Isolation of two flavonoids from Tanacetum microphyllum as PMA-induced ear edema inhibitors

Santin (5,7-Dihydroxy-3,6,4'-Trimetoxy-Flavone) Enhances TRAIL-Mediated Apoptosis in Colon Cancer Cells

TRAIL (Tumor necrosis factor-Related Apoptosis-Inducing Ligand) has the ability to selectively kill cancer cells without being toxic to normal cells. This endogenous ligand plays an important role in surveillance and anti-tumor immunity. However, numerous tumor cells are resistant to TRAIL-induced apoptosis. In this study, the apoptotic effect of santin in combination with TRAIL on colon cancer cells was examined. Flow cytometry was used to detect the apoptosis and expression of death receptors (TRAIL-R1/DR4 and TRAIL-R2/DR5). Mitochondrial membrane potential (ΔΨm) was evaluated by DePsipher staining with the use of fluorescence microscopy. We have shown for the first time that flavonoid santin synergizes with TRAIL to induce apoptosis in colon cancer cells. Santin induced TRAIL-mediated apoptosis through increased expression of death receptors TRAIL-R1 and TRAIL-R2 and augmented disruption of the mitochondrial membrane in SW480 and SW620 cancer cells. The obtained data may indicate the potential role of santin in colon cancer chemoprevention through the enhancement of TRAIL-mediated apoptosis.

An Overview on the Potential Antimycobacterial Agents Targeting Serine/Threonine Protein Kinases from Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), still remains an urgent global health issue, mainly due to the emergence of multi-drug resistant strains. Therefore, there is a pressing need to develop novel and more efficient drugs to control the disease. In this context, targeting the pathogen virulence factors, and particularly signal mechanisms, seems to be a promising approach. An important transmembrane signaling system in Mtb is represented by receptor-type Serine/ Threonine protein kinases (STPKs). Mtb has 11 different STPKs, two of them, PknA and PknB, are essential. By contrast PknG and PknH are involved in Mtb virulence and adaptation, and are fundamental for the pathogen growth in infection models. Therefore, STPKs represent a very interesting group of pharmacological targets in M. tuberculosis. In this work, the principal inhibitors of the mycobacterial STPKs will be presented and discussed. In particular, medicinal chemistry efforts have been focused on discovering new antimycobacterial compounds, targeting three of these kinases, namely PknA, PknB and PknG. Generally, the inhibitory effect on these enzymes do not correlate with a significant antimycobacterial action in whole-cell assays. However, compounds with activity in the low micromolar range have been obtained, demonstrating that targeting Mtb STPKs could be a new promising strategy for the development of drugs to treat TB infections.

Chromone Studies. Part 14.1 Unprecedented Dimerisation of Chromone-3-Carbaldehyde-Derived Baylis–Hillman Adducts

1,4-Diazabicyclo[2.2.2]octane (DABCO)-catalysed Baylis-Hillman reactions of selected chromone-3-carbaldehydes with methyl acrylate have been shown to afford mixtures of the expected Baylis-Hillman products and unprecedented dimeric derivatives. The Baylis–Hillman products, on heating at 80°C in the presence of DABCO, are converted to the corresponding dimers, the structures of which have been unambiguously established by NMR and X-ray crystallographic analysis. Electron-impact and electrospray MS data for the dimeric systems are discussed.

New Alkaloid and Aromatic Glucoside from the Flowers of Cymbidium Lunagrad Eternal Green

In this paper, we investigated the chemical components of the flowers of Cymbidium Lunagrad Eternal Green for the first time. In the whole post-fertilization, a new alkaloid, named Lunagrad A (1), and a new aromatic glucoside, named Lunagrad B (2), were isolated from the MeOH extract of the flowers of Cymbidium Lunagrad Eternal Green, along with other six known aromatic compounds (3–8) and three flavone glucosides (9–11). These structures were determined on the basis of NMR experiments, as well as chemical evidence.

