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PubMed2005

Cryptoxanthin structural isomers in oranges, orange juice, and other fruits.

Citrus fruits contain a wide range of bioactive compounds. Their carotenoid fraction is inter alia dominated by structural cryptoxanthin isomers as beta-cryptoxanthin and zeinoxanthin. Both xanthophylls were identified in saponified citrus fruit extracts by comparison to reference compounds extracted from corn and by their typical fragmentation pattern in LC-(APCI)MS analyses. alpha-Cryptoxanthin, another structural cryptoxanthin isomer usually found in carrot leaves, was not identified in the citrus fruits studied. Cryptoxanthin concentrations of direct orange juices (D) and reconstituted juices (C) were compared. Although the respective mean values [beta-cryptoxanthin, 62 (C) versus 110 microg/100 g (D); zeinoxanthin, 22 (C) versus 37 microg/100 g (D)] were statistically distinguishable (P < 0.05%), a doubtless classification is not possible because the concentration ranges overlap. To identify esters of structural cryptoxanthin isomers in native orange juice extracts, four saturated acyl esters were synthesized. LC-(APCI)MS studies revealed for the first time that the dominant acylation partners of both xanthophylls were C12:0, C14:0, and C16:0 in nearly equal amounts of roughly one-third, whereas C10:0 and C18:1 were present at lower extents of 5-14%; other acylation partners were not identified. The presented method is appropriate to gain deeper insight into the pattern of structural cryptoxanthin isomers of citrus fruits. Knowledge of acylated cryptoxanthin isomers may be important in the evaluation of the bioavailability of individual esters in future human digestion studies.

Beverages↗
PubMed2005

Absorption and bioavailability of artepillin C in rats after oral administration.

Artepillin C (AC), an active ingredient of Brazilian propolis, permeates intact across Caco-2 cells by transcellular passive diffusion. The permeation of AC across Caco-2 cells is as efficient as that of phenolic acids and the microbial metabolites of poorly absorbed polyphenols, which are actively absorbed by the monocarboxylic acid transporter (MCT) (Biochim. Biophys. Acta 2005, 1713, 138-144). Here, the absorption of orally administered AC in rats has been studied to evaluate its pharmacokinetics and bioavailability in vivo in comparison with those of p-coumaric acid (CA), a substrate of MCT. Rats were given 100 micromol/kg of body weight of AC or CA, and blood was subsequently collected from the portal vein and abdominal artery. AC, CA, and their metabolites were quantified by coulometric detection using HPLC-ECD. The serum concentration of intact AC and CA in the portal vein peaked at 5-10 min after administration, with a C(max) of 19.7 micromol/L for AC and 74.8 micromol/L for CA. The area under the curve (AUC) for intact AC and CA in the portal vein was calculated from the serum concentration as 182.6 and 3057.3 micromol.min.L(-1), respectively. The absorption efficiency of CA was about 17-fold higher than that of AC. Furthermore, the bioavailability of CA was about 278-fold higher than that of AC, and the ratio of AUC in the abdominal artery to AUC in the portal vein was 0.04 and 0.70, for AC and CA, respectively. Thus, AC is likely to be more susceptible to hepatic elimination than is CA. The bioactive compound of AC in vivo should be investigated further.

Animals↗
PubMed2006

Amelioration of obesity and glucose intolerance in high-fat-fed C57BL/6 mice by anthocyanins and ursolic acid in Cornelian cherry (Cornus mas).

Much attention has been focused on food that may be beneficial in preventing diet-induced body fat accumulation and possibly reduce the risk of diabetes and heart disease. Cornelian cherries (Cornus mas) are used in the preparation of beverages in Europe and also to treat diabetes-related disorders in Asia. In this study, the most abundant bioactive compounds in C. mas fruits, the anthocyanins and ursolic acid, were purified, and their ability to ameliorate obesity and insulin resistance in C57BL/6 mice fed a high-fat diet was evaluated. Mice were initially fed a high-fat diet for 4 weeks and then switched to a high-fat diet containing anthocyanins (1 g/kg of high-fat diet) and ursolic acid (500 mg/kg of high-fat diet) for an additional 8 weeks. The high-fat diet induced glucose intolerance, and this was prevented by anthocyanins and ursolic acid. The anthocyanin-treated mice showed a 24% decrease in weight gain. These mice also showed decreased lipid accumulation in the liver, including a significant decrease in liver triacylglycerol concentration. Anthocyanin and ursolic acid treated mice exhibited extremely elevated insulin levels. Both treatments, however, showed preserved islet architecture and insulin staining. Overall, these data suggest that anthocyanins and ursolic acid purified from C. mas fruits have biological activities that improve certain metabolic parameters associated with diets high in saturated fats and obesity.

