马鞭草裂环环烯醚萜苷类成分的分离与鉴定

目的研究马鞭草中裂环环烯醚萜苷类成分。方法采用反复硅胶柱色谱、Sephadex LH-20柱色谱和半制备高效液相色谱等方法进行分离纯化,依据MS、1D和2D NMR(1H-1H COSY、HMQC和HMBC)进行结构鉴定。结果从马鞭草乙醇提取物的正丁醇可溶部分分离得到5个裂环环烯醚萜苷类化合物,分别鉴定为三叶草苷(trifloroside,1)、macrophylloside(2)、3′-acetylsweroside(3)、当药苦苷(swertiamarin,4)和龙胆苦苷(gentiopicroside,5)。结论化合物1~4为首次从马鞭草属植物中分离得到。     

HPLC-DAD-ESI-MS analysis of the constituents of aqueous preparations of verbena and lemon verbena and evaluation of the antioxidant activity

Verbena and lemon verbena aqueous preparations were investigated for their content of constituents, especially polyphenols by HPLC/DAD/ESI/MS analysis because they are used worldwide as herbal teas. The main class of compounds of these plants were phenylpropanoids (from 16 to 120 mg/g of dried extract), being verbascoside the most abundant in all the preparations up to 97% of the total phenylpropanoids. Also iridoids, hastatoside and verbenalin together with flavonoids, mono- and di-glucuronidic derivatives of luteolin and apigenin were found. These simple preparations, especially that obtained from infusion of lemon verbena, could be lyophilized to obtain a powder having interesting technological properties to be used as ingredients of cosmetics, food supplements and herbal medicinal products do to the many biological properties of verbascoside. In addition, the antioxidant property of the lemon verbena infusion was evaluated by the DPPH test using Trolox as the reference compound.     

巴戟天根皮中的醌类成分的分离与鉴定

目的研究巴戟天(Morinda officinalisHow.)化学成分。方法运用多种色谱学方法对巴戟天根皮体积分数70%乙醇提取物的化学成分进行分离,并根据光谱数据鉴定化合物的结构。结果从该植物中分离得到17个化合物,分别鉴定为rubiasin A(1)、rubiasin B(2)、2-羟基-1-甲氧基蒽醌(2-hydroxy-1-methoxy-anthraquinone,3)、3-羟基-1-甲氧基-2-甲基蒽醌(3-hydroxy-1-methoxy-2-methyl-anthraquinone,4)、1,3-二羟基-2-甲氧基蒽醌(1,3-dihydroxy-2-methoxy-anthraquinone,5)、2-甲基蒽醌(2-methyl-anthraquinone,6)、1,3-二羟基-2-甲基蒽醌(1,3-dihydroxy-2-methyl-anthraqui-none,7)、2-羟甲基蒽醌(2-hydroxymethyl-anthraquinone,8)、3-羟基-1,2-二甲氧基蒽醌(3-hydroxy-1,2-dimethoxy-anthraquinone,9)、1,8-二羟基-3-甲氧基-6-甲基蒽醌(1,8-dihydroxy-3-methoxy-6-methyl-anthraquinone,10)、苯乙醇-O-β-D-吡喃葡萄糖苷(2-phenylethyl-O-β-D-glucopyranoside,11)、2-丁醇-O-β-D-吡喃葡萄糖苷(sec-butyl-O-β-D-glucopyranoside,12)、3,4-二羟基苯乙醇(3,4-di-hydroxyphenylethanol,13)、3-(4-羟基-苯基)-1,2-丙二醇(3-(4-hydroxyphenyl)-1,2-propandiol,14)、阿魏酸(ferulic acid,15)、熊果酸(ursolic acid,16)、β-谷甾醇(β-sitosterol,17)。结论化合物1,2,11~14为首次从巴戟天属植物中分离得到。     

