Transdermal delivery of tea catechins by electrically assisted methods.

Tea polyphenols, including (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin-3-gallate (EGCG), have been shown to possess potent antioxidant and chemopreventive activities. The aim of this study was to assess the effects of electroporation, iontophoresis, and their combination on the transdermal delivery of tea catechins across porcine skin. The permeation characteristics were investigated using various analogues of catechins, pH values, and modes of electroporation and iontophoresis. The mechanisms by which these catechins were transported via the skin were elucidated by examining the electric conductivity, transepidermal water loss (TEWL), and fusion of stratum corneum lipid liposomes (SCLL). The isomers, (+)-catechin and (-)-epicatechin, showed different behaviors of skin permeation and local skin deposition with the electrically assisted methods. The results suggest evidence of selective skin absorption of (-)-epicatechin over (+)-catechin. A synergistic effect was detected for (+)-catechin but not for (-)-epicatechin after application of electroporation followed by iontophoresis. The presence of a gallic acid ester in the structure of EGCG significantly increased the skin uptake of catechins. However, a negligible amount of or no EGCG molecules permeated across the skin. The mechanisms involved in the enhancement of electroporation may be the skin reservoir effect and an increase in skin permeability. The TEWL profiles suggest that in addition to the force of electrorepulsion, the skin hydration effect and structural alterations may also have contributed to the enhancement by iontophoresis. Electroporation did not influence the skin barrier function, although the skin permeability increased according to the SCLL fusion study.

A nationwide survey on epidemiological characteristics of childhood Henoch-Schönlein purpura in Taiwan.

OBJECTIVE: To evaluate the annual incidence and other epidemiological characteristics of Henoch-Schönlein purpura (HSP) among children in Taiwan. METHODS: The records of patients were derived from the research database of the Bureau of National Health Insurance, Taiwan, Republic of China, from January 1999 to December 2002. Children younger than 17 yr of age with the diagnosis of HSP were included into this study. Data for each patient including sex, age, date of onset and length of hospitalization were recorded and analysed. RESULTS: A total of 2759 cases were included with an annual incidence of 12.9 (11.8-13.4) per 100 000 children <17 yr of age. The occurrence of HSP had a peak at the age of 5 to 6 yr. In this study, 1118 (40.5%) patients had been hospitalized at some stage. There were 1454 males and 1305 females, for a male to female ratio of 1.11. Males had a higher annual incidence before the age of 10 yr (P = 0.04), and had a lower incidence than females at older ages (P = 0.02). Disease onset was more common in autumn and winter, and no apparent change in seasonal pattern was noted over 4 yr. CONCLUSIONS: Insurance claim data provide useful information on the epidemiology of HSP in Taiwan. Childhood HSP in Taiwan, with an incidence of 12.9 per 100 000 children, occurs commonly in autumn and winter; and at the age of 5 to 6 yr. The characteristics presented in this study may provide valuable data for understanding and further studies of HSP.

Effects of garlic components diallyl sulfide and diallyl disulfide on arylamine N-acetyltransferase activity and 2-aminofluorene-DNA adducts in human promyelocytic leukemia cells.

Two components of garlic, diallyl sulfide (DAS) and diallyl disulfide (DADS), inhibited arylamine N-acetyltransferase (NAT) activity and 2-aminofluorene-DNA adduct in human promyelocytic leukemia cells (HL-60). The NAT activity was measured by high performance liquid chromatography assaying for amounts of N-acetyl-2-aminofluorene (2-AAF) and remaining 2-aminofluorene (2-AF). Cellular cytosols and intact cell suspensions were assayed. The inhibition of NAT activity and 2-AF-DNA adduct formation in human leukemia cells by DAS and DADS were dose-dependent and were directly proportional. The data also indicated that DAS and DADS decrease the apparent values of Km and Vmax from human leukemia cells in both assays. This is the first report of garlic components affecting human leukemia cell NAT activity and 2-AF-DNA adduct formation.

Inhibitory actions of luteolin on the growth and arylamine N-acetyltransferase activity in strains of Helicobacter pylori from ulcer patients.

Helicobacter pylori is now recognized as an important cause of type B gastritis, which is strongly associated with gastric and duodenal ulcer disease. H. pylori may be a causative factor in patients with gastric cancer. The growth inhibition and N-acetylation of 2-Aminofluorene (AF) or P-aminobenzoic acid (PABA) by arylamine N-acetyltransferase (NAT) in H. pylori were inhibited by luteolin, a component in herbal medicine. The growth inhibition was based on the changes of optical density (OD) by using a spectrophotometer. The N-acetylation of AF or PABA by NAT from H. pylori were assayed by the amounts of acetylated and non-acetylated AF or PABA in cytosols and intact bacteria of H. pylori by using HPLC. An inhibition of growth on H. pylori demonstrated that luteolin elicited a dose-dependent growth inhibition in the H. pylori cultures. Cytosols and suspensions of H. pylori with or without specific concentrations of luteolin co-treatment showed different percentages of AF or PABA acetylation. The data indicated that there was decreased NAT activity associated with increased levels of luteolin in H. pylori cytosols and suspensions. Using standard steady-state kinetic analysis, it was demonstrated that luteolin was a possible uncompetitive inhibitor to NAT enzyme in H. pylori. This report is the first demonstration to show that luteolin can inhibit H. pylori growth and NAT activity.

Effects of berberine on arylamine N-acetyltransferase activity and 2-aminofluorene-DNA adduct formation in human leukemia cells.

Berberine is an alkaloid occurring in the plant genera Berberis and Coptis. Although berberine had been demonstrated to have antineoplastic function by inhibiting DNA-synthesis in activated lymphocytes, there is no available information to address berberine affects on human leukemia cell N-acetyltransferase (NAT) activity and 2-aminofluorene (AF)-DNA adduct formation. Thus, berberine was tested for inhibition of arylamine NAT activity and AF-DNA adduct formation in human leukemia cells. The NAT activity was measured by a high performance liquid chromatography assaying for the amounts of N-acetyl-2-aminofluorene (AAF) and N-acetyl-p-aminobenzoic acid (N-Ac-PABA) and the remaining AF and p-aminobenzoic acid (PABA). The NAT activity and AF-DNA adduct formation in human leukemia cells were inhibited by berberine in a dose-dependent manner, i.e. the higher the concentration of berberine, the higher the inhibition of NAT activity and AF-DNA adduct. The data also indicate that berberine decreased the apparent values of Km and Vmax from human leukemia cells in both cytosol and intact cells.

Female lung cancer mortality and sex ratios at birth near a petroleum refinery plant.

This study was conducted to assess whether female mortality from lung cancer is associated with residence in communities adjacent to a petroleum refinery plant and whether petroleum air pollution could affect the sex ratios of births. The Kaohsiung Refinery of the Chinese Petroleum Corp. is the oldest oil refinery in Taiwan and is located between the Tso-Ying and the Nan-Tzu municipalities. Standardized mortality ratios (SMRs) for female lung cancer and sex ratios of births were calculated for each municipality for the years 1971-1996. Cumulative-sum techniques were used to detect the occurrence of changes in the SMRs. The study results show that mortality from female lung cancer rose gradually about 30 to 37 years after the operation of a petroleum refinery plant began. However, the association between exposure to the petroleum air pollution and abnormal sex ratios at birth was not significant.