Animals↗
PubMed2006

Comparison of methods for the exhaustive extraction of hypericins, flavonoids, and hyperforin from Hypericum perforatum L.

Renewed interest in plant-derived drugs has led to an increased need for efficient extraction methods. Hypericum perforatum L. contains several groups of bioactive compounds with noteworthy pharmacological activities. Direct sonication of H. perforatum was investigated and compared with conventional maceration, indirect sonication, Soxhlet extraction, and accelerated solvent extraction (ASE). Highly selective liquid chromatography/tandem mass spectrometry analysis showed that the content of six investigated active compounds (hypericin, pseudohypericin, hyperoside, rutin, quercitrin, and hyperforin) in extracts obtained by direct sonication was significantly higher than in extracts obtained by the other methods. The active compound contents increased on increasing the ultrasonic power from 40 to 60 W when using direct sonication. Conventional maceration gave the lowest amount of analyzed active compounds. Soxhlet extraction gave better results than ASE or indirect sonication.

Anthracenes↗
PubMed2005

Apples prevent mammary tumors in rats.

Regular consumption of fruits and vegetables has been consistently shown to be associated with reduced risk of developing chronic diseases such as cancer and cardiovascular disease. Apples are commonly consumed and are the major contributors of phytochemicals in human diets. It was previously reported that apple extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. Phytochemicals, including phenolics and flavonoids, are suggested to be the bioactive compounds contributing to the health benefits of apples. Here it is shown that whole apple extracts prevent mammary cancer in a rat model in a dose-dependent manner at doses comparable to human consumption of one, three, and six apples a day. This study demonstrated that whole apple extracts effectively inhibited mammary cancer growth in the rat model; thus, consumption of apples may be an effective strategy for cancer protection.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2006

Quantification and stability studies on the flavonoids of Radix hedysari.

Radix hedysari is not only a restorative food but also a famous Traditional Chinese Medicine. In this study, a simple, reliable, and reproducible high-performance liquid chromatography-ultraviolet method was developed for the first time to determine the true contents of five major flavoniods, naringenin-7-O-alpha-L-rhamanopyranosyl-(1-->2)-beta-d-glucopyranoside, ononin, formononetin, medicarpin, and an unstable flavonoid malonate (formononetin-7-O-beta-D-glucoside-6' '-O-malonate, FGM), and the stability of FGM was also investigated. Flavoniods were selected as chemical markers because they have appeared as one of the major bioactive compound groups in Radix hedysari. The stability results of FGM at different pH showed that it remained relatively stable in acidic aqueous methanol of pH 3. The HPLC assay with an improved sample preparation scheme can be readily utilized as a suitable "chemical" quality control method for Radix hedysari.

Chromatography, High Pressure Liquid↗
PubMed2007

Comparison of extraction methods for the quantification of selected phytochemicals in peanuts (Arachis hypogaea).

Peanuts have been reported to contain bioactive phytochemicals, particularly isoflavones (genistein, daidzein, and biochanin A) and trans-resveratrol. Currently, limited data are available regarding the levels of these bioactive compounds in peanuts with variations in reported levels. The purpose of this study was to compare four methods of extraction [stirring, sonication, Soxtec, and microwave-assisted sonication (MAS)] for runner peanuts. Quantification of the selected compounds was conducted by reverse-phase high-performance liquid chromatography (RP-HPLC). The results showed that the MAS and Soxtec methods extracted significantly higher amounts of the phytochemicals. Also, the defatted peanuts gave significantly higher amounts of the phytochemicals compared to the nondefatted peanuts. The high levels of the isoflavones may be attributed to heat-induced conversion of conjugate glycosides to aglycons. The MAS and Soxtec methods may be used for total isoflavone content quantitation, while sonication or stirring may be the method of choice for quantitation of isoflavone composition (aglycons and glycoside conjugates) in peanuts.

