Masayoshi Hisama

Antimutagenic activity of flavonoids from Chrysanthemum morifolium.

A methanol extract from the flower heads of Chrysanthemum morifolium showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract was re-extracted with hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction showed a suppressive effect. Suppressive compounds in the ethyl acetate fraction were isolated by silica gel column chromatography and identified as the flavonoids acacetin (1), apigenin (2), luteolin (3), and quercetin (4) by EI-MS, IR, and 1H and 13C NMR spectroscopy. Compounds 1-4 suppressed the furylfuramide-induced SOS response in the umu test. Compounds 1-4 suppressed 60.2, 75.7, 90.0, and 66.6% of the SOS-inducing activity at a concentration of 0.70 μmol/ml. The ID50 (50% inhibitory dose) values of 1-4 were 0.62, 0.55, 0.44, and 0.59 μmol/ml. These compounds had the suppressive effects on umu gene expression of the SOS response against other mutagens, 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), which do not require liver-metabolizing enzymes. These compounds also showed the suppression of SOS-inducing activity against the other mutagens aflatoxin B1 (AfB1) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver-metabolizing enzymes, and UV irradiation. In addition to the antimutagenic activities of these compounds against furylfuramide, Trp-P-1 and activated Trp-P-1 were also assayed by the Ames test using S. typhimurium TA100.

Effect of a Novel Ascorbic Derivative, Disodium Isostearyl 2-O-L-Ascorbyl Phosphate, on Normal Human Dermal Fibroblasts against Reactive Oxygen Species

The novel amphiphilic vitamin C derivative disodium isostearyl 2-O-L-ascorbyl phosphate (VCP-IS-2Na), which has a C18 alkyl chain attached to the stable ascorbate derivative sodium L-ascorbic acid 2-phosphate (VCP-Na), was evaluated for reduction of cell damage induced by oxidative stress, ultraviolet A (UVA), ultraviolet B (UVB), and H2O2; stimulation of collagen synthesis against UVA irradiation; and inhibition of matrix metalloproteinase-1 (MMP-1) activity induced by UVA in human normal dermal fibroblasts. VCP-IS-2Na pretreatment resulted in significant protection against cell damage induced by UVB, UVA, and H2O2. The amount of type I collagen following UVA irradiation was increased by treatment with VCP-IS-2Na in a concentration-dependent manner. These effects of VCP-IS-2Na were superior to those of L-ascorbic acid (vitamin C, VC) and VCP-Na. On the other hand, VCP-IS-2Na suppressed 65% of the excess MMP-1 irradiated UVA, and VC and VCP-Na slightly suppressed it.

In vitro eye irritancy test of lauryl derivatives using the reconstructed rabbit corneal epithelium model

The rabbit corneal epithelium model (RCE model) was developed as a three-dimensional in vitro model to replace animal testing for the assessment of eye tolerance. In the model, a stratified culture of rabbit corneal epithelial cells is grown at the air-liquid interface on an amniotic membrane acting as a parabasal membrane. The alkaline exposure was restored each day in the presence of no irritants, although with the addition of SLS, which is a major irritant, the restoration of deficit was inhibited on the RCE model in a dose-dependent manner. The results of this test were comparable with those of the Draize test, and thus, this method using the RCE model may prove to be a useful and sensitive in vitro eye irritation test. The lauryl fatty chain derivatives, such as polyoxyethylene (9) lauryl ether (PLE), sodium polyoxyethylene (2) lauryl ether sulfate (SPLE), mono glyceryl laurate (MGL), and sodium N-lauroyl-l-glutaminate (SLG), which are widely used as surfactants for toiletry products and cosmetics, were evaluated for in vitro eye irritation potential using the RCE model. SLS, PLE, SPLE, MGL, and SLG inhibited 88.7%, 59.2%, 69.0%, 47.5%, and 15.7% of the restoration of deletion 24h after treatment at a concentration of 0.05%. The IC(50) (50% inhibitory concentration) values of SLS, PLE, SPLE, MGL, and SLG were 0.002%, 0.021%, 0.005%, 0.056%, and 0.448%, respectively. These results indicated that a functional group at the end of lauryl chain is an important factor for inhibiting the restoration of deletion using the RCE model.

Inhibitory effects of phytoncide solution on melanin biosynthesis.

To determine the component-activity relationships of phytoncide solutions on inhibitory activity in melanin biosynthesis, four types of phytoncide solution (A-type, AB-type, D-type, and G-type) were evaluated for inhibition of mushroom tyrosinase activity and melanin synthesis on murine B-16 melanoma cells and a human reconstituted skin model. The A-type, AB-type, D-type, and G-type of phytoncide solution treatment resulted in significant inhibition of tyrosinase activity. The amount of melanin was increased by treatment with phytoncide solutions in a concentration-dependent manner on murine B-16 melanoma cells without affecting cell growth. Furthermore, phytoncide solutions also suppressed melanin synthesis in a concentration-dependent manner on a human reconstituted skin model. These effects of A-type solution were superior to those of other solutions.

Synthesis and Characterization of a New Hydroquinone Derivative: Disodium p-Phenylene Diisostearyl Diphosphate.

A novel amphiphilic hydroquinone derivative having a C18 alkyl chain phosphate attached to the hydroquinone (HQ) moiety was chemically synthesized. The thermal stability, distribution between organic and aqueous phases, and in vitro skin permeability were evaluated. This HQ derivative was identified as disodium p-phenylene diisostearyl diphosphate (HQ-2P2IS) by UV, infrared, mass, and nuclear magnetic resonance spectroscopies. Product HQ-2P2IS was obtained in good yield (56%), and it exhibited satisfactory stability in neutral solution, comparable to that of HQ. Its skin permeability was also higher than that of HQ. HQ-2P2IS is susceptible to enzymatic hydrolysis by tissue phosphatase, which releases HQ in the skin tissues. Thus, these characteristics indicate that the novel hydroquinone derivative presented herein, i.e., HQ-2P2IS, may serve as an effective pro-hydroquinone for skin care applications.