Antiplatelet activity of 3-butyl-6-bromo-1(3H)-isobenzofuranone on rat platelet aggregation

Effects of mandarin peel powder on growth, biochemical, immune, and intestinal health in Oreochromis niloticus at suboptimal temperatures

This 60-day study aimed to examine the efficacy of a diet supplemented with mandarin peel powder (MP) in enhancing the health and survival of Oreochromis niloticus under suboptimal temperature conditions (21 ℃). One hundred and eighty Nile tilapia fish (22.51 ± 0.04 g) were randomly distributed into four experimental groups; each of 3 replicates (15 fish per replicate). The first group (CONT) received a basal diet without MP. The second (MP10%), third (MP15%), and fourth (MP20%) groups were fed diets containing 10, 15, and 20% MP powder, respectively. At the end of the feeding trail, growth performance, serum growth hormone, α-amylase enzyme, lysozyme activity, nitric oxide, protease activity, globulin, serum levels of IL-1ß, antioxidant status, and intestinal histology were measured. The results showed insignificant differences between CONT, MP15%, and MP20% groups in the final body weight and specific growth rate. The growth hormones in the MP15% and MP20% groups did not show a significant difference compared to fish fed a normal basal diet (CONT). However, the amylase enzymes were significantly greater in both groups. The MP20% and MP15% groups showed a significant increase in antioxidant, lysozyme, nitric oxide, and protease activities compared to CONT. The results also showed that fish that were fed a diet with MP had significantly less of the pro-inflammatory cytokine interleukin-1 beta, and their intestinal villi got wider, especially in the MP20% group. It could be concluded that feeding tilapia on a diet with 20% MP is an effective strategy to improve their health when the temperature is below 21 °C. This is because the fish exhibit higher levels of antioxidant activity, reduced pro-inflammatory responses, and improved intestinal health without difference in the growth performance in compared to control group.

Efficacy of sequential N-butylphthalide therapy on psychiatric and behavioral functions in acute ischemic stroke

BACKGROUND

Stroke can cause physical and mental problems. This study examined how the sequential therapy of N-butylphthalide (NBP) could effectively improve physical movement, life activities, and psychological disorders in stroke patients.

METHODS

This double-blind, randomized controlled trial included middle-aged or elderly patients with acute ischemic stroke that had commenced within 48 hours before enrolment in the study. The experimental group was administered 100 mL NBP injections twice a day in the first 14 days, and a sequential 200 mg NBP soft capsule 3 times a day for the next 76 days. The control group was administered 100 mL NBP placebo injections twice a day in the first 14 days and 200 mg sequential NBP placebo soft capsule 3 times a day for the next 76 days. Primary outcomes were the National Institutes of Health Stroke Scale, the Barthel Index of activities of daily living, and Modified Rankin Scale which were evaluated at day 0, day 14, and month 1 or at day 14, month 3, and month 6. Secondary outcomes included the Hamilton Anxiety Scale and the Hamilton Depression Scale, all were evaluated on day 0, month 3, and month 6. Moreover, the adverse reaction of NBP or other serious adverse events were evaluated at each time.

RESULTS

Our therapy significantly increased the Barthel Index of activities of daily living scores, decreased the National Institutes of Health Stroke Scale and Modified Rankin Scale scores, and the incidence of the Hamilton Anxiety Scale and the Hamilton Depression Scale of ischemic stroke patients (P < .05).

CONCLUSION

Our results indicated that 90 days' sequential therapy with NBP as an additional therapy in the treatment of ischemic stroke can better improve patients' psychological and behavioral functions without significant side effects.

