Synthesis and Biological Properties of Pyranocoumarin Derivatives as Potent Anti-Inflammatory Agents.

This study aimed to synthesize 23 coumarin derivatives and analyze their anti-inflammatory effects on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages. A cytotoxicity test performed on LPS-induced RAW264.7 macrophages revealed that none of the 23 coumarin derivatives were cytotoxic. Among the 23 coumarin derivatives, coumarin derivative 2 showed the highest anti-inflammatory activity by significantly reducing nitric oxide production in a concentration-dependent manner. Coumarin derivative 2 inhibited the production of proinflammatory cytokines, including tumor necrosis factor alpha and interleukin-6, and decreased the expression level of each mRNA. In addition, it inhibited the phosphorylation of extracellular signal-regulated kinase, p38, c-Jun NH2-terminal kinase, nuclear factor kappa-B p65 (NF-κB p65), and inducible nitric oxide synthase. These results indicated that coumarin derivative 2 inhibited LPS-induced mitogen-activated protein kinase and NF-κB p65 signal transduction pathways in RAW264.7 cells, as well as proinflammatory cytokines and enzymes related to inflammatory responses, to exert anti-inflammatory effects. Coumarin derivative 2 showed potential for further development as an anti-inflammatory drug for the treatment of acute and chronic inflammatory diseases.

Naturally Occurring Calanolides: Occurrence, Biosynthesis, and Pharmacological Properties Including Therapeutic Potential.

Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leaves and twigs of Calophyllum lanigerum var. austrocoriaceum (Whitmore) P. F. Stevens, is the first member of this group of compounds with anti-HIV-1 activity mediated by reverse transcriptase inhibition. Calanolides are classified pharmacologically as non-nucleoside reverse transcriptase inhibitors (NNRTI). There are at least 15 naturally occurring calanolides distributed mainly within the genus Calophyllum, but some of them are also present in the genus Clausena. Besides significant anti-HIV properties, which have been exploited towards potential development of new NNRTIs for anti-HIV therapy, calanolides have also been found to possess anticancer, antimicrobial and antiparasitic potential. This review article provides a comprehensive update on all aspects of naturally occurring calanolides, including their chemistry, natural occurrence, biosynthesis, pharmacological and toxicological aspects including mechanism of action and structure activity relationships, pharmacokinetics, therapeutic potentials and available patents.

Synthesis and Evaluation of Anticancer Activity of New 4-Acyloxy Derivatives of Robustic Acid.

In the present study, a series of 4-acyloxy robustic acid derivatives were synthesized and characterized for evaluation of their anti-cancer activity. The structures of these derivatives were elucidated by mass spectra (MS) nuclear magnetic resonance spectra (NMR). The single-crystal X-ray diffraction structure of one of these compounds was obtained, for further validation of the target compound structures. The anticancer activities of the target products were evaluated against human leukemic cells HL-60, human non-small cell lung carcinoma cells A-549, human hepatic carcinoma cells SMMC-7721, human hepatocellular carcinoma cells HepG2, and human cervical carcinoma cells Hela. Three compounds among them exhibited potent in-vitro cytotoxicity and excellent DNA topoisomerase I inhibitory activity, even at 0.1 mM concentrations. The most noteworthy observation was the minor toxicity of two of these compounds to normal cells, with an activity similar to the positive control in cancerous cells. A Surflex-Dock docking study was performed to investigate the topoisomerase I activity of all compounds. Of all the other compounds, the most sensitive compound was selected for further investigation of its effect on apoptosis induction and cell cycle regulation in HL-60 cells. Our results suggest that the anticancer effects of these compounds can be attributed to their pharmacological effects on topoisomerase I, cell apoptosis, and cell cycle. These findings suggest that robustic acid derivatives could be used as potential antitumor drugs.

Anti-proliferative activity of CGK012 against multiple myeloma cells via Wnt/ß-catenin signaling attenuation.

The aberrant activation of Wnt/ß-catenin signaling is involved in the development of multiple myeloma; thus, this signaling pathway is a potential target for the development of therapeutics for this malignancy. Here, we performed cell-based chemical screening and found that CGK012, a pyranocoumarin compound, suppressed the Wnt3a-CM-mediated activation of ß-catenin response transcription. CGK012 induced ß-catenin phosphorylation at Ser33/Ser37/Thr41, leading to proteasomal degradation and reducing the level of intracellular ß-catenin. Furthermore, CGK012 consistently decreased the amount of ß-catenin and repressed the expression of cyclin D1, c-myc, and axin-2 (downstream target genes of ß-catenin) in RPMI-8226 multiple myeloma cells. In addition, CGK012 inhibited the proliferation of RPMI-8226 cells and promoted apoptosis, as indicated by the increase in the population of Annexin V-FITC-stained cells and caspase-3/7 activity. These findings suggest that CGK012 could exert antiproliferative activity against multiple myeloma cells by attenuating the Wnt/ß-catenin pathway; thus, it may have potential as a therapeutic agent for multiple myeloma treatment.

