Cladophialophora bantiana metabolites are efficient in the larvicidal and ovicidal control of Aedes aegypti, and Culex quinquefasciatus and have low toxicity in zebrafish embryo

Mosquitoes' current insecticide resistance status in available public health insecticides is a serious threat to mosquito control initiatives. Microbe-based control agents provide an alternative to conventional pesticides and insecticides, as they can be more targeted than synthetic insecticides. The present study was focused on identifying and investigating the mosquitocidal potential of Cladophialophora bantiana, an endophytic fungus isolated from Opuntia ficus-indica. The Cladophialophora species was identified through phylogenetic analysis of the rDNA sequence. The isolated fungus was first evaluated for its potential to produce metabolites against Aedes aegpti and Culex quinquefasciatus larvae in the 1-4th instar. The secondary metabolites of mycelium extract were assessed at various test doses (100, 200, 300, 400, and 500 μg/mL) in independent bioassays for each instar of selected mosquito larvae. After 48 h of exposure, A. aegypti expressed LC₅₀ values of 13.069, 18.085, 9.554, and 11.717 μg/mL and LC₉₀ = 25.702, 30.860, 17.275, and 19.601 μg/mL; followed by C. quinquefasciatus LC₅₀ = 14.467, 11.766, 5.934, and 7.589 μg/mL, and LC₉₀ = 29.529, 20.767, 11.192, and 13.296 μg/mL. The mean % of ovicidal bioassay was recorded 120 h after exposure. The hatchability (%) was proportional to mycelia metabolite concentration. The enzymatic level of acetylcholinesterase in fungal mycelial metabolite treated 4th instar larvae indicated a dose-dependent pattern. The GC-MS profile of C. bantiana extracts identified five of the most abundant compounds, namely cyclobutane, trans-3-undecene-1,5-diyne, 1-bromo-2-chloro, propane, 1,2,3-trichloro-2-methyl-, 5,5,10,10-tetrachlorotricyclo, and phenol, which had the killing effect in mosquitoes. Furthermore, the C. bantiana fungus ethyl acetate extracts had a strong larvicidal action on A. aegypti and C. quinquefasciatus. Finally, the toxicity test on zebrafish embryos revealed the induction of malformations only at concentrations above 1 mg/mL. Therefore, our study pioneered evidence that C. bantiana fungal metabolites effectively control A. aegypti and C. qunquefasciastus and show less lethality in zebrafish embryos at concentrations up to 500 μg/mL.

Synthesis and Biological Evaluation of Falcarinol-Type Analogues as Potential Calcium Channel Blockers

A series of enantiomers of falcarinol analogues (2) were synthesized using a chiral 1,1'-binaphth-2-ol (BINOL)-based catalytic system. The neuroprotective effects of falcarinol (1a) and its analogues (2) on PC12 cells injured by sodium azide (NaN₃) were investigated. The structure-function relationships and possible mechanism were studied. Pretreatment of PC12 cells with falcarinol analogues (R)-2d and (R)-2i for 1 h following addition of NaN₃ and culture in a CO₂ incubator for 24 h resulted in significant elevation of cell viability, as determined by a CCK-8 assay and Hoechst staining, with reduction of LDH release and MDA content, increase of SOD activity, and decrease of ROS stress, when compared with the activity of natural falcarinol (1a). These observations indicated that the falcarinol analogues (R)-2d and (R)-2i can protect PC12 cells against NaN₃-induced apoptosis via increasing resistance to oxidative stress. For the first time, falcarinol (1a) and its analogue (R)-2i were found to have potential L-type calcium channel-blocking activity, as recorded using a manual patch clamp technique on HEK-293 cells stably expressing hCav1.2 (α1C/β2a/α2δ1). These findings suggest that the mechanism of the L-type calcium channel-blocking activity of falcarinol (1a) and its analogue (R)-2i might be involved in neuroprotection by falcarinol-type analogues by inhibiting calcium overload in the upstream of the signaling pathway.

Protective Effect of Panaxynol Isolated from Panax vietnamensis against Cisplatin-Induced Renal Damage: In Vitro and In Vivo Studies

Polyacetylenic compounds isolated from Panax species are comprised of non-polar C17 compounds, exhibiting anti-inflammatory, antitumor, and antifungal activities. Panaxynol represents the major component of the essential oils of ginseng. We investigated whether panaxynol isolated from Panax vietnamensis (Vietnamese ginseng, VG) could prevent cisplatin-induced renal damage induced in vitro and in vivo. Cisplatin-induced apoptotic cell death was observed by staining with annexin V conjugated with Alexa Fluor 488, and western blotting evaluated the molecular mechanism. Panaxynol at concentrations above 0.25 μM prevented cisplatin-induced LLC-PK1 porcine renal proximal tubular cell death. LLC-PK1 cells treated with cisplatin demonstrated an increase in apoptotic cell death, whereas pretreatment with 2 and 4 μM panaxynol decreased this effect. Cisplatin demonstrated a marked increase in the phosphorylation of c-Jun N-terminal kinase (JNK), P38, and cleaved caspase-3. However, pretreatment with 2 and 4 μM panaxynol reversed the upregulated phosphorylation of JNK, P38, and the expression of cleaved caspase-3. We confirmed that the protective effect of panaxynol isolated from P. vietnamensis in LLC-PK1 cells was at least partially mediated by reducing the cisplatin-induced apoptotic damage. In the animal study, panaxynol treatment ameliorated body weight loss and blood renal function markers and downregulated the mRNA expression of inflammatory mediators.

