The use of snail mucin motifs as rectal absorption enhancer for insulin has been evaluated. The mucin motifs were extracted from the giant African snail Archachatina marginata by differential precipitation with acetone. The mucin motifs were found to have a molecular weight of 5780 Da and an isoelectric point of 3.4. At the concentrations evaluated, the mucin exhibited rectal absorption enhancing property for the administration of insulin in rats. The % basal blood glucose level of the rats that received the batch of suppositories containing no mucin were consistently above 100% except at the ninetieth minute when it came down slightly to 97.2%. Rats dosed with the batch containing 7%w/w suppositories showed the greatest blood glucose reduction with mean % basal blood glucose concentration of 61.2%. Batches of the suppository containing 5% and 7% mucin showed more marked and consistent lowering in blood glucose concentration than the other batches containing lower amounts of the rectal absorption enhancer. The batch with 7% mucin reduced the basal glucose level to 44% within 2 h of administration of the glycero-gelatin suppository loaded mucin.

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The effects of five antifungal drugs, fluconazole, itraconazole, micafungin, miconazole, and voriconazole, on cytochrome P450 (CYP) 2C9-mediated tolbutamide hydroxylation, CYP2C19-mediated S-mephenytoin 4′-hydroxylation, and CYP3A4-mediated nifedipine oxidation activities in human liver microsomes were compared. In addition, the effects of preincubation were estimated to investigate the mechanism-based inhibition. The IC₅₀ value against tolbutamide hydroxylation was the lowest for miconazole (2.0 μM), followed by voriconazole (8.4 μM) and fluconazole (30.3 μM). Similarly, the IC₅₀ value against S-mephenytoin 4′-hydroxylation was the lowest for miconazole (0.33 μM), followed by voriconazole (8.7 μM) and fluconazole (12.3 μM). On the other hand, micafungin at a concentration of 10 or 25 μM neither inhibited nor stimulated tolbutamide hydroxylation and S-mephenytoin 4′-hydroxylation, and the IC₅₀ values for itraconazole against these were greater than 10 μM. These results suggest that miconazole is the strongest inhibitor of CYP2C9 and CYP2C19, followed by voriconazole and fluconazole, whereas micafungin would not cause clinically significant interactions with other drugs that are metabolized by CYP2C9 or CYP2C19 via the inhibition of metabolism. The IC₅₀ value of voriconazole against nifedipine oxidation was comparable with that of fluconazole and micafungin and higher than that of itraconazole and miconazole. The stimulation of the inhibition of CYP2C9-, CYP2C19-, or CYP3A4-mediated reactions by 15-min preincubation was not observed for any of the antifungal drugs, suggesting that these drugs are not mechanism-based inhibitors.

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We previously reported that a decrease in hepatic NADPH generation results in reduced hepatic first-pass clearance of propranolol in rats with bilateral ureteral ligation (BUL)-induced renal failure. The aim of the present study was to evaluate the mechanisms responsible for the reduced NADPH generation in the supernatant of liver homogenates (SUP) obtained from rats with BUL. The NADPH generation in the SUP in the presence of NADP⁺ was decreased in BUL rats as compared with control rats. After the addition of glucose-6-phosphate or 6-phosphogluconic acid, the increase in NADPH in the SUP of BUL rats was similar to that in control rats. The NADPH generation in the SUP after the addition of the ultrafiltrate of BUL rat SUP was smaller than that after the addition of the ultrafiltrate of control rat SUP. These findings suggest that the enzymatic activities in the pentose phosphate pathway were not decreased significantly in BUL rats, and that the decrease in the generation of NADPH in BUL rats was mainly caused by the decreased concentration of endogenous substrate(s) and/or the increased concentration of endogenous inhibitor(s) for the pentose phosphate pathway.

