Effects of Sargaquinoic Acid in Sargassum Serratifolium on Inducing Brown Adipocyte-like Phenotype in Mouse Adipocytes In Vitro.

A previous study showed that the meroterpenoid-rich fraction of an ethanolic extract of Sargassum serratifolium (MES) stimulated adipose tissue browning and inhibited diet-induced obesity and metabolic syndrome. Sargaquinoic acid (SQA) is a major component in MES. We investigated the effects of SQA on the differentiation of preadipocytes to the beige adipocytes. SQA was treated in 3T3-L1 adipocytes differentiated under a special condition that has been reported to induce the browning of adipocytes. SQA at 10 µM reduced lipid accumulation by approximately 23%. SQA at 2.5 - 10 µM induced the differentiation of white adipocytes to beige adipocytes partially by increasing the mitochondrial density and the expression of beige/brown adipocyte markers. In addition, SQA activated lipid catabolic pathways, evidenced by the increased expression levels of perilipin, carnitine palmitoyltransferase 1, and acyl-CoA synthetase long-chain family member 1. As a partial mechanism, biochemical and in silico analyses indicate that SQA activated AMP-activated protein kinase signaling in adipocytes.

Thymoquinone influences the expression of genes involved in self-renewal and immunomodulatory potential of mouse bone marrow-derived mesenchymal stem cells in vitro.

Thymoquinone (TQ) is an active ingredient of some medicinal herbs. Despite extensive studies on the biological and pharmacological properties of TQ, its effect on the characteristics of stem cells remains to be clarified. Therefore, this study was aimed to investigate the effect of TQ on viability, proliferation and immunomodulatory potential of mouse bone marrow-derived mesenchymal stem cells (BM-MSCs) in vitro. The BM-MSCs were isolated from young NMRI mice. The cytotoxic effect of TQ on the BM-MSCs was evaluated using MTT assay. Then, the effect of TQ on the proliferation of BM-MSCs and the mRNA expression of genes involved in self-renewal and immunomodulatory potential of MSCs was assessed by the cell counting and real-time PCR assays. Results showed that TQ reduces the number of BM-MSCs in a dose- and time-dependent manner. In addition, the half-maximal inhibitory concentration values of TQ on the BM-MSCs were 8 µg/ml at 24h and 4 µg/ml at 48 and 72h after treatment. Furthermore, about 90% of the BM-MSCs were alive after treatment with concentrations ≤2 µg/ml of TQ for 24h. The results of cell counting assay indicated that TQ at concentrations of 1-2 µg/ml significantly enhanced the proliferation of BM-MSCs (P < 0.05). The gene expression analysis also showed that Tlr3, Tlr4, Ccl2, Ccl3, Sox2, and Rex1 are overexpressed (Fold change ≥1.5) in the TQ-treated BM-MSCs compared with the untreated samples. In conclusion, these findings propose that TQ may regulate self-renewal and immunomodulatory potential of MSCs. However, the exact mechanisms and the roles of this regulation are required to be elucidated in further study.

Addition of 17-(allylamino)-17-demethoxygeldanamycin to a suboptimal caspofungin treatment regimen in neutropenic rats with invasive pulmonary aspergillosis delays the time to death but does not enhance the overall therapeutic efficacy.

Caspofungin (CAS) which is used as salvage therapy in patients with invasive pulmonary aspergillosis (IPA) inhibits the 1,3-ß-D-glucan synthesis in Aspergillus fumigatus. Inhibiting 1,3-ß-D-glucan synthesis induces a stress response and in an invertebrate model it was demonstrated that inhibiting this response with geldamycin enhanced the therapeutic efficacy of CAS. Since geldamycin itself is toxic to mammalians, the therapeutic efficacy of combining geldamycin with CAS was not studied in rodent models. Therefore in this study we investigated if the geldamycin derivate 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) was able to enhance the therapeutic efficacy of CAS in vitro and in our IPA model in transiently neutropenic rats. In vitro we confirmed the earlier demonstrated synergy between 17-AAG and CAS in ten A. fumigatus isolates. In vivo we treated A. fumigatus infected neutropenic rats with a sub-optimal dose of 0.75 mg/kg/day CAS and 1 mg/kg/day 17-AAG for ten days. Survival was monitored for 21 days after fungal inoculation. It appeared that the addition 17-AAG delayed death but did not improve overall survival of rats with IPA. Increasing the doses of 17-AAG was not possible due to hepatic toxicity. This study underlines the need to develop less toxic and more fungal specific geldamycin derivatives and the need to test such drugs not only in invertebrate models but also in mammalian models.