L-3-n-butylphthalide attenuates inflammation response and brain edema in rat intracerebral hemorrhage model

L-3-n-butylphthalide(NBP), a compound found in Apium graveolens Linn seed extracts, has a therapeutic effect on acute ischemic stroke. The pathological inflammatory pathways and consequent brain edema in intracerebral hemorrhage (ICH) share some similar characteristics with ischemic stroke. We hypothesized that NBP has anti-inflammatory and therapeutic effects on rats with ICH. ICH was induced by an infusion of bacterial collagenase type IV into the unilateral striatum of anesthetized rats. The therapeutic effect of NBP was measured by assessing neurological function, brain water content, blood-brain barrier permeability, and expression of tumor necrosis factor-alpha (TNF-α) and matrix metalloproteinase-9 (MMP-9) around the hematoma 48 hours after surgery. Magnetic resonance imaging was performed 4 and 48 hours after ICH induction, and ICH-induced injured area volumes were measured using T2-weighted images. The NBP treatment group performed better in the neurological function test than the vehicle group. Moreover, in comparison with the vehicle group, NBP group showed a lower expanded hematoma volume, brain water content, blood-brain barrier permeability, and TNF-α/ MMP-9 expression level. Our results indicate that NBP attenuates inflammation and brain edema in rat ICH model. Therefore, our findings also provide a potential therapeutic strategy for the treatment of ICH with NBP.

Synthesis, Bioevaluation, Structure-Activity Relationship and Docking Studies of Natural Product Inspired (Z)-3-benzylideneisobenzofuran-1(3H)-ones as Highly Potent antioxidants and Antiplatelet agents

For the first time, a series of highly potent natural product inspired substituted (Z)-3-benzylideneisobenzofuran-1(3H)-ones 28a-t, embraced with electron-withdrawing groups (EWG) and electron-donating groups (EDG) at site I and site II, were prepared and assessed for their in vitro antioxidant activities (DPPH free radical scavenging assay) and arachidonic acid (AA)-induced antiplatelet activities using ascorbic acid (IC₅₀ = 4.57 µg/mL) and aspirin (IC₅₀ = 21.34 µg/mL), as standard references, respectively. In this study, compounds 28f-g, 28k-l and 28q have shown high order of in vitro antioxidant activity. Infact, 28f and 28k were found to show 10-folds and 8-folds more antioxidant activity than ascorbic acid, respectively and was found to be the most active analogues of the series. Similarly, Compounds 28c-g, 28k-l, 28o and 28q-t were recognized as highly potent antiplatelet agents (upto 6-folds) than aspirin. Furthermore, in silico studies of the most active antioxidants 28f, 28k and 28l and very active antiplatelet molecules 28f, 28k, 28l and 28s were carrying out for the validation of the biological results. This is the first detailed study of the discovery of several (Z)-3-benzylideneisobenzofuran-1(3H)-ones as highly potent antioxidants and antiplatelet agents.

Viol LC, Maia AFDS, Santos EG, da Silva ÍEP, Mendes TADO, da Silva AM, Dias RS, da Silva CC, Polêto MD, Teixeira RR, de Paula SO. Discovery of novel West Nile Virus protease inhibitor based on isobenzonafuranone and triazolic derivatives of eugenol and indan-1,3-dione scaffolds

The West Nile Virus (WNV) NS2B-NS3 protease is an attractive target for the development of therapeutics against this arboviral pathogen. In the present investigation, the screening of a small library of fifty-eight synthetic compounds against the NS2-NB3 protease of WNV is described. The following groups of compounds were evaluated: 3-(2-aryl-2-oxoethyl)isobenzofuran-1(3H)-ones; eugenol derivatives bearing 1,2,3-triazolic functionalities; and indan-1,3-diones with 1,2,3-triazolic functionalities. The most promising of these was a eugenol derivative, namely 4-(3-(4-allyl-2-methoxyphenoxy)-propyl)-1-(2-bromobenzyl)-1H-1,2,3-triazole (35), which inhibited the protease with IC50 of 6.86 μmol L-1. Enzyme kinetic assays showed that this derivative of eugenol presents competitive inhibition behaviour. Molecular docking calculations predicted a recognition pattern involving the residues His51 and Ser135, which are members of the catalytic triad of the WNV NS2B-NS3 protease.

rLj-RGD3, a novel recombinant toxin protein from Lampetra japonica, prevents coronary thrombosis-induced acute myocardial infarction by inhibiting platelet functions in rats