Anti-inflammatory effect of corymbocoumarin from Seseli gummiferum subsp. corymbosum through suppression of NF-κB signaling pathway and induction of HO-1 expression in LPS-stimulated RAW 264.7 cells.

This study investigated the anti-inflammatory activity of corymbocoumarin, an angular-type pyranocoumarin isolated from Seseli gummiferum subsp. corymbosum in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Corymbocoumarin not only inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2), but also inhibited the protein and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Corymbocoumarin also attenuated pro-inflammatory cytokine tumor necrosis factor-α (TNF-α). Investigation of the effect on nuclear factor κB (NF-κB) signaling pathway showed that corymbocoumarin inhibited the phosphorylation of Akt and inhibitory κB (IκB)-α and decreased the subsequent translocation of the p65 and p50 NF-κB subunits to the nucleus. A further study revealed that corymbocoumarin exerted anti-inflammatory activity through induction of heme oxygenase (HO)-1 expression. The in vivo study showed that corymbocoumarin (20mg/kg, i.p.) reduced paw swelling in carrageenan-induced acute inflammation model. Taken together, these results suggest that corymbocoumarin exerts its anti-inflammatory effect in LPS-stimulated RAW 264.7 cells by suppressing NF-κB activation and inducing HO-1 expression. Corymbocoumarin may provide a useful therapeutic approach for inflammation-associated diseases.

Chemopreventive Effects of Korean Angelica versus Its Major Pyranocoumarins on Two Lineages of Transgenic Adenocarcinoma of Mouse Prostate Carcinogenesis.

We showed previously that daily gavage of Angelica gigas Nakai (AGN) root ethanolic extract starting 8 weeks of age inhibited growth of prostate epithelium and neuroendocrine carcinomas (NE-Ca) in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. Because decursin (D) and its isomer decursinol angelate (DA) are major pyranocoumarins in AGN extract, we tested the hypothesis that D/DA represented active/prodrug compounds against TRAMP carcinogenesis. Three groups of male C57BL/6 TRAMP mice were gavage treated daily with excipient vehicle, AGN (5 mg per mouse), or equimolar D/DA (3 mg per mouse) from 8 weeks to 16 or 28 weeks of age. Measurement of plasma and NE-Ca D, DA, and their common metabolite decursinol indicated similar retention from AGN versus D/DA dosing. The growth of TRAMP dorsolateral prostate (DLP) in AGN- and D/DA-treated mice was inhibited by 66% and 61% at 16 weeks and by 67% and 72% at 28 weeks, respectively. Survival of mice bearing NE-Ca to 28 weeks was improved by AGN, but not by D/DA. Nevertheless, AGN- and D/DA-treated mice had lower NE-Ca burden. Immunohistochemical and mRNA analyses of DLP showed that AGN and D/DA exerted similar inhibition of TRAMP epithelial lesion progression and key cell-cycle genes. Profiling of NE-Ca mRNA showed a greater scope of modulating angiogenesis, epithelial-mesenchymal transition, invasion-metastasis, and inflammation genes by AGN than D/DA. The data therefore support D/DA as probable active/prodrug compounds against TRAMP epithelial lesions, and they cooperate with non-pyranocoumarin compounds to fully express AGN efficacy against NE-Ca.

Anti-cancer and other bioactivities of Korean Angelica gigas Nakai (AGN) and its major pyranocoumarin compounds.

Korean Angelica gigas Nakai (AGN) is a major medicinal herb used in Asian countries such as Korea and China. Traditionally, its dried root has been used to treat anemia, pain, infection and articular rheumatism in Korea, most often through boiling in water to prepare the dosage forms. The pyranocoumarin compound decursin and its isomer decursinol angelate (DA) are the major chemical components in the alcoholic extracts of the root of AGN. The in vitro anti-tumor activities of decursin and/or DA against prostate cancer, lung cancer, breast cancer, colon cancer, bladder cancer, sarcoma, myeloma and leukemia have been increasingly reported in the past decade whereas the in vivo efficacy in mouse models was established only for a few organ sites. Preliminary pharmacokinetic studies by us and others in rodent models indicated that decursinol (DOH), which has much less in vitro direct anticancer activities by itself, is the major and rapid in vivo hydrolysis metabolite of both decursin and DA. Besides decursin, DA and DOH, other chemical components in AGN such as polysaccharides and polyacetylenes have been reported to exert anti-cancer and anti-inflammation activities as well. We systematically reviewed the published literature on the anti-cancer and other bio-activities effects of AGN extract and decursin, DA and DOH, as well as other chemicals identified from AGN. Although a number of areas are identified that merit further investigation, one critical need is first-in-human studies of the pharmacokinetics of decursin/DA to determine whether humans differ from rodents in absorption and metabolism of these compounds.

Pyranocoumarins: a new class of anti-hyperglycemic and anti-dyslipidemic agents.