Cytotoxicity of Plumbagin, Rapanone and 12 other naturally occurring Quinones from Kenyan Flora towards human carcinoma cells.

BACKGROUND: Cancer is a major public health concern globally and chemotherapy remains the principal mode of the treatment of various malignant diseases. METHODS: This study was designed to investigate the cytotoxicity of 14 naturally occurring quinones including; 3 anthraquinones, 1 naphthoquinone and 10 benzoquinones against 6 human carcinoma cell lines and normal CRL2120 fibroblasts. The neutral red uptake (NR) assay was used to evaluate the cytotoxicity of the compounds, whilst caspase-Glo assay was used to detect caspases activation. Cell cycle and mitochondrial membrane potential (MMP) were all analyzed via flow cytometry meanwhile levels of reactive oxygen species (ROS) were measured by spectrophotometry. RESULTS: Anthraquinone: emodin (2), naphthoquinone: plumbagin (4), and benzoquinones: rapanone (9), 2,5-dihydroxy-3-pentadecyl-2,5-cyclohexadiene-1,4-dione (10), 5-O-methylembelin (11), 1,2,4,5-tetraacetate-3-methyl-6-(14-nonadecenyl)-cyclohexadi-2,5-diene (13), as well as doxorubicin displayed interesting activities with IC50 values below 100 µM in the six tested cancer cell lines. The IC50 values ranged from 37.57 µM (towards breast adenocarcinoma MCF-7 cells) to 99.31 µM (towards small cell lung cancer A549 cells) for 2, from 0.06 µM (MCF-7 cells) to 1.14 µM (A549 cells) for 4, from 2.27 µM (mesothelioma SPC212 cells) to 46.62 µM (colorectal adenocarcinoma DLD-1 cells) for 9, from 8.39 µM (SPC212 cells) to 48.35 µM (hepatocarinoma HepG2 cells) for 10, from 22.57 µM (MCF-7 cells) to 61.28 µM (HepG2 cells) for 11, from 9.25 µM (MCF-7 cells) to 47.53 µM (A549 cells) for 13, and from 0.07 µM (SPC212 cells) to 1.01 µM (A549 cells) for doxorubicin. Compounds 4 and 9 induced apoptosis in MCF-7 cells mediated by increased ROS production and MMP loss, respectively. CONCLUSION: The tested natural products and mostly 2, 4, 9, 10, 11 and 13 are potential cytotoxic compounds that deserve more investigations towards developing novel antiproliferative drugs against human carcinoma.

Effects of benzo[a]pyrene as an environmental pollutant and two natural antioxidants on biomarkers of reproductive dysfunction in male rats.

Benzo[a]pyrene (B[a]P) is an environmental toxicant and endocrine disruptor. Therefore, the aim of the present study was to investigate the toxicity of B[a]P in testis of rats and also to study the role of silymarin and thymoquinone (TQ) as natural antioxidants in the alleviation of such toxicity. Data of the present study showed that levels of testosterone, estrogen and progesterone were significantly decreased after treatment of rats with B[a]P. In addition, B[a]P caused downregulation of the expressions of steroidogenic enzymes including CYP17A1 and CP19A1, and decreased the activity of 17-ß hydroxysteroid dehydrogenase (17ß-HSD). Moreover, B[a]P decreased the activities of antioxidant enzymes including catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD), and significantly increased free radicals levels in testis of male rats. However, pretreatment of rats with silymarin prior to administration of B[a]P was found to restore the level of free radicals, antioxidant status, and activities of steroidogenic enzymes to their normal levels in testicular tissues. Moreover, histopathological finding showed that silymarin recovered the abnormalities occurred in tubules caused by B[a] P in testis of rats. On the other hand, TQ showed pro-oxidant effects and did not ameliorate the toxic effects of B[a] P on the testicular tissue since it decreased antioxidant enzymes activities and inhibited the protein expression of CYP11A1 and CYP21A2 compared to control rats. Moreover, TQ decreased the levels of testosterone, estrogen, and progesterone either in the presence or absence of B[a]P. It is concluded that B[a]P decreased testosterone levels, inhibited antioxidant enzymes activities, caused downregulation of CYP isozymes involved in steroidogenesis, and increased free radical levels in testis. Moreover, silymarin was more effective than TQ in restoring organism health and alleviating the deleterious effects caused by B[a]P in the testis of rats. Due to its negative impact, it is highly recommended to limit the use of TQ as a dietary supplement since millions of people in the Middle East are using it to improve their health.