Comparison in antioxidant and antitumor activities of pine polyphenols and its seven biotransformation extracts by fungi

Microbial transformation can strengthen the antioxidant and antitumor activities of polyphenols. Polyphenols contents, antioxidant and antitumor activities of pine polyphenols and its biotransformation extracts by Aspergillus niger, Aspergillus oryzae, Aspergillus carbonarius, Aspergillus candidus, Trichodermas viride, Mucor wutungkiao and Rhizopus sp were studied. Significant differences were noted in antioxidant and antitumor activities. The highest antioxidant activities in Trolox equivalent antioxidant capacity (TEAC), DPPH radical scavenging activity, superoxide anion radical scavenging activity, hydroxyl radical scavenging activity, reducing power assay and antitumor activity against LoVo cells were biotransformation extract of Aspergillus carbonarius (BAC), biotransformation extract of Mucor wutungkiao (BMW), biotransformation extract of Aspergillus carbonarius (BAC), biotransformation extract of Aspergillus niger (BAN), biotransformation extract of Aspergillus oryzae (BAO) and BMW, respectively. Correlation analysis found that antioxidant and antitumor activities were associated with polyphenols contents and types of free radicals and tumors. A. carbonarius can make polyphenol oxidation, hydroxylation and methylation, and form new polyphenols. In conclusion, A. carbonarius, A. niger and M. wutungkiao are valuable microorganisms used for polyphenols biotransformation and enhance the antioxidant and antitumor activities of polyphenols.

Acetylcholinesterase Inhibitory Activities of Flavonoids from the Leaves ofGinkgo bilobaagainst Brown Planthopper

Ginkgo bilobais a traditional Chinese medicinal plant which has potent insecticidal activity against brown planthopper. The MeOH extract was tested in the acetylcholinesterase (AChE) inhibitory assay with IC50values of 252.1 μg/mL. Two ginkgolides and thirteen flavonoids were isolated from the leaves ofGinkgo biloba. Their structures were established on the basis of spectroscopic data interpretation. It revealed that the 13 isolated flavonoids were found to inhibit AChE with IC50values ranging from 57.8 to 133.1 μg/mL in the inhibitory assay. AChE was inhibited dose dependently by all tested flavonoids, and compound6displayed the highest inhibitory effect against AChE with IC50values of 57.8 μg/mL.

Eunicidiol, an anti-inflammatory dilophol diterpene from Eunicea fusca

A new dilophol diterpene, eunicidiol (1), has been isolated from the crude extract of Eunicea fusca, a gorgonian coral collected from Hillsboro Ledge, Florida. This compound was purified, along with fuscol (2) and eunicol (3), using a combination of normal- and reversed-phase chromatography methods. The structure of eunicidiol (1) was elucidated by 1D and 2D NMR spectroscopic analysis, and the absolute configuration was assigned using Mosher's method. The anti-inflammatory activity of 1-3 was evaluated by measuring their ability to reduce phorbol myristate acetate (PMA)-induced edema in a mouse ear model. Topical application of a 100 μg/ear dose of diterpenes 1-3 significantly reduced edema by 44%, 46%, and 54%, respectively. This activity was superior to indomethacin, a known anti-inflammatory used as a control.

The analgesic, anti-inflammatory and calcium antagonist potential ofTanacetum artemisioides

