Metabolites of hirsuteine and hirsutine, the major indole alkaloids of Uncaria rhynchophylla, in rats.

The metabolic fate of hirsuteine (HT) and hirsutine (HS), the major indole alkaloids of Uncaria rhynchophylla, was investigated using rats. On HPLC analysis, urine from rats orally administered HT were found to contain two metabolites (HT1 and HT2) together with unchanged HT. Similarly HS also was metabolized to two compounds (HS1 and HS2). Metabolite structures were determined to be 11-hydroxyhirsuteine-11-O-beta-D-glucuronide (HT1), 11-hydroxyhirsuteine (HT2), 11-hydroxyhirsutine-11-O-beta-D-glucuronide (HS1) and 11-hydroxyhirsutine (HS2), based on spectroscopic and chemical data. HT1 and HS1 were also detected in bile from rats administered HT and HS, respectively. Total cumulative urinary excretion within 72 h of oral administration was approximately 14% and 26% of the HT and HS doses, respectively, while total cumulative biliary excretion was 35% and 46%, respectively. HT and HS 11-hydroxylation were catalyzed by rat liver microsomes. This 11-hydroxylation activity was inhibited by addition of SKF-525A (a nonselective CYP inhibitor) or cimetidine (a CYP2C inhibitor). These results indicate that orally administered HT and HS are converted to 11-hydroxy metabolites in rats, and that the metabolites are predominantly excreted in bile rather than urine following glucuronidation. Furthermore, the results suggest that CYP2C enzymes are involved, at least in part, in the specific 11-hydroxylation of HT and HS.

Metabolic fate of fraxin administered orally to rats.

Naturally occurring fraxin (1) was administered orally to rats to investigate its metabolism. Urinary metabolites were analyzed by three-dimensional HPLC, and fraxetin-7-O-sulfate (2), fraxetin-7-O-beta-glucuronide (3), fraxetin (4), 6,7,8-trihydroxycoumarin (5), and fraxidin (6) were isolated. Fraxin (1) was extensively metabolized to 4, which was partly metabolized to 5 in a rat fecal suspension after incubation for 24 h. Urinary excretion of 4 and 5 in rats administered orally with 1 was substantially reduced when the rats were treated with antibiotics to suppress their intestinal flora. Incubation of 1 with a rat liver S-9 mixture yielded 6. These results suggest that hydrolysis and demethylation of 1 are performed by intestinal microflora, while methylation occurs in the liver.

Antipyretic, analgesic and muscle relaxant activities of pueraria isoflavonoids and their metabolites from Pueraria lobata Ohwi-a traditional Chinese drug.

We evaluated the antipyretic, analgesic, and muscle relaxant activities of Pueraria isoflavonoids and their metabolites in mice. The glycosides daidzin and genistin significantly reduced fever induced by lipopolysaccharide (LPS). Their metabolites, daidzein and p-ethylphenol, also significantly reduced fever induced by LPS. In addition, daidzin, daidzein, dihydrodaidzein, and p-ethylphenol showed analgesic activity as assessed by the acetic acid-induced writhing test. Furthermore, equol and p-ethylphenol showed muscle relaxant activity in the rotarod and horizontal wire test. These results suggest that these compounds play a major role in the therapeutic activity of Pueraria isoflavonoids.

Metabolic fate of orally administered phyllodulcin in rats.

Naturally occurring phyllodulcin (1) was orally administered to rats to investigate its metabolic fate. Urinary metabolites were analyzed by three-dimensional HPLC. Phyllodulcin-3'-O-sulfate (2), phyllodulcin-3'-O-beta-glucuronide (3), 2-[2-(3,4-dihydroxyphenyl)ethyl]-6-hydroxybenzoic acid (4), and one novel bibenzyl derivative, 2-[2-(3-hydroxy-4-methoxyphenyl)ethyl]-6-hydroxybenzoic acid (5), together with thunberginol G (6) and hydrangenol (7) were isolated from the phyllodulcin-treated urine. 1 was extensively metabolized to 4-6 by a rat fecal suspension after incubation for 24 h. Urinary excretion of 4-6 in rats administered phyllodulcin orally was substantially reduced when the rats were treated with antibiotics to suppress their intestinal flora. On the other hand, the incubation of 1 with rat liver S-9 mix showed the presence of 7 together with 4 and 5.