Immunomodulatory and cytotoxic effects of Nigella sativa and thymoquinone on rat splenocytes.

Three different concentrations of Nigella sativa (N. sativa) ethanolic extract, thymoquinone (TQ), dexamethasone, and saline were examined to see whether they had any effects on cell viability, proliferation, and interleukin 4 (IL-4) and interferon-γ (IFN-γ) secretion in non-stimulated, phytohemagglutinin (PHA) and concavaline A (Con A)-stimulated splenocytes. In PHA and Con A-stimulated splenocytes, cell viability and proliferation were increased and Con A shifted cytokine profile towards Th2 balance. Dexamethasone treatment showed a suppression in viability, IFNγ and IL-4 secretion in non-stimulated and stimulated splenocytes. Extract and TQ reduced the viability and inhibited the proliferation of stimulated and non-stimulated splenocytes concentration-dependently. Higher concentrations of N. sativa (1000 mg/ml) and TQ (5 and 10 mg/ml) reduced the secretion of IL-4 in stimulated cells. Two higher concentrations of N. sativa had decreased IFNγ secretion in both stimulated and non-stimulated cells. In non-stimulated cells, only the highest and in Con A-stimulated cells, all TQ concentrations had inhibited IFNγ secretion. The highest concentration of N. sativa increased IFNγ/IL-4 ratio in both stimulated and non-stimulated cells while higher concentrations of TQ only had the same effect on stimulated cells. N. sativa and TQ showed cytotoxic inhibitory effect on rat splenocytes and on Th1/Th2 cytokines concentration-dependently. Higher concentrations of extract and TQ increased cytokines balance in Th1/Th2.

Moles of a Substance per Cell Is a Highly Informative Dosing Metric in Cell Culture.

BACKGROUND: The biological consequences upon exposure of cells in culture to a dose of xenobiotic are not only dependent on biological variables, but also the physical aspects of experiments e.g. cell number and media volume. Dependence on physical aspects is often overlooked due to the unrecognized ambiguity in the dominant metric used to express exposure, i.e. initial concentration of xenobiotic delivered to the culture medium over the cells. We hypothesize that for many xenobiotics, specifying dose as moles per cell will reduce this ambiguity. Dose as moles per cell can also provide additional information not easily obtainable with traditional dosing metrics. METHODS: Here, 1,4-benzoquinone and oligomycin A are used as model compounds to investigate moles per cell as an informative dosing metric. Mechanistic insight into reactions with intracellular molecules, differences between sequential and bolus addition of xenobiotic and the influence of cell volume and protein content on toxicity are also investigated. RESULTS: When the dose of 1,4-benzoquinone or oligomycin A was specified as moles per cell, toxicity was independent of the physical conditions used (number of cells, volume of medium). When using moles per cell as a dose-metric, direct quantitative comparisons can be made between biochemical or biological endpoints and the dose of xenobiotic applied. For example, the toxicity of 1,4-benzoquinone correlated inversely with intracellular volume for all five cell lines exposed (C6, MDA-MB231, A549, MIA PaCa-2, and HepG2). CONCLUSIONS: Moles per cell is a useful and informative dosing metric in cell culture. This dosing metric is a scalable parameter that: can reduce ambiguity between experiments having different physical conditions; provides additional mechanistic information; allows direct comparison between different cells; affords a more uniform platform for experimental design; addresses the important issue of repeatability of experimental results, and could increase the translatability of information gained from in vitro experiments.

Natural products as topoisomerase II poisons: effects of thymoquinone on DNA cleavage mediated by human topoisomerase IIα.