Several species of the genus Tanacetum are traditionally used in a variety of health conditions including pain, inflammation, respiratory and gastrointestinal disorders. In the current investigation, we evaluated the plant extract of T. artemisioides and some of its pure compounds (flavonoids) for analgesic, anti-inflammatory and calcium antagonist effects in various in-vivo and in vitro studies. Using the actetic acid induced writhing test, intraperitoneal (i.p) administration of the plant extract (25-50 mg/kg) and its flavonoid compounds TA-1 and TA-2 (1-5 mg/kg ) exhibited significant analgesic actvity. The maximum analgesic effect observed with the crude extract of the plant was 71% at 50 mg/kg, while that of compounds TA-1 and TA-2 (5 mg/kg i.p) was 75 and 47%, respectively. The plant extract and its pure compounds caused inhbition of formalin induced paw licking in mice predominatly in the second phase of the test. Diclofenac sodium, a standard reference compound, showed a simlar effect in these chemical induced pain models. In the carrgeenan induced rat paw edema assay, the plant extract (50-200 mg/kg i.p) demonstrated significant (P< 0.01) anti-inflammatory activity which was comparable to that obtained with diclofenac sodium and indomethacin. In isolated rabbit jejunum preprations the plant extract showed an atropine sensitive dose-dependent (0.10-1.0 mg/mL) spasmogenic activity followed by a spasmolytic effect at the next higher doses (3-5 mg/mL). The crude extract of the plant also inhibited the high K+-induced contractions, indicating a calcium channel blocking (CCB) activity, which was further confirmed when the plant extract caused a rightward shift in the Ca++ concentration response curves in the isolated rabbit jejunum preparations, similar to that seen with verapamil. The flavonoid compounds isolated from the plant were devoid of any activity in the isolated tissue preparations. These results indicate that the plant extract of T. artemisioides possesses analgesic, anti-inflammatory and CCB activities. The flavonoid compounds of the plant may have a role in its observed analgesic and antiinflammatory activities, while the CCB activity of the plant may be attributed to some other chemical constituents present. Moreover the findings support the traditional reputation of the genus Tanacetum for its therapeutic benefits in pain and inflammatory conditions.

Antimycobacterial flavones from Haplopappus sonorensis

Crude extracts of Haplopappus sonorensis (A. Gray) S.F. Blake (Asteraceae), showed activity against Mycobacterium tuberculosis H(37)Rv. By assay-guided fractionation, 5-hydroxy-3,7,4'-trimethoxyflavone (1). 5,7-dihydroxy-3,4'-dimethoxyflavone (2). and 5,4'-dihydroxy-3,7-dimethoxyflavone (3). were identified as the antimycobacterial principles. Compound 2 was the most active compound.

The biochemistry and medical significance of the flavonoids

Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells. The flavonoids are used by botanists for taxonomical classification. They regulate plant growth by inhibition of the exocytosis of the auxin indolyl acetic acid, as well as by induction of gene expression, and they influence other biological cells in numerous ways. Flavonoids inhibit or kill many bacterial strains, inhibit important viral enzymes, such as reverse transcriptase and protease, and destroy some pathogenic protozoans. Yet, their toxicity to animal cells is low. Flavonoids are major functional components of many herbal and insect preparations for medical use, e.g., propolis (bee's glue) and honey, which have been used since ancient times. The daily intake of flavonoids with normal food, especially fruit and vegetables, is 1-2 g. Modern authorised physicians are increasing their use of pure flavonoids to treat many important common diseases, due to their proven ability to inhibit specific enzymes, to simulate some hormones and neurotransmitters, and to scavenge free radicals.

Antifungal highly oxygenated guaianolides and other constituents from Ajania fruticulosa

Three highly oxygenated guaianolides were isolated from the aerial parts of Ajania fruticulosa along with 17 known phytochemicals including a triterpene (alpha-amyrin), two plant sterols (beta-sitosterol, daucosterol), four flavonoids (axillarin, centaureidin, santin and 5,7,4'-trihydroxy-3,3'-dimethoxyflavone), and ten sesquiterpenes [1alpha-hydroperoxy-4beta,8alpha,10alpha,13-tetrahydroxyguaia-2-en-12,6alpha-olide, 1alpha-hydroperoxy-4alpha,10alpha-dihydroxyguaia-9alpha-angeloyloxyguaia-2,11(13)-dien-12,6alpha-olide, 3beta,4alpha-dihydroxyguaia-11(13),10(14)-dien-12,6alpha-olide, 1alpha,4alpha,10alpha-trihydroxy-9alpha-angeloyloxyguaia-2,11(13)-dien-12,6alpha-olide, 1beta,2beta-epoxy-3beta,4alpha,10alpha-trihydroxy-guaia-11(13)-en-12,6alpha-olide and 2-oxo-8alpha-hydroxyguaia-1(10),3,11(13)-trien-12,6alpha-olide, ketoplenolide B, alantolactone, 9beta-hydroxyeudesma-4,11(13)-dien-12-oic acid and 9beta-acetoxyeudesma-4,11(13)-dien-12-oic acid]. The structures of the three guaianolides were elucidated by a combination of spectroscopic methods (EIMS, HREIMS, COSY, HMQC, HMBC and NOESY) as 1beta,2beta-epoxy-3beta,4alpha,8beta,10alpha-tetrahydroxyguaia-11(13)-en-12,6alpha-olide (1), 1beta,2beta-epoxy-3beta,4alpha,9alpha,10alpha-tetrahydroxyguaia-11(13)-en-12,6alpha-olide (2) and 1beta,2beta-epoxy-10alpha-hydroperoxy-3beta,4alpha,8beta-trihydroxyguaia-11(13)-en-12,6alpha-olide (3), respectively. Antifungal bioassay of all isolates showed that guaianolides 1, 2, 3, and 1beta,2beta-epoxy-3beta,4alpha,10alpha-trihydroxyguaia-11(13)-en-12,6alpha-olide were inhibitory to the growth of Candida albicans with MICs being 20, 20, 20, and 40 microg/ml, respectively.