[Effect of Kampo medicines on the peripheral blood flow rate of betamethason-induced Oketsu syndrome mice by laser Doppler flow meter].

Stagnation of peripheral blood flow is the cause of various diseases. Changes in peripheral blood flow after oral administration of Kampo medicines in mice with betamethasone-induced oketsu syndrome and normal mice were examined using a laser Doppler blood flow meter. The Kampo medicines used were: Toki-shakuyaku-san; Kami-shoyo-san; Keishi-bukuryo-gan; Daio-botanpi-to; Tokaku-joki-to; Goshuyu-to; and Hange-koboku-to. In the oketsu mice, blood flow was improved by single-dose administration of Toki-shakuyaku-san, Kami-shoyo-san, Keishi-bukuryo-gan, Daio-botanpi-to, Tokaku-joki-to, and Goshuyu-to, but only Toki-shakuyaku-san increased blood flow significantly in normal mice. In addition, blood flow decreased after single-dose administration of Keishi-bukuryo-gan, Daio-botanpi-to, and Tokaku-joki-to in normal mice.

Urinary metabolites of nobiletin orally administered to rats.

During the course of our systematic investigation of the metabolism of flavonoids, the polymethoxyflavone nobiletin, occurring in the fruits of Citrus depressa, was orally administered to rats. The urinary metabolites were separated and identified by three-dimensional HPLC equipped with a photodiode array detector and the structure was determined by spectroscopic methods to be 4'-hydroxy-3',5,6,7,8-pentamethoxyflavone (1).

Antidepressant-like effects of apigenin and 2,4,5-trimethoxycinnamic acid from Perilla frutescens in the forced swimming test.

We studied the effects of apigenin and 2,4,5-trimethoxycinnamic acid (TMCA) on the behavioral despair test (forced swimming test), and the central noradrenergic, dopaminergic and serotonergic activities in mice. Apigenin at intraperitoneal doses of 12.5 and 25 mg/kg significantly decreased the duration of immobility in the forced swimming test in mice. At 100 mg/kg, the duration of immobility was returned to the control level in the test. On the other hand, TMCA treatment (25-200 mg/kg, i.p.) failed to significantly alter the duration of immobility. Based on the behavioral data, we examined changes in the monoamine turnover in mice having been subjected to forced swimming for 40 min. The monoamine turnover was measured in seven brain regions. Forced swimming exposure induced a significant decrease in dihydroxyphenylacetic acid (DOPAC)/dopamine (DA) in the striatum and amygdala and in 5-hydroxyindoleacetic acid (5-HIAA)/5-hydroxytriptamine (5-HT) in the hypothalamus, and a significant increase in DOPAC/DA in the thalamus and hypothalamus and in 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG)/norepinephrine (NE) in the amygdala, frontal cortex, hypothalamus, and midbrain. Apigenin (25 mg/kg) treatment produced attenuation of forced swim test-induced decrease of DA turnover in the amygdala and increase of DA turnover in the hypothalamus. Furthermore, intraperitoneal administration of haloperidol (0.2 mg/kg), a dopamine D(2) antagonist, blocked the apigenin (25 mg/kg)-induced decrease in immobility in the forced swimming test. These behavioral and biochemical results indicate the antidepressant properties of apigenin, which may be mediated by the dopaminergic mechanisms in the mouse brain.

Inhibitory effects of urinary metabolites on platelet aggregation after orally administering Shimotsu-To, a traditional Chinese medicine, to rats.

