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PubMed2005

Dry granulation and compression of spray-dried plant extracts.

The purpose of this research was to evaluate the influence of dry granulation parameters on granule and tablet properties of spray-dried extract (SDE) from Maytenus ilicifolia, which is widely used in Brazil in the treatment of gastric disorders. The compressional behavior of the SDE and granules of the SDE was characterized by Heckel plots. The tablet properties of powders, granules, and formulations containing a high extract dose were compared. The SDE was blended with 2% magnesium stearate and 1% colloidal silicon dioxide and compacted to produce granules after slugging or roll compaction. The influences of the granulation process and the roll compaction force on the technological properties of the granules were studied. The flowability and density of spray-dried particles were improved after granulation. Tablets produced by direct compression of granules showed lower crushing strength than the ones obtained from nongranulated material. The compressional analysis by Heckel plots revealed that the SDE undergoes plastic deformation with a very low tendency to rearrangement at an early stage of compression. On the other hand, the granules showed an intensive rearrangement as a consequence of fragmentation and rebounding. However, when the compaction pressure was increased, the granules showed plastic deformation. The mean yield pressure values showed that both granulation techniques and the roll compaction force were able to reduce the material's ability to undergo plastic deformation. Finally, the tablet containing a high dose of granules showed a close dependence between crushing strength and the densification degree of the granules (ie, roll compaction force).

Compressive Strength↗

PubMed2005

In-vitro evaluation of khaya and albizia gums as compression coatings for drug targeting to the colon.

Khaya and albizia gums were evaluated as compression coatings for target drug delivery to the colon using indometacin (a water insoluble drug) and paracetamol (a water soluble drug) as model drugs. The core tablets were compression-coated with 300 and 400 mg of 100% khaya gum, 100% albizia gum and a mixture of khaya and albizia gum (1:1). Drug release studies were carried out in 0.1(M) HCl (pH 1.2) for 2 h, Sorensen's buffer (pH 7.4) for 3 h and then in phosphate-buffered saline (pH 6.8) or in simulated colonic fluid for the rest of the experiment to mimic the physiological conditions from the mouth to colon. The results indicated that khaya and albizia gums were capable of protecting the core tablet in the physiological environment of the stomach and small intestine, with albizia gum showing greater ability than khaya gum. The release from tablets coated with the mixture of khaya and albizia gums was midway between the two individual gums, indicating that there was no interaction between the gums. Studies carried out using rat caecal matter in phosphate-buffered saline at pH 6.8 (simulated colonic fluid) showed that the gums were susceptible to degradation by the colonic bacterial enzymes, leading to release of the drug. The results demonstrate that khaya gum and albizia gum have potential for drug targeting to the colon.

Acetaminophen↗

PubMed2002

Screening of South American plants against human immunodeficiency virus: preliminary fractionation of aqueous extract from Baccharis trinervis.

Ethanolic and aqueous extracts of 14 South American medicinal plants were tested for inhibitory activity on human immunodeficiency virus (HIV). Both extracts were relatively non-toxic to human lymphocytic MT-2 cells, but only the aqueous extract of Baccharis trinervis exhibited potent anti-HIV activity in an in vitro MTT assay. To delineate the extract-sensitive phase, some studies of the antiviral properties of the active extract are described in this paper. Based on the results presented here, a separation scheme was devised, which permitted the preliminary fractionation of the extract, with the aim of finding an inhibitor of this virus.

Baccharis↗

PubMed2003

Studies on the antioxidant activities of Desmodium gangeticum.

Desmodium gangeticum is herbal species which is widely used in the indigenous system of medicine and is reported to contain flavone and isoflavanoid glycosides. In view of its wide use and it's chemical composition, this study was aimed at examining the antioxidant activity of the extract of D. gangeticum. The extract was studied for diphenyl picryl hydrazyl (DPPH), nitric oxide, ferryl-bipyridyl and hypochlorous acid scavenging activity along with lipid peroxidation. Nitric oxide was generated using sodium nitroprusside and was studied using Griess reagent. In order to study the iron chelating capacity of the extract, the percentage ferryl-bipyridyl inhibition was studied. Hypochlorous acid scavenging activity was tested by measuring the inhibition of 5-thio-2-nitrobenzoic acid oxidation. The extract was also studied for lipid peroxidation assay by thiobarbituric acid-reactive substances (TBARS) method using rat brain homogenate. The results indicate that D. gangeticum extract has potent antioxidant activity.

