Hyun-Ku Kim

Optimisation of microwave‐assisted extraction for functional properties of Vitis coignetiae extract by response surface methodology

BACKGROUND Consumer preference for selection of natural substances, with their safe and beneficial effects on the human body as well as various physiological efficacies, is increasing. In this study, response surface methodology (RSM) was used to monitor the extraction characteristics of Vitis coignetiae (wild grape) and thereby optimise the functional properties of the resulting extract. RESULTS A maximum total polyphenol content (TPC) of 415.74 mg per 100 g was obtained at a microwave power (MWP) of 102.36 W, an ethanol concentration (ETC) of 42.62% (by volume) and an extraction time (EXT) of 12.35 min. Electron-donating ability (EDA) reached a maximum of 69.20% at 125.65 W MWP, 41.81% ETC and 13.65 min EXT. The maximum nitrite-scavenging ability (NSA) obtained was 87.50% at 119.13 W MWP, 37.41% ETC and 13.20 min EXT. Superoxide dismutase (SOD) showed a maximum pseudo-activity (SDA) of 56.74% at 69.54 W MWP, 94.88% ETC and 10.32 min EXT. The effect of ETC was most prominent among the studied factors. CONCLUSION Based on the superimposition of four-dimensional response surfaces with respect to TPC, EDA, NSA and SDA, the optimum ranges of extraction conditions were 70-150 W MWP, 30-50% ETC and 8-18 min EXT.

Melatonin attenuates doxorubicin-induced testicular toxicity in rats.

This study investigated the protective effects of melatonin (MLT) against doxorubicin (DXR)‐induced testicular toxicity and oxidative stress in rats. DXR was given as a single intraperitoneal dose of 10 mg kg−1 body weight to male rats at 1 h after MLT treatment on day 6 of the study. MLT at 15 mg kg−1 body weight was administered daily by gavage for 5 days before DXR treatment followed by an additional dose for 5 days. Sperm analysis, histopathological examination and biochemical methods were used for this investigation. DXR caused a decrease in the weight of seminal vesicles, epididymal sperm count and motility and an increase in the incidence of histopathological changes of the testis. In addition, an increased malondialdehyde (MDA) concentration and decreased glutathione content, glutathione reductase (GR), glutathione‐S‐transferase (GST), superoxide dismutase (SOD) and catalase activities were observed. On the contrary, MLT treatment significantly ameliorated DXR‐induced testicular toxicity in rats. Moreover, MDA concentration and GR, GST and SOD activities were not affected when MLT was administered in conjunction with DXR. These results indicate that MLT had a protective effect against DXR‐induced testicular toxicity and that the protective effects of MLT may be due to both the inhibition of lipid peroxidation and increased antioxidant activity.

Pterostilbene from Vitis coignetiae protect H2O2-induced inhibition of gap junctional intercellular communication in rat liver cell line

In this study, we identified various stilbenoids derived from Vitis coignetiae and investigated the protective effect of the main component, pterostilbene, against the inhibition of gap junctional intercellular communication (GJIC) induced by H(2)O(2) in WB-F344 rat liver epithelial cells. We analyzed seven kinds of stilbenoids, pterostilbene, astringin, piceid, vitisin, rhaponticin, resveratrol, and rhapontigenin, using DAD/UV HPLC. Total stilbenoid content was 127.37+/-19.29 mg/100g dry weight. Pretreatment with 0.5, 1.0, and 5.0 microM pterostilbene for 24h was shown to recover GJIC blocked by 500 microM H(2)O(2). Pretreatment with pterostilbene prevented the inhibition of GJIC via the down-regulation of connexin43 phosphorylation by the inactivation of ERK1/2 and p38 MAP kinase. Our results suggest that pterostilbene may be a functional chemopreventative agent and that dietary exposure of pterostilbene would be helpful for improving health.