Investigation of the volatile fraction of rosemary infusion extracts

The relative proportions of chemical classes (hydrocarbons, oxides, alcohols, ketones, esters) in the essential oil of rosemary (Rosmarinus officinalis L., Lamicaeae) and in the volatile fraction of the infusion extracts were examined and showed remarkable differences.The volatile compounds of the infusion were isolated by two different methods, hydrodistillation and solid phase extraction (SPE). The main constituents of the volatile fraction of the infusion were (hydrodistillation/SPE): 1,8-cineole (42.4%/44.7%), camphor (31.4%/31.8%), α-terpineol (8.6%/8.1%) and borneol (8.3%/7.8%). The qualitative and quantitative composition of the volatile compounds of the infusion was compared to the essential oil isolated by hydrodistillation directly from the leaves. The major constituents of the essential oil of the leaves were 1,8-cineole (41.6%), camphor (17.0%), α-pinene (9.9%), α-terpineol (4.9%) and borneol (4.8%). Comparison of the total essential oil yield quantified by hydrodistillation of the infusion (0.36% v/w) with the essential oil yield of the leaves (1.84% v/w) revealed that only 19.6% of the initial oil could be extracted by infusion.     

Chemical composition and antioxidant activities of the essential oil and methanol extracts of Psammogeton canescens

This study is outlined to probe the chemical composition of essential oil and in vitro antioxidant activity of the essential oil and methanol extracts of Psammogeton canescens. The chemical composition of the hydrodistilled essential oil of the aerial parts of P. canescens was analyzed by GC and GC/MS. The main constituents of the oil were found to be β-bisabolene (33.35%), apiole (28.34%), α-pinene (11.86%) and dill apiole (8.17%). Antioxidant activities of the samples were determined by three various testing systems namely DPPH, β-carotene/linoleic acid, and reducing power assay. In DPPH system, the highest radical-scavenging activity was seen by the polar subfraction of methanol extract (49.5 ± 1.21 μg/ml). Furthermore, in the second case the inhibition capacity (%) of the polar subfraction (92.40% ± 0.72) found to be the stronger one. However, in the reducing power assay, a reverse activity pattern more than in the first two systems was observed, and the essential oil was stronger radical reducer than was the methanol extract in all of the concentration tested. Our findings demonstrate that the essential oil and methanol extracts of P. canescens possess significant antioxidant activities and may be suggested as a new potential source of natural antioxidant.     

Molecular cloning of the major lethal toxins from two kraits (Bungarus flaviceps and Bungarus candidus).

The major lethal toxins present in the venoms of the red-headed krait, Bungarus flaviceps, and the Malayan krait, Bungarus candidus, have both been purified. Each consists of two polypeptide chains, A and B, joined by a disulfide bond. In the present study, primary structures of these toxins were determined by Edman degradation and by nucleotide sequencing of the cDNA clones. Amino acid sequencing of the N-terminus and enzymatically digested peptides revealed that the A and B chains were highly homologous to those of beta-bungarotoxins (beta-Bgts) from Bungarus multicinctus, respectively. We isolated cDNA clones encoding the A and B chains from both B. flaviceps and B. candidus venom gland cDNA libraries using probes designed based on the cDNA sequence of beta-Bgt from B. multicinctus. Two isoforms of the A chain and one isoform of the B chain were obtained from B. flaviceps, and one isoform of the A chain and two isoforms of the B chain were obtained from B. candidus. Both of the two A chains from B. flaviceps are made up of 119 amino acids and comprise 15 cysteine residues, while the A chains of beta-Bgt from other Bungarus species including B. candidus comprise 13 cysteine residues. The B chains from both species are composed of 59 amino acid residues and comprise seven cysteines. In conclusion, the lethal toxin from B. flaviceps is considered to be a novel isoform of beta-Bgt, which has a different pattern of cysteine residues from known beta-Bgts.     

Comparative study on extracts from the tissue covering the stingers of freshwater (Potamotrygon falkneri) and marine (Dasyatis guttata) stingrays.

