithstanding the widespread human exposure, there are limited data on the reproductive toxicity of BIO. This study evaluated the developmental toxicity of BIO (0, 125, 250, 500 and 1000 mg/kg body weight/day) given orally to rats on days 6-15 of gestation (GD6-15). C-section was on GD21 and implantations, living and dead fetuses and resorptions were recorded. Fetuses were weighed, and examined for external abnormalities and skeleton and visceral anomalies. The embryotoxicity of a single oral dose of BIO (1000 mg/kg body wt) given on GD11 was evaluated as well. At the highest dose, BIO reduced weight gain and produced chromodacryorrhea and other signs of toxicity. BIO did not increase the frequency of malformations nor did it retard fetal growth. Nonetheless, BIO decreased the pregnancy rate in the group of females exposed on GD6-15, and increased the resorption rate in those treated on GD11 only. In conclusion, except for a higher embryolethality at a maternally toxic dose, BIO caused no embryotoxic effect over the dose range tested and the study NOAEL for maternal and developmental toxicity was 500 mg of BIO/ kg of body weight/day.

Characterizations on the Stability and Release Properties of ß-ionone Loaded Thermosensitive Liposomes (TSLs).

Liposomes with phase transition temperatures, Tm, near pathogenic site temperature are potential chemoprophylactic delivery vehicles. We prepared and characterized the thermal properties of liposomes composed of 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC) and hydrogenated soy phosphatidylcholine (HSPC) incorporating ß-ionone with Tm at 42 °C. Liposomes with ß-ionone/lipid ratio (w/w) of 1:20 and 1:8 had the necessary stability and released most of the ß-ionone. The molecular architecture surrounding Tm was studied by fluorescent probes, Raman spectroscopy, and differential scanning calorimeter (DSC). ß-Ionone was found to be preferentially located in the deep regions of the lipid bilayer (toward the long chain alkyl of the lipid) at moderate loading. The results showed that ß-ionone encapsulated liposomes have a superior release at higher loading amount. Increasing ß-ionone leads to disorder in the liquid crystalline state and accelerates the release rate. These studies provide information on the membrane structural properties of ß-ionone loaded liposomes that guide rational bioactive molecular delivery systems design for health products.

A New Megastigmane Sesquiterpenoid from Zanthoxylum Schinifolium Sieb. et Zucc.

Zanthoxylum schinifolium Sieb. et Zucc. (Rutaceae), a dioecious shrub with hooked prickly branches, has been used as folk medicine for the treatment of the common cold, stomach ache, diarrhea, and jaundice in China, Korea, and Japan. In our phytochemical investigations on this genus, a new megastigmane sesquiterpenoid, which is referred to as schinifolenol A (1), was isolated from Z. schinifolium. The stereochemistry was characterized via the analyses of extensive spectra. The absolute configuration was established by the application of a modified Mosher's experiment and assisted by a time-dependent density functional theory (TD-DFT) on calculated electronic circular dichroism (ECD). Bioactivity screenings showed that compound 1 exhibited a safe hypotoxicity and a better selectivity on anti-Kaposi's sarcoma associated herpes virus (KSHV).

ß-ionone induces cell cycle arrest and apoptosis in human prostate tumor cells.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase is the rate-limiting activity in the mevalonate pathway that provides essential intermediates for posttranslational modification of growth-associated proteins. Assorted dietary isoprenoids found in plant foods suppress HMG CoA reductase and have cancer chemopreventive activity. ß-Ionone, a cyclic sesquiterpene and an end-ring analog of ß-carotene, induced concentration-dependent inhibition of the proliferation of human DU145 (IC50 = 210 µmol/L) and LNCaP (IC50 = 130 µmol/L) prostate carcinoma cells and PC-3 prostate adenocarcinoma cells (IC50 = 130 µmol/L). Concomitantly, ß-ionone-induced apoptosis and cell cycle arrest at the G1 phase in DU145 and PC-3 cells were shown by fluorescence microscopy, flow cytometry, and TUNEL reaction, and downregulation of cyclin-dependent kinase 4 (Cdk4) and cyclin D1 proteins. Growth suppression was accompanied by ß-ionone-induced downregulation of reductase protein. A blend of ß-ionone (150 µmol/L) and trans, trans-farnesol (25 µmol/L), an acyclic sesquiterpene that putatively initiates the degradation of reductase, suppressed the net growth of DU145 cells by 73%, an impact exceeding the sum of those of ß-ionone (36%) and farnesol (22%), suggesting a synergistic effect. ß-ionone, individually or in combination with other HMG CoA reductase suppressors, may have potential in prostate cancer chemoprevention and/or therapy.

ß-Ionone arrests cell cycle of gastric carcinoma cancer cells by a MAPK pathway.