New guaianolides and xanthine oxidase inhibitory flavonols from ajania fruticulosa

Two new guaianolides (1 and 2) were isolated from the aerial parts of Ajania fruticulosa along with a triterpene (alpha-amyrin), two plant sterols (beta-sitosterol and daucosterol), four flavonols [santin (3), axillarin (4), centaureidin, and 5,7,4'-trihydroxy-3, 3'-dimethoxyflavone], and five sesquiterpenes [ketoplenolide B, 9beta-hydroxyeudesma-4,11(13)-dien-12-oic acid, 9beta-acetoxyeudesma-4,11(13)-dien-12-oic acid, 1alpha,4alpha, 10alpha-trihydroxy-9alpha-angeloyloxyguaia-2,11(13)-dien-12, 6alpha-olide, and 3beta,4alpha-dihydroxyguaia-11(13),10(14)-dien-12, 6alpha-olide]. The structures of the new guaianolides were established as 1alpha-hydroperoxy-4beta,8alpha,10alpha, 13-tetrahydroxyguaia-2-en-12,6alpha-olide (1) and 1alpha-hydroperoxy-4alpha, 10alpha-dihydroxy-9alpha-angeloyloxyguaia-2,11(13)-dien-12, 6alpha-olide (2), respectively. Xanthine oxidase assays of all isolates revealed that santin (3) and axillarin (4) inhibited the enzyme with IC(50) values of 36.5 and 36.0 &mgr;M (that of allopurinol used as a positive control in the study was 24.2 &mgr;M), respectively.

Anti-inflammatory effects of South American Tanacetum vulgare

In recent years the role of phenolic compounds and sesquiterpene lactones, particularly parthenolide, in the anti-migraine and anti-inflammatory effects of Tanacetum parthenium (Asteraceae) has attracted much attention. However, the closely-related cosmopolitan species T. vulgare has remained outside the mainstream of research in this field. After treating the aerial parts of T. vulgare with dichloromethane and methanol, and applying conventional column and thin-layer chromatographic techniques, it was possible to isolate from the moderately lipophilic fractions the principles responsible for the anti-inflammatory activity of this plant against the mouse-ear oedema induced by 12-O-tetradecanoylphorbol 13-acetate. These were identified by ultraviolet and nuclear magnetic resonance spectroscopy as parthenolide (93% oedema inhibition at 0.5 mg/ear, ID50 (dose of drug inhibiting the oedema by 50%) = 0.18 micromol/ear) and the methoxyflavones jaceosidin (80% oedema inhibition at 0.5 mg/ear, ID50 = 0.50 micromol/ear), eupatorin, chrysoeriol and diosmetin. Because in molar terms the potency of parthenolide was nearly three times greater than that of the most active of the flavones and because it is obtained from the plant in considerably larger amounts, the flavonoids must only be partially responsible, and to a minor extent, for the observed in-vivo anti-inflammatory local effect.