Dietary Polyacetylenic Oxylipins Falcarinol and Falcarindiol Prevent Inflammation and Colorectal Neoplastic Transformation: A Mechanistic and Dose-Response Study in A Rat Model

Falcarinol (FaOH) and falcarindiol (FaDOH) are cytotoxic and anti-inflammatory polyacetylenic oxylipins, which are commonly found in the carrot family (Apiaceae). FaOH and FaDOH have previously demonstrated a chemopreventive effect on precursor lesions of colorectal cancer (CRC) in azoxymethane (AOM)-induced rats. The purpose of the present study was to elucidate possible mechanisms of action for the preventive effect of FaOH and FaDOH on colorectal precancerous lesions and to determine how this effect was dependent on dose. Gene expression studies performed by RT-qPCR of selected cancer biomarkers in tissue from biopsies of neoplastic tissue revealed that FaOH and FaDOH downregulated NF-κβ and its downstream inflammatory markers TNFα, IL-6, and COX-2. The dose-dependent anti-neoplastic effect of FaOH and FaDOH in AOM-induced rats was investigated in groups of 20 rats receiving a standard rat diet (SRD) supplemented with 0.16, 0.48, 1.4, 7 or 35 µg FaOH and FaDOH g⁻¹ feed in the ratio 1:1 and 20 rats were controls receiving only SRD. Analysis of aberrant crypt foci (ACF) showed that the average number of small ACF (<7 crypts) and large ACF (>7 crypts) decreased with increasing dose of FaOH and FaDOH and that this inhibitory effect on early neoplastic formation of ACF was dose-dependent, which was also the case for the total number of macroscopic neoplasms. The CRC protective effects of apiaceous vegetables are mainly due to the inhibitory effect of FaOH and FaDOH on NF-κB and its downstream inflammatory markers, especially COX-2.

The Antitumor Natural Compound Falcarindiol Disrupts Neural Stem Cell Homeostasis by Suppressing Notch Pathway

Neural stem cells (NSCs) are undifferentiated, multi-potent cells that can give rise to functional neurons and glial cells. The disruption in NSC homeostasis and/or the impaired neurogenesis lead to diverse neurological diseases, including depression, dementia, and neurodegenerative disorders. Falcarindiol (FAD) is a polyacetylene found in many plants, and FAD shows the cytotoxicity against breast cancers and colon cancers. However, there is no research on the consequence of FAD treatment in normal stem cells. Here, we suggest that FAD has anticancer roles against glioblastoma cells by inducing the differentiation of glioblastoma stem-like cells, as well as activating apoptosis pathway in glioblastoma cells. On the other hand, we also show that FAD has detrimental effects by disrupting the maintenance of normal NSCs and altering the balance between self-renewal and differentiation of NSCs.

Falcarinol Is a Potent Inducer of Heme Oxygenase-1 and Was More Effective than Sulforaphane in Attenuating Intestinal Inflammation at Diet-Achievable Doses

Nuclear factor- (erythroid-derived 2) like 2 (Nrf2) is a transcription factor that regulates the expression of a battery of antioxidant, anti-inflammatory, and cytoprotective enzymes including heme oxygenase-1 (Hmox1, Ho-1) and NADPH:quinone oxidoreductase-1 (Nqo1). The isothiocyanate sulforaphane (SF) is widely understood to be the most effective natural activator of the Nrf2 pathway. Falcarinol (FA) is a lesser studied natural compound abundant in medicinal plants as well as dietary plants from the Apiaceae family such as carrot. We evaluated the protective effects of FA and SF (5 mg/kg twice per day in CB57BL/6 mice) pretreatment for one week against acute intestinal and systemic inflammation. The phytochemical pretreatment effectively reduced the magnitude of intestinal proinflammatory gene expression (IL-6, Tnfα/Tnfαr, Infγ, STAT3, and IL-10/IL-10r) with FA showing more potency than SF. FA was also more effective in upregulating Ho-1 at mRNA and protein levels in both the mouse liver and the intestine. FA but not SF attenuated plasma chemokine eotaxin and white blood cell growth factor GM-CSF, which are involved in the recruitment and stabilization of first-responder immune cells. Phytochemicals generally did not attenuate plasma proinflammatory cytokines. Plasma and intestinal lipid peroxidation was also not significantly changed 4 h after LPS injection; however, FA did reduce basal lipid peroxidation in the mesentery. Both phytochemical pretreatments protected against LPS-induced reduction in intestinal barrier integrity, but FA additionally reduced inflammatory cell infiltration even below negative control.

Notopterygium incisum extract and associated secondary metabolites inhibit apple fruit fungal pathogens

In the search for antifungal lead compounds from natural resources, Notopterygium incisum, a medicine plant only distributed in China, showed antifungal potential against apple fruit pathogens. Based on the bioassay-guided isolation, chromatography fraction 6 of the ethyl acetate partition exhibited significant in vitro and in vivo antifungal activities against apple fruit pathogens. Furthermore, nine antifungal secondary metabolites, including five linear furocoumarins (1-5), two phenylethyl esters (6-7), one falcarindiol (8), and one sesquiterpenoid (9), were isolated and elucidated from fraction 6. Compound 5 is a new metabolite, and 9 isolated from the genus Notopterygium for the first time. The purified compounds (1-9) were firstly reported to exhibit antifungal activities against apple fruit pathogens of Colletotrichum gloeosporioides and Botryosphaeria dothidea with the MIC values ranging from 8 to 250 mg L^-1, especially 8 of 16 and 8 mg L^-1, respectively. Moreover, 8 could inhibit the spore germination and new sporulation of B. dothidea, as well as enhance the membrane permeabilization of B. dothidea spores. This was the first investigation for the antifungal components against apple fruit pathogens from Notopterygium incisum, which has great potential to be developed into bio-fungicides.