The seeds of Nigella sativa (often referred to as black seed) have long been utilized as a medicinal herb in Middle Eastern, Northern African, and Indian cultures. Historically, black seed has been used to treat a variety of illnesses associated with inflammation. More recent studies have found that it induces apoptosis and displays anticancer activity in animal and cellular models. The major bioactive compound of black seed is thymoquinone, which shares structural features with 1,4-benzoquinone and other covalent topoisomerase II poisons. Because a number of anticancer drugs target type II topoisomerases, we determined the effects of thymoquinone and a series of related quinones on human topoisomerase IIα. Thymoquinone enhanced enzyme-mediated DNA cleavage ~5-fold, which is similar to the increase seen with the anticancer drug etoposide. In order to enhance cleavage, compounds had to have at least two positions available for acylation. Furthermore, activity was decreased by the inclusion of electron-donating groups or bulky substituents. As predicted for a covalent topoisomerase II poison, the activity of thymoquinone (and related compounds) was abrogated by the addition of a reducing agent. Also, thymoquinone inhibited topoisomerase IIα activity when incubated with the enzyme prior to the addition of DNA. Cleavage complexes formed in the presence of the compound were stable for at least 8 h. Lastly, black seed extract and black seed oil both increased levels of enzyme-mediated DNA cleavage, suggesting that thymoquinone is active even in more complex herbal formulations. These findings indicate that thymoquinone can be added to the growing list of dietary and medicinal natural products with activity against human type II topoisomerases.

Embelin - a drug of antiquity: shifting the paradigm towards modern medicine.

INTRODUCTION: Embelia ribes or Embelia tsjeriam-cottam, more commonly known as vidanga, is a type of ayurvedic medicine that has been used to treat various diseases for a number of years. Bright orange embelin -rich fruits have been well established as ethnomedicinals, for a number of years with their pharmacological actions attributed to their hydroxybenzoquinone active constituent. Embelin has become known specifically for its antihelminthic and contraceptive use. AREAS COVERED: This drug evaluation provides a historical summary of embelin along with its therapeutic use, phytochemistry and toxicology. Embelin's pharmacotherapeutical properties are also discussed along with its molecular targets. It is hoped that this article will help to draw the attention of researchers and biopharmaceutical companies to the untapped potential in bioprospection for the development of new drugs. EXPERT OPINION: Embelin is the only known non-peptide small-molecule X-linked inhibitor of the apoptosis protein (XIAP) - an anti-apoptotic protein considered a promising cancer therapeutic target. Embelin acts as an NF-κB blocker and potential suppressor of tumorigenesis. It also exhibits potent cytotoxic, antioxidant and cancer chemopreventive effects. Given the potential uses of embelin, it is recommended that further investigations take place to properly explore its pharmacological and clinical effects.

Antitrypanosomal isoflavan quinones from Abrus precatorius.

Human African trypanosomiasis is a neglected tropical disease in sub Saharan Africa that is fatal if left untreated. In a search for new natural products with antitrypanosomal activity, we recently identified abruquinones B and I from Abrus precatorius as potent in vitro trypanocidal compounds with high selectivity indices. To obtain sufficient compound for in vivo efficacy tests in mice, a second batch of plant material was re-collected and extracted. However, the chemical profiles of the two batches differed, and additional abruquinones were isolated and identified by HR-ESI-MS, and 1D and 2D NMR ((1)H, (13)C, COSY, HMBC, HSQC, and NOESY) spectroscopy. Abruquinones J (1), K (2), and L (3) were new, while abruquinones A (4) and D (5) were known from the first batch of plant material. The absolute configuration of compounds 1 to 3 was determined by comparison of electronic circular dichroism (ECD) spectra with calculated ECD data. Compounds 2 to 5 showed high in vitro activity against T. b. rhodesiense (IC50 of 0.01, 0.02, 0.02 and 0.01 µM, respectively), and remarkable SIs of 508, 374, 1379, and 668, respectively.

Novel anti-nociceptive effects of cardamonin via blocking expression of cyclooxygenase-2 and transglutaminase-2.

