Effect of linalool as a component of Humulus lupulus on doxorubicin-induced antitumor activity.

As malignant neoplasm is a major public health problem, there is a need for the development of a novel modulator that enhances antitumor activity and reduces adverse reactions to antitumor agents. In this study, the effects of some volatile oil components in Humulus lupulus on doxorubicin (DOX) permeability in tumor cells and DOX-induced antitumor activity were examined. In vitro, DOX levels in tumor cells by combined linalool as its component significantly increased in the DOX influx system, and the increased effect by linalool on DOX cytotoxicity was shown. In vivo, the combination of DOX with linalool significantly decreased tumor weight compared with that of DOX alone treated group. The promotion of DOX influx level by combined linalool did not depend on energy, whereas it was suppressed by the absence of Na(+). This promoting effect was suppressed by the presence of S-(4-nitrobenzyl)-6-thioinosine and inhibited dependently on phlorizin concentration. It is considered that linalool promoted DOX influx in tumor cells because of its action on DOX transport through concentrative Na(+)-dependent nucleoside transporter 3, which increased DOX concentration in tumor cells and thus enhanced the antitumor activity of DOX. Therefore, linalool as a food component is anticipated to be an effective DOX modulator.

Beneficial effects by intake of Euphausiacea pacifica on high-fat diet-induced obesity.

Obesity is a major health problem showing increased incidence in developed and developing countries. We examined the effect of Euphausia pacifica (E. pacifica) (Pacific Krill) on high-fat diet (HFD)-induced obesity in C57BL/6 mice. No significant differences were observed in average food intake between the HFD and HFD with E. pacifica group, or the low-fat diet (LFD) and LFD with E. pacifica group for 18 weeks. The increased ratio of body weight in the HFD containing E. pacifica group was significantly reduced, being 10% lower than that with HFD group in the 18th week (HFD, 298.6±18.8% vs. HFD with E. pacifica, 267.8±16.2%; p<0.05), while the ratio for the LFD containing E. pacifica group was reduced by 4% compared with LFD group (LFD, 244.2±11.6% vs. LFD with E. pacifica, 234.1±18.0%). There were no effects of E. pacifica on total cholesterol levels in serum and liver, whereas the supplement of E. pacifica tended to decrease triglyceride levels in the HFD groups. The leptin level in serum was significantly decreased in the HFD group (p<0.01) by E. pacifica. The adipocyte area (1926±1275 µm(2)) in the HFD containing E. pacifica group was significantly reduced by 20% (p<0.001) compared with the HFD group. These results suggested that E. pacifica supplementation in the diet is beneficial for the prevention of HFD-induced obesity.

Drug release properties of a gel bead prepared with pectin and hydrolysate.

A calcium-induced pectin gel bead (PB) containing pectin hydrolysate was prepared, and the drug release profiles and degradation properties of the PB were investigated in aqueous media. The stiff PB swelled in physiological saline and its drug release rate decreased with exposure to increasing concentrations of CaCl2 during preparation. And erosion of the PB was not observed in physiological saline. However, the PB did disintegrate in phosphate buffer (pH 6.8) and the rate of disintegration depended on the calcium chloride concentration used to prepare the PB. In addition, the drug release rate of the PB in buffer solution decreased as the rate of gel erosion declined. Consequently, it appears that the PB gel matrix is an effective medium by which to control the release of drug within the gastrointestinal tract.

Derivation of hydroxamic acid from pectin and its applications in colorimetric determination.

A hydroxamic acid (HX) derivative of pectin was prepared, and its potential application to simple colorimetric determination of polysaccharides was investigated. The coupling reaction between pectin and hydroxylamine (HA) progresses in the presence of 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluenesulfonate (CMEC). The calibration curve for pectin showed good agreement and the lower limit of detection was 0.5 mg. This is a very simple and rapid determination method, which does not require tedious pre-treatment, for polysaccharides containing carboxyl groups.