Structure elucidation of compounds extracted from the Chinese medicinal plant Patrinia heterophylla.

For several hundred years, Patrinia heterophylla has been used in traditional Chinese medicine as a treatment for abscesses, hepatitis, tonsillitis, ulcers, etc. Recent research suggests that it may also have some anti-cancer activity. We have extracted five pure compounds from this plant; two known flavonols without bio-activity, one known isocoumarin glucoside that exhibits some cytotoxic activity toward HeLa cervical cancer cells, and two novel compounds that show considerable cytotoxic activity toward HeLa cells.

Anthocyanin-rich extract decreases indices of lipid peroxidation and DNA damage in vitamin E-depleted rats.

Anthocyanins are secondary plant metabolites responsible for the blue, purple, and red color of many plant tissues. The phenolic structure of anthocyanins conveys marked antioxidant activity in model systems via donation of electrons or hydrogen atoms from hydroxyl moieties to free radicals. Dietary intakes of anthocyanins may exceed 200 mg/day, however, little is known about their antioxidant potency in vivo. Consequently, the aim of this study was to establish whether anthocyanins could act as putative antioxidant micronutrients. Rats were maintained on vitamin E-deficient diets for 12 weeks in order to enhance susceptibility to oxidative damage and then repleted with rations containing a highly purified anthocyanin-rich extract at a concentration of 1 g/kg diet. The extract consisted of the 3-glucopyranoside forms of delphinidin, cyanidin, petunidin, peonidin, and malvidin. Consumption of the anthocyanin-repleted diet significantly improved (p <.01) plasma antioxidant capacity and decreased (p <.001) the vitamin E deficiency-enhanced hydroperoxides and 8-Oxo-deoxyguanosine concentrations in liver. These compounds are indices of lipid peroxidation and DNA damage, respectively. Dietary consumption of anthocyanin-rich foods may contribute to overall antioxidant status, particularly in areas of habitually low vitamin E intake.

Identification of cytochrome P450 isozymes involved in metabolism of the alpha1-adrenoceptor blocker tamsulosin in human liver microsomes.

1. The in vitro human liver metabolism of the alpha1-adrenoceptor blocker tamsulosin was investigated. When 14C-tamsulosin was incubated with human liver microsomes, it was converted to five known urinary metabolites and at least three unknown metabolites. Of the former group, the predominant metabolite was the O-deethylated metabolite (M-1), followed by the o-ethoxyphenoxy acetic acid (AM-1) and the m-hydroxylated metabolite (M-3). 2. There was a good linear relationship between AM-1 formation and testosterone 6beta-hydroxylase activity in microsomes from each of 10 individual donors. The rate of M-1 formation also correlated with the same activity, albeit the correlation curve did not pass through the origin. By contrast, the rates of M-3 and the O-demethylated metabolite (M-4) formation correlated with dextromethorphan O-demethylase activity. 3. Ketoconazole strongly inhibited AM-1 formation and reduced that of M-1 by c. 60%. Immunoinhibition studies using anti-rat antibodies supported these results. The formation of M-3 and M-4 was inhibited by quinidine and sparteine. 4. It is concluded that formation of tamsulosin metabolites, AM-1 and M-1, is catalysed by CYP3A4 whereas that of M-3 and M-4 is catalysed by CYP2D6. However, minor contributions from other CYPs cannot be excluded.

HPLC analysis of allicin and other thiosulfinates in garlic clove homogenates.

Reversed-phase high Performance liquid chromatography (C18-HPLC) was used to separate and quantitate all the detectable alkyl and alkenyl thiosulfinates, including configurational isomers, of garlic homogenates. Pure thiosulfinates were synthesized or isolated and identified by (1)H-NMR, and their extinction coefficients determined. Some configurational isomers required Separation by silica-HPLC. Five previously unreported thiosulfinates have been found, four of which contain the TRANS-1-propenyl group and increase several-fold to over half the content of allicin upon storage of garlic bulbs at 4 degrees C with a concomitant decrease in a gamma-glutamyl peptide. The variation in thiosulfinate yield between different countries, stores, bulbs, cloves, and storage times was investigated. A method for standardizing the quantitation of allicin yield from garlic is proposed and compared to other methods of allicin analysis.