Stingrays are elasmobranchs found along the seacoast and in some rivers of Brazil. Pain is the most conspicuous symptom observed in patients wounded by the bilaterally retroserrate stingers located in the tail, which are covered by glandular and integument tissues. In addition, cutaneous necrosis is commonly observed in injuries caused by freshwater stingrays. The aim of this work was to characterize and compare certain properties of tissue extracts obtained from the glandular tissues covering the stinger apparatus of Potamotrygon falkneri and Dasyatis guttata stingrays. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), tissue extracts have similar bands above 80 kDa, but most differences were observed below this molecular mass. Lethal, dermonecrotic and myotoxic activities were detected only in P. falkneri tissue extract. Edematogenic activity was similar and dose dependent in both tissue extracts. Nociceptive activity was verified in both tissue extracts, but P. falkneri presented a two-fold higher activity than D. guttata tissue extract. No direct hemolysis, phospholipase A2 and coagulant activities were observed in both tissue extracts. Antigenic cross-reactivity was noticed by ELISA and Western blotting, using antisera raised in rabbits. Species-specific sera reacted with several components of both tissue extracts, noticeably above 22kDa. Both tissue extracts presented gelatinolytic, caseinolytic and fibrinogenolytic activities, which were not caused by the action of metalloproteinases. Hyaluronidase activity was detected only in P. falkneri tissue extract. Our experimental observations suggest that P. falkneri tissue extract is more toxic than D. guttata tissue extract. These results may explain why injuries caused by freshwater stingrays are more severe in human accidents.     

Anti-mitotic activity towards sea urchin embryos in extracts from the marine haptophycean Phaeocystis pouchetii (Hariot) Lagerheim collected along the coast of northern Norway.

The marine bloom-forming alga Phaeocystis pouchetii is suspected to produce some toxic compound responsible for reduced growth, fecundity and survival of other marine organisms. Sea urchin early development was used as a model to investigate the degree and nature of toxicity. Colonial cells of P. pouchetii were collected during its spring-bloom along the coast of northern Norway and maintained in culture for a short period of time in order to evaluate the concentration of toxic compounds present inside the cells or excreted to the surrounding seawater medium. Cells were harvested by filtration and toxins were extracted separately from the collected cells and the filtrate using organic solvents. We found that extracts from the filtered seawater at a concentration corresponding to 9.0 x 10(5) cells ml(-1) completely blocked cell divisions in embryos of the sea urchin Sphaerechinus granularis, whereas extracts from intact algal cells were only mildly cytotoxic. When the extracts from seawater culture medium were purified by RP-HPLC, cytotoxic activity towards S. granularis embryos was recovered in three consecutive fractions. Moreover, unfertilised eggs incubated in the active HPLC fractions became unproductive, whereas incubation of sperm gave a reduced fertilisation rate. This anti-proliferative effect was further characterized by immunofluorescence staining of sea urchin embryos. DNA labelling revealed that incubating sea urchin embryos in the purified algal extracts inhibited both pronuclei migration and fusion. Incorporation and detection of the DNA-base analogue 5-bromo-2-deoxyuridine showed that DNA-replication was blocked. Furthermore, staining of alpha-tubulin subunits demonstrated that embryonic tubulin organisation was altered. We conclude that P. pouchetii produce some anti-mitotic compound, and that senescent colonial cells to a great extent excrete this compound to their surroundings.     

Uterine contractile effects of the aqueous and ethanol leaf extracts of Newbouldia Laevis (Bignoniaceae) in vitro

Based on traditional reports, the aqueous and ethanol extracts of the leaves of N. laevis were tested on isolated uterine preparations of non-pregnant rats. The effects of increasing cumulative concentrations of the extracts on the amplitude and frequency of spontaneously contracting uterine tissues were tested. Direct effects of the extracts and acetylcholine on uterine smooth muscle were also tested in organ baths containing aerated physiological salt solution maintained at 37°. The EC₅₀ and Emax were determined and analyzed using one way ANOVA with Dunnett''s post hoc test. The extract significantly increased the frequency (P<0.05) of spontaneous contractions without significantly affecting the amplitude. The extracts and acetylcholine were observed to directly stimulate uterine contractions, however there were significant differences (P<0.05) in their EC₅₀ and Emax. In conclusion, the leaves of N. laevis increase the frequency of spontaneously contracting tissues and directly stimulate uterine contractions which may account for the use of the leaf extract traditionally.     

