E. Jian Lee

Camphoratins A−J, Potent Cytotoxic and Anti-inflammatory Triterpenoids from the Fruiting Body of Taiwanofungus camphoratus

Ten new triterpenoids, camphoratins A-J (1-10), along with 12 known compounds were isolated from the fruiting body of Taiwanofungus camphoratus. Their structures were established by spectroscopic analysis and chemical methods. Compound 10 is the first example of a naturally occurring ergosteroid with an unusual cis-C/D ring junction. Compounds 2-6 and 11 showed moderate to potent cytotoxicity, with EC(50) values ranging from 0.3 to 3 μM against KB and KB-VIN human cancer cell lines. Compounds 6, 10, 11, 14-16, 18, and 21 exhibited anti-inflammatory NO-production inhibition activity with IC(50) values of less than 5 μM, and were more potent than the nonspecific NOS inhibitor N(ω)-nitro-L-arginine methyl ester.

Constituents of the Roots of Clausena lansium and Their Potential Anti-inflammatory Activity

Eight new carbazole alkaloids, claulamines C (1), D (2), and E (5) and clausenalines B-F (3, 4, 6-8), four new coumarins, clausemarins A-D (9-12), and 43 known compounds were isolated from the roots of Clausena lansium. The structures of the new compounds were established on the basis of 2D-NMR spectroscopic analysis, and their absolute configurations were established from their ECD spectra. The configuration of wampetin was revised as E using a NOESY experiment. Most of the isolated compounds were evaluated for their potential anti-inflammatory activity. The results showed that compounds 9, 13-18, and 20-22 exhibited strong inhibition of superoxide anion generation with IC50 values ranging from 1.9 to 8.4 μM, while compounds 18, 19, and 21 inhibited elastase release with IC50 values in the range from 2.0 to 6.9 μM.

Flavonoids and ent-labdane diterpenoids from Andrographis paniculata and their antiplatelet aggregatory and vasorelaxing effects

Two new flavones, designated as andropaniculosin A (1) and andropaniculoside A (2), and 30 known compounds were isolated as a result of detailed chemical examination on the whole plants of Andrographis paniculata. Their structures have been elucidated mainly by 1D and 2D NMR, and MS spectroscopic methods. Among them, four flavonoids showed potent inhibition of collagen, arachidonic acid, thrombin, and platelet activation factor induced platelet aggregation. Furthermore, a diterpenoid demonstrated moderate vasorelaxing effect in isolated rat thoracic aorta.

Early reperfusion improves the recovery of contralateral electrophysiological diaschisis following focal cerebral ischemia in rats.

Abstract Objectives: We evaluated electrophysiological benefits of reperfusion following ischemic stroke. Methods: Rats received either transient proximal occlusion of the right middle cerebral artery for 30 (Group I, n=8) or 90 minutes (Group II, n=8) or permanent thermocoagulation of the distal right middle cerebral artery (Group III, n=6). Neurobehavioral outcome and somatosensory evoked potentials (SSEPs) were examined before and at 7 days after the onset of brain ischemia. Brain infarction was assessed after the rats were euthanized. Results: Before ischemia, stable SSEPs were consistently recorded. At 7 days post-insult, Group III (permanent occlusion) had the greatest reduction in the SSEPs recorded ipsilaterally and contralaterally. Groups I and II (transient ischemic groups) also had depressant SSEPs recorded from the ipsilateral ischemic and the contralateral intact brain (electrophysiological diaschisis). However, prolonged ischemia resulted in greater brain infarction and increased neurological deficits in addition to greater reductions in the ipsilateral and the contralateral SSEPs. Conclusion: Early reperfusion facilitates the electrophysiological recovery in both ipsilateral lesional and the contralateral intact brain, which may be closely relevant to post-injury brain rewiring. We also demonstrated that contralateral electrophysiological diaschisis could be greatly reversed by early reperfusion and is independent of the lesion size of striatum.

Chemical Constituents and Anti-inflammatory Principles from the Fruits of Forsythia suspensa

Fifty compounds were isolated from the fruits of Forsythia suspensa, including 13 new compounds characterized as eight new diterpenoids (1-8), three new lignans (9-11), a new iridoid (12), and a new triterpenoid (13). Their structures were established on the basis of spectroscopic and spectrometric analysis. Most of the isolated compounds were examined for their anti-inflammatory activity in vitro. The results showed that several compounds displayed significant inhibition of fMLP/CB-induced superoxide anion generation and elastase release, with IC50 values ranging from 0.6 ± 0.1 to 8.6 ± 0.8 μg/mL and from 0.8 ± 0.3 to 7.3 ± 1.1 μg/mL, respectively.

Melatonin protects brain against ischemia/reperfusion injury by attenuating endoplasmic reticulum stress

Endoplasmic reticulum (ER) stress plays a vital role in mediating ischemic reperfusion damage in brain. In this study, we evaluated whether melatonin inhibits ER stress in cultured neurons exposed to oxygen and glucose deprivation (OGD) and in rats subjected to transient focal cerebral ischemia. Sprague-Dawley rats were treated with melatonin (5 mg/kg) or control at reperfusion onset after transient occlusion of the right middle cerebral artery (MCA) for 90 min. Brain infarction and hemorrhage within infarcts were measured. The expression of ER stress proteins of phosphorylation of PRKR-like endoplasmic reticulum kinase (p-PERK), phosphorylation of eukaryotic translation initiation factor 2α (p-eIF2α), activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) were detected by western blotting and immunohistochemistry analysis. The terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) method, cleaved caspase-3 and cytochrome c were used to investigate cell apoptosis in OGD-induced cultured neurons. Our results demonstrated that animals treated with melatonin had significantly reduced infarction volumes and individual cortical lesion sizes as well as increased numbers of surviving neurons. Melatonin can significantly modulate protein levels by decreasing both p-PERK and p-eIF2α in the ischemic core and penumbra. Moreover, the expressions of ATF4 and CHOP were restrained in the ischemic core and penumbra, respectively. Furthermore, pretreatment with melatonin at 10–100 µM effectively reduced the levels of p-PERK and p-eIF2α in cultured neurons after OGD injury. Melatonin treatment also effectively decreased neuron apoptosis resulting from OGD-induced neuron injury. These results indicate that melatonin effectively attenuated post-ischemic ER stress after ischemic stroke.