Shimotsu-To, which consists of four herbal extracts, has been used clinically for improving abnormal blood coagulation, fibrinolysis, atherosclerosis and chronic inflammation in Japan and China. We have investigated the pharmacological relationship between the effects and chemical components of Shimotsu-To after oral administration to rats. The urinary constituents were separated and identified by three dimensional (3D-) HPLC equipped with a photodiode array detector as a new tool and the chemical structures were determined by spectroscopic methods to be trans-ferulic acid-3-O-sulfate (1), vanillic acid (2), m-hydroxyphenylpropionic acid (3), trans-ferulic acid (4) and cis-ferulic acid (5). Of these compounds, 2-5 strongly inhibited platelet aggregation induced by ADP and arachidonic acid. Compound 1, the sulfate conjugate of 4, did not show any inhibitory effect, which suggested that the inhibitory effect on platelet aggregation was inactivated by sulfate conjugation. These results indicated that compounds 2-5 partly contributed to the anti-Oketsu effect of Shimotsu-To through the inhibition of platelet aggregation.

Metabolites of orally administered Magnolia officinalis extract in rats and man and its antidepressant-like effects in mice.

As a part of our search for the active metabolite from the bark of Magnolia officinalis (Magnoliaceae), the aqueous extract was orally administered to rats, and metabolites in the urine were analysed by a high-performance liquid chromatograph equipped with a photodiode array detector. When the extract was given to rats, five metabolites (sinapic acid-4-O-sulfate (1), sinapic acid-4-O-beta-glucuronide (2), sinapic acid (3), 3-[2',6-dihydroxy-5'-(2-propenyl)[1,1'-biphenyl]-3-yl]-(E)-2-propenoic acid (4), and an unchanged form, magnolol (5)) were detected in the urine. It was revealed that metabolites 1-3 and 4 were respectively derived from syringin and magnolol contained in the extract. In a human urine sample, metabolites 3-5 and dihydroxydihydromagnolol (6) were detected. These structures were identified by a combination of spectral methods and/or by comparison with authentic compounds obtained by synthesis. Among these free form metabolites (3-6), acute treatments with magnolol and dihydroxydihydromagnolol (50-100 mg kg(-1), i.p.) attenuated the forced swim-induced experimental depression in mice. The results indicated that magnolol and dihydroxydihydromagnolol were the antidepressant constituents of Magnolia officinalis.

Metabolism of [6]-gingerol in rats.

The metabolic fate of [6]-gingerol, one of the active constituents of Zingiber officinale Roscoe, was investigated using rats. The bile of rats orally administered [6]-gingerol was shown to contain a major metabolite (1) by HPLC analysis. Although the metabolites derived from [6]-gingerol were not detected in the urine, the ethyl acetate extract of the urine after enzymatic hydrolysis was shown to contain six minor metabolites (2-7). Their structures were determined to be (S)-[6]-gingerol-4'-O-beta-glucuronide (1), vanillic acid (2), ferulic acid (3), (S)-(+)-4-hydroxy-6-oxo-8-(4-hydroxy-3-methoxyphenyl) octanoic acid (4), 4-(4-hydroxy-3-methoxyphenyl)butanoic acid (5), 9-hydroxy [6]-gingerol (6) and (S)-(+)-[6]-gingerol (7) based on spectroscopic and chemical data. The total cumulative amount of 1 excreted in the bile and 2-7 in the urine during 60 h after the oral administration of [6]-gingerol were approximately 48% and 16% of the dose, respectively. The excretion of 2-7 in the urine decreased after gut sterilization. On the other hand, the incubations of [6]-gingerol with rat liver showed the presence of 9-hydroxy [6]-gingerol, gingerdiol (8), and (S)-[6]-gingerol-4'-O-beta-glucuronide (1). These findings suggest that the gut flora and enzymes in the liver play an important part in the metabolism of [6]-gingerol.