Tetracycline and penicillin resistant Clostridium perfringens isolated from the fangs and venom glands of Loxosceles laeta: Its implications in loxoscelism treatment

The venom of Loxosceles spiders produces severe dermonecrotic damage, intravascular hemolysis, systemic alterations and risk of death. Clostridium perfringens is present in the microbial flora of the fangs and venom glands of Loxosceles intermedia. Its inoculation with the venom may infect the wound site and exacerbate the dermonecrotic damage. This anaerobic bacterium is widely distributed in nature and capable of damage with similar characteristics and severity to the spider venom. In this study we isolated and characterized species of Clostridium from the fangs and venom glands of Loxosceles laeta, including C. perfringens. The sensitivity patterns of different isolates of C. perfringens were evaluated by minimum inhibitory concentration against penicillin, ampicillin, erythromycin, gentamicin, chloramphenicol, clindamycin and tetracycline, under anaerobic conditions, using the method of microdilution in broth. Strain C. perfringens H28 showed resistance to penicillin, ampicillin, tetracycline and chloramphenicol. Resistance to penicillin and ampicillin was mediated by β-lactamase. In vivo evaluation of dermonecrosis in rabbits using L. laeta venom co-inoculated with isolate C. perfringens H28 produced an increase in the area of dermonecrotic lesions in the presence of penicillin and tetracycline, but not with gentamicin. Antibiotic therapy Loxosceles poisoning should be re-evaluated, considering the existence of multi-resistant strains of C. perfringens.     

Bicyclol protects HepG2 cells against D-galacto-samine-induced apoptosis through inducing heat shock protein 27 and mitochondria associated pathway

Aim:

To study the inducing effect of bicyclol on heat shock protein 27 (HSP27) and its role on anti-apoptosis in HepG2 cells intoxicated with D-galactosamine (D-GaIN).

Methods:

HepG2 cells were treated with various concentrations of bicyclol and then subjected to D-GaIN intoxication. Apoptosis was assayed by hoechst 33258 staining and flow cytometry analysis. HSP27, cytochrome c, apoptosis inducing factor (AIF) and c-Jun N-terminal kinase (JNK) were assayed by Western blot. Heat shock factor 1 (HSF1) was determined by electrophoretic mobility shift assay and the interactions of HSP27 with cytochrome c and AIF were detected by co-immunoprecipitation.

Results:

The results showed that bicyclol induced HSP27 protein and mRNA expression in HepG2 cells in both time- and dose-dependent manners (the maximal response: 1.23 fold increase at 100 μmol/L). Bicyclol treatment stimulated HSF1 activation and increased the HSF1-HSE binding activity (the maximal response: 2.1 fold increase at 100 μmol/L). This inducing effect of bicyclol on HSP27 and HSF1 was markedly blocked by quercetin. Pretreatment of the cells with bicyclol markedly attenuated D-GaIN-induced apoptosis and the release of cytochrome c and AIF from mitochondria. The induced HSP27 by bicyclol suppressed the activity of caspase-3 and the phosphorylation of JNK caused by D-GaIN in HepG2 cells. All the above effect of bicyclol against D-GaIN-induced hepatocytes apoptosis were significantly reversed by quercetin.

Conclusion:

HSP27 is involved in the anti-hepatocytes apoptosis of bicyclol, and this effect of bicyclol-induced HSP27 is mainly through inhibition of mitochondria and JNK apoptotic pathways.     

Mechanisms involved in the antinociception caused by ethanolic extract obtained from the leaves of Melissa officinalis (lemon balm) in mice