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The effects of five antifungal drugs, fluconazole, itraconazole, micafungin, miconazole, and voriconazole, on cytochrome P450 (CYP) 1A2-mediated 7-ethoxyresorufin O-deethylation, CYP2D6-mediated debrisoquine 4-hydroxylation, and CYP2E1-mediated chlorzoxazone 6-hydroxylation activities in human liver microsomes were compared. In addition, the effect of preincubation was estimated in order to investigate the mechanism-based inhibition. IC₅₀ values of miconazole against CYP1A2 and CYP2D6 activities were 2.90 and 6.46 μM, respectively, and miconazole at 10 μM concentration slightly inhibited CYP2E1 activity. On the other hand, other antifungal drugs neither inhibited nor stimulated all of the metabolic activities. The stimulation of the inhibition of the metabolic activities mediated by CYP1A2, CYP2D6, or CYP2E1 by 15-min preincubation was not observed for any of the antifungal drugs, suggesting that these antifungal drugs are not mechanism-based inhibitors. These results suggest that miconazole is the strongest inhibitor against CYP1A2, CYP2D6, and CYP2E1 among the antifungal drugs investigated.

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The effects of Alchornea glandulosa ethyl acetate fraction (AGF) on hydrogen peroxide (H₂O₂), nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production in peritoneal macrophages activated with lipopolysaccharide (LPS) or phorbol myristate acetate (PMA) were investigated. Analysis by thin layer chromatography (TLC) of AGF showed several constituents, including flavonoids, which may have anti-inflammatory activity. Inhibitory effects of the fraction in H₂O₂ and NO production ranged from 8.59±7.84% to 70.56±4.16% and from 16.06±3.65% to 38.73±3.90%, respectively. The TNF-α production was only partially inhibited in the tested concentrations (12.21±6.23%—15.16±0.96%). According to these results, it is suggested that AGF has anti-inflammatory activity. This medicinal plant may have therapeutic potential in the control of inflammatory disorders.

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To investigate the high incidence of atherosclerosis in the patients affected with rheumatoid arthritis, we examined the effect of feeding a cholesterol-enriched diet on the development of hypercholesterolemia in pX transgenic mice, which spontaneously develop chronic inflammatory arthritis. Cholesterol feeding to pX transgenic mice induced a striking elevation in serum total cholesterol (ca. 500 mg/dl) compared with their littermates, BALB/c mice used as controls. The pX transgenic mice exhibited elevated mRNA levels of ACAT1, and ABCG5 in the small intestine compared with their littermates, and furthermore, apoA1, ABCA1, ABCG5, ACAT1, and ACAT2 mRNAs were induced more easily by a cholesterol-enriched diet in pX transgenic mice than their littermates. As ACAT1 mRNA in the small intestine is known not to be induced by feeding a cholesterol-enriched diet, a possibility was inferred that interferon-gamma induced by Tax, a pX gene product, might play an important role in the induction of ACAT1 mRNA and the following hypercholesterolemia. These findings suggest that pX gene plays an important role in inducing hypercholesterolemia in BALB/c mice, which are genetically less susceptible to hypercholesterolemia and atherosclerosis and that RA patients carrying HTLV-1 virus have a predilection for hypercholesterolemia, a main risk factor for cardiovascular diseases.

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In this study, the quantitative analysis of saikosaponins from Radix Bupleuri in China was performed by high performance liquid chromatography. Saikosaponin-a and -d were converted completely into saikosaponin-b₁ and -b₂ by mild acid treatment. Distinctive measuring of these converted diene-saponins provided a rapid and selective method for the determination of saikosaponin-a and -d in commercial samples of Radix Bupleuri. The conditions of extraction and conversion of saikosaponins were optimized using orthogonal design L₉(3⁴). The HPLC analysis was performed on ODS-C₁₈ column with a flow rate of 1.0 ml/min and detection wavelength of 250 nm. Well resolved chromatograms of saikosaponin-b₁ and -b₂ were obtained with an isocratic elution of acetonitrile : 1% formic acid water (37.5 : 62.5). Calibration curves of saikosaponin-b₁ and -b₂ were linear in the range of 4.9—98.0 μg/ml and 3.5—71.0 μg/ml, respectively. The average recovery of saikosaponin-b₁ and -b₂ were 98.3% (RSD=3.1%) and 96.4% (RSD=1.8%), respectively. Seventeen samples of different species and habitats of Radix Bupleuri were analyzed by the developed HPLC method.

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