Effective Antimalarial Activities of α-Hydroxy Diynes Isolated from Ongokea gore

Three diynes, octadec-17-ene-9,11-diynoate ethyl (1: ), 8-hydroxy-octadeca-13,17-diene-9,11-diynoate ethyl (2: ), and 8-hydroxy-octadec-13-ene-9,11-diynoate ethyl (3: ), were isolated from Ongokea gore seed oil. The structure assignment of these three compounds was based according to chemical and spectroscopic data. They were screened against Plasmodium falciparum, the parasite that causes malaria. In vitro micro-test (Mark III, supported by the World Health Organization) was developed to assess the response of P. falciparum to the isolated three compounds, and statistical analysis were performed for determination of the concentration that inhibits 50% of the parasite maturation (IC₅₀). Two of the three diynes (2: and 3: ) showed a very effective in vitro antimalarial activity with an IC₅₀ of 4.5 and 1.7 µM, respectively. Compound 3: exhibited better activity than quinine (IC₅₀ 1.9 µM), the drug reference, while compound 1: had no antimalarial activity (IC₅₀ > 125 µM). In the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cytotoxicity screening, all compounds showed no toxicity (mean IC₅₀ of 90 µM for each compound).

Identifying panaxynol, a natural activator of nuclear factor erythroid-2 related factor 2 (Nrf2) from American ginseng as a suppressor of inflamed macrophage-induced cardiomyocyte hypertrophy

ETHNOPHARMACOLOGICAL RELEVANCE

American ginseng is capable of ameliorating cardiac dysfunction and activating Nrf2, a master regulator of antioxidant defense, in the heart. This study was designed to isolate compounds from American ginseng and to determine those responsible for the Nrf2-mediated resolution of inflamed macrophage-induced cardiomyocyte hypertrophy.

MATERIALS AND METHODS

A standardized crude extract of American ginseng was supplied by the National Research Council of Canada, Institute for National Measurement Standards. A bioassay-based fractionization of American ginseng was performed to identify the putative substances which could activate Nrf2-mediated suppression of pro-inflammatory cytokine expression in macrophages and macrophage-mediated pro-hypertrophic growth in cardiomyocytes.

RESULTS

A hexane fraction of an anti-inflammatory crude extract of American ginseng was found to be most effective in suppressing the inflammatory responses in macrophages. Preparative, reverse-phase HPLC and a comparative analysis by analytical scale LC-UV/MS revealed the hexane fraction contains predominantly C17 polyacetylenes and linolenic acid. Panaxynol, one of the major polyacetylenes, was found to be a potent Nrf2 activator. Panaxynol posttranscriptionally activated Nrf2 by inhibiting Kelch-like ECH-associated protein (Keap) 1-mediated degradation without affecting the binding of Keap1 and Nrf2. Moreover, panaxynol suppressed a selected set of cytokine expression via the activation of Nrf2 while minimally regulating nuclear factor-kappa B (NF-κB)-mediated cytokine expression in macrophages. It also dramatically inhibited the inflamed macrophage-mediated cardiomyocyte death and hypertrophy by activating Nrf2 in macrophages.

CONCLUSIONS

These results demonstrate that American ginseng-derived panaxynol is a specific Nrf2 activator and panaxynol-activated Nrf2 signaling is at least partly responsible for American ginseng-induced health benefit in the heart.

Capillin, a major constituent of Artemisia capillaris Thunb. flower essential oil, induces apoptosis through the mitochondrial pathway in human leukemia HL-60 cells

BACKGROUND

Natural products are one of the most important sources of drugs used in pharmaceutical therapeutics. Screening of several natural products in the search for novel anticancer agents against human leukemia HL-60 cells led us to identify potent apoptosis-inducing activity in the essential oil fraction from Artemisia capillaris Thunb. flower.

METHODS

The cytotoxic effects of extracts were assessed on human leukemia HL-60 cells by XTT assay. Induction of apoptosis was assessed by analysis of DNA fragmentation and nuclear morphological change. The plant name was checked with the plant list website (http://www.theplantlist.org).

RESULTS

A purified compound from the essential oil fraction from Artemisia capillaris Thunb. flower that potently inhibited cell growth in human leukemia HL-60 cells was identified as capillin. The cytotoxic effect of capillin in cells was associated with apoptosis. When HL-60 cells were treated with 10(-6) M capillin for 6 h, characteristic features of apoptosis such as DNA fragmentation and nuclear fragmentation were observed. Moreover, activation of c-Jun N-terminal kinase (JNK) was detected after treatment with capillin preceding the appearance of characteristic properties of apoptosis. Release of cytochrome c from mitochondria was also observed in HL-60 cells that had been treated with capillin.

CONCLUSION

Capillin induces apoptosis in HL-60 cells via the mitochondrial apoptotic pathway, which might be controlled through JNK signaling. Our results indicate that capillin may be a potentially useful anticancer drug that could enhance therapeutic efficacy.

Dietary acetylenic oxylipin falcarinol differentially modulates GABAA receptors

The dietary oxylipins falcarinol (1a) and falcarindiol (1b) trap thiols by direct nucleophilic addition to their diyne system, but despite this, only falcarinol (1a) is a reversible agonist of cannabinoid receptors, providing a rationale for comparing their activity also on other neuronal targets. Because GABAA receptors (GABAARs) are exquisitely sensitive to polyacetylenic oxylipins in terms of either potentiation (falcarindiol, 1b) or inhibition (oenanthotoxin, 2a), the activity of 1a was investigated on synaptic (α1β2γ2L) and extrasynaptic (α1β2δ and α1β2) subtypes of GABAARs. Falcarinol (1a) significantly enhanced the amplitude of currents mediated by α1β2γ2L receptors, but this effect was associated with a use-dependent block. Conversely, α1β2 receptors were inhibited without any sign of use-dependent block for the entire range of concentrations tested (1-10 μM). Interestingly, responses mediated by α1β2δ receptors, showing no or very little macroscopic desensitization, were strongly potentiated by 1a, exhibiting a fading reminiscent of macroscopic desensitization. When compared to the activity of falcarindiol (1b), falcarinol (1a) showed a higher affinity for GABAARs and, overall, a substantially different profile of pharmacological action. Taken together, the present data support the view that modulation of GABAARs might underlie the insecticidal and sedative activity of falcarinol (1a).