The present study examined the antinociceptive effect of the ethanolic extract from Melissa officinalis L. and of the rosmarinic acid in chemical behavioral models of nociception and investigates some of the mechanisms underlying this effect. The extract (3-1000 mg/kg), given orally (p.o.) 1 h prior to testing, produced dose-dependent inhibition of acetic acid-induced visceral pain, with ID50 value of 241.9 mg/kg. In the formalin test, the extract (30-1000 mg/kg, p.o.) also caused significant inhibition of both, the early (neurogenic pain) and the late (inflammatory pain), phases of formalin-induced licking. The extract (10-1000 mg/kg, p.o.) also caused significant and dose-dependent inhibition of glutamate-induced pain, with ID50 value of 198.5 mg/kg. Furthermore, the rosmarinic acid (0.3-3 mg/kg), given p.o. 1 h prior, produced dose-related inhibition of glutamate-induced pain, with ID50 value of 2.64 mg/kg. The antinociception caused by the extract (100 mg/kg, p.o.) in the glutamate test was significantly attenuated by intraperitoneal (i.p.) treatment of mice with atropine (1 mg/kg), mecamylamine (2 mg/kg) or l-arginine (40 mg/kg). In contrast, the extract (100 mg/kg, p.o.) antinociception was not affected by i.p. treatment with naloxone (1 mg/kg) or d-arginine (40 mg/kg). It was also not associated with non-specific effects, such as muscle relaxation or sedation. Collectively, the present results suggest that the extract produced dose-related antinociception in several models of chemical pain through mechanisms that involved cholinergic systems (i.e. through muscarinic and nicotinic acetylcholine receptors) and the l-arginine-nitric oxide pathway. In addition, the rosmarinic acid contained in this plant appears to contribute for the antinociceptive property of the extract. Moreover, the antinociceptive action demonstrated in the present study supports, at least partly, the ethnomedical uses of this plant.     

Isolation and characterization of ellagic acid derivatives isolated from Casearia sylvestris SW aqueous extract with anti-PLA2 activity

The Casearia sylvestris SW (Flacourtiaceae) is utilized in folk medicine (Brazil and all Latin American) to treat several pathologic processes as inflammation, cancer, microbial infection and snake bites. Studies showed that C. sylvestris aqueous extract can inhibit many toxic effects caused by snake venoms (or caused by phospholipase A₂ isolated) from different species, mainly of Bothrops genus. Inhibition of enzymatic and myotoxic activities, decrease of edema formation and increase of the survival rate of rats injected with lethal doses of bothropic venoms are some toxic effects inhibited by C. sylvestris. In this study, four ellagic acid derivatives from aqueous extracts of C. sylvestris were isolated, characterized, and tested against effects from both total venom and PLA₂ (Asp 49 BthTX-II) from the venom of Bothrops jararacussu. The isolated compounds were as follows: ellagic acid (A), 3′-O-methyl ellagic acid (B), 3,3′-di-O-methyl ellagic acid (C), 3-O-methyl-3′,4′-methylenedioxy ellagic acid (D). The inhibition constant values (Ki) for enzymatic activity, as well the IC₅₀ values found in the edematogenic and myotoxic activities, indicate that the ellagic acid is the best inhibitor of these activities, while compounds C and D are the substances with lowest capacity on inhibiting these same effects. Our results show that the presence of hydroxyls at position 3 or 3′ (compounds A and B) increases the capacity of these derivatives on inhibiting these toxic effects. However, the presence of methoxyl groups at position 3 or 3′ reduced, but did not completely inhibit the capacity of compounds C and D on inhibiting all the toxic effects studied.     

Purification and cloning of cysteine-rich proteins from Trimeresurus jerdonii and Naja atra venoms.

Three 26 kDa proteins, named as TJ-CRVP, NA-CRVP1 and NA-CRVP2, were isolated from the venoms of Trimeresurus jerdonii and Naja atra, respectively. The N-terminal sequences of TJ-CRVP and NA-CRVPs were determined. These components were devoid of the enzymatic activities tested, such as phospholipase A(2), arginine esterase, proteolysis, L-amino acid oxidase, 5'nucleotidase, acetylcholinesterase. Furthermore, these three components did not have the following biological activities: coagulant and anticoagulant activities, lethal activity, myotoxicity, hemorrhagic activity, platelet aggregation and platelet aggregation-inhibiting activities. These proteins are named as cysteine-rich venom protein (CRVP) because their sequences showed high level of similarity with mammalian cysteine-rich secretory protein (CRISP) family. Recently, some CRISP-like proteins were also isolated from several different snake venoms, including Agkistrodon blomhoffi, Trimeresurus flavoviridis, Lanticauda semifascita and king cobra. We presumed that CRVP might be a common component in snake venoms. Of particular interest, phylogenetic analysis and sequence alignment showed that NA-CRVP1 and ophanin, both from elapid snakes, share higher similarity with CRVPs from Viperidae snakes.     

