ABSTRACT
A noncollinear optical parametric amplifier is presented that generates transform-limited sub-10-fs pulses that are tunable in both the visible and the near infrared (NIR). The pulse-front-matched pump geometry realizes tilt-free signal amplification, and pulses as short as 6.1 fs can be obtained from 550 to 700 nm. The large angular dispersion of the idler specific to the group-velocity-matching interaction is effectively eliminated by a grating-telescope compensator, and 9-fs NIR pulses are also successfully obtained from 900 to 1300 nm. This is believed to be the first tunable sub-10-fs light source.
ABSTRACT
In order to develop naturally occurring antioxidants from edible plants, the antioxidative effect of hot water extracts of Lagerstroemia speciosa leaves, known by the Tagalog name of banaba in the Phillipines, was studied. The content of tannin in banaba extract was 36.8% in dry weight. Banaba extract showed strong antioxidative activity in a linoleic acid autoxidation system. Banaba extract was found to have a potent radical scavenging action on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and superoxide radicals (O(2-) ) generated by a hypoxanthine (HPX)/xanthine oxidase (XOD) system. In vitro lipid peroxidation of rat liver homogenate induced by tert-butyl hydroperoxide (BHP) was inhibited by the addition of banaba extract in a dose-dependent manner. From these results, banaba extract was demonstrated to be useful as an antioxidant or free radical scavenger to protect biological systems against oxidative stress.
ABSTRACT
The effects of a green tea (Camellia sinensis) extract on ethanol metabolism in ICR male mice were studied. A crude green tea extract (GTE) and the tea components as (-)-epigallocatechin gallate (EGCg), (-)-epigallocatechin (EGC), and caffeine were administered before the tests. One hour later, the mice were orally given 2g/kg body weight (b.w.) of ethanol (20% ethanol w/v). The results show that the levels in the blood and liver of ethanol and acetaldehyde were lower, and that the levels of acetate and acetone were higher than in the controls orally given 500 mg/kg b.w. of GTE. After the administration of 75 mg/kg b.w. and 225 mg/kg b.w. of EGCg, the acetate and acetone concentrations in the blood and liver were lower than in the controls. The mice given caffeine at the same dose as that in GTE showed almost the same effects as the group treated with GTE. This suggests that EGCg and caffeine, the principal components of GTE, both had an effect on ethanol metabolism.
Subject(s)
Alcoholic Intoxication/diet therapy , Caffeine/pharmacology , Catechin/analogs & derivatives , Ethanol/metabolism , Flavonoids/pharmacology , Tea/chemistry , Acetaldehyde/metabolism , Acetates/metabolism , Acetone/metabolism , Administration, Oral , Alcoholic Intoxication/metabolism , Animals , Catechin/pharmacology , Ethanol/blood , Liver/metabolism , Male , Mice , Mice, Inbred ICR , Plant Extracts/pharmacologyABSTRACT
The hypoglycemic effects of Lagerstroemia speciosa L., known by the Tagalog name of banaba in the Phillipines, were studied using hereditary diabetic mice (Type II, KK-AY/Ta Jcl). The mice were fed a test diet containing 5% of the hot-water extract (HWE) from banaba leaves, 3% of the water eluent of the partial fraction unadsorbed onto HP-20 resin of HWE (HPWE), and 2% of the methanol eluent of the partial fraction adsorbed onto HP-20 resin of it (HPME) for a feeding period of 5 weeks. The elevation of blood plasma glucose level in non-insulin dependent diabetic mice fed the cellulose as control (CEL) diet were almost entirely suppressed by addition of either HWE or HPME in place of cellulose in the CEL diet. Water intakes were inclined to increase gradually in the group fed either CEL or HPWE, but lower in the mice fed either HWE or HPME than in the animals given either CEL or HPME. The level of serum insulin and the amount of urinary excreted glucose were also lowered in mice fed HWE. Plasma total cholesterol level was also lowered in mice fed the either HWE or HPME. It is suggested that HWE, especially HPME, obtained from banaba leaves have beneficial effects on control of the level of plasma glucose in non-insulin dependent diabetes mellitus.