Animals↗

PubMed2004

Isolation of angiotensin converting enzyme (ACE) inhibitory flavonoids from Sedum sarmentosum.

Bioassay-guided fractionation of the EtOAc-soluble extract of Sedum sarmentosum afforded a new flavonoid, quercetin-3-O-alpha-(6'''-caffeoylglucosyl-beta-1,2-rhamnoside) (1), along with four known flavonoids, quercetin 3-O-alpha-(6'''-p-coumaroylglucosyl-beta-1,2-rhamnoside) (2), isorhamnetin-3-beta-glucopyranoside (3), quercetin-3-beta-glucopyranoside (4), and kaempferol-3-alpha-arabinopyranoside (5). Purification of these compounds was conducted with the application of various chromatographic methods. Compounds 1-5 inhibited angiotensin I converting enzyme (ACE) activity in a concentration-dependent manner. Compounds 1-5 had 50% inhibitory concentration values of 158.9+/-11.1 microgM, 351.6+/-3.9 microgM, 408.9+/-4.6 microgM, 708.8+/-23.1 microgM, and 392.8+/-13.4 microgM.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2005

Cytochrome P450 2D6 (CYP2D6) inhibitory constituents of Catharanthus roseus.

The MeOH-soluble fraction of the water extract of Catharanthus roseus from Indonesia, having shown potent inhibitory activity on the metabolism mediated by CYP2D6, was subjected to activity-guided isolation to yield two triterpenes, ursolic acid (1) and oleanolic acid (2), and three alkaloids, vindoline (3), ajmalicine (4), and serpentine (5). The isolated compounds were tested for their inhibitory activity on the metabolism mediated by CYP3A4 or CYP2D6 using [N-methyl-14C]erythromycin or [O-methyl-14C]dextromethorphan as a substrate, respectively. Ajmalicine (4) and serpentine (5) showed very potent inhibitory activity against CYP2D6 with IC50 values of 0.0023 and 3.51 microM, respectively. All isolated compounds showed weak or no inhibition against CYP3A4. On time-, concentration-, and NADPH-dependent assay, serpentine (5) appear to be the mechanism-based inhibitor for CYP2D6 enzyme in which the inhibition was irreversible and driven by catalytic process. K(I) and k(inact) values for serpentine (5) were 0.148 microM and 0.090 min-1, respectively. On the other hand, ajmalicine (4) showed no time-dependent inhibition or reversible inhibition, and thus appear to be not mechanism-based inhibitor.

Catharanthus↗

PubMed2005

Phylogenetic relationship of Glycyrrhiza lepidota, American licorice, in genus Glycyrrhiza based on rbcL sequences and chemical constituents.

Two known saponins, licorice-saponin H2 and macedonoside A, were isolated from the stolons of Glycyrrhiza lepidota (American licorice) as major saponins. Since licorice-saponin H2 and macedonoside A are minor saponins isolated from the three glycyrrhizin-producing species (i.e. G. glabra, G. uralensis, G. inflata) and the three macedonoside C-producing species (i.e. G. macedonica, G. echinata, G. pallidiflora), respectively, the present study suggests that G. lepidota is an intermediate of both glycyrrhizin-producing and macedonoside C-producing species. The phylogenetic tree constructed from the nucleotide sequences of ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) of these seven Glycyrrhiza plants indicated that G. lepidota was separated from the other six Glycyrrhiza species, and this phylogenetic relationship was in accordance with their saponin compositions.

Glycyrrhiza↗

PubMed2005

Antioxidant effects of aqueous extracts from dried calyx of Hibiscus sabdariffa Linn. (Roselle) in vitro using rat low-density lipoprotein (LDL).

The present study quantitatively investigated the antioxidant effects of the aqueous extracts from dried calyx of Hibiscus sabdariffa LINN. (roselle) in vitro using rat low-density lipoprotein (LDL). Formations of the conjugated dienes and thiobarbituric acid reactive substances (TBARs) were monitored as markers of the early and later stages of the oxidation of LDL, respectively. Thus, we demonstrated that the dried calyx extracts of roselle exhibits strong antioxidant activity in Cu(2+)-mediated oxidation of LDL (p<0.05) in vitro. The inhibitory effect of the extracts on LDL oxidation was dose-dependent at concentrations ranging from 0.1 to 5 mg/ml. Moreover, 5 mg/ml of roselle inhibited TBARs-formation with greater potency than 100 microM of vitamin E. In conclusion, this study provides a quantitative insight into the potent antioxidant effect of roselle in vitro.

