The methanol soluble portion of black cumin oil, which is prepared by compression of seeds of Nigella sativa L., showed inhibitory effects on arachidonic acid (AA)-induced platelet aggregation and blood coagulation. By bioactive assay of AA-induced platelet aggregation, the methanol soluble part was purified to isolate a new compound 2-(2-methoxypropyl)-5-methyl-1,4-benzenediol (1) and two known compounds, thymol (2), carvacrol (3), having very strong inhibitory activity. Further, we then examined the isolated compounds (1-3) and eight related compounds by the screening test for AA-induced platelet aggregation. Compounds possessing aromatic hydroxyl and acetoxyl group had more potent activity than aspirin, which is well known as a remedy for thrombosis.

ABSTRACT:Oseltamivir, an ester-type prodrug of the neuraminidase inhibitor [3R,4R,5S]-4-acetamido-5-amino-3-(1-ethylpropoxy)-1-cyclohexene-1-carboxylate phosphate (Ro 64-0802), has been developed for the treatment of A and B strains of the influenza virus but has neuropsychiatric and other side effects. In this study, we characterized the transport across intestinal epithelial cells and the absorption of oseltamivir in rats. Uptake by Caco-2 cells (human carcinoma cell line) and HeLa cells transfected with peptide transporter 1 (HeLa/ PEPT1) was time-and temperature-dependent and was inhibited by typical PEPT1 inhibitors such as glycyl-sarcosine (Gly-Sar). The uptake by Caco-2 cells and HeLa/PEPT1 was saturable, with similar K m values. Oseltamivir absorption in adult rats was greatly reduced by simultaneous administration of milk, casein, or Gly-Sar. Furthermore, the plasma and brain concentrations of oseltamivir were higher in fasting than in nonfasting rats after oral administration. These results suggest that oseltamivir is a substrate of PEPT1 and that PEPT1 is involved in its intestinal absorption.Various transporters are expressed on apical and basolateral membranes of intestinal epithelial cells, serving to take up nutrients and to excrete xenobiotics into the lumen. Influx transporters are able to accept nutrients and also various drugs as substrates. In particular, peptide transporter 1 (PEPT1, SLC15A1), localized at brush-border membranes of human small intestine (Saito et al., 1995), plays important roles in the absorption of not only di-/tripeptides (Tamai et al., 1994) but also peptide-mimetic compounds, such as orally administered ␤-lactam antibiotics (Ganapathy et al., 1995;Sai et al., 1996) and the anticancer agent bestatin (Tomita et al., 1990;Inui et al., 1992). Several researchers recently found that intestinal PEPT1 can transport L-valine ester prodrugs, such as valacyclovir and valganciclovir (Balimane et al., 1998;Han et al., 1998;Sugawara et al., 2000). Therefore, such structural modification of drugs may result in increased intestinal absorption, mediated by PEPT1.Oseltamivir phosphate (oseltamivir), manufactured under the trade name Tamiflu as an ester-type prodrug of the neuraminidase inhibitor Ro 64-0802, has been developed for the treatment of A and B strains of the influenza virus. This drug has been reported to be associated with neuropsychiatric side effects (http://www.fda.gov/cder/drug/ infopage/tamiflu/QA20051117.htm and http://www.mhlw.go.jp/ english/index.html), which are likely to be caused by distribution of oseltamivir and/or its metabolite(s) to the central nervous system. We recently examined the possible role of P-glycoprotein (P-gp) as the determinant of brain distribution of oseltamivir and Ro 64-0802 both in vitro using LLC-GA5-COL150 cells, which overexpress human multidrug resistance (or resistant) 1 (MDR1) P-gp on the apical membrane, and in vivo using mdr1a/1b knockout mice (Morimoto et al., 2008). The permeability of oseltamivir in the basolateral-to-apical dire...

