Antioxidant and antibacterial activities of Artemisia absinthium and Citrus paradisi extracts repress viability of aggressive liver cancer cell line.

BACKGROUND: Numerous reports show that herbal medicines can be utilized in the treatment of different liver disorders. In this study, antioxidant, antibacterial, and anticancer activities of individual as well as combined 80% ethanolic extracts of Artemisia absinthium leaves and Citrus paradisi peels were investigated. METHODS AND RESULTS: Values of total phenolic contents (TPC), total flavonoid contents (TFC), DPPH-radical scavenging activity, and ferric reducing antioxidant power (FRAP) were measured to explore the antioxidant capacity. To assess antibacterial activity, four bacterial strains (Escherichia coli, Staphylococcus aureus, Salmonella enterica, and Klebsiella pneumoniae) were used. Anticancer activity was assessed on Huh-7 (liver cancer) and Vero (non-cancerous) cell lines. FRAP activity of combined plants extract was higher as compared to their individual effect; the trend did not hold in the case of DPPH-radical scavenging activity. Antibacterial activity of combined extracts by disk diffusion method was observed only against E.coli. MTT results indicated that both plants had a cytotoxic effect on Huh-7 cell line but did not show any effect on Vero cell line. Our data showed a strong negative correlation between the amount of TPC, TFC, & DPPH radicals-scavenging activity and viability of Huh-7 cell line.However, no effect was shown on the non-cancerous cell line. CONCLUSION: The ethanolic extracts of Artemisia absinthium leaves and Citrus paradisi peels can be used against liver cancer because of their antioxidant, antibacterial, and anticancer activities.

Parallel evolution of UbiA superfamily proteins into aromatic O-prenyltransferases in plants.

Plants produce ∼300 aromatic compounds enzymatically linked to prenyl side chains via C-O bonds. These O-prenylated aromatic compounds have been found in taxonomically distant plant taxa, with some of them being beneficial or detrimental to human health. Although their O-prenyl moieties often play crucial roles in the biological activities of these compounds, no plant gene encoding an aromatic O-prenyltransferase (O-PT) has been isolated to date. This study describes the isolation of an aromatic O-PT gene, CpPT1, belonging to the UbiA superfamily, from grapefruit (Citrus × paradisi, Rutaceae). This gene was shown responsible for the biosynthesis of O-prenylated coumarin derivatives that alter drug pharmacokinetics in the human body. Another coumarin O-PT gene encoding a protein of the same family was identified in Angelica keiskei, an apiaceous medicinal plant containing pharmaceutically active O-prenylated coumarins. Phylogenetic analysis of these O-PTs suggested that aromatic O-prenylation activity evolved independently from the same ancestral gene in these distant plant taxa. These findings shed light on understanding the evolution of plant secondary (specialized) metabolites via the UbiA superfamily.

The structure-property relationships of acid- and alkali-extracted grapefruit peel pectins.

Structure and properties of pectin can be affected by extraction methods. In this study, grapefruit peel pectins extracted by HCl (at pH 1 [P1], 2 [P2], and 3 [P3]) and NaOH (at pH 9 [P9], 10 [P10], and 11 [P11]) were prepared and characterized. Atomic force microscopy (AFM) provided direct evidence of complex nano-structural patterns of pectins and revealed cross-linked networks of P10 and P11. Small-angle X-ray scattering (SAXS) demonstrated that P1, P2, and P3 possessed a relatively extended conformation, whereas P9, P10, and P11 displayed a three-dimensional structure and folded conformation. The compact and extended conformations of P3 contributed to its high viscosity in solution and the stability of the formed emulsion (75%). Porous surface and larger three-dimensional nanostructure (Dmax: 23 nm) of P10 facilitated its ion-binding capacity. Our results provide valuable insight into relationship between extraction methods and structure-properties of pectin, facilitating design of functional pectins.

Pectin Hydrolysates from Different Cultivars of Pink/Red and White Grapefruits (Citrus Paradisi [macf.]) as Culture and Encapsulating Media for Lactobacillus Plantarum.