ß-Ionone is an end ring analog of ß-carotenoid which has been shown to possess potent anti-proliferative activity both in vitro and in vivo. To investigate the possible inhibitory effects of ß-ionone, we studied cell growth characteristics, DNA synthesis, cell cycle progression, as well as mitogen-activated protein kinases (MAPKs) pathways in the human gastric adenocarcinoma cancer cell line (SGC-7901). Our results show that cell growth and DNA synthesis were inhibited, and the cell cycle was arrested at the G0/G1 phase in a dose-dependent manner in cells treated with ß-ionone (25, 50, 100 and 200 µmol/L) for 24 h. We found that the ß-ionone significantly decreased the extracellular signal-regulated kinase protein expression and significantly increased the levels of p38 and Jun-amino-terminal kinase protein expression (P < 0.01). ß-Ionone also inhibited cell cycle-related proteins of Cdk4, Cyclin B1, D1 and increased p27 protein expression in SGC-7901 cells. These results suggested that the cell cycle arrest observed may be regulated through a MAPK pathway by transcriptional down-regulation of cell cycle proteins. These results demonstrate potent ability of ß-ionone to arrest cell cycle of SGC-7901 cells and decrease proliferation.

A novel mechanism of filaggrin induction and sunburn prevention by ß-damascenone in Skh-1 mice.

Understanding how oral administration of aroma terpenes can prevent sunburn or skin cancer in mice could lead to more effective and safer ways of blocking sun damage to human skin. To establish sunburn preventive activity, female Skh-1 mice were given oral ß-damascenone followed by irradiation with UVR from fluorescent 'sunlamps'. The following endpoints were evaluated versus controls at various times between 1 and 12 days after the terpene: whole genome gene expression and in situ immunohistochemistry of PCNA, keratin 10, filaggrin and caspase 14, and sunburn was evaluated at 5 days. UVR-induced sunburn was prevented by a single oral ß-damascenone dose as low as 20 µL (0.95 mg/g body weight). Microarray analysis showed sunburn prevention doses of ß-damascenone up-regulated several types of cornification genes, including keratins 1 and 10, filaggrin, caspase 14, loricrin, hornerin and 6 late cornified envelope genes. Immunohistochemical studies of PCNA labeling showed that ß-damascenone increased the proliferation rates of the following cell types: epidermal basal cells, follicular outer root sheath cells and sebaceous gland cells. Keratin 10 was not affected by ß-damascenone in epidermis, and filaggrin and caspase 14 were increased in enlarged sebaceous glands. The thickness of the cornified envelope plus sebum layer nearly doubled within 1 day after administration of the ß-damascenone and remained at or above double thickness for at least 12 days. ß-Damascenone protected against sunburn by activating a sebaceous gland-based pathway that fortified and thickened the cornified envelope plus sebum layer in a way that previously has been observed to occur only in keratinocytes.

Effects of beta-ionone on mammary carcinogenesis and antioxidant status in rats treated with DMBA.

Recent chemopreventive studies from our group showed that dietary beta -ionone inhibited 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis by the inhibition of cell proliferation and apoptosis initiation. In this study, we examined the chemopreventive effects of varied doses of dietary beta -ionone on the development and growth of DMBA-induced rat mammary tumors as well as plasma antioxidant status. beta -ionone treatment groups were given 9, 18, and 36 mmol/kg in the AIN76A diet starting 2 wk prior to DMBA administration and continuing for the 24 wk. Results showed that tumor incidence was dose dependently reduced by 35.4, 68.3, and 87.8%, respectively, compared to the positive control. Tumor sizes were dose dependently smaller, and tumor weight was less in each group, each rat, and each tumor compared to the positive control (P < 0.05). A significant decrease in lipid peroxidation was observed in the tumor-induced rats treated with dietary beta -ionone, whereas the plasma activities of antioxidant enzymes such as glutathione peroxidase, glutathione reductase, superoxide dismutase, and the nonenzymatic antioxidant glutathione were increased in the beta -ionone treated rats when compared to control. The levels of catalase and lactate dehydrogenase were remarkably decreased in the beta -ionone treated groups compared to the positive control group. These results suggest that dietary beta -ionone has biologically relevant antioxidant activity and plays a chemopreventive role against DMBA induced mammary gland tumors.

Beta-ionone activates and bleaches visual pigment in salamander photoreceptors.

Vision begins with photoisomerization of 11-cis retinal to the all-trans conformation within the chromophore-binding pocket of opsin, leading to activation of a biochemical cascade. Release of all-trans retinal from the binding pocket curtails but does not fully quench the ability of opsin to activate transducin. All-trans retinal and some other analogs, such as beta-ionone, enhance opsin's activity, presumably on binding the empty chromophore-binding pocket. By recording from isolated salamander photoreceptors and from patches of rod outer segment membrane, we now show that high concentrations of beta-ionone suppressed circulating current in dark-adapted green-sensitive rods by inhibiting the cyclic nucleotide-gated channels. There were also decreases in circulating current and flash sensitivity, and accelerated flash response kinetics in dark-adapted blue-sensitive (BS) rods and cones, and in ultraviolet-sensitive cones, at concentrations too low to inhibit the channels. These effects persisted in BS rods even after incubation with 9-cis retinal to ensure complete regeneration of their visual pigment. After long exposures to high concentrations of beta-ionone, recovery was incomplete unless 9-cis retinal was given, indicating that visual pigment had been bleached. Therefore, we propose that beta-ionone activates and bleaches some types of visual pigments, mimicking the effects of light.