The cabbage butterfly, Pieris rapae, produces an ADP-ribosylating cytotoxic protein, pierisin-1. Unlike other ADP-ribosylating toxins, the acceptor site for ADP-ribosylation by pierisin-1 is the N-2 position of guanine bases in DNA. The present study was designed to characterize this novel guanine-specific ADP-ribosyltransferase, pierisin-1. The N-terminal polypeptide from Met-1 to Arg-233, but not the C-terminal Ser-234-Met-850 polypeptide, was found to exhibit guanine ADP-ribosyltransferase activity. Trypsin-treated pierisin-1, which is considered to be a "nicked" full-length form composed of associated N- and C-terminal fragments, also demonstrated such activity. Optimum conditions for the N-terminal polypeptide of pierisin-1 were pH 8-10, 37-40 degrees C, in the presence of 100-200 mM NaCl or KCl. Other metal ions such as Ca(2+) or Mg(2+) were not required. Kinetic studies demonstrated potent ADP-ribosyltransferase activity with a K(M) value for NAD of 0.17 mM and k(cat) of 55 per second. Under these optimum conditions, the specific activity of trypsin-treated pierisin-1 was about half (k(cat) = 25 per second). When the conditions were changed to pH 5-7 or 10-20 degrees C, some activity (6-55% or 5-20%, respectively, of that under optimal conditions) of the N-terminal polypeptide was still evident; however, almost all of the trypsin-treated enzyme activity disappeared. This implies the inhibition of the N-terminal enzyme domain by the associated C-terminal fragment. Long-term reactions indicated that a single molecule of pierisin-1 has the capacity to generate more than 10(6) ADP-ribosylated DNA adducts, which could cause the death of a mammalian cell.

The inhibitory effects of 40 extracts prepared from 38 traditional Turkish folk medicines on human aldose reductase (h-AR) and hematological activity were investigated. Seven plants containing 5 species of Cistus genus exhibited a potent inhibition of h-AR. Ferulago amani (root) inhibited the platelet aggregation induced by sodium arachidonate, while C. laurifolius (fruit) was found to possess strong inhibition in the blood coagulation assay. An AcOEt extract derived from the leaf of C. laurifolius was purified to isolate three known flavonoids. The activity of one, quercetin-3-O-methyl ether, was found to be as potent as that of eparlestat, which is known to be a remedy for treating complications associated with diabetes.

A kind of N-nitrosobile acid conjugate, N-nitrosotaurocholic acid (NO-TCA), was incubated with calf thymus DNA, and formation of an adduct was detected by the 32P-postlabeling method under nuclease P1 conditions. To examine the nucleotides containing the adduct from NO-TCA, each of 2'-deoxyribonucleotide 3'-monophosphates (3'-dAp, 3'-dGp, 3'-dCp, or 3'-Tp) was incubated with NO-TCA. The same adduct spot was detected in the reaction of NO-TCA with 3'-dCp. The structure of this adduct was determined to be 3-ethanesulfonic acid-dC by several spectrometry techniques. Moreover, bulky adducts containing bile acid moiety were also produced from the reaction of NO-TCA with 3'-dCp and 3'-dAp. From comparison with spectral data for authentic compounds, these adducts were concluded to be N4-cholyl-dC and N6-cholyl-dA. N4-Cholyl-dC and N6-cholyl-dA were also detected in calf thymus DNA treated with NO-TCA. In addition, 3-ethanesulfonic acid-dC and N4-deoxycholyl-dC were found to be produced from N-nitrosotaurodeoxycholic acid (NO-TDCA) with dC. NO-TCA and NO-TDCA induced mutations in Salmonella typhimurium TA100 but not in TA98. Mutational spectrum analysis revealed that NO-TCA induced G to A transitions predominantly. When NO-TCA (250 mg/kg) was singly administered to male Wistar rats by gavage, both ethanesulfonic acid-dC and N4-cholyl-dC could be detected in the glandular stomach and colon. The levels of ethanesulfonic acid-dC were 0.22-0.29 per 10(6) nucleotides, but values for N4-cholyl-dC were about 500-fold lower. These observations suggest that N-nitroso bile acid conjugates, NO-TCA and NO-TDCA, may induce G to A base substitutions in genes via DNA adduct formation, producing ethanesulfonic acid- and/or (deoxy)cholic acid-DNA and, therefore, may be related to human carcinogenesis as endogenous mutagens.