Recombinant Lampetra japonica RGD-peptide (rLj-RGD3), a soluble protein containing three RGD sequences, was acquired from the oral salivary glands of Lampetra japonica using recombinant DNA technology. The aim of this study was to investigate the protective effects of rLj-RGD3 against acute myocardial infarction (AMI) induced by coronary artery thrombosis, as well as the underlying mechanisms. A rat model of AMI caused by ferric chloride-induced thrombosis on the surface of the left anterior descending (LAD) coronary artery was successfully established. Rats were given various doses of rLj-RGD3 (12 μg/kg, 24 μg/kg and 48 μg/kg) via sublingual intravenous delivery 10 min before AMI. ST segment elevation was recorded by electrocardiogram (ECG) until the end of the model. Left ventricular Evans blue content and histopathological changes were examined. Blood samples were collected to determine 5-hydroxytryptamine (5-HT), β-thromboglobulin (β-TG), platelet factor 4 (PF4) and cAMP levels. The effects of rLj-RGD3 on platelet aggregation, adhesion and intracellular calcium concentrations were also measured. rLj-RGD3 significantly reduced ST segment elevation, prevented thrombus formation in the coronary artery and decreased Evans blue content in the left ventricular myocardium. Meanwhile, rLj-RGD3 exerted an inhibitory effect on adenosine diphosphate (ADP)-induced platelet aggregation and blocked platelet adhesion to collagen. Treatment with rLj-RGD3 prevented 5-HT, β-TG and PF4 release and significantly elevated intracellular cAMP levels in a dose-dependent manner but decreased the level of cytosolic-free Ca²⁺, an aggregation-inducing molecule. These results show that rLj-RGD3 can effectively reduce coronary thrombosis in AMI rats by strongly inhibiting platelet function, indicating that the recombinant RGD toxin protein rLj-RGD3 may serve as a potent clinical therapeutic agent for AMI.

Protective Effects of Sodium (±)-5-Bromo-2-(α-Hydroxypentyl) Benzoate in a Rodent Model of Global Cerebral Ischemia

The aim of the current study was to explore the protective effects of sodium (±)-5-bromo-2-(α-hydroxypentyl) benzoate (brand name: brozopine, BZP) in a rat model of global cerebral ischemia. The rat model was established using a modified Winocur's method; close postoperative observation was conducted at all times. Neurological function was detected through prehensile traction and beam-walking test. BZP reduced mortality and prolonged the survival time of rats with global cerebral ischemia, within 24 h. There was a decreased survival rate (60%) in the Model group, while the survival rate of the BZP (3 and 12 mg/kg) remarkably increased the survival rate (to 80 and 90%, respectively), in a dose-dependent manner. Compared with the Model group (survival time: 18.50 h), the administration of BZP (0.75, 3, and 12 mg/kg) prolonged the survival time (to 20.38, 21.85, and 23.90 h, respectively), particularly in BZP 12 mg/kg group (P < 0.05). Additionally, the BZP (12 mg/kg) group exhibited an improvement in their motor function (P < 0.05). The BZP groups (0.75, 3, and 12 mg/kg) displayed significantly reduced necrosis and the percentage of apoptotic cells (P < 0.05 and P < 0.01, respectively). Compared with Model group, BZP (0.75, 3, and 12 mg/kg) increased the NeuN optical density values (P < 0.01). Rats with global ischemia had a high expression of Cyt-c, caspase-3, and the Bax/Bcl-2 ratio compared with sham group (P < 0.01). BZP (0.75, 3, and 12 mg/kg), however, reduced the expression of Cyt-c, caspase-3, and the Bax/Bcl-2 ratio, in a dose-dependent manner (P < 0.01). There was low expression of p-Akt and PI3K in Model group, compared with the sham group (P < 0.01). Meanwhile, BZP (0.75, 3, and 12 mg/kg) increased the expression of p-Akt and PI3K in a dose-dependent manner (P < 0.01). We also found the expression of Cyt-c, caspase-3, Bax/Bcl-2 ratio, PI3K, p-Akt, and comprehensive score were directly related. In conclusion, BZP had therapeutic potential and prevented stroke in rat model of global cerebral ischemia. The underlying mechanisms may be related to the inhibition of apoptosis and activation of the survival-signaling-pathway.