Recently, we reported that Alpinia katsumadai (AK) has anti-nociceptive activity in vivo and that cardamonin (CDN) from AK suppresses the activity and expression of transglutaminase-2 (Tgase-2). However, it remains unknown whether CDN contributes to the anti-nociceptive activities of AK in vivo. We examined the anti-inflammatory effects of CDN in MG63 osteoblast-like cells and Raw264.7 macrophage-like cells treated with interleukin-1ß treatment. CDN suppressed the expression of Tgase-2, cyclooxygenase-2 (COX-2), and p65 (nuclear factor-κB) in a concentration-dependent manner, and restored the expression of IκB in MG63 and Raw264.7 cells. However, CDN did not inhibit the activity of COX-2. Gene silencing of Tgase-2 reduced the COX-2 expression in MG63 cells. Phenylbenzoquinone (PBQ)-induced writhing, carrageenan-induced hyperalgesia, and rota-rod test were used to evaluate the anti-nociceptive activity in vivo. CDN (3-30 mg/kg, orally administered) significantly inhibited PBQ-induced writhing. CDN also produced a significant, dose-dependent increase in the withdrawal response latencies in carrageenan-induced hyperalgesia. The effects of CDN on PBQ-induced writhing were not caused by impaired motor functions. These results suggest that CDN might be helpful in controlling the pain from inflammatory diseases.

Thymoquinone causes multiple effects, including cell death, on dividing plant cells.

Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1mg/mL greatly reduced wheat seed germination rate, whereas 0.2mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1h of TQ treatment (0.2mg/mL), with severe cell death occurring in this zone after 2h of treatment. Light microscopy of TQ-treated (0.2mg/mL) onion hairy root tips for 1h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2mg/mL) for 1h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAG-like gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ.

Phytochemical investigations and bioactivity evaluation of liverworts as a function of anti-inflammatory and antinociceptive properties in animal models.

CONTEXT: Liverworts (Marchantiophyta) are the second largest group of bryophytes exhibiting promising pharmacological and biological activities. They have been used as remedies for cuts, fractures, burns, bruises, open wounds, inflammation and pneumonia. OBJECTIVE: In the present study, eight liverwort species [Corsinia coriandrina (Spreng.) Lindb. (Corsiniaceae), Mannia androgyna (L.) A. Evans (Aytoniaceae), Plagiochasma rupestre (J.R. Forst et G. Forst) Steph. (Aytoniaceae), Porella cordaeana (Huebener) Moore (Porellaceae), Porella platyphylla (L.) Pfeiff. (Porellaceae), Reboulia hemisphaerica (L.) Raddi (Aytoniaceae), Riccia fluitans L. (Ricciaceae), and Targionia hypophylla L. (Targioniaceae)] have been investigated for their phytochemical composition and pharmacological effects as a function of anti-inflammatory and antinociceptive potentials, in connection with the major volatile components of the extracts. MATERIAL AND METHODS: The chemical compositions of these species and major constituents were identified using GC/MS. In addition, carrageenan-induced paw edema and p-benzoquinone-induced abdominal constriction models were used for the activity assessments. RESULTS: Sesquiterpenes were detected as common constituents of all liverworts. The in vivo experimental models revealed that P. cordeana, P. rupestre and R. haemispherica show significant inhibitory effect on carrageenan-induced paw edema with the inhibition values of 25.4, 27.2 and 29.4%, respectively. Porella cordaeana, P. platyphylla, P. rupestre and R. haemispherica exhibit promising suppressing effect on p-benzoquinone-induced abdominal constriction animal models with the values of 27.6, 31.5, 44.6, and 41.1%, respectively. DISCUSSION: It is suggested that the sesquiterpenes are partly responsible for mentioned activities of the liverworts. CONCLUSION: The present study confirms the claimed anti-inflammatory activity of liverworts in a scientific platform.

Prophylactic effect of egualen sodium, a stable azulene derivative, on gastrointestinal damage induced by ischemia/reperfusion, double antiplatelet therapy and loxoprofen in rats.

We examined the effect of egualen, a stable azulene derivative, against gastric damage induced by ischemia/reperfusion (I/R), gastric bleeding induced by double antiplatelet therapy with aspirin (ASA) plus clopidogrel, and small intestinal damage generated by loxoprofen, and investigated the possible mechanisms involved in its protective action. Male C57BL/6 mice or SD rats were used under urethane anesthesia (gastric lesions) or in a conscious (intestinal lesions) state. I/R-induced gastric injury was produced in mice by clamping the celiac artery for 30 min, followed by reperfusion for 60 min. Gastric bleeding was induced in rats by luminal perfusion with 25 mM ASA+50 mM HCl for 2 hours in the presence of clopidogrel (30 mg/kg). To produce small intestinal lesions the rats were given loxoprofen (60 mg/kg) p.o. and killed 24 hours later. Egualen was given i.d. 60 min before I/R or ASA perfusion, while given p.o. twice 30 min before and 6 hours after loxoprofen. Egualen significantly prevented the I/R-induced gastric damage, and the effect was equivalent to that of seratrodast (TXA2 antagonist). This agent also significantly suppressed gastric bleeding induced by ASA plus clopidogrel, similar to PGE2. Likewise, egualen significantly prevented loxoprofen-induced damage in the small intestine, accompanied by an increase in the secretion of mucus and suppression of bacterial invasion as well as iNOS expression. These results suggest that egualen has a prophylactic effect against various lesions in the gastrointestinal mucosa, probably through its characteristic pharmacological properties, such as TXA2 antagonistic action, local mucosal protection, and stimulation of mucus secretion.