Monitoring of Chemical Changes in Explosively Puffed Ginseng and the Optimization of Puffing Conditions

Response surface methodology was used to predict the optimum conditions of explosive puffing process for ginseng. A central composite design was used to monitor the effect of moisture content and puffing pressure on dependent variables such as functional compounds (extract yield, crude saponin, acidic polysaccharide, and total phenolic content) and sensory properties. Correlation coefficients (R²) of models for crude saponin, acidic polysaccharide, and total phenolic content were 0.9176 (p＜0.05), 0.9494 (p＜0.05), and 0.9878 (p＜0.001), respectively. Functional compounds increased with decreasing moisture content and increasing puffing pressure. Overall palatability was high at 15-20% moisture content and 98-294 ㎪ of puffing pressure. On the basis of superimposed contour maps for functional compounds and overall palatability of puffed ginseng, the optimum ranges of puffing conditions were 10-17% moisture content and 294-392 ㎪ puffing pressure.

Melatonin prevents gentamicin-induced testicular toxicity and oxidative stress in rats

This study investigated the protective effects of melatonin (MT) against gentamicin (GM)‐induced testicular toxicity and oxidative damage in rats. GM (100 mg kg−1) was injected intraperitoneally (i.p.) to rats for 6 days. MT (15 mg kg−1) was administered i.p. to rats for 6 days at 1 hr after the GM treatment. GM caused a decrease in prostate and seminal vesicle weights, sperm count and sperm motility. Histopathological examination showed various morphological alterations in the testis, characterised by degeneration of spermatogonia/spermatocytes, decrease in the number of early spermatogenic cells and vacuolisation. In addition, an increased malondialdehyde concentration and decreased glutathione content and glutathione reductase, catalase and glutathione‐S‐transferase activities were found in the testis. In contrast, MT treatment significantly attenuated the testicular toxicity of GM, including decreased reproductive organ weights, sperm count, and sperm motility and increased histopathological alterations. MT also had an antioxidant benefit by decreasing the lipid peroxidative product malondialdehyde and increasing the level of the antioxidant glutathione and the activities of antioxidant enzymes in the testis. These results indicate that MT prevents testicular toxicity induced by GM in rats, presumably due to its potent antioxidant activity, and its ability to inhibit lipid peroxidation, and restore antioxidant enzyme activity.

Development of a molecular marker to discriminate Korean Rubus species medicinal plants based on the nuclear ribosomal DNA internal transcribed spacer and chloroplast trnL-F intergenic region sequences

Rubi Fructus (Bokbunja in Korean) is a traditional oriental medicine often prescribed as the immature fruit of Rubus coreanus in the Korean pharmacopoeia or Rubus chingii in the Chinese pharmacopoeia. However, Rubus crataegifolius is presently the most popular form in the market. Correctly identifying these fruits is difficult due to morphological similarities in their dried immature forms. Therefore, nucleotide sequences of nuclear ribosomal DNA (nrDNA), internal transcribed spacer, chloroplast DNA (cpDNA) trnL-F, and psbA-trnH intergenic spacer were analyzed to develop objective methods for discrimination among R. coreanus, R. crataegifolius, and R. chingii. Based on trnL-F intergenic sequences, three sequence characterized amplified region (SCAR) markers (CorF/CorR, HwaF2/HwaR2, SanF/SanR) were developed to distinguish the three species. Furthermore, phylogenetic analysis of the trnL-F intergenic sequences showed that R. crataegifolius is widely distributed in the Korean Rubi Fructus market as Korean product and imported goods from China. Single nucleotide polymorphism (SNP) that can be used to discriminate Korean Bokbunja medicine from those imported from China was developed, established the SNP marker, and conducted real-time PCR with a designed inflorescence probe. The developed SCAR marker and SNP probe were useful for distinguishing and authenticating the Korean and Chinese species that constitute Rubi Fructus medicines.

Apoptotic cell death in rat epididymis following epichlorohydrin treatment

Epichlorohydrin (ECH) is an antifertility agent that acts both as an epididymal toxicant and an agent capable of directly affecting sperm motility. This study identified the time course of apoptotic cell death in rat epididymides after ECH treatment. Rats were administrated with a single oral dose of ECH (50 mg/kg). ECH-induced apoptotic changes were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and its related mechanism was confirmed by Western blot analysis and colorimetric assay. The TUNEL assay showed that the number of apoptotic cells increased at 8 h, reached a maximum level at 12 h, and then decreased progressively. The Western blot analysis demonstrated no significant changes in proapoptotic Bcl-2-associated X (Bax) and anