Tae Bum Kim

Neuroprotective iridoid glycosides from Cornus officinalis fruits against glutamate-induced toxicity in HT22 hippocampal cells.

The methanolic extract of the fruits of Cornus officinalis S et Z. (Cornaceae) showed the significant neuroprotective activity against glutamate-induced toxicity in HT22 hippocampal cells. Chemical profile of n-BuOH fraction of the methanolic extract of C. officinalis fruits, which showed the most potent activity, was established using HPLC-diode array detector-electrospray-MS (HPLC-DAD-ESI-MS). Through bioactivity-guided isolation, five iridoid glycosides including one new compound, 7-O-butylmorroniside (1), loganin (2), morroniside (3), 7R-O-methylmorroniside (4), 7S-O-methylmorroniside (5) were isolated from the n-BuOH fraction. The protective activities of the isolated compounds, themselves, were not statistically significant. However, the hydrolyzed products of compounds 1, 4 and 5 significantly protected glutamate-injured HT22 cells up to 78±2.2%, 60±3.2% and 59±2.5% of non-treated control, respectively.

Cognition-enhancing and neuroprotective activities of the standardized extract of Betula platyphylla bark and its major diarylheptanoids.

Diarylheptanoids have been the center of the intensive research efforts for Alzheimers disease and other neurodegenerative diseases. The present study aimed to determine the effect of the standardized extract of B. platyphylla bark and its major diarylheptanoids in scopolamine-induced amnesic mice through cyclic AMP response element-binding protein (CREB) activation. Oral administration of the standardized extract of B. platyphylla bark (100mg/kg body weight), aceroside VIII (1mg/kg body weight) and platyphylloside (1 or 2mg/kg body weight) significantly ameliorated scopolamine-induced amnesia in passive avoidance test. CREB phosphorylation and brain-derived neurotrophic factor (BDNF) expression in the cortex and hippocampus of the scopolamine-treated mice were markedly increased by the treatment of the standardized extract of B. platyphylla bark and platyphylloside. The standardized extract of B. platyphylla bark and its major diarylheptanoids also significantly protected HT22 cells against neurotoxicity induced by glutamate insult. The standardized extract of B. platyphylla bark and platyphylloside may ameliorate memory deficits by activating the CREB-BDNF pathway and prevent a neurodegeneration by inhibiting neuronal cell death.

Inhibition of antigen-induced degranulation by aryl compounds isolated from the bark of Betula platyphylla in RBL-2H3 cells.

The methanolic extract of the bark of Betula platyphylla was found to suppress antigen mediated degranulation of RBL-2H3 cells. Four arylbutanoids (1-4) and eight diarylhepatonoids (5-12) were isolated from the methanolic extract using bioassay-guided fractionation. Among them, compounds 4 and 12 were isolated and assigned for the first time. Compounds 1, 2, 3, 5, 10, and 12 showed remarkable inhibitory activity against the degranulation of RBL-2H3 by antigen stimulation in a dose dependent manner at the concentrations ranging from 10 microM to 100 microM.

Prickly Pear Cactus (Opuntia ficus indica var. saboten) Protects Against Stress-Induced Acute Gastric Lesions in Rats

The protective activity of prickly pear cactus (Opuntia ficus indica var. saboten) fruit juice and its main constituent, betanin, were evaluated against stress-induced acute gastric lesions in rats. After 6 h of water immersion restraint stress (WIRS), gastric mucosal lesions with bleeding were induced in Sprague-Dawley rats. Pretreatment of a lyophilized powder containing O. ficus indica var. saboten fruit juice and maltodextrin (OFSM) and betanin significantly reduced stress lesions (800-1600 mg/kg). Both OFSM and betanin effectively prevented the decrease in gastric mucus content as detected by alcian blue staining. In addition, OFSM significantly suppressed WIRS-induced increases in the level of gastric mucosal tumor necrosis factor-α and myeloperoxidase (MPO). Betanin alone was only effective in decreasing MPO. These results revealed the protective activity of OFSM against stress-induced acute gastric lesions and that betanin may contribute to OFSMs gastric protective activity, at least in part. When OFSM and betanin were taken together, OFSM exerted gastroprotective activity against stress-induced gastric lesions by maintaining gastric mucus, which might be related to the attenuation of MPO-mediated damage and proinflammatory cytokine production.

Acylphloroglucinolated Catechin and Phenylethyl Isocoumarin Derivatives from Agrimonia pilosa

Eight new compounds (1-8), including five acylphloroglucinolated catechins (1-5) and three phenylethyl isocoumarin glycosides (6-8), were isolated from Agrimonia pilosa along with six other known compounds (9-14). The new compounds were characterized structurally by NMR, MS, and ECD analyses. Compounds 4 and 5 were assigned as acylphloroglucinolated procyanidin derivatives, which are described for the first time from Nature. The absolute configuration of compound 8 was elucidated by computational analysis of its ECD spectrum. The isolated compounds were evaluated for their inhibitory activity against lipopolysaccharide-induced NO production in BV2 microglial cells.

Protective Effects of Ethyl Acetate Soluble Fraction of Limonium tetragonum on Diethylnitrosamine-Induced Liver Fibrosis in Rats

Diethylnitrosamine (DEN) is a potent toxic material that can cause necrosis and subsequent fibrosis in the liver. Based on the previously reported hepatoprotective effect of Limonium tetragonum against the proliferation of hepatic stellate cells, we tested the EtOAc soluble fraction of L. tetragonum extract (EALT) in a DEN-induced hepatotoxic rat model. The development of hepatotoxicity including mononuclear cell infiltration and fibrosis induced by intraperitoneal injections of DEN (70 mg/2 mL/kg body weight (b.w.) per week) was observed at 4, 6 and 8 weeks after the first DEN treatment. Administration of EALT (200 mg/kg body weight, per os (p.o.)) induced significant reductions in serum alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), and triglycerides (TG) in DEN-injected rats. Increased oxidative stress in DEN-induced liver fibrosis rats was diminished by EALT treatment through a decrease in malondialdehyde (MDA) and increase in superoxide dismutase (SOD). Histologic findings that included markedly attenuated mononuclear cell infiltration and fibrosis could be observed in liver samples from the EALT-treated groups. An extract of Hovenia dulcis fruit and Sylimarin were used as positive controls. The present study provides direct experimental evidence for EALT attenuated hepatic injury and fibrosis in DEN-treated mice. The L. tetragonum EtOAc fraction might be useful in treating fibrotic liver diseases.

Quantitation of α‐Galactosides in Rehmannia glutinosa by Hydrophilic Interaction Chromatography–Evaporative Light Scattering Detector

INTRODUCTION The use of raffinose family oligosaccharides (RFOs) to control several diseases and stimulate immune systems has been studied. Rehmannia glutinosa is reported to contain RFOs; however, there are no reports on their content level in R. glutinosa. Furthermore, it is difficult to analyse RFOs using common reverse-phase chromatographic techniques due to their high polarity. OBJECTIVE To develop a rapid and reliable chromatographic method for the simultaneous quantitation of multiple RFOs in R. glutinosa. METHODOLOGY Chromatographic separation was performed by using hydrophilic interaction liquid chromatography coupled with an evaporative light scattering detector. For efficient ultrasound-assisted extraction of oligosaccharides, a central composite design was used. RESULTS Response surface analysis estimated the highest-obtained yields of raffinose, stachyose and verbascose to be 58.31, 408.75 and 26.59 mg, respectively, from 1 g of R. glutinosa, while under optimal conditions, experimental yields per gram were 56.79, 391.42 and 27.69 mg, respectively. CONCLUSION A rapid and reliable chromatographic method to simultaneously quantitate multiple RFOs in R. glutinosa was developed. Three RFOs in R. glutinosa were separated within 10 min using isocratic conditions. Quantitative analysis of RFOs showed that R. glutinosa may be a rich source of α-galacto-oligosaccharides, especially stachyose.

Argininosecologanin, a secoiridoid-derived guanidine alkaloid from the roots of Lonicera insularis

Abstract A new secoiridoid-derived guanidine alkaloid, argininosecologanin (1), along with 12 known iridoids and secoiridoids (2–13), was isolated from the roots of Lonicera insularis. The structures of the isolated compounds were established by the spectroscopic analysis and comparison of their spectral data with previously reported data. Compound 1 was assigned as the first secoiridoid-derived guanidine alkaloid isolated as a natural product. A plausible biogenetic pathway for 1 is suggested based on its structural similarity to (E)-aldosecologanin (4).

Chemical and genomic diversity of six Lonicera species occurring in Korea

Lonicera spp. (Caprifoliaceae) are important not only as a common medicinal herb in East Asia but also as one of the most problematic invasive species in North America. In the present study, we performed a systemic analysis of genomic and chemical diversity among six Lonicera species occurring in Korea, L. japonica, L. maackii, L. insularis, L. sachalinensis, L. praeflorens, and L. vesicaria, using chloroplast DNA whole genome shotgun (WGS) sequencing and LC-MS analyses. The phylogenetic and phylochemical relationships did not coincide with each other, but partial consistency could be found among them. InDel-based cDNA marker for authentication was developed based on the genome sequences. Flavonoids, iridoids, and organic acids were identified in the LC-MS analyses, and their inter-species distribution and localization were also revealed.

Hepatoprotective flavonoids in Opuntia ficus-indica fruits by reducing oxidative stress in primary rat hepatocytes

Background: Liver disorder was associated with alcohol consumption caused by hepatic cellular damages. Opuntia ficus-indica fruit extracts (OFIEs), which contain betalain pigments and polyphenols including flavonoids, have been introduced as reducing hangover symptoms and liver protective activity. Objective: To evaluate hepatoprotective activity of OFIEs and isolated compounds by high-speed countercurrent chromatography (HSCCC). Materials and Methods: The extract of O. ficus-indica fruits was fractionated into methylene chloride and n-butanol. The n-butanol fraction was isolated by HSCCC separation (methylene chloride-methanol-n-butanol-water, 5:4:3:5, v/v/v/v). The hepatoprotective activity of OFIEs and isolated compounds was evaluated on rat primary hepatocytes against ethanol-induced toxicity. Antioxidative parameters such as glutathione reductase and glutathione peroxidase (GSH-Px) enzymes and the GSH content were measured. Results: Two flavonoids, quercetin 3-O-methyl ester (1) and (+)-taxifolin, and two flavonoid glycosides, isorhamnetin 3-O-β-d-glucoside (3) and narcissin (4), were isolated from the n-butanol fraction by HSCCC separation. Among them, compound 2 significantly protected rat primary hepatocytes against ethanol exposure by preserving antioxidative properties of GR and GSH-Px. Conclusions: OFIEs and (+)-taxifolin were suggested to reduce hepatic damage by alcoholic oxidative stress.