Preventive and therapeutic effect of brozopine on stroke in Dahl Salt-sensitive hypertensive rats

Our aim was to explore the preventive and therapeutic effects of sodium (±)-5-bromo-2-(α-hydroxypentyl) benzoate (brand name: brozopine, BZP) on stroke in Dahl Salt-sensitive (Dahl-SS) hypertensive rats. Dahl-SS rats were fed a high-salt diet to observe the effect of BZP on blood pressure, and brain, heart, and kidney tissues. Additionally, the incidence of stroke was recorded according to the neurological score. The relative mechanisms investigated included anti-oxidative effects and anti-platelet aggregation. BZP reduced the incidence of stroke, neuronal necrosis in the brain, and cell swelling and inflammatory infiltration in the kidney. Its mechanisms were related to the increased activities of gluthatione peroxidase and catalase and the decreased level of plasma nitric oxide. BZP inhibited arachidonic acid (AA) - induced platelet aggregation (IC₅₀: 12µM) rather than that of adenosine diphosphate (ADP) - and/or thrombin-induced platelet aggregation in vitro. Interestingly, BZP inhibited ADP-, thrombin-, or AA-induced platelet aggregation and elevated the level of AMP-activated protein kinase, cyclic guanosine monophosphate, and vasodilator-stimulated-phosphoprotein, and attenuated ATP contents and mitogen-activated protein kinase levels in platelet and inhibited thrombus formation in a carotid artery thrombosis model, dose-dependently, in Dahl-SS hypertensive-induced stroke rats. In conclusion, BZP can have therapeutic and preventive effects on stroke in Dahl-SS hypertensive rats, the mechanisms of which may be related to anti-oxidant, anti-platelet aggregation and anti-thrombus formation.

Preclinical Pharmacokinetics, Tissue Distribution, and Plasma Protein Binding of Sodium (±)-5-Bromo-2-(α-Hydroxypentyl) Benzoate (BZP), an Innovative Potent Anti-ischemic Stroke Agent

Sodium (±)-5-bromo-2-(α-hydroxypentyl) benzoate (BZP) is a potential cardiovascular drug and exerts potent neuroprotective effect against transient and long-term ischemic stroke in rats. BZP could convert into 3-butyl-6-bromo-1(3H)-isobenzofuranone (Br-NBP) in vitro and in vivo. However, the pharmacokinetic profiles of BZP and Br-NBP still have not been evaluated. For the purpose of investigating the pharmacokinetic profiles, tissue distribution, and plasma protein binding of BZP and Br-NBP, a rapid, sensitive, and specific method based on liquid chromatography coupled to mass spectrometry (LC-MS/MS) has been developed for determination of BZP and Br-NBP in biological samples. The results indicated that BZP and Br-NBP showed a short elimination half-life, and pharmacokinetic profile in rats (3, 6, and 12 mg/kg; i.v.) and beagle dogs (1, 2, and 4 mg/kg; i.v.gtt) were obtained after single dosing of BZP. After multiple dosing of BZP, there was no significant accumulation of BZP and Br-NBP in the plasma of rats and beagle dogs. Following i.v. single dose (6 mg/kg) of BZP to rats, BZP and Br-NBP were distributed rapidly into all tissues examined, with the highest concentrations of BZP and Br-NBP in lung and kidney, respectively. The brain distribution of Br-NBP in middle cerebral artery occlusion (MCAO) rats was more than in normal rats (P < 0.05). The plasma protein binding degree of BZP at three concentrations (8000, 20,000, and 80,000 ng/mL) from rat, beagle dog, and human plasma were 98.1–98.7, 88.9–92.7, and 74.8–83.7% respectively. In conclusion, both BZP and Br-NBP showed short half-life, good dose-linear pharmacokinetic profile, wide tissue distribution, and different degree protein binding to various species plasma. This was the first preclinical pharmacokinetic investigation of BZP and Br-NBP in both rats and beagle dogs, which provided vital guidance for further preclinical research and the subsequent clinical trials.

