Botany, Phytochemistry, Pharmacology and Toxicity of Strychnos nux-vomica L.: A Review.

Strychnos nux-vomica L. belongs to the genus Strychnos of the family Loganiaceae and grows in Sri Lanka, India and Australia. The traditional medicinal component is its seed, called Nux vomica. This study provides a relevant and comprehensive review of S. nux-vomica L., including its botany, ethnopharmacology, phytochemistry, pharmacology and toxicology, thus providing a foundation for future studies. Up to the present day, over 84 compounds, including alkaloids, iridoid glycosides, flavonoid glycosides, triterpenoids, steroids and organic acids, among others, have been isolated and identified from S. nux-vomica. These compounds possess an array of biological activities, including effects on the nervous system, analgesic and anti-inflammatory actions, antitumor effects, inhibition of the growth of pathogenic microorganisms and regulation of immune function. Furthermore, toxicity and detoxification methods are preliminarily discussed toward the end of this review. In further research on S. nux-vomica, bioactivity-guided isolation strategies should be emphasized. Its antitumor effects should be investigated further and in vivo animal experiments should be performed alongside in vitro testing. The pharmacological activity and toxicology of strychnine [Formula: see text]-oxide and brucine [Formula: see text]-oxide should be studied to explore the detoxification mechanism associated with processing more deeply.

Novel Synthetic PEGylated Conjugate of α-Lipoic Acid and Tempol Reduces Cell Death in a Neuronal PC12 Clonal Line Subjected to Ischemia.

α-Lipoic acid (α-LA), a natural thiol antioxidant, and Tempol, a synthetic free radical scavenger, are known to confer neuroprotection following ischemic insults in both in vivo and in vitro models. The aim of this study was to synthesize and characterize a conjugate of α-LA and Tempol linked by polyethylene glycol (PEG) in order to generate a more efficacious neuroprotectant molecule. AD3 (α-Tempol ester-ω-lipo ester PEG) was synthesized, purified, and characterized by flash chromatography and reverse phase high pressure liquid chromatography and by 1H nuclear magnetic resonance, infrared spectroscopy, and mass spectrometry. AD3 conferred neuroprotection in a PC12 pheochromocytoma cell line of dopaminergic origin, exposed to oxygen and glucose deprivation (OGD) insult measured by LDH release. AD3 exhibited EC50 at 10 µM and showed a 2-3-fold higher efficacy compared to the precursor moieties, indicating an intrinsic potent neuroprotective activity. AD3 attenuated by 25% the intracellular redox potential, by 54% lipid peroxidation and prevented phosphorylation of ERK, JNK, and p38 by 57%, 22%, and 21%, respectively. Cumulatively, these findings indicate that AD3 is a novel conjugate that confers neuroprotection by attenuation of MAPK phosphorylation and by modulation of the redox potential of the cells.

Toxic effects of strychnine and strychnine N-oxide on zebrafish embryos.

AIM: The application of strychnine (S) is limited due to its toxicity; strychnine N-oxide (SNO) is a derivative of strychnine. The aim was to employ zebrafish embryos to investigate and compare the developmental toxicity induced by S and SNO. METHODS: The toxicity of S and SNO was examined through the hatching rate and survival rate. Morphological changes of the zebrafish were observed with a dissecting microscope. Apoptosis was detected through acridine orange (AO) staining and flow cytometry. Apoptotic genes were measured by RT-PCR. RESULTS: Embryo malformation was observed in the embryos exposed to S at 200 µmol·L(-1). When SNO concentration was increased to 1 mmol·L(-1), scoliolosis, and pericardial edema could be seen in some embryos. Results from fluorescence microscopy and flow cytometry analysis showed that S at 200 µmol·L(-1) induced apoptosis, whereas the apoptotic rate in the SNO-treated group (200 µmol·L(-1)) was much lower than that in the S group. RT-PCR analysis showed that p53 mRNA expression and the ratio of Bax/Bcl-2 in the S group were significantly altered compared with the control group (*P < 0.05). Moreover, Bax mRNA expression in both S and SNO group were significantly different from that in the control group (**P < 0.01). CONCLUSION: These results lead to the conclusion that SNO has significantly lower toxicity than S in zebrafish embryos.

Superoxide dismutase mimetic, tempol, aggravates renal injury in advanced-stage stroke-prone spontaneously hypertensive rats.