Combination of electrochemistry and nuclear magnetic resonance spectroscopy for metabolism studies.

During the development of new materials demonstrating biological activity, prediction and identification of reactive intermediates generated in the course of drug metabolism in the human liver is of great importance. We present a rapid and purely instrumental method for the structure elucidation of possible phase I metabolites. With electrochemical (EC) conversion adopting the oxidative function of liver-inherent enzymes and nuclear magnetic resonance (NMR) spectroscopy enabling structure elucidation, comprehensive knowledge on potential metabolites can be gained. Paracetamol (APAP) has been known to induce hepatotoxicity when exceeding therapeutic doses and was therefore selected as the test compound. The reactive metabolite N-acetyl-p-benzoquinone imine has long been proven to be responsible for the toxic side effects of APAP and can easily be generated by EC. EC coupled online to NMR is a straightforward technique for structure elucidation of reactive drug intermediates at an early stage in drug discovery.

Anti-malarial, anti-trypanosomal, and anti-leishmanial activities of jacaranone isolated from Pentacalia desiderabilis (Vell.) Cuatrec. (Asteraceae).

Leishmaniasis, Chagas disease, and malaria affect the poorest population around the world, with an elevated mortality and morbidity. In addition, the therapeutic alternatives are usually toxic or ineffective drugs especially those against the trypanosomatids. In the course of selection of new anti-protozoal compounds from Brazilian flora, the CH(2)C(l2) phase from MeOH extract obtained from the leaves of Pentacalia desiderabilis (Vell.) Cuatrec. (Asteraceae) showed in vitro anti-leishmanial, anti-malarial, and anti-trypanosomal activities. The chromatographic fractionation of the CH(2)Cl(2) phase led to the isolation of the bioactive compound, which was characterized as jacaranone [methyl (1-hydroxy-4-oxo-2,5-cyclohexandienyl)acetate], by spectroscopic methods. This compound showed activity against promastigotes of Leishmania (L.) chagasi, Leishmania (V.) braziliensis, and Leishmania (L.). amazonensis showing an IC(50) of 17.22, 12.93, and 11.86 µg/mL, respectively. Jacaranone was also tested in vitro against the Trypanosoma cruzi trypomastigotes and Plasmodium falciparum chloroquine-resistant parasites (K1 strain) showing an IC(50) of 13 and 7.82 µg/mL, respectively, and was 3.5-fold more effective than benznidazole in anti-Trypanosoma cruzi assay. However, despite of the potential against promatigotes forms, this compound was not effective against amastigotes of L. (L.) chagasi and T. cruzi. The cytotoxicity study using Kidney Rhesus monkey cells, demonstrated that jacaranone showed selectivity against P. falciparum (21.75 µg/mL) and a selectivity index of 3. The obtained results suggested that jacaranone, as other similar secondary metabolites or synthetic analogs, might be useful tolls for drug design for in vivo studies against protozoan diseases.

Oral and intraperitoneal LD50 of thymoquinone, an active principle of Nigella sativa, in mice and rats.