Arachis↗
PubMed2007

Quantitation of tocotrienol and tocopherol in various rice brans.

Rice bran is abundant in bioactive compounds including tocotrienol (T3, unsaturated vitamin E). T3 has been reported about its potential functionalities (i.e., antiangiogenic effect), so much attention has been paid on usability of rice bran T3. Hence, we developed a rapid screening method for T3-rich rice bran by one-step equilibrium direct solvent extraction followed by normal phase high-performance liquid chromatography (HPLC). The method gave high-extraction rate of rice bran T3 and tocopherol (above 90%), and the determination of vitamin E by HPLC was completed within 15 min. Using the method, an average of total T3 content in 109 kinds of rice bran samples was 830 mug/g dry wt. Kouchi-Akamai, Joushuu, and Wataribune were found as the T3-rich rice bran varieties (1350-1430 microg T3/g dry wt). According to T3 ratio against total vitamin E (wt %), the average ratio was 61%. Hirayama, Moritawase, and Kaneko were found as the varieties having the highest T3 ratio (80-86%). Since T3 content in Koshihikari rice bran (the leading variety in Japan) was a little above the average, we cross-fertilized Koshihikari with T3-rich varieties and found that T3 content or ratio in F1 was improved compared with Koshihikari. The varieties found rich in T3 could be used for nutraceutical purpose.

Agriculture↗
PubMed1999

Validation of a novel estrogen receptor-based microtitration plate assay for the determination of phytoestrogens in soy-based foods.

A novel, nonisotopic microtitration plate assay based on the human estrogen receptor has been used to screen soy-based and soy-containing foods for their phytoestrogen content (measured as genistein equivalents). The validation of the assay for use with food extracts has been demonstrated by investigation of recoveries after acidic and enzymic hydrolysis, by investigation of matrix effects, and by comparison of results with HPLC analysis. Phytoestrogen levels in soy products analyzed ranged between 520 and 1872 microgram of genistein equiv/g of soy flour, 5-282 microgram/g of soy concentrates, 503-1292 microgram/g of soy-protein isolates, and 108-226 microgram/g of soy-based infant formulas. Samples of textured vegetable protein and bread containing soy and linseed gave values of 1114 and 68 microgram/g, respectively. Comparison of results for 12 samples analyzed both by the receptor assay and by HPLC showed good correlation (r(2) = 0.905). The assay, which is rapid and simple to perform, is suitable for screening phytoestrogen-containing foods in order to assess human exposure to these bioactive compounds. The assay sensitivity is 3.4 microgram/g, and 14 samples/plate can be analyzed in 4 h following hydrolysis.

Chromatography, High Pressure Liquid↗
PubMed2003

Elicitation, a new window into plant chemodiversity and phytochemical drug discovery.

Plant extracts collected from the wild are important sources for drug discovery. However, these extracts suffer from a lack of reproducible bioactivity and chemical composition caused by the highly inducible, variable, and transitory nature of plant secondary metabolism. Here, we demonstrate that exposing roots of hydroponically grown plants to chemical elicitors selectively and reproducibly induced the production of bioactive compounds, dramatically increased the hit rate, and more than doubled the number of plant species showing in vitro activity against bacteria, fungi, or cancer. Elicitation performed under controlled conditions dramatically improves reliability and efficiency of plant extracts in drug discovery while preserving wild species and their habitats.

Anti-Bacterial Agents↗
PubMed2002

Syntheses and antitumor targeting G1 phase of the cell cycle of benzoyldihydroisoquinolines and related 1-substituted isoquinolines.