OBJECTIVE: The aim of this study was to determine whether antioxidant therapy could relieve hypertension and retard the progression of renal damage in advanced-stage hypertensive rats. METHODS: Twenty-four-week-old spontaneously hypertensive stroke-prone rats were treated for 8 weeks with the superoxide dismutase mimetic tempol, low-dose or high-dose candesartan (an angiotensin receptor blocker), or hydralazine, and blood pressure and renal damage were compared. RESULTS: Elevated blood pressure and renal damage with heterogeneity were present after 8 weeks, with greater glomerulosclerosis in the juxtamedullary glomeruli than in the superficial glomeruli. Although both tempol and candesartan effectively reduced reactive oxygen species production in the kidney, tempol did not decrease blood pressure and exacerbated urine protein and histological damage, such as glomerulosclerosis and interstitial fibrosis, particularly in juxtamedullary nephrons (tempol vs. untreated: glomerulosclerosis index, 2.0 vs. 1.5, P<0.01; fibrosis, 15 vs. 10%, P<0.001). In contrast, high-dose candesartan and hydralazine prevented these forms of renal damage with lowering blood pressure. Low-dose candesartan also prevented this renal damage without lowering blood pressure. Moreover, there were increased numbers of larger and smaller glomeruli in the juxtamedullary cortex of tempol-treated rats, suggesting that changes in glomerular hemodynamics may be responsible for the exacerbation of glomerulosclerosis. Both candesartan- and hydralazine-treated rats had glomeruli that were slightly decreased in size. CONCLUSION: These results suggest that single-antioxidant therapy starting at an advanced-stage may be ineffective for hypertension and rather exacerbate renal damage in nonsalt loaded SHRSP. Furthermore, lowering blood pressure and inhibiting the renin-angiotensin system could be critical for slowing the progression of hypertensive renal damage at an advanced stage.

Cytotoxic and HLE-inhibitory tetramic acid derivatives from marine-derived fungi.

Tetramic acid derivatives are an important class of nitrogen heterocycles with a pyrrolidine-2,4-dione core as a key structural motif. From the sponge-derived fungus Beauveria bassiana, a new equisetin-like tetramic acid derivative, beauversetin (1), was isolated. The sea weed-derived fungus Microdiplodia sp. produced the tetramic acid derivative 2 (Sch210972) which was shown to inhibit human leucocyte elastase (HLE) with an IC50 of 1.04 microg mL(-1).

The cytotoxicity induced by brucine from the seed of Strychnos nux-vomica proceeds via apoptosis and is mediated by cyclooxygenase 2 and caspase 3 in SMMC 7221 cells.

To study the cytotoxicity of four alkaloids: brucine, strychnine, brucine N-oxide and isostrychnine from nux vomica on SMMC 7721 cells and their possible mechanisms, MET assay was used to examine the growth inhibitory effects of these alkaloids. Brucine revealed the strongest growth inhibitory effect on SMMC-7721 cells. Furthermore, as directly observed under an inverted microscope, fluorescent microscope and transmission electronic microscope, brucine caused SMMC-7721 cell shrinkage, membrane blobbing, formation of apoptotic body as well as nucleus condensation, all of which are typical characteristics of apoptotic programmed cell death. In addition, brucine dose-dependently caused SMMC-7721 cells apoptosis via formation of subdipolid DNA and phosphatidylserine externalization, as evidenced by flow cytometry analysis. The brucine-induced apoptosis was partially attributed to the activation of caspase 3 as well as cyclooxygenase 2 inhibition, since neither caspase 3 specific inhibitor, z-DEVD-fmk nor was exogenous addition of prostaglandin E(2) able to completely abrogate the brucine-induced SMMC 7721 cell apoptosis. In sum, this paper indicate that the major alkaloids present in the seed of Strychnos nux-vomica are effective against SMMC-7721 cells proliferation, among which brucine proceeds SMMC-7721 cells death via apoptosis, probably through the participation of caspase 3 and cyclooxygenase 2.

Use of spin-traps during warm ischemia-reperfusion in rat liver: comparative effect on energetic metabolism studied using 31P nuclear magnetic resonance.

Detection of free radicals by electron spin resonance (ESR) proves the involvement of reactive oxygen species (ROS) in reperfused organ injuries. Spin-traps are known to ameliorate hemodynamic parameters in an isolated postischemic heart. The effects of 5 mmol/L DMPO (5,5-dimethyl-1-pyrroline-N-oxide) or DEPMPO (5-(diethlphosphoryl)-5-methyl-1-pyrroline N-oxide) on intracellular pH (pHin) and ATP level were evaluated by 31P nuclear magnetic resonance on isolated rat liver submitted to 1 hour of warm ischemia and reperfusion. At the end of the reperfusion period, during which pHin recovered to its initial value (7.16 +/- 0.03) in all groups, the ATP recovery level (expressed in percentage of initial value) was similar in controls and DEPMPO (60% +/- 5%, n = 6 and 54% +/- 4%, n = 6, respectively), but only 37% +/- 1% in DMPO-treated livers (n = 6) (p < 0.05 versus controls and p < 0.05 versus DEPMPO). Oxidative phosphorylation was not affected by an addition of nitrones on isolated mitochondria extracted from livers not submitted to ischemia-reperfusion. In contrast, mitochondria extracted at the end of the ischemia-reperfusion showed an impairment in the phosphorylation parameters, particularly in the presence of DMPO. Mass spectrum of ischemic liver perchloric acid extracts evidenced probable catabolites in treated groups. The differences in the effect of the two nitrones on energetic metabolism may be explained by the production of deleterious catabolites by DMPO as compared to DEPMPO. Even though a specific radical scavenging effect could be operative in the liver, our results indicate that catabolic effects were predominant. The absence of deleterious effects of DEPMPO in contrast to DMPO on the liver energetic metabolism was evidenced, allowing the use of DEPMPO for ESR detection.