Polyyne hybrid compounds from Notopterygium incisum with peroxisome proliferator-activated receptor gamma agonistic effects

In the search for peroxisome proliferator-activated receptor gamma (PPARγ) active constituents from the roots and rhizomes of Notopterygium incisum, 11 new polyacetylene derivatives (1-11) were isolated. Their structures were elucidated by NMR and HRESIMS as new polyyne hybrid molecules of falcarindiol with sesquiterpenoid or phenylpropanoid moieties, named notoethers A-H (1-8) and notoincisols A-C (9-11), respectively. Notoincisol B (10) and notoincisol C (11) represent two new carbon skeletons. When tested for PPARγ activation in a luciferase reporter assay with HEK-293 cells, notoethers A-C (1-3), notoincisol A (9), and notoincisol B (10) showed promising agonistic activity (EC50 values of 1.7 to 2.3 μM). In addition, notoincisol A (9) exhibited inhibitory activity on NO production of stimulated RAW 264.7 macrophages.

Placotylene A, an inhibitor of the receptor activator of nuclear factor-κB ligand-induced osteoclast differentiation, from a Korean sponge Placospongia sp

A new inhibitor, placotylene A (1), of the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation, and a regioisomer of placotylene A, placotylene B (2), were isolated from a Korean marine sponge Placospongia sp. The chemical structures of placotylenes A and B were elucidated on the basis of 1D and 2D NMR, along with MS spectral analysis and revealed as an iodinated polyacetylene class of natural products. Placotylene A (1) displayed inhibitory activity against RANKL-induced osteoclast differentiation at 10 μM while placotylene B (2) did not show any significant activity up to 100 μM, respectively.

Identification of potential anticancer compounds from Oplopanax horridus

Oplopanax horridus is a plant native to North America. Previous reports have demonstrated that this herb has antiproliferative effects on cancer cells but study mostly focused on its extract or fractions. Because there has been limited phytochemical study on this herb, its bioactive compounds are largely unknown. We recently isolated and identified 13 compounds, including six polyynes, three sesquiterpenes, two steroids, and two phenolic acids, of which five are novel compounds. In this study, we systemically evaluated the anticancer effects of compounds isolated from O. horridus. Their antiproliferative effects on a panel of human colorectal and breast cancer cells were determined using the MTS assay. Cell cycle distribution and apoptotic effects were analyzed by flow cytometry. The in vivo antitumor effect was examined using a xenograft tumor model. Among the 13 compounds, strong antiproliferative effects were observed from falcarindiol and a novel compound oplopantriol A. Falcarindiol showed the most potent antiproliferative effects, significantly inducing pro-apoptosis and cell cycle arrest in the S and G2/M phases. The anticancer potential of falcarindiol was further verified in vivo, significantly inhibiting HCT-116 tumor growth in an athymic nude mouse model at 15 mg/kg. We also analyzed the relationship between polyyne structures and their pharmacological activities. We observed that both the terminal hydroxyl group and double bond obviously affected their anticancer potential. Results from this study supplied valuable information for future semi-synthesis of polyyne derivatives to develop novel cancer chemopreventive agents.

Structure, synthesis, and biological activity of a C-20 bisacetylenic alcohol from a marine sponge Callyspongia sp

An optically inactive C-20 bisacetylenic alcohol, (4E,16E)-icosa-4,16-diene-1,19-diyne-3,18-diol, was isolated from a marine sponge Callyspongia sp. as a result of screening of antilymphangiogenic agents from marine invertebrates. An optical resolution using chiral-phase HPLC gave each enantiomer, (-)-1 and (+)-2. Because the natural and synthetic enantiomers 1 and 2 showed different biological properties, we investigated the structure-activity relationships of bisacetylenic alcohols using 11 synthetic derivatives, and it is clarified that the essential structural unit for antiproliferative activity is the "1-yn-3-ol" on both termini and that there is a minimum chain length that connects the "1-yn-3-ol" moieties.

Growth inhibition and induction of differentiation by panaxydol in rat C6 glioma cells

OBJECTIVES

Panaxydol is a naturally occurring non-peptidyl small molecule isolated from the lipophilic fractions of Panax notoginseng, a well-known Chinese traditional medicine. In this study, we aimed to investigate the effects of panaxydol on growth inhibition and its mechanisms in C6 rat glioma cells.

METHODS

The effects of panaxydol on cell proliferation, morphologic changes, glial fibrillary acidic protein (GFAP) expression and cell cycle regulation in rat C6 cells were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, hematoxylin and eosin (HE) staining, immunocytochemistry, flow cytometric analysis and Western blot respectively.

RESULTS

Panaxydol markedly inhibited the proliferation of C6 cells in a dose-dependent manner with IC50 of 39.5 +/- 2.3 microM. In addition, the cell morphologic changes and increased expression of GFAP in C6 cells in the presence of panaxydol implied a cellular differentiation. Flow cytometric analysis revealed that panaxydol-treated cells accumulated in G0/G1 phase with a marked decrease in the number of C6 cells at S phase. Western blot analysis demonstrated that panaxydol resulted in an increase in the protein expression of p27 in C6 cells as early as 3 hours after treatment consistent with the differentiation response, but protein expression of p53, p21, p16 and pRb remained unchanged.