Centrosymmetric resonance-assisted intermolecular hydrogen bonding chains in the enol form of β-diketone: Crystal structure and theoretical study

Isobenzofuran-1(3H)-ones (phtalides) are heterocycles that present a benzene ring fused to a γ-lactone functionality. This structural motif is found in several natural and synthetic compounds that present relevant biological activities. In the present investigation, the 3-(2-hydroxy-4,4-dimethyl-6-oxocyclohexen-1-yl)isobenzofuran-1(3H)-one was characterized by single-crystal X-ray analysis. In the crystal structure, there are two molecules per asymmetric unit. One of them exhibits resonance assisted hydrogen bonds (RAHBs). Semi-empirical and DFT calculations were performed to obtain electronic structure and π-delocalization parameters, in order to better understand the energy stabilization of RAHBs in the crystal packing of the studied molecule. The structural parameters showed good agreement between theoretical and experimental data. The theoretical investigation revealed that the RAHBs stabilization energy is directly related to the electronic delocalization of the enol form fragment. In addition, RAHBs significantly affected the HOMO and charge distribution around the conjugated system.

LC-MS/MS Analysis and Pharmacokinetics of Sodium (±)-5-Bromo-2-(α-hydroxypentyl) Benzoate (BZP), an Innovative Potent Anti-Ischemic Stroke Agent in Rats

A rapid, sensitive and selective liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of sodium (±)-5-bromo-2-(α-hydroxypentyl) benzoate (BZP) and its active metabolite 3-butyl-6-bromo-1(3H)-isobenzofuranone (Br-NBP) in rat plasma using potassium 2-(1-hydroxypentyl)-benzoate (PHPB) and l-3-n-butylphthalide (NBP) as internal standards (IS). Chromatographic separation was achieved on a Hypersil GOLD C18 column using a gradient elution of ammonium acetate and methanol at a flow rate of 0.2 mL/min. Good linearity was achieved within the wide concentration range of 5–10,000 ng/mL. The intra-day and inter-day precision was less than 8.71% and the accuracy was within −8.53% and 6.38% in quality control and the lower limit of quantitation samples. BZP and Br-NBP were stable during the analysis and the storage period. The method was successfully applied to pharmacokinetic studies of BZP in Sprague-Dawley rats for the first time. After a single intravenous administration of BZP at the dose of 0.75 mg/kg, the plasma concentration of BZP and Br-NBP declined rapidly and the AUC_0-t of BZP was significantly greater in female rats compared to male rats (p < 0.05). The data presented in this study serve as a firm basis for further investigation of BZP in both preclinical and clinical phases.

The Antileishmanial Potential of C-3 Functionalized Isobenzofuranones against Leishmania (Leishmania) Infantum Chagasi

Leishmaniases are diseases caused by protozoan parasites of the genus Leishmania. Clinically, leishmaniases range from cutaneous to visceral forms, with estimated global incidences of 1.2 and 0.4 million cases per year, respectively. The treatment of these diseases relies on multiple parenteral injections with pentavalent antimonials or amphotericin B. However, these pharmaceuticals are either too toxic or expensive for routine use in developing countries. These facts call for safer, cheaper, and more effective new antileishmanial drugs. In this investigation, we describe the results of the assessment of the activities of a series of isobenzofuran-1(3H)-ones (phtalides) against Leishmania (Leishmania) infantum chagasi, which is the main causative agent of visceral leishmaniasis in the New World. The compounds were tested at concentrations of 100, 75, 50, 25 and 6.25 µM over 24, 48, and 72 h. After 48 h of treatment at the 100 µM concentration, compounds 7 and 8 decreased parasite viability to 4% and 6%, respectively. The concentration that gives half-maximal responses (LC50) for the antileishmanial activities of compounds 7 and 8 against promastigotes after 24 h were 60.48 and 65.93 µM, respectively. Additionally, compounds 7 and 8 significantly reduced parasite infection in macrophages.