白及不同提取部位对小鼠止血活性实验

目的确定白及的止血活性部位,为其止血活性成分的筛选提供线索和依据。方法用70%乙醇(EtOH)对白及原药材进行渗漉提取,然后,依次用石油醚(Pet)、乙酸乙酯(EtOAc)、正丁醇(n-BuOH)对醇浸膏进行萃取,分别制得Pet部分、EtOAc部分、n-BuOH部分和H2O部分,通过测定小鼠凝血时间和出血时间,考察其活性部位。结果 n-BuOH部分和H2O部分具有止血作用,而EtOAc部分具有延长凝血、出血时间作用。结论白及中具有止血作用的活性成分主要存在于n-BuOH部分和H2O部分,而EtOAc部分具有活血作用。     

Cytotoxicity and DNA topoisomerase inhibitory activity of constituents isolated from the fruits ofEvodia officinalis

Four alkaloids (1-4), three quinolone alkaloids (5-7), and three flavanoid glucosides (8-10) were isolated from the fruits of Evodia officinalis Dode, and their structures were determined from chemical and spectral data. Compounds, 3, 8, 9 and 10 were isolated from this plant for the first time. Of these compounds, 1-3 and 5-7 exhibited moderate cytotoxicities against cultured human colon carcinoma (HT-29), human breast carcinoma (MCF-7), and human hepatoblastoma (HepG-2). Compound 8 showed strong inhibitory effects on DNA topoisomerases I and II (70 and 96% inhibition at a concentration of 20 microM, respectively).     

Toxicological evaluation of aqueous leaf and berry extracts of Phytolacca dioica L. in male Wistar rats

Despite the widespread use of Phytolacca dioica L. in folklore medicine of South Africa, there is dearth of information on its safety/toxicity. The aim of this study was to evaluate the toxicological effect of aqueous leaf and berry extracts of the plant at different dosages for 14 days on the liver and kidney function indices in male Wistar rats. Phytochemical screening indicated that the extracts are rich in phytonutrients including alkaloid, tannin, saponins, phenolics, lectins and flavonoids; while triterpenoids and phlobatanins were absent. The extracts significantly reduced the body and absolute organ weights of the animals at all the dosages investigated. Whereas, significant increase was observed in the serum levels of alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), alanine transaminase (ALT), aspartate transaminase (AST), bilirubin, calcium, creatinine, urea and uric acid; the serum concentration of total protein, albumin and globulin were reduced in the serum following treatment with the extracts. Generally, the effect of the herb appeared to be dosage dependent. This investigation clearly showed that P. dioica can impair normal hepatic and renal functions. This is an indication that the extracts may not be completely safe in male rats when continuously administered for 14 days.     

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus (Amaryllidaceae).