CONCLUSION

These findings suggest that panaxydol inhibits the proliferation of C6 cells via G0/G1 cell cycle arrest in association with induction of p27 expression and differentiation.

Antimycobacterials from lovage root (Ligusticum officinale Koch)

The n-hexane extract of Lovage root was found to significantly inhibit the growth of both Mycobacterium smegmatis mc²155 and Mycobacterium bovis BCG, and therefore a bioassay-guided isolation strategy was undertaken. (Z)-Ligustilide, (Z)-3-butylidenephthalide, (E)-3-butylidenephthalide, 3-butylphthalide, α-prethapsenol, falcarindiol, levistolide A, psoralen and bergapten were isolated by chromatographic techniques, characterized by NMR spectroscopy and MS, and evaluated for their growth inhibition activity against Mycobacterium tuberculosis H₃₇Rv using the whole-cell phenotypic spot culture growth inhibition assay (SPOTi). Cytotoxicity against RAW 264.7 murine macrophage cells was employed for assessing their degree of selectivity. Falcarindiol was the most potent compound with a minimum inhibitory concentration (MIC) value of 20 mg/L against the virulent H₃₇Rv strain; however, it was found to be cytotoxic with a half-growth inhibitory concentration (GIC₅₀) in the same order of magnitude (SI < 1). Interestingly the sesquiterpene alcohol α-prethapsenol was found to inhibit the growth of the pathogenic mycobacteria with an MIC value of 60 mg/L, being more specific towards mycobacteria than mammalian cells (SI ~ 2). Colony forming unit analysis at different concentrations of this phytochemical showed mycobacteriostatic mode of action.

The Canadian medicinal plant Heracleum maximum contains antimycobacterial diynes and furanocoumarins

ETHNOPHARMACOLOGICAL RELEVANCE

Heracleum maximum is amongst the most commonly used plants by the indigenous peoples of North America. The First Nations of the eastern Canada use infusions of Heracleum maximum roots for the treatment of respiratory ailments including tuberculosis. Previous investigations of extracts derived from the roots of Heracleum maximum have shown it to possess antimycobacterial activity.

AIM OF THE STUDY

To isolate and identify antimycobacterial constituents from the roots of Heracleum maximum.

MATERIALS AND METHODS

A methanolic extract of Heracleum maximum roots was subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The antimycobacterial constituents were identified by NMR, MS and polarimetry.

RESULTS

The polyacetylene (3R,8S)-falcarindiol and the furanocoumarins bergapten, isobergapten, angelicin, sphondin, pimpinellin, isopimpinellin and 6-isopentenyloxyisobergapten were isolated from the Heracleum maximum root extract. (3R,8S)-Falcarindiol and 6-isopentenyloxyisobergapten exhibited MICs of 24 μM and 167 μM and IC50s of 6 μM and 27 μM against Mycobacterium tuberculosis H37Ra respectively. The remaining furanocoumarins bergapten, isobergapten, angelicin, sphondin, pimpinellin, and isopimpinellin were less active, with MICs of 925, 1850, 2149, 1859, 812 and 1625 μM and IC50s of 125, 344, 350, 351, 389 and 406 μM.

CONCLUSIONS

(3R,8S)-Falcarindiol, bergapten, isobergapten, angelicin, sphondin, pimpinellin, isopimpinellin and 6-isopentenyloxyisobergapten were identified as the principal constituents responsible for the antimycobacterial activity of the roots of Heracleum maximum. This work supports the ethnopharmacological use of Heracleum maximum by Canadian First Nations and Native American communities as a treatment for infectious diseases, specifically tuberculosis.

Falcarindiol allosterically modulates GABAergic currents in cultured rat hippocampal neurons

Falcarindiol (1), a C-17 polyacetylenic diol, shows a pleiotropic profile of bioactivity, but the mechanism(s) underlying its actions are largely unknown. Large amounts of 1 co-occur in water hemlock (Oenanthe crocata) along with the convulsant polyacetylenic toxin oenanthotoxin (2), a potent GABA(A) receptor (GABA(A)R) inhibitor. Since these compounds are structurally and biogenetically related, it was considered of interest to evaluate whether 1 could affect GABAergic activity, and for this purpose a model of hippocampal cultured neurons was used. Compound 1 significantly increased the amplitude of miniature inhibitory postsynaptic currents, accelerated their onset, and prolonged the decay kinetics. This compound enhanced also the amplitude of currents elicited by 3 μM GABA and accelerated their fading, reducing, however, currents evoked by a saturating (10 mM) GABA concentration. Moreover, kinetic analysis of responses to 10 mM GABA revealed that 1 upregulated the rate and extent of desensitization and slowed the current onset and deactivation. Taken together, these data show that 1 exerts a potent modulatory action on GABA(A)Rs, possibly by modulating agonist binding and desensitization, overall potentially decreasing the toxicity of co-occurring GABA-inhibiting convulsant toxins.

Antitrypanosomal properties of Panax ginseng C. A. Meyer: new possibilities for a remarkable traditional drug

African trypanosomiasis is still a major health problem in many sub-Saharan countries in Africa. We investigated the effects of three preparations of Panax ginseng, Panax notoginseng, isolated ginsenosides, and the polyacetylene panaxynol on Trypanosoma brucei brucei and the human cancer cell line HeLa. Hexane extracts and the pure panaxynol were toxic and at the same time highly selective against T. b. brucei, whereas methanol extracts and 12 isolated ginsenosides were significantly less toxic and showed only weak selectivity. Panaxynol was cytotoxic against T. b. brucei at the concentration of 0.01 µg/mL with a selectivity index of 858, superior even to established antitrypanosomal drugs. We suggest that the inhibition of trypanothione reductase, which is only found in trypanosomes, might explain the observed selectivity. The high selectivity together with a cytotoxic concentration in the range of the bioavailability makes panaxynol and other polyacetylenes in general very promising lead compounds for the treatment of African trypanosomiasis.