Citrus pectin hydrolysates (Citrus paradisi [Mafc.]) from "Foster," "Red Shambar," "Tangelo Orlando," and "Citrumelo Swingle" cultivars were obtained by partial chemical hydrolysis and their properties as culture media (sole carbon/nutrient source) and encapsulating agents of Lactobacillus plantarum CIDCA 83114 were evaluated. The concentration of neutral sugars was maximal after 2-hour hydrolysis. All hydrolysates were rich in glucose >xylose >galactose >galacturonic acid >mannose >arabinose. "Citrumelo Swingle" cultivar was the one with the highest concentration of xylose. After 24 hr of fermentation with L. plantarum CIDCA 83114, bacterial viability increased from 6.76 ± 0.14 to almost 9 log CFU/mL, and lactic acid concentration, from 2.63 ± 0.41 to 7.82 ± 0.15 mmol/L in all hydrolysates. Afterwards, bacteria were entrapped in pectate-calcium beads by ionotropic gelation. Bacterial viability did not significantly decrease after freeze-drying and storage the beads at 4 °C for 45 days. PRACTICAL APPLICATION: Pectin hydrolysates were adequate culture media for microorganisms, as determined by the viabililty and lactic acid production. Considering that citrus peels are agro-wastes obtained in large quantities, their use as encapsulating materials provides a solution to overcome the environmental problem they entail.

Effects of graft copolymer of chitosan and salicylic acid on reducing rot of postharvest fruit and retarding cell wall degradation in grapefruit during storage.

This study was to evaluate the effect of graft copolymer (CTS-g-SA) of chitosan (CTS) and salicylic acid (SA) on the storability of grapefruit fruits during postharvest storage. Results indicate that the graft copolymer treatment significantly depressed green mold caused by Penicillium digitatum. The graft copolymer application kept fruit firmness without impairing the fruit quality. Moreover, the graft copolymer treatment inhibited the activity and gene expression of cell wall-modifying enzymes such as polygalacturonase, cellulase, pectin methylesterase, α-l-arabinofuranosidase, ß-galactosidase, and suppressed the modification of cell wall components including covalently bound polysaccharide (sodium carbonate soluble pectin, 24% KOH-soluble fraction), which were associated with fruit softening. These results suggested that graft copolymer application can be recognized as a postharvest technique to suppress rotting and delay softening through inhibiting solubilization of cell wall polysaccharides.

Clinically Relevant Pharmacokinetic Herb-drug Interactions in Antiretroviral Therapy.

For healthcare professionals, the volume of literature available on herb-drug interactions often makes it difficult to separate experimental/potential interactions from those deemed clinically relevant. There is a need for concise and conclusive information to guide pharmacotherapy in HIV/AIDS. In this review, the bases for potential interaction of medicinal herbs with specific antiretroviral drugs are presented, and several botanicals are discussed for which clinically relevant interactions in humans are established. Such studies have provided, in most cases, sufficient ground to warrant the avoidance of concurrent administration of antiretroviral (ARVs) drugs with St John's wort (Hypericum perforatum), black pepper (Piper species) and grapefruit juice. Other botanicals that require caution in the use with antiretrovirals include African potato (Hypoxis hemerocallidea), ginkgo (Ginkgo biloba), ginseng (Panax species), garlic (Allium sativum), goldenseal (Hydrastis canadensis) and kava kava (Piper methysticum). The knowledge of clinically significant herb-drug interaction will be important in order to avoid herb-induced risk of sub-therapeutic exposure to ARVs (which can lead to viral resistance) or the precipitation of toxicity (which may lead to poor compliance and/or discontinuation of antiretroviral therapy).

Food-drug interaction of tacrolimus with pomelo, ginger, and turmeric juice in rats.

Tacrolimus is a well-known potent immunosuppressant agent, which has various drug-drug or food-drug interactions. Previously, we found a renal transplant recipient who increased tacrolimus blood concentrations after ingestion of pomelo as a rare case. So, we investigated the effect of pomelo after its administration for one day or 3 consecutive days on the pharmacokinetics of tacrolimus in rats. We also confirmed the effects of grapefruit, turmeric, and ginger. The tacrolimus blood concentrations of the rats pre-treated with 100% pomelo juice were significantly higher than those pre-treated with water. On the other hand, the tacrolimus blood concentrations of the rats pre-treated with 50% pomelo juice were not significantly different from those pre-treated with water. The pomelo-tacrolimus interaction showed concentration dependency. Even low concentration of pomelo juice could enhance the blood concentrations of tacrolimus by repeated administration. The inhibitory effect of 100% pomelo juice disappeared 3 days after intake. The AUC values of tacrolimus in the rats pre-treated with grapefruit juice, ginger juice, and turmeric juice were significantly larger than those pre-treated with water. We could confirm the pomelo-tacrolimus interaction, which we discovered in a case study, quantitatively. We newly found the influence of turmeric and ginger on tacrolimus pharmacokinetics, comparable to pomelo.