Therapeutic window for YC‑1 following glutamate‑induced neuronal damage and transient focal cerebral ischemia

3-(5′-Hydroxymethyl-2′-furyl)-1-benzylindazole (YC-1), has been demonstrated to inhibit platelet aggregation, vascular contraction and hypoxia-inducible factor 1 activity in vitro and in vivo. The present study investigated the neuroprotective efficacy of YC-1 in cultured neurons exposed to glutamate-induced excitotoxicity and in an animal model of stroke. In a cortical neuronal culture model, YC-1 demonstrated neurotoxicity at a concentration >100 µM, and YC-1 (10–30 µM) achieved potent cytoprotection against glutamate-induced neuronal damage. Additionally, YC-1 (30 µM) effectively attenuated the increase in intracellular Ca2+ levels. Delayed treatment of YC-1 (30 µM) also protected against glutamate-induced neuronal damage and cell swelling in cultured neurons, though only at 4 h post-treatment. In addition, immediate treatment of YC-1 (30 µM) following the exposure of cortical neurons to glutamate (300 µM) produced a marked reduction in intracellular pH. Delayed treatment of YC-1 (25 mg/kg) protected against ischemic brain damage in vivo, though only when administered at 3 h post-insult. Thus, YC-1 exhibited neuroprotection against glutamate-induced neuronal damage and in mice subjected to transient focal cerebral ischemia. This neuroprotection may be mediated via its ability to limit the glutamate-induced excitotoxicity. However, the neuroprotective therapeutic window of YC-1 is only at 3 h in vivo and 4 h in vitro, which may, at least in part, be attributed to its ability to reduce the intracellular pH in the early phase of ischemic stroke. Although YC-1 provided the potential for clinical therapy, the treatment time point must be carefully evaluated following ischemia.

YC‑1 reduces inflammatory responses by inhibiting nuclear factor‑κB translocation in mice subjected to transient focal cerebral ischemia

3-(5-hydroxymethyl-2-furyl)-1-benzyl-indazole (YC-1) is understood to protect against ischemic stroke, but the molecular basis for its neuroprotection remains to be fully characterized. The present study investigated the influence of YC-1 on inflammatory responses following experimental stroke. Previous studies indicated that nuclear factor (NF)-κB-driven signals serve a pivotal role in mediating inflammatory responses following stroke. Ischemic stroke results in activation of NF-κB to induce gene expression of factors including inducible nitric oxide synthase, interleukin (IL)-1β, IL-6 and matrix metalloproteinases (MMPs). The results of the present study demonstrated that YC-1 effectively reduced brain infarction and brain edema, and improved blood-brain barrier leakage. Additionally, animals treated with YC-1 exhibited significant reductions in neutrophil and macrophage infiltration into the ischemic brain. Furthermore, YC-1 effectively inhibited NF-κB translocation and binding activity, and the activity and expression of MMP-9 following ischemic stroke. In conclusion, YC-1 may effectively attenuate NF-κB-induced inflammatory damage following cerebral ischemia-reperfusion.

THE STABILIZING EFFECT OF POSTERIOR FIXATIONS IN A DESTABILIZED ATLANTOAXIAL COMPLEX MODEL IN CANINES

Purpose: This study was conducted to evaluate the kinematic responses and the restorative effectiveness of three posterior fixations in a canine atlantoaxial (C1-2) complex model. Methods: Nine canine ligamentous C1-2 complexes were non-destructively tested in an intact condition, after ligamentous destabilization, and after bilateral stabilization with each of three posterior fixation methods: (1) Halifax inter-laminar clamps; (2) sub-laminar wiring; and (3) individual fixation of the C1 lateral mass and the C2 pedicle with screws and plates. Specimens were subjected to a relevantly applied loads through a loading frame rigidly attached to the C1. Two sets of three markers was separately attached to the mounting jigs of the C1 and the C2 to record the spatial locations after each loading step with a Vicron 370 system. The load-deformation data were analyzed. Results: Under a realistic loading paradigm, destabilized canine C1-2 complex had 3-dimensional motion ranges highly consistent with the corresponding values observed in destabilized cadaveric human C1-2 complex following a non-destructive loading paradigm. All the three posterior fixations significantly restricted the motion range of axial rotation loads (P<0.05). However, fixation either with posterior inter-articular screws and plates or inter-laminar clamps also effectively restricted the motion ranges of flexion/extension and lateral bending loads, whereas posterior wiring did not. Conclusion: We described a destabilized canine C1-2 complex model. Under a realistic loading paradigm, the model had kinematic analogue of destabilized human C1-2 complex. Our results indicated that posterior stabilization using inter-articular fixation techniques or inter-laminar clamps could effectively restrict hypermotility caused by C1-2 ligamentous destabilization, and, therefore, appeared to be reliable fixation methods. In contrast, posterior wiring alone would preserve more residual motions, and, thus, might need other adjunctive fixations to offer an optimal condition for solid bony fusion.