BACKGROUND: Thymoquinone is the major active principle of Nigella sativa (N. sativa) and constitutes about 30% of its volatile oil or ether extract. N. sativa oil and seed are commonly used as a natural remedy for many ailments. Using modern scientific techniques, a number of pharmacological actions of N. sativa have been investigated including immunostimulant, anti-inflammatory, anticancer, antioxidant, antihistaminic, antiasthmatic, hypoglycemic, antimicrobial and antiparasitic. There are only few reports regarding the toxicity of thymoquinone. METHODS: The present study was carried out to determine LD50 of thymoquinone both in mice and rats, orally as well as intraperitoneall, by the method of Miller and Tainter. Autopsy and histopathology of liver, kidney, heart and lungs were also determined. RESULTS: The LD50 in mice after intraperitoneal injection was determined to be 104.7 mg/kg (89.7-119.7, 95% confidence interval) and after oral ingestion was 870.9 mg/kg (647.1-1094.8, 95% confidence interval). Whereas, LD50 in rats after intraperitoneal injection was determined to be 57.5 mg/kg (45.6-69.4, 95% confidence intervals) and after oral ingestion was 794.3 mg/kg (469.8-1118.8, 95% confidence intervals). The LD50 values presented here after intraperitoneal injection and oral gavages are 10-15 times and 100-150 times greater than doses of thymoquinone reported for its anti-inflammatory, anti-oxidant and anti-cancer effects. CONCLUSION: Thymoquinone is a relatively safe compound, particularly when given orally to experimental animals.

Assessment of anti-inflammatory and antinociceptive activities of Daphne pontica L. (Thymelaeaceae).

The n-hexane, diethylether, ethyl acetate and methanol extracts from roots, leaves, stems and flowers with young leaves of Daphne pontica L. (Thymelaeaceae) were investigated for their in vivo anti-inflammatory and antinociceptive activities. For the anti-inflammatory activity assessment, carrageenan-induced hind paw edema, PGE(2)-induced hind paw edema and 12-O-tetradecanoyl-13-acetate (TPA)-induced mouse ear edema models and for the antinociceptive activity, p-benzoquinone-induced abdominal constriction test were used. Only ethyl acetate extracts of the roots showed significant anti-inflammatory activity on carrageenan-induced (22.7-32.0% inhibition) and PGE(2)-induced hind paw edema (3.2-27.3% inhibition) as well as 12-O-tetradecanoyl-13-acetate (TPA)-induced mouse ear edema (47.8-43.3% inhibition) models at 50 mg/kg dose without inducing any apparent gastric lesion or acute toxicity, whereas the other extracts were shown to be ineffective. In addition to roots, ethyl acetate extracts of the stems exhibited 19.5-29.9%; 5.3-23.9%; 36.6-28.1% inhibition on carrageenan-induced and PGE(2)-induced hind paw edema as well as 12-O-tetradecanoyl-13-acetate (TPA)-induced mouse ear edema models, respectively. On the other hand, none of the extracts showed any significant antinociceptive activity.

Wound healing activity of embelin isolated from the ethanol extract of leaves of Embelia ribes Burm.

Ethanol extract of the leaves of Embelia ribes Burm. (Myrsinaceae) and its isolated quinone compound embelin were screened for wound healing activity by excision, incision and dead space wound models on Swiss Albino Rats. Significant wound healing activity was observed in both ethanol crude extract (30 mg/ml) and the constituent treated groups. In embelin treated groups (4 mg/ml of 0.2% sodium alginate gel), epithelialization of the incision wound was faster with a high rate of wound contraction. The tensile strength of the incision wound was significantly increased than the ethanol extract. In dead space wound model also the weight of the granulation was increased indicating increase in collagenation. The histological examination of the granulation tissue of embelin treated group showed increased cross-linking of collagen fibers and absence of monocytes. The wound healing effect was comparatively evaluated with the standard skin ointment Framycetin.

Bioactive alkyl phenols and embelin from Oxalis erythrorhiza.

The benzoquinone embelin and four alkyl phenols were isolated from an Argentinean collection of Oxalis erythrorhiza. 3-Heptadecyl-5-methoxy-phenol is reported for the first time. The structures were determined by spectroscopic methods. Embelin presented inhibitory effect on methicillin-resistant Staphylococcus aureus, Escherichia coli and the dermatophytic fungi Epidermophyton floccosum, Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes and Trichophyton rubrum with MICs ranging between 50 and 100 microg/ml. Furthermore, embelin was active against Trypanosoma cruzi trypomastigotes with 100% lysis at 100 microg/ml and cytotoxicity below the trypanocidal concentration. The new alkyl phenol 3-heptadecyl-5-methoxy-phenol was active towards Leishmania amazonensis and Leishmania donovani promastigotes with 100% lysis at 100 microg/ml. The cytotoxicity (IC50) of embelin and the new alkyl phenol on human lung fibroblasts were 739 and 366 microM, respectively. The plant is used to treat heart complains, a symptomatology related to Chagas' disease which is endemic in the San Juan Province, Argentine.