Anti-mycobacterial diynes from the Canadian medicinal plant Aralia nudicaulis

ETHNOPHARMACOLOGICAL RELEVANCE

Aralia nudicaulis, or wild sarsaparilla, is used as a traditional medicinal plant for the treatment of various illnesses by many of the Canadian First Nations. Iroquois and Algonquin First Nations of Eastern Canada use a tea prepared from dried Aralia nudicaulis rhizome as a cough medicine and for the treatment of tuberculosis. Previous investigations of aqueous extracts of Aralia nudicaulis rhizomes have shown it to possess antimycobacterial activity.

AIM OF THE STUDY

To isolate and identify antimycobacterial constituents from Aralia nudicaulis rhizomes.

MATERIALS AND METHODS

Methanolic extracts of Aralia nudicaulis rhizomes were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The antimycobacterial constituents were identified by NMR, MS and polarimetry.

RESULTS

Two C17 polyacetylenes with significant antimycobacterial activity were isolated from the Aralia nudicaulis rhizome extract. The polyacetylenes were identified as (3R)-falcarinol and (3R, 9R, 10S)-panaxydol. Falcarinol and panaxydol displayed MICs of 25.6μM and 36.0μM and IC(50)s of 15.3μM and 23.5μM against Mycobacterium tuberculosis H37Ra.

CONCLUSIONS

Falcarinol and panaxydol were identified as the principal constituents responsible for the antimycobacterial activity of Aralia nudicaulis rhizomes validating an ethnopharmacological use of this plant by the Canadian First Nations.

Components of rhizome extract of Cnidium officinale Makino and their in vitro biological effects

The anti-inflammatory and anticancer activities of a methanol extract of the rhizome of Cnidium officinale were investigated. Four compounds, namely falcarindiol (1), 6-hydroxy-7-methoxy-dihydroligustilide (2), ligustilidiol (3), and senkyunolide H (4) were isolated from the extract of the rhizome of Cnidium officinale and their structures were elucidated by analysis of their spectroscopic data and by comparison with previously reported data. These compounds showed anti-inflammatory activities, measured as inhibition of nitric oxide (NO) release in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells, with IC₅₀ values of 4.31 ± 5.22, 152.95 ± 4.23, 72.78 ± 5.13, and 173.42 ± 3.22 μM, respectively. They also inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression induced by LPS. Among these compounds, falcarindiol (1) was found to have anti-proliferative effect against MCF-7 human breast cancer cells by induction of a G₀/G₁ cell cycle block of the cells, with an IC₅₀ value of 35.67 μM. Typical apoptotic effects were observed by phase contrast microscopy and were also exhibited in fluorescence microscopy with Hoechst 33342 staining. In addition, falcarindiol induced apoptosis through strongly increased mRNA expression of Bax and p53, and slightly reduced Bcl-2 mRNA levels in a dose dependent manner. This study suggested that C. officinale extract and its components would be valuable candidates in therapeutic applications for anti-inflammatory and anti-cancer agents.

Spectroscopic studies on bioactive polyacetylenes and other plant components in wild carrot root

Polyacetylenes and other common plant components, such as starch, pectin, cellulose, and lignin, were studied in roots of the wild carrot (Daucus carota) subspecies D. carota subsp. gummifer and D. carota subsp. maximus by Raman spectroscopy. The components were measured in situ, directly in the plant tissue and without any preliminary sample preparation. The analysis was performed on the basis of the intense and characteristic key bands observed in the Raman spectrum. The two main carrot polyacetylenes falcarinol (1) and falcarindiol (2) have similar molecular structures, but their Raman spectra exhibit a small band shift in the symmetric -C≡C-C≡C- mode from 2258 cm⁻¹ to 2252 cm⁻¹. Quantum chemical calculations confirmed that the differences observed between the samples may be due to conformational and environmental changes. The polyacetylenes were also detected by Raman mapping, which visualized the distribution of the compounds across sections of carrot roots. The mapping technique was also applied to assess the distribution of lignin and polysaccharide compounds. The results showed the tissue-specific accumulation of starch and cell wall components such as lignin, pectin, and cellulose.

Anticomplement activity of polyacetylenes from leaves of Dendropanax morbifera Leveille

The present study evaluated the anticomplement effect of polyacetylenes from Dendropanax morbifera (Araliaceae) in the classical pathway complement system. The leaves of D. morbifera were evaluated with regard to its anticomplement activity, and its active principles identified following activity-guided isolation. An aqueous CCl(4) fraction of the leaves of D. morbifera exhibited significant anticomplement activity on the classical pathway complement system, which was expressed as total hemolytic activity. Three polyacetylenes isolated from the leaves of D. morbifera, namely (3S)-falcarinol (1), (3S,8S)-falcarindiol (2) and (3S)-diynene (3). Compounds 1, 2 and 3 showed inhibitory activity against complement system with 50% inhibitory concentrations (IC(50)) values of 87.3 µM, 15.2 µM and 39.8 µM. Among the compounds tested, 2 showed the most potent anticomplement activity (IC(50), 15.2 µM).