Discovery of 3-n-butyl-2,3-dihydro-1H-isoindol-1-one as a potential anti-ischemic stroke agent

To develop novel anti-ischemic stroke agents with better therapeutic efficacy and bioavailability, we designed and synthesized a series of 3-alkyl-2,3-dihydro-1H-isoindol-1-ones compounds (3a-i) derivatives, one of which (3d) exhibited the strongest inhibitory activity for the adenosine diphosphate-induced and arachidonic acid-induced platelet aggregation. This activity is superior to that of 3-n-butylphthalide and comparable with aspirin and edaravone. Meanwhile, 3d not only exhibited a potent activity in scavenging free radicals and improving the survival of HT22 cells against the reactive oxygen species-mediated cytotoxicity in vitro but also significantly attenuated the ischemia/reperfusion-induced oxidative stress in ischemic rat brains. Results from transient middle cerebral artery occlusion and permanent middle cerebral artery occlusion model, indicated that 3d could significantly reduce infarct size, improve neurobehavioral deficits, and prominently decrease attenuation of cerebral damage. Most importantly, 3d possessed a very high absolute bioavailability and was rapidly distributed in brain tissue to keep high plasma drug concentration for the treatment of ischemic strokes. In conclusion, our findings suggest that 3-alkyl-2,3-dihydro-1H-isoindol-1-ones, a novel series of compounds, might be candidate drugs for the treatment of acute ischemic strokes, and 3d may be a promising therapeutic agent for the primary and secondary prevention of ischemic stroke.

Synthesis of 3-[(coumarinyl)carbonyl]-3a,8b-dihyroindeno[1,2-b]pyrrole-4(1H)-ones and their conversion to coumarin bearing spiro[isobenzofuran-1,2′-pyrrole] moiety compounds via oxidative cleavage reaction

The synthesis of substituted coumarin derivatives bearing indenopyrrole and spiro[isobenzofuran-1,2′-pyrrole] in a four-component sequential reaction and following oxidative cleavage reaction.

Isobenzofuranone derivatives exhibit antileishmanial effect by inhibiting type II DNA topoisomerase and inducing host response

Leishmania, a protozoan parasite, causes a wide range of human diseases ranging from the localized self-healing cutaneous lesions to fatal visceral leishmaniasis. Toxicity of traditional first line drugs and emergence of drug-resistant strains have worsened the situation. DNA topoisomerase II in kinetoplastid protozoan parasites are of immense interest as drug target because they take part in replication of unusual kinetoplast DNA network. In this study, we have taken target-based therapeutic approaches to combat leishmaniasis. Two isobenzofuranone compounds, viz., (1) 3,5-bis(4-chlorophenyl)-7-hydroxyisobenzofuran-1(3H)-one (JVPH3) and (2) (4-bromo)-3'-hydroxy-5'-(4-bromophenyl)-benzophenone(JVPH4) were synthesized chemically and characterized by NMR and mass spectrometry analysis. Activity of type II DNA topoisomerase of leishmania (LdTOPII) was monitored by decatenation assay and plasmid cleavage assay. The antiparasitic activity of these compounds was checked in experimental BALB/c mice model of visceral leishmaniasis. Isobenzofuranone derivatives exhibited potent antileishmanial effect on both antimony (Sb) sensitive and resistant parasites. Treatment with isobenzofuranone derivatives on promastigotes caused induction of reactive oxygen species (ROS)-mediated apoptosis like cell death in leishmania. Both the compounds inhibited the decatenation activity of LdTOPII but have no effect on bi-subunit topoisomerase IB. Treatment of LdTOPII with isobenzofuranone derivatives did not stabilize cleavage complex formation both in vitro and in vivo. Moreover, treatment with isobenzofuranone derivatives on Leishmania donovani-infected mice resulted in clearance of parasites in liver and spleen by induction of Th1 cytokines. Taken together, our data suggest that these compounds can be exploited as potential antileishmanial agents targeted to DNA topoisomerase II of the parasite.

Decichine enhances hemostasis of activated platelets via AMPA receptors

INTRODUCTION

Dencichine, one of the non-protein amino acids present in the roots of Panax notoginseng, has been found to shorten bleeding time of mice and increase the number of platelets. However, the exact underlying mechanisms have not been elucidated yet. This study was aimed to identify the hemostatic effect of dencichine and uncover its mechanisms.