A series of 1-substituted 3,4-dihydroisoquinolines were synthesized and tested in vitro against the leukemia L 1210 cell line to evaluate their ability to perturb the cell cycle by arresting cells in the G1 phase. 1-Benzoylimines, 1-phenylimines, and 1-alkylimines were synthesized. The most powerful cytotoxic derivatives, 1-benzoyl-3,4-dihydroisoquinolines (1-26), were obtained from amides I via 1-benzyl-3,4-dihydroisoquinoline in good yield by a direct selective oxidation of the benzylic carbon of the corresponding imines through 10% Pd/C in acetonitrile. SAR studies let us to identify the essential structural features for cytotoxic activity. The most bioactive compounds (with IC(50) < 5 microM) were BzDHIQ (13, 22, 21, 8, 9, 11, 1, 20, 6, and 19), and they are characterized by the following: (i) An alpha-ketoimine moiety is necessary for potent antiproliferative activity (1-phenyl- and 1-alkyl-3,4-dihydroisoquinoline derivatives, 34-40, are less active). (ii) An hydrophobic, benzyloxy, alkyloxy, or allyloxy group at the C-6 position seems to be relevant for cytotoxicity. (iii) Regarding the influence of the benzoylic moiety, both the unsubstituted (13, 8, 9, 11, 1, and 6) and the 3'-monosubstituted (22, 21, 20, and 19) compounds were more potent than compounds with other substitutions.

Animals↗
PubMed2005

Fast small molecule similarity searching with multiple alignment profiles of molecules represented in one-dimension.

Multiple sequence alignment has proven to be a powerful method for creating protein and DNA sequence alignment profiles. These profiles of protein families are useful tools for identifying conserved motifs, such as the catalytic triad of the serine protease family or the seven transmembrane helices of the G-protein coupled receptor family. Ultimately, the understanding of the critical motifs within a family is useful for identifying new members of the family. Due to the complexity of protein-ligand recognition, no universally accepted method exists for clustering small molecules into families with the same or similar biological activity. A combination of the concept of multiple sequence alignment and the 1-dimensional molecular representation described earlier offers a new method for profiling sets of small molecules with the same biological activity. These small molecule profiles can isolate key commonalities within the set of bioactive compounds much like a multiple sequence alignment can isolate critical motifs within a protein family. The small molecule profiles then make useful tools for searching small molecule databases for new compounds with the same biological activity. The technique is demonstrated here using the human ether-a-go-go potassium channel and the kinase SRC.

Algorithms↗
PubMed1998

Enantiospecific semisynthesis of (+)-almuheptolide-A, a novel natural heptolide inhibitor of the mammalian mitochondrial respiratory chain.

The development of novel styryl lactone derivatives as bioactive compounds and the semisynthesis of both 4,5-dialkoxylated eight-membered-ring lactones with a heptolide skeleton (almuheptolide-A (1) type) and 7-alkoxylated delta-lactones with a saturated furanopyrone skeleton (etharvensin (8) type) have been successfully achieved from the chiral unsaturated alpha-pyrone altholactone (7). This new method is a direct and one-step enantiospecific alkoxylation of altholactone (7) in concentrated acid medium, followed by formation of the eight-membered-ring zeta-lactone. The reaction mechanism operating in the synthesis of the heptolide skeleton is postulated to be a direct Michael-type addition. Concerted opening of both the alpha-pyrone and tetrahydrofuran rings and subsequent intramolecular rearrangement with the ring closure lead to almuheptolide-A (1). This compound (1) and its diacetated derivative (1a) showed potent and selective inhibitory activity toward mammalian mitochondrial respiratory chain complex I. This mechanism of action, reported here for the first time, provides a possible explanation for the cytotoxic and antitumor activities previously described for related natural compounds.

Animals↗
PubMed2001

Probing sponge-derived terpenoids for human 15-lipoxygenase inhibitors.

A human 15-lipoxygenase (15-HLO) assay has been employed to discover new marine-sponge-derived bioactive compounds. Extracts from two different sponges, Jaspis splendens (order Choristida, family Jaspidae) and Suberea sp. (order Verongida, family Aplysinellidae), exhibited potent IC(50) values of 0.4 and 0.1 microg/mL, respectively. Both are sources of terpenoids, and the former is a known source of (+)-jasplakinolide (7), which is inactive as a 15-HLO inhibitor. The terpenoids included (+)-(5S,6S)-subersin (1, IC(50) > 100 microM), (-)-(5R,10R)-subersic acid (2, IC(50) = 15 microM), jaspaquinol (3, IC(50) = 0.3 microM), and (-)-jaspic acid (4, IC(50) = 1.4 microM). Structure elucidations and lipoxygenase activity studies of these compounds are reported.