Aliphatic C(17)-polyacetylenes of the falcarinol type as potential health promoting compounds in food plants of the Apiaceae family

Many epidemiological studies have provided evidence that a high intake of fruits and vegetables is associated with a reduced risk for the development of cancer and cardiovascular diseases. Fruits and vegetables are known to contain health promoting components such as vitamins, minerals, antioxidants and dietary fibers, however, it is unclear which of these are responsible for the health promoting properties of fruits and vegetables. Aliphatic C(17)-polyacetylenes of the falcarinol type, which occur in common food plants of the Apiaceae family such as carrot, celeriac, parsnip and parsley, have demonstrated interesting bioactivities including antibacterial, antimycobacterial, and antifungal activity as well as anti-inflammatory, anti-platelet-aggregatory, neuritogenic and serotonergic effects. In addition, the cytotoxicity of falcarinol type polyacetylenes towards human cancer cells, bioavailability, and their potential anticancer effect in vivo indicates that these compounds may contribute to the health effects of certain vegetables and hence could be important nutraceuticals. The bioactivity of falcarinol type polyacetylenes occurring in food plants of the Apiaceae family, their possible mode of action and possible health promoting effects are discussed in this review as well as the effect of storage, processing and other factors that can influence the content of these compounds in particular root vegetables and products. Moreover, recent patents on bioactivity of falcarinol type polyacetylenes and inventions making use of this knowledge are presented and discussed.

Exocarpic acid inhibits mycolic acid biosynthesis in Mycobacterium tuberculosis

Exocarpic acid (13 E-octadecene-9,11-diynoic acid) from Exocarpos latifolius R.Br. (Santalaceae) was previously shown to have specific antimycobacterial activity. Microarray data suggested inhibition of fatty acid metabolism as a potential mode of action. Experiments designed to elucidate the mechanism of action showed that exocarpic acid was effective at inhibition of mycolic acid biosynthesis and did not act by dissipating the proton gradient in treated M. tuberculosis. Amide derivatives of exocarpic acid displayed similar properties to exocarpic acid, while other polyacetylenic fatty acids varied in their effects on mycolic acid biosynthesis.

New antibacterial and cytotoxic activities of falcarindiol isolated in Crithmum maritimum L. leaf extract

Bioassay-guided fractionation of a chloroformic extract obtained from Crithmum maritimum leaves led to the chemical isolation of falcarindiol, a polyacetylene widely distributed within the Apiaceae family. Structure of this compound was confirmed by NMR and activity was tracked using a screening microplate bioassay. Falcarindiol strongly inhibited the growth of Micrococcus luteus and Bacillus cereus, with a minimum inhibitory concentration (MIC) value of 50 microg ml(-1). Moreover, this compound showed cytotoxicity against IEC-6 cells with an IC50 value of 20 microM after 48 h of exposition. These results suggest that Crithmum maritimum could be potentially used in food manufactures and cosmetology as preservative agents and biopesticides, or in medicine as new antibiotics, confirming the interest in studying halophytic species as sources of bioactive compounds.

Antimycobacterial activity of Exocarpos latifolius is due to exocarpic acid

Lipophilic fractions of stem extracts from Exocarpos latifolius, native to Papua New Guinea, showed significant activity against Mycobacterium tuberculosis H37Ra. Bioactivity-guided fractionation yielded exocarpic acid (E-octadeca-13-ene-9,11-diynoic-acid) as the major active component. Several new exocarpic acid analogs were also shown to be active. Exocarpic acid has previously been reported active against gram-positive, but not gram-negative bacteria. Work presented here demonstrates the selective activity of exocarpic acid against Mycobacterium tuberculosis H37Ra.

Differential effects of falcarinol and related aliphatic C(17)-polyacetylenes on intestinal cell proliferation

Quantitative major polyacetylenes of carrots (falcarinol and falcarindiol) and American ginseng roots (falcarinol and panaxydol) were isolated and tested in human intestinal epithelial cells of normal (FHs 74 Int.) and cancer (Caco-2) origin. A hormesis effect was seen for all isolated polyacetylenes when added to Caco-2 cells in concentrations ranging from 1 ng/mL to 20 microg/mL. The relative inhibitory potency was falcarinol > panaxydol > falcarindiol. No hormesis effect was observed when adding the polyacetylenes to FHs 74 Int. cells. Instead, an inhibitory growth response was observed above 1 microg/mL. The relative inhibitory potency was panaxydol > falcarinol > falcarindiol. Maximal inhibition at 20 microg/mL corresponded to approximately 95% and 80% inhibition of cell proliferation in normal and cancer cells, respectively. Combinations of falcarinol and falcarindiol added to normal and cancer cells showed a synergistic response for the inhibition of cell growth. Furthermore, the oxidized form of falcarinol, falcarinon, showed a significantly less growth inhibitory effect in intestinal cells of both normal and cancer origin; hence, a hydroxyl group at C-3 may be important for activity of falcarinol-type polyacetylenes. Extracts of carrots, containing different amounts of falcarinol, falcarindiol, and falcarindiol 3-acetate had significant inhibitory effects on both normal and cancer cell proliferation. In cancer cells, the extract containing the highest concentration of falcarinol tended to have the highest growth inhibitory effect, in accordance with a higher potency of falcarinol than falcarindiol. The present study demonstrates that aliphatic C(17)-polyacetylenes are potential anticancer principles of carrots and related vegetables and that synergistic interaction between bioactive polyacetylenes may be important for their bioactivity.

Polyacetylenes from sardinian Oenanthe fistulosa: a molecular clue to risus sardonicus

An investigation of Oenanthe fistulosa from Sardinia afforded oenanthotoxin (1a) and dihydrooenanthotoxin (1b) from the roots and the diacetylenic epoxydiol 2 from the seeds. The absolute configuration of 1a and 1b was established as R by the modified Mosher's method, and the structure of 2 by chemical correlation with (+)-(3R,8S)-falcarindiol. Oenanthotoxin (1a) and dihydrooenanthotoxin (1b) were found to potently block GABAergic responses, providing a molecular rationale for the symptoms of poisoning from water-dropwort (Oenanthe crocata) and related plants. These observations bear relevance for a series of historical and ethnopharmacological observations on the identification of the Sardonic herb and the molecular details of the facial muscular contraction caused by its ingestion (risus sardonicus).