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus plant (Amaryllidaceae) were investigated in vitro and in vivo against the venoms of three notable snake species: Echis ocellatus, Bitis arietans and Naja nigricollis. The extract was prepared by cold marceration in 50% methanol at 37 degrees C with intermittent shaking for 48 h. An yield of 12.8% w/w dry extract was obtained. Oral administration of C. jagus extract (1000 mg/kg) protected 50% of mice, while injection of a 30 min pre-incubated mixture of the same dose of extract and venom gave 100% protection against the lethal effects of E. ocellatus venom (10 mg/kg, i.m.). The intraperitoneal administration of the extract at 250 mg/kg, 30 min before the injection of E. ocellatus venom (10mg/kg, i.m.), significantly (p<0.05) prolonged the death time of poisoned mice. C. jagus extract (500 mg/kg, per os), gave 50% protection against B. arietans venom (9.5mg/kg, i.m.) in mice while the pre-incubation of a mixture of the same dose of venom and extract (500 mg/kg), prior to injection (i.p.) of the mixture, gave only 33.3% protection. The pre-incubation of 500 mg/kg of C. jagus extract with N. nigricollis venom (6 mg/kg) prior to i.p. injection of the mixture protected 50% of the treated mice. There were generally no significant differences in the death times of mice that were given the same dose of the extract orally 30 min before injection of the venoms and those administered with the pre-incubated mixtures of venom and extract. The pre-incubation of the extract and E. ocellatus venom (5mg/kg) for 30 min, before the i.m. injection of the mixture, significantly reduced infiltration of inflammatory cells to the site of injection 4h post treatment. The concentrations of plasma creatine kinase in poisoned mice were significantly (p<0.01 or p<0.05) reduced after the injection (i.p.) of C. jagus extract (1000 mg/kg) pre-incubated with E. ocellatus (5mg/kg) or B. arietans (7 mg/kg) venom, respectively. The bulb extract of C. jagus blocked the haemorrhagic activity of a standard haemorrhagic dose (2.8 mg/ml) of E. ocellatus venom at various concentrations (1.7, 3.3 and 6.7 mg/ml). The methanolic bulb extract of C. jagus was therefore able to significantly protect mice from death, myonecrosis and haemorrhage induced by the lethal effects of venoms of notable snake species in Nigeria.     

Protective effects of Coriandrum sativum extracts on carbon tetrachloride-induced hepatotoxicity in rats

Oxidative damage is implicated in the pathogenesis of various liver injuries. The study was aimed to investigate the antioxidant activity of Coriandrum sativum on CCl₄ treated oxidative stress in Wistar albino rats. CCl₄ injection induced oxidative stress by a significant rise in serum marker enzymes and thiobarbituric acid reactive substances (TBARS) along with the reduction of antioxidant enzymes. In serum, the activities of enzymes like ALP, ACP and protein and bilirubin were evaluated. Pretreatment of rats with different doses of plant extract (100 and 200 mg/kg) significantly lowered SGOT, SGPT and TBARS levels against CCl₄ treated rats. Hepatic enzymes like SOD, CAT, GPx were significantly increased by treatment with plant extract, against CCl₄ treated rats. Histopathological examinations showed extensive liver injuries, characterized by extensive hepatocellular degeneration/necrosis, inflammatory cell infiltration, congestion, and sinusoidal dilatation. Oral administration of the leaf extract at a dose of 200 mg/kg body weight significantly reduced the toxic effects of CCl₄. The activity of leaf extract at the dose of 200 mg/kg was comparable to the standard drug, silymarin. Based on these results, it was observed that C. sativum extract protects liver from oxidative stress induced by CCl₄ and thus helps in evaluation of traditional claim on this plant.     

Irciniastatin A induces JNK activation that is involved in caspase-8-dependent apoptosis via the mitochondrial pathway

Irciniastatin A (ISA)/psymberin, a pederin-type natural product isolated from marine sponge, exhibits extremely potent and selective cytotoxicity against certain human cancer cell lines, but its molecular target and cytotoxic mechanisms are still unknown. Here we show that ISA is a potent inhibitor of protein translation, and induces apoptosis accompanied with activation of the stress-activated protein kinases via the mitochondrial pathway in human leukemia Jurkat cells. ISA potently inhibited protein translation, and induced a slow but prolonged activation of the stress-activated protein kinases, JNK and p38, at between 1h and 6h after treatment. In Bcl-x(L)-transfected cells, the activation of JNK and p38 by ISA was shortened. The same results were obtained in the cells treated with N-acetyl-L-cysteine, suggesting that the prolonged activation of JNK and p38 by ISA is mediated by reactive oxygen species generated from mitochondria. ISA strongly induced apoptosis, which was partially suppressed by the JNK inhibitor SP600125, but not by the p38 inhibitor SB202190. Apoptosis induction by ISA was partially reduced, but not suppressed by SP600125 in caspase-8-deficient Jurkat cells. These results suggest that ISA activates stress-activated kinases by a mitochondria-mediated mechanism, and that activation of JNK is required for caspase-8-dependent apoptosis.