MATERIALS AND METHODS

Hemostatic effect was assessed by measuring tail bleeding time and coagulation indices of rats. PT, APTT, TT and FIB concentration were measured using a Sysmex CA-1500 plasma coagulation analyzer. Platelet aggregation rate was determined by using a platelet aggregometer. Concentration of cyotosolic calcium was evaluated by Fluo-3 and levels of cyclic adenosine monophosphate (cAMP) and thromboxane A₂ (TXA₂) were measured by ELISA method.

RESULTS AND CONCLUSION

Dencichine administered orally shortened tail bleeding time, reduced APTT and TT but increased the concentration of FIB in plasma in a dose-dependent manner. When induced with trap, dencichine could elevate the cytoplasmic concentration of calcium, and secretion of TXA₂ as well as the ratio of TXA₂ to PGI₂ from platelets. Meanwhile, it decreased the level of intracellular cAMP. However, CNQX could block the enhanced hemostatic effect of dencichine. These results suggested that dencichine exerted hemostatic function via AMPA receptors on platelets, therefore, facilitated coagulation cascade in a paracrine fashion by control of platelet cytosolic calcium influx, cAMP production and TXA₂ release. Current study may contribute to its clinical use in therapy of hemorrhage.

Synthetic analogues of the natural compound cryphonectric acid interfere with photosynthetic machinery through two different mechanisms

A series of isobenzofuran-1(3H)-ones (phthalides), analogues of the naturally occurring phytotoxin cryphonectric acid, were designed, synthesized, and fully characterized by NMR, IR, and MS analyses. Their synthesis was achieved via condensation, aromatization, and acetylation reactions. The measurement of the electron transport chain in spinach chloroplasts showed that several derivatives are capable of interfering with the photosynthetic apparatus. Few of them were found to inhibit the basal rate, but a significant inhibition was brought about only at concentrations exceeding 50 μM. Some other analogues acted as uncouplers or energy transfer inhibitors, with a remarkably higher effectiveness. Isobenzofuranone addition to the culture medium inhibited the growth of the cyanobacterium Synechococcus elongatus , with patterns consistent with the effects measured in vitro upon isolated chloroplasts. The most active derivatives, being able to completely suppress algal growth at 20 μM, may represent structures to be exploited for the design of new active ingredients for weed control.

Synthesis and antiproliferative activity of C-3 functionalized isobenzofuran-1(3H)-ones

A series of thirteen C-3 functionalized isobenzofuran-1(3H)-ones (phtalides) was synthesized via condensation, aromatization, and acetylation reactions. NMR (one and two dimensional experiments), IR, and mass spectrometry analysis allowed confirmation of the identity of the synthesized compounds. The substances were submitted to in vitro bioassays against U937 (lymphoma) and K562 (myeloid leukemia) cancer cell lines using the MTT cytotoxicity assay. Some derivatives inhibited 90% of cell viability at 100 µM. Also, two phtalides presented biological activity superior than that of etoposide (VP16), a commercial drug used as a positive control in the assays. In silico drug properties of the evaluated compounds were calculated and the results are discussed.

5-Meth-oxy-2-benzofuran-1(3H)-one

In the title compound, C₉H₈O₃, the mol­ecular skeleton is almost planar, with an r.m.s. deviation of 0.010 (2) Å. In the crystal, weak C—H⋯O hydrogen bonds connect the mol­ecules into a two-dimensional network parallel to the ac plane.

A novel antioxidant isobenzofuranone derivative from fungus Cephalosporium sp.AL031

Bioassay-guided fractionation of metabolites from the fungus Cephalosporium sp.AL031 isolated from Sinarundinaria nitida led to the discovery of a new isobenzofuranone derivative, 4,6-dihydroxy-5-methoxy-7-methylphthalide (1), together with three known compounds: 4,5,6-trihydroxy-7-methyl-1,3-dihydroisobenzofuran (2), 4,6-dihydroxy-5-methoxy-7-methyl-1,3-dihydroisobenzofuran (3) and 4,5,6-trihydroxy-7-methylphthalide (4). The structure of the new compound 1 was determined based on MS, 1D and 2D NMR spectral data. Compounds 1–4 showed potent antioxidant activity with EC₅₀ values of 10, 7, 22 and 5 μM by 1,1-diphenyl-2-picryhydrazyl (DPPH) radical-scavenging assay.