Animals↗

PubMed2005

Evaluation of the estrogenic activity of Leguminosae plants.

The plant extracts of the Leguminosae family were screened for their estrogenic activity with the Ishikawa cell system. Of the tested plants, Desmodium oxyphyllum, Dunbaria villosa, Kummerowia striata, Lespedeza bicolor, Maackia amurensis, Maackia fauriei, Pueraria thunbergiana, and Sophora flavescens were highly estrogenic with EC50 values of less than 10 microg/ml.

Cell Line, Tumor↗

PubMed2005

Hypnotic activities of chamomile and passiflora extracts in sleep-disturbed rats.

In the present study, we investigated hypnotic activities of chamomile and passiflora extracts using sleep-disturbed model rats. A significant decrease in sleep latency was observed with chamomile extract at a dose of 300 mg/kg, while passiflora extract showed no effects on sleep latency even at a dose of 3000 mg/kg. No significant effects were observed with both herbal extracts on total times of wakefulness, non-rapid eye movement (non-REM) sleep and REM sleep. Flumazenil, a benzodiazepine receptor antagonist, at a dose of 3 mg/kg showed a significant antagonistic effect on the shortening in sleep latency induced by chamomile extract. No significant effects were observed with chamomile and passiflora extracts on delta activity during non-REM sleep. In conclusion, chamomile extract is a herb having benzodiazepine-like hypnotic activity.

Animals↗

PubMed2006

Anti-asthmatic activity of an ethanol extract from Saururus chinensis.

As an attempt to find bioactive medicinal herbs exerting anti-asthmatic activity, the effects of an ethanol extract from the parts of Saururus chinensis were evaluated in both in vitro and in vivo. The ethanol extract of S. chinensis (ESC) inhibited generation of the cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D(2) in bone marrow-derived mast cells in a concentration-dependent manner with an IC(50) value of 14.3 microg/ml. ESC also inhibited leukotriene C(4) production with an IC(50) value of 0.3 microg/ml. This demonstrates that ESC has COX-2/5-lipoxygenase dual inhibitory activity. In addition, this compound inhibited degranulation reaction in a dose dependent manner, with an IC(50) value of 1.3 microg/ml. An ovalbumin induced mouse asthmatic animal model was used to determine its in vivo anti-asthmatic activity. The oral administration (50-200 mg/kg) of ESC reduced the number of infiltrated eosinophil in a bronchoalveolar lavage fluid. Furthermore, ESC (100 mg/kg) inhibited the eotaxin and IL-4 mRNA expression levels. These results suggest that the anti-asthmatic activity of S. chinensis might in part occur via the inhibition of eicosanoid generation, degranulation as well as the down regulation of IL-4 and eotaxin mRNA expression.

Animals↗

PubMed2007

Endothelium-dependent vasodilatory and hypotensive effects of Crotalaria sessiliflora L. in rats.

The aim of the present study was to investigate the vasoactive effect of Crotalaria sessiliflora L. extract (CSE) on rats and its mechanism when combining in vivo and in vitro approaches. CSE (0.5-5 mg/ml) induced concentration-dependent relaxation on endothelium-intact thoracic aortic rings precontracted with phenylephrine (PE, 10(-5) M). This effect disappeared with the removal of functional endothelium. Pretreatment of the aortic strips with either N(G)-nitro-L-arginine (L-NNA, 10(-5) M) or methylene blue (10(-5) M) significantly reduced the relaxation induced by CSE. The endothelium-dependent relaxation caused by CSE was associated with production of cGMP. CSE (5 mg/ml) increased the production of cGMP in endothelium-intact aortic rings and this effect was significantly attenuated by L-NNA (10(-5) M) and methylene blue (10(-5) M). Relaxation in response to CSE in strips precontracted with PGF2alpha (3x10(-5) M) was eliminated by removing extracellular Ca2+ and significantly reduced by pretreatment with ruthenium red (10(-5) M). In in vivo tests, injection of 40 mg/kg of CSE induced an increase in plasma NO production, and this effect was blocked by L-NNA. Furthermore, CSE produced dose-dependent and transient decrease in blood pressure in normotensive rats and this effect was blocked by atropine as well as L-NNA. These findings suggest that CSE induces endothelium-dependent relaxation via NO/cGMP signaling by promoting extracellular Ca2+ influx and the release of Ca2+ from intracellular stores of endothelium, probably due to endothelial muscarinic receptor activation.