Evaluation of a nitroxyl fatty acid as liver contrast agent for magnetic resonance imaging.

In this study, we report the synthesis and the evaluation as MRI contrast agent of a new compound (nitroxyl fatty acid, NFA), where a pyrrolidinoxyl radical (3-carboxy-proxyl, PCA) is linked to a fatty acid moiety. Fatty acids were selected as vector because they present a high affinity for the liver, their efficient cellular uptake being the result of a specific interaction with a transmembrane transporter (liver plasma membrane-fatty acid binding protein). The uptake of 3H-oleic acid is inhibited after the injection of 1 mmol/kg of NFA, suggesting that NFA recognizes the same transmembrane transporter as the natural fatty acids. The higher relaxivity R1 of NFA in albumin solutions, compared with PCA, was explained by the immobilization of the nitroxyl radical in the protein. MR imaging was performed using T1-weighted images on mice in order to compare the contrast effect obtained after the injection of 1 mmol/kg of radical. The % signal enhancement in the liver 5 min after intravenous injection was 49 +/- 4 and 14 +/- 5 for NFA and PCA, respectively. NFA allowed a better delimitation of some necrotic tumors (Novikoff hepatocarcinoma) due to its preferential uptake by the nontumorous tissue.

[Nitroxyl derivatives of rubomycin]. / Nitroksil'nye proizvodnye rubomitsina.

The toxic and antitumor effects of new analogs of rubomycin were studied. It was shown that the spin-labeled derivatives had the lowest toxicity and highest antitumor activity. The diamagnetic analog was similar to rubomycin in its antitumor effect. It was demonstrated that ruboxyl-l had a lower cardiotoxicity than rubomycin and did not inhibit hemopoiesis at the maximum tolerated doses.

Phase I study of indicine N-oxide in patients with advanced cancer.

Indicine N-oxide is a pyrrolizidine alkaloid isolated from Heliotropium indicum, one of the widely used herbs in Ayurvedic medicine. Thirty-seven patients with solid tumors received the drug: 15 men and 22 women (mean age, 53 years). All had had prior chemotherapy, and 25 had had prior radiotherapy. Eighty-four percent had a performance status of 0-3 (Cancer and Leukemia Group B criteria). The drug was given as a short infusion over 15 minutes and repeated with a median interval of 4 weeks. Doses were escalated from 1 to 9 g/m2. A total of 55 courses were evaluable. Dose-limiting toxic effects were leukopenia and thrombocytopenia, and the toxicity was cumulative with repeated doses. Other toxic effects included nausea and vomiting, anemia, and hepatic dysfunction. The hematologic toxicity tended to be more pronounced in patients with hepatic dysfunction, poor marrow reserve, and heavy prior chemotherapy and radiotherapy. There were no complete or partial responses. One patient with skin melanoma and another with ovarian carcinoma had improvement lasting 2 months. The maximally tolerated dose is 9 g/m2 in our population. A recommended dose for therapeutic study is 7 g/m2. High-risk patients should be started at a dose of 5 g/m2. The treatment may be repeated at 4-week intervals with close monitoring of wbc and platelet counts. Dose reductions may be necessary for repeated courses.

[Some pharmacological actions of furazan hydrazides and of 2 correspondent furoxan derivatives]. / Alcune azioni farmacologiche dell'idrazide furazanica e dei due corrispondenti derivati furossanici

A study has been made of the acute toxicity, action on the guinea pig ileum, on the ventricle edge, on frog spinal reflex, and on the respiratory and cardiac activity and pulse of the following compounds: 3-methyl-4-furazancarbohydrazide (I); 3-methyl-4-furoxancarbohydrazide (II); 4-methyl-3-furoxancarbohydrazide (III). The compounds had no action on guinea pig ileum or ventricle edge. Compound (I) showed depressant activity on frog spinal reflex whereas compound (II) showed excitation and compound (III) had no direct spinal action. The compounds tested affected respiration and ECG only at the highest doses used. The pulse rate was raised by substance (I) in all cases whereas substances (II) and (III) raised pulse rate only at low doses.