A series of pyranocoumarin derivatives were synthesized and evaluated in vivo for their anti-hyperglycemic as well as anti-dyslipidemic activities. Compounds 7a, 7c, 8a, 8b, 8c, 8e and 8f have shown promising anti-hyperglycemic activities in sucrose loaded model (SLM) as well as sucrose challenged streptozotocin induced diabetic rat model (STZ). Compounds 8a and 8b were showing 38.0% and 42.0% blood glucose lowering activity in db/db mice model. In vitro anti-hyperglycemic activity evaluation exhibited that compounds 8a (IC(50)=24.5 microM) and 8b (IC(50)=36.2 microM) are potential PTP-1B inhibitors thereby revealing their possible mechanism of anti-diabetic action. Compounds 7a, 7b, 8a, 8b, 8d, 8e and 8f have shown significant anti-dyslipidemic activity in triton induced dyslipidemia in rats.

Synthesis and evaluation of novel substituted 5-hydroxycoumarin and pyranocoumarin derivatives exhibiting significant antiproliferative activity against breast cancer cell lines.

A library of novel 5-hydroxycoumarin and pyranocoumarin derivatives was constructed via silica sulfuric acid-catalyzed pechmann reaction and Pd(0)-catalyzed suzuki coupling in tandem, and their antiproliferative activities against breast cancer cells MCF-7 and MDA-MB-231 were evaluated. The results showed that compounds such as 6b, 6d, 6h, and 6k possess significant antiproliferative activity against MCF-7 cell line with the IC(50) values of 7.2, 5.3, 3.3, and 6.5 microM, respectively.

In vivo anti-cancer activity of Korean Angelica gigas and its major pyranocoumarin decursin.

We have reported that a 10-herbal traditional formula containing Korean Angelica gigas Nakai (AGN) exerts potent anti-cancer efficacy and identified decursin and decursinol angelate (DA) from AGN as novel anti-androgens. Here, we determined whether AGN would exert in vivo anti-cancer activity and whether decursin or DA could account for its efficacy. The AGN ethanol extract was tested against the growth of mouse Lewis lung cancer (LLC) allograft in syngenic mice or human PC-3 and DU145 prostate cancer xenograft in immunodeficient mice. The pharmacokinetics of decursin and DA were determined. The AGN extract significantly inhibited LLC allograft growth (30 mg/kg) and PC-3 and DU145 xenograft growth (100 mg/kg) without affecting the body weight of the host mice. Biomarker analyses revealed decreased cell proliferation (Ki67, PCNA), decreased angiogenesis (VEGF, microvessel density) and increased apoptosis (TUNEL, cPARP) in treated tumors. Decursin and DA injected intraperitoneally were rapidly hydrolyzed to decursinol. Decursinol and decursin at 50 mg/kg inhibited LLC allograft growth to the same extent, comparable to 30 mg AGN/kg. Therefore the AGN extract possessed significant in vivo anti-cancer activity, but decursin and DA only contributed moderately to that activity, most likely through decursinol.

Antinociceptive activity of the pyranocoumarin seselin in mice.

Seselin an angular pyranocoumarin at dose of 0.5, 4.5 or 40.5 mg/kg inhibited the writhing response induced by acetic acid in a significant and dose-dependent manner, by 19.5%, 26.2% and 41.4%, respectively. Using the same doses, seselin elicited a significant inhibition of formalin response during the second phase (inflammatory), by 90.3%, 97.8% and 95.3%, respectively. Besides, a significant reduction of licking time was observed during the first phase (neurogenic) at the highest doses of seselin, by 34.4% and 66.9%, respectively. On the contrary, in the hot plate test no effect was observed after seselin treatment. In conclusion, seselin was able to inhibit inflammatory hyperalgesia, suggesting that this natural product possesses both important peripheral anti-inflammatory and antinociceptive properties.

Pyranocoumarin(+/-)-4'-O-acetyl-3'-O-angeloyl-cis-khellactone induces mitochondrial-dependent apoptosis in HL-60 cells.

The pyranocoumarin (+)-4'-O-acetyl-3 'O-angeloyl-cis-khellactone (PC) isolated from Radix Peucedani (root of Peucedanum praeruptorum Dunn) showed a dose-dependent effect at 10 -30 pg/mL on causing apoptotic DNA and nuclear fragmentations in HL-60 cells. After 24 h of PC treatment there were losses of mitochondrial membrane potential and cytochrome c. PC also increased total cellular and mitochondrial Bax protein, stimulated an increase in caspase-dependent Bcl-2 cleavage but showed no effect on Bcl-Xv. These observations strongly suggest activation of the mitochondria apoptotic pathway. The pan-specific caspase inhibitor, ZVAD-fmk, abolished the PC-induced apoptosis,whereas the caspase-8 inhibitor IETD-fmk showed no effect, implying the involvement of the caspase 9 pathway. PC caused a 2 to 12 hour transient increase in phospho-ERK, and a 72 h-long activation of JNK. Pre-treatment with the MEK inhibitor PD98059, which suppresses ERK activation, paradoxically promoted PC-induced mitochondrial cytochrome c release, procaspase-3 and -8 cleavage, and enhanced apoptosis. Our results show that PC triggers mitochondria-mediated apoptosis in HL-60 cells, and the involvement of ERK and JNK signal pathways in the process.