Animals↗

PubMed2002

Taxumairols X--Z, new taxoids from Taiwanese Taxus mairei.

In addition to 19-dydroxybaccatin III, 1beta-hydroxy-5 alpha-deacetylbaccatin I, taxayuntin G and 13-O-deacetyltaxumairol Z (4), three new taxane diterpenoids, taxumairols X (1), Y (2), Z (3) have been isolated from extracts of the Formosan Taxus mairei (LEMEE & LEVL.) S. Y. HU. Compounds 1-2 belong to the 11(15-->1)-abeo-taxane system, having a tetrahydrofuran ring at C-2, C-3, C-4 and C-20. The new compound 3 and 4, which was misidentified previously are derivatives of 11(15-->1)-abeo-taxane with an intact oxirane system. The structures of compounds 1-4 were elucidated on the basis of extensive two dimensional (2D)-NMR analysis.

Magnetic Resonance Spectroscopy↗

PubMed2003

Highly-oxygenated isopimarane-type diterpenes from Orthosiphon stamineus of Indonesia and their nitric oxide inhibitory activity.

From the methanolic extract of Indonesian Orthosiphon stamineus, nine new highly-oxygenated isopimarane-type diterpenes [7-O-deacetylorthosiphol B (1), 6-hydroxyorthosiphol B (2), 3-O-deacetylorthosiphol I (3), 2-O-deacetylorthosiphol J (4), siphonols A-E (5-9)] have been isolated together with nine known diterpenes [orthosiphols H (10), K (11), M (12) and N (13); staminols A (14) and B (15); neoorthosiphols A (16) and B (17); norstaminol A (18)]. Their structures were determined based on the spectroscopic data. The isolated diterpenes inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophage-like J774.1 cells. Compounds 4-7, 9, 10, 14, and 17 showed inhibitory activities more potent (IC(50), 10.8-25.5 microM) than a positive control N(G)-monomethyl-L-arginine (L-NMMA; IC(50), 26.0 microM).

Animals↗

PubMed2003

Three new quassinoids, ailantinol E, F, and G, from Ailanthus altissima.

Three new quassinoids, ailantinol E (1), ailantinol F (2), and ailantinol G (3), and related compounds were isolated from Ailanthus altissima grown in Taiwan. Their structures were elucidated from spectral evidence. Each new quassinoid was evaluated for its antitumor promoting effects against Epstein-Barr virus early antigen activation introduced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. The new quassinoids were found to show potent activity without showing any cytotoxicity. The screening for inhibitors against nitric oxide donor action was also conducted using the new quassinoids and some standard samples.

Ailanthus↗

PubMed2004

Microbial metabolism. Part 5. Dihydrokawain.

Preparative scale fermentation of (6S)-dihydrokawain (1) with Rhizopus arrhizus (ATCC 11145) gave 3'-hydroxydihydrokawain (2) and (8S)-hydroxydihydrokawain (3). Structure elucidation of the metabolites was based on spectroscopic data. The C-8 absolute configuration of (3) was assessed via its Mosher's esters.

Kava↗

PubMed2004

A novel podophyllotoxin lignan from Justicia heterocarpa.

Chromatographic separation of the extract of Justicia heterocarpa T. ANDERS. afforded, in addition to known fatty acids, terpenoids and steroids, a new podophyllotoxin lignan. Structures were elucidated by spectroscopic methods, and the structure of the new lignan was confirmed by single crystal X-ray diffraction studies, which have shown that there is a H-bonding stabilized dimer.

Justicia↗

PubMed2004

New lathyrane and podocarpane diterpenoids from Jatropha curcas.

Chemical investigation on Jatropha curcas resulted in the isolation of twenty constituents among which four diterpenoids were unknown and six compounds, tetradecyl-(E)-ferulate, 3-O-(Z)-coumaroyl oleanolic acid, heudelotinone, epi-isojatrogrossidione, 2alpha-hydroxy-epi-isojatrogrossidione, and 2-methyanthraquinone had not been reported earlier from this species. The structures of the new compounds were established by extensive studies of their 1D- and 2D-NMR spectra.

Diterpenes↗