Indoleacetic acid falcarindiol ester induces granulocytic differentiation of the human leukemia cell line HL-60

Indoleacetic acid falcarindiol ester (compound 1) has previously been isolated and purified using an SiO2 column and ODS HPLC from an acetone extract of Japanese ivy (Hedera rhombea). Here we investigate the differentiation-inducing activity of compound 1 using the human promyelocytic leukemia HL-60 cell line. The effect of compound 1 on HL-60 cell viability and proliferation was determined at different treatment times using the 3-(4,5-dimethythiazol-2-yl)-2,5-diohenyl-2 H-tetrazolium bromide (MTT) assay and flow cytometry analysis. Also cell cycle kinetics were examined using propidium iodide staining of DNA. Cell differentiation was assessed by specific and non-specific esterase double staining assays, and by detection of the cell surface differentiation markers CD11b and CD14 using flow cytometry. The results showed HL-60 cell growth inhibition at 0.1 and 1.0 microg/mL compound 1, whereas 10 microg/mL was cytotoxic. The growth suppression induced by compound 1 was accompanied by G0/G1 phase arrest in the cell cycle at 1.0 microg/mL. Moreover, staining and immunochemical analysis indicated that compound 1 induced granulocytic differentiation in HL-60 cells. This is the first report describing granulocytic differentiation activity of a falcarindiol derived polyacetylenic compound on leukemia cells.

The polyacetylene falcarindiol with COX-1 activity isolated from Aegopodium podagraria L

Extracts of Aegopodium podagraria L. were screened in vitro for cyclooxygenase-1 (COX-1) inhibitory activity. The isolation of the active compound falcarindiol was achieved by bioassay-guided fractionation. The identification of the active compound was confirmed by (1)H NMR and (13)C NMR. The IC(50)-value of falcarindiol was 0.3 microM in the COX-1 assay. A quantitative determination of the seasonal variation in the content of falcarindiol in different plant parts was carried out by HPLC analysis. The flowers from Aegopodium podagraria collected in June 2006 had the highest concentration of falcarindiol (88 mg/g plant material).

A small molecule Smac mimic potentiates TRAIL-mediated cell death of ovarian cancer cells

OBJECTIVES

Ovarian cancer remains a leading cause of death in women and development of new therapies is essential. Second mitochondria derived activator of caspase (Smac) has been described to sensitize for apoptosis. We have explored the proapoptotic activity of a small molecule mimic of Smac/DIABLO on ovarian cancer cell lines (A2780 cells and its chemoresistant derivatives A2780/ADR and A2780/DDP), cancer cell lines and in primary ovarian cancer cells.

METHODS

The effects of a small molecule mimic of Smac/DIABLO on ovarian cancer cell lines and primary ovarian cancer cells were determined by cell proliferation, apoptosis and biochemical assays.

RESULTS

This compound added alone elicited only a weak proapoptotic effect; however, it strongly synergizes with tumor necrosis factor-related apoptosis inducing ligand (TRAIL) or agonistic TRAILR2 antibody (Lexatumumab) in inducing apoptosis of ovarian cancer cells.

CONCLUSIONS

These observations suggest that small molecule mimic of Smac/DIABLO could be useful for the development of experimental strategies aiming to treat ovarian cancer. Interestingly, in addition to its well known proapoptotic effects, Smac/DIABLO elicited a significant increase of pro-caspase-3 levels.

Biphasic effect of falcarinol on caco-2 cell proliferation, DNA damage, and apoptosis

The polyacetylene falcarinol, isolated from carrots, has been shown to be protective against chemically induced colon cancer development in rats, but the mechanisms are not fully understood. In this study CaCo-2 cells were exposed to falcarinol (0.5-100 microM) and the effects on proliferation, DNA damage, and apoptosis investigated. Low-dose falcarinol exposure (0.5-10 microM) decreased expression of the apoptosis indicator caspase-3 concomitantly with decreased basal DNA strand breakage. Cell proliferation was increased (1-10 microM), whereas cellular attachment was unaffected by <10 microM falcarinol. At concentrations above 20 microM falcarinol, proliferation of CaCo-2 cells decreased and the number of cells expressing active caspase-3 increased simultaneously with increased cell detachment. Furthermore, DNA single-strand breakage was significantly increased at concentrations above 10 microM falcarinol. Thus, the effects of falcarinol on CaCo-2 cells appear to be biphasic, inducing pro-proliferative and apoptotic characteristics at low and high concentrations of falcarinol, respectively.

Induction of apoptosis in rat C6 glioma cells by panaxydol

Panaxydol is a naturally occurring non-peptidyl small molecule isolated from the lipophilic fractions of Panax notoginseng, a well-known Chinese traditional medicine. Previous studies have shown that panaxydol inhibited the growth of various kinds of malignant cell lines. To date, there has been no report concerning the effect of panaxydol on cell growth inhibition in glioma cells. In this paper, we examined panaxydol's antiproliferation and proapoptotic effects on rat C6 glioma cells and investigated its mechanism. Cell growth inhibition of panaxydol was determined by MTT reduction assay. Apoptosis of cells was measured by both Hoechst 33258 staining and Annexin V analysis. It was found that panaxydol markedly inhibited proliferation of C6 cells in a dose-dependent manner with ID(50) of 40 microM. The cell apoptosis was observed at 48 h in the presence of panaxydol. In concert with these findings, Western blot analysis showed a decreased expression of bcl-2 and increased levels of Bax and caspase-3 in C6 cells treated by panaxydol. In conclusion, panaxydol has profound effects on growth and apoptosis of C6 cells, suggesting that panaxydol may be a potential candidate for the treatment of malignant gliomas.