Potential risks resulting from fruit/vegetable-drug interactions: effects on drug-metabolizing enzymes and drug transporters.

It has been well established that complex mixtures of phytochemicals in fruits and vegetables can be beneficial for human health. Moreover, it is becoming increasingly apparent that phytochemicals can influence the pharmacological activity of drugs by modifying their absorption characteristics through interactions with drug transporters as well as drug-metabolizing enzyme systems. Such effects are more likely to occur in the intestine and liver, where high concentrations of phytochemicals may occur. Alterations in cytochrome P450 and other enzyme activities may influence the fate of drugs subject to extensive first-pass metabolism. Although numerous studies of nutrient-drug interactions have been published and systematic reviews and meta-analyses of these studies are available, no generalizations on the effect of nutrient-drug interactions on drug bioavailability are currently available. Several publications have highlighted the unintended consequences of the combined use of nutrients and drugs. Many phytochemicals have been shown to have pharmacokinetic interactions with drugs. The present review is limited to commonly consumed fruits and vegetables with significant beneficial effects as nutrients and components in folk medicine. Here, we discuss the phytochemistry and pharmacokinetic interactions of the following fruit and vegetables: grapefruit, orange, tangerine, grapes, cranberry, pomegranate, mango, guava, black raspberry, black mulberry, apple, broccoli, cauliflower, watercress, spinach, tomato, carrot, and avocado. We conclude that our knowledge of the potential risk of nutrient-drug interactions is still limited. Therefore, efforts to elucidate potential risks resulting from food-drug interactions should be intensified in order to prevent undesired and harmful clinical consequences.

Advances of molecular clinical pharmacology in gastroenterology and hepatology.

During developmental age, differences in pharmacodynamic reactions to several drugs may reflect polymorphisms of genes encoding drug-transporting proteins, receptors, drug targets, and gene products, whose disturbed activity sometimes plays an important role in certain diseases. Administration of drugs with a narrow therapeutic index may quite easily be associated with changes in pharmacokinetics and development of adverse drug reactions, which occasionally may cause fatalities. In such cases, polypragmasy and resulting drug interactions may enhance effects of changes in drug-metabolizing enzymes' activities. Phenotyping and genotyping of patients slowly are finding their place in some therapeutic regimens used in clinical gastroenterology and hepatology. At present, some assays to measure, for example, thiopurine S-methyltransferase activity are already commercially available. Polymorphisms of CYP450 enzymes, interleukins, and altered gene expression play an important role in some patients' various gastrointestinal tract and liver diseases. Herbal drugs also affect proinflammatory and antiinflammatory cytokine and nitric oxide balance in the body. Therapeutic use of recombined proteins, such as infliximab, natalizumab, onercept, humanized antibody to integrin α-4 ß-7, or IFN-ß in some large-bowel diseases increased therapeutic efficacy. IFN-α used in the patients with chronic hepatitis C improved cellular immunity in these subjects and exerted antiviral activity. Practical application of progress in pharmacogenetics, pharmacokinetics, pharmacodynamics, and use of bioproducts in novel therapeutic regimens has opened therapeutic frontiers and increased clinical safety.

[Pharmacokinetic problems in clinical practice: role of drug transporters]. / Pharmakokinetische Probleme in der Praxis: Rolle von Arzneimitteltransportern.

Drug disposition is controlled by drug metabolism and drug transport. In the last decade numerous drug transporters have been identified and characterized in the context of drug uptake, efflux and interactions. This article reviews major advancements in this field. Efflux pumps like the multidrug resistance protein 1 (MDR1, ABCB1) are expressed in the intestine where they secrete drugs back into the intestinal lumen. Inhibitors of ABCB1 can increase the bioavailability of such drugs due to an increased absorption. Inducers of metabolism (rifampicin, carbamazepine, St. John's Wort) also induce the expression of drug transporters like ABCB1. Subsequently, an increased intestinal secretion in addition to an increased metabolism can diminish plasma levels of drugs, for example ciclosporin. The relevance of uptake transporters is increasingly recognized. SLCO1B1 is a hepatic uptake transporter involved in the absorption of statins. Inhibition of SLCO1B1 as well as common genetic variants can lead to increased bioavailability and to adverse reactions, ultimately culminating in rhabdomyolysis.