Animals↗
PubMed2003

Preparation of protected syn-alpha,beta-dialkyl beta-amino acids that contain polar side chain functionality.

We report the synthesis of syn-alpha,beta-dialkyl beta-amino acid derivatives suitably protected for solid-phase synthesis that give rise to residues containing positively charged lysine-like side chains. These amino acids, as well as syn-alpha,beta-dialkyl beta-amino acids that contain diverse hydrophobic side chains, are prepared in good de and ee. The key step in this route involves Davies's protocol for the conjugate addition of a chiral lithium amide to alpha,beta-unsaturated tert-butyl esters (Davies, S. G.; Ichihara, O.; Walters, I. A. S. J. Chem. Soc., Perkin Trans. 1 1994, 9, 1141). syn-alpha,beta-Dialkyl beta-amino acids are interesting building blocks because of their sheet-forming propensity and because of their presence in bioactive compounds.

Amino Acids↗
PubMed2005

Synthesis of 1,3,5-trisubstituted hydantoins by regiospecific domino condensation/aza-Michael/O-->N acyl migration of carbodiimides with activated alpha,beta-unsaturated carboxylic acids.

[reaction: see text] Carbodiimides and suitably activated alpha,beta-unsaturated carboxylic acids react effectively to afford a vast array of 1,3,5-trisubstituted hydantoins by means of a regiospecific domino condensation/aza-Michael/N-->O acyl migration. The reaction works well in very mild conditions (20 degrees C, dichloromethane) with fumaric acid derivatives bearing an electron-withdrawing group in the beta position. Good results have been obtained also with less activated substrates bearing only one electron-withdrawing group in the beta position, using more polar solvents (acetonitrile, DMF), and in the presence of a base (2,4,6-trimethylpyridine). Reactions with asymmetric carbodiimides are generally highly chemo- and regioselective, giving rise to the formation of a single regioisomeric hydantoin. However, asymmetric carbodiimides bearing one alkyl group and one aryl group can produce variable amounts of N-acylurea byproducts. The latter could be easily recovered and transformed into the corresponding hydantoins. A detailed study of the influence of key reaction parameters such as solvent, base, and structure of the reactants on the reaction outcome and mechanism is presented. This methodology is particularly convenient for the synthesis of trifluoromethyl-substituted hydantoins, which could be interesting as bioactive compounds in medicinal chemistry, as well as precursors of the corresponding alpha-amino acids.

Carbodiimides↗
PubMed2005

Controlling the outcome of an N-alkylation reaction by using N-oxide functional groups.

Covalent modifiers of proteins are of importance in chemical proteomics, an emerging chemical technology used to assign protein function. In this study, high-field (1)H NMR techniques were used to analyze the reaction of the bioactive compound, 2,3-bis(bromomethyl)quinoxaline 1,4-dioxide, with amines (a model system for proteins containing nitrogen-based nucleophiles). Unexpectedly, the results show that a double nucleophilic substitution reaction involving 2 equiv of the amine is preferred to an intramolecular cyclization pathway. A direct comparison with the reaction carried out on a substrate lacking the N-oxide functional groups is also provided. X-ray crystal structures and computational studies are used to rationalize the observed differences in reactivity between the two systems.

Alkylation↗
PubMed2006

Synthesis and biological evaluation of azido- and aziridino-hydroxyl-beta-lactams through stereo- and regioselective epoxide ring opening.

Two new classes of azido- and aziridino-hydroxyl-beta-lactam containing structures have been prepared by means of a stereo- and regioselective epoxide ring opening. The straightforwardness of the procedure makes this strategy useful for the synthesis of potentially bioactive compounds. Some selected examples showed promising activity in acyl CoA-cholesterol acyltransferase inhibition assays.

Azides↗