Understanding the grapefruit-drug interaction.

The inhibitory interaction of grapefruit juice and CYP3A4 medication metabolism was discovered in 1989. CYP3A4 enzymes are responsible for the metabolism of more than 60% of orally-administered drugs. Grapefruit components inhibit CYP3A4 drug oxidation and P-glycoprotein transportation, allowing more systemic drug bioavailability. This inhibitory interaction should be kept in mind when prescribing drugs that are metabolized by CYP3A4, such as orally administered midazolam, triazolam, and diazepam.

Effect of cytochrome P450 inhibitors (diethyl dithiocarbamate, ketoconazole and grapefruit juice) on the pharmacokinetics of all-trans-retinoic acid.

Diethyl dithiocarbamate (DEDTC) has been reported to be a more powerful inhibitor of all-trans-retinoic acid (ATRA) in vitro metabolism than the well-established cytochrome P450 (CYP) inhibitor ketoconazole (KC). In recent years grapefruit juice (GJ) has been shown to be able to increase the oral bioavailability of several drugs by inhibiting intestinal CYP. This study investigated the in vivo effect of these CYP inhibitors on the pharmacokinetics of ATRA. The latter was administered to rats as a constant-rate intravenous (i.v.) infusion (0.48 mg h(-1) kg(-1)) during 10 h and orally (1.6 mg kg(-1)). DEDTC (320 mg kg(-1) x 2 i.v., 6.4 and 32 mg kg(-1) per os (p.o.)) did not change the ATRA concentration-time profiles, whereas KC (320 and 32 mg kg(-1) p.o.)--with i.v. infused or orally dosed ATRA--increased the mean concentration-time curve value by 160% and 78%, respectively. A high dose of DEDTC (320 mg kg(-1) p.o.) caused a marked decrease in plasma levels of ATRA. GJ (6.4 ml kg(-1) p.o.) did not affect the plasma levels of ATRA. It is concluded that the in vivo effect of CYP inhibitors (DEDTC and KC) on the elimination rate of ATRA is qualitatively different from that expected from in vitro studies.

6'7'-Dihydroxybergamottin contributes to the grapefruit juice effect.

OBJECTIVE: Our objective was to assess the contribution of 6',7'-dihydroxybergamottin (DHB) to the inhibitory effect of grapefruit juice toward intestinal cytochrome P450 (CYP) 3A4. METHODS: An aqueous extract was prepared from grapefruit juice by centrifugation, filtration, and repeated washing of the particulate with water. The concentrations of various furanocoumarins in this grapefruit juice "serum" and in whole grapefruit juice were measured by HPLC and their identities confirmed by liquid chromatography-tandem mass spectrometry. Five healthy volunteers were given a single tablet of felodipine (10 mg) with whole grapefruit juice, orange juice-containing serum, or plain orange juice (control). The pharmacokinetic outcomes of felodipine were evaluated by noncompartmental methods. The effects of serum and purified DHB (at the same concentrations as those measured in the orange juice-containing serum used in the clinical study) were compared, in vitro, with regard to (1) the reversible and mechanism-based inhibition of the catalytic activity of complementary deoxyribonucleic acid-expressed CYP3A4 and (2) the time-dependent loss of immunoreactive CYP3A4 protein in modified Caco-2 cells. RESULTS: The concentration of DHB in serum was comparable to that measured in whole grapefruit juice (38 micromol/L versus 43 micromol/L), and the concentrations of other known furanocoumarins were well below the lowest published concentration required to inhibit catalytic activity by 50%. Relative to plain orange juice, orange juice-containing serum significantly increased the median felodipine area under the plasma concentration-time curve by 1.9-fold (P =.04) and increased the maximum concentration by 1.7-fold (P =.01). In vitro, serum and purified DHB had similar inhibitory effects toward CYP3A4 activity with respect to both reversible inhibition (95% confidence interval, 85% +/- 5.7% and 75% +/- 4.5%, respectively) and mechanism-based inhibition after a 15-minute preincubation (95% confidence interval, 79% +/- 6.8% and 78% +/- 5.7%, respectively). In Caco-2 cells the time-averaged extents of CYP3A4 protein loss caused by serum and purified DHB were identical (43%). CONCLUSION: The interaction between grapefruit juice serum and felodipine can be attributed largely to DHB. This establishes DHB as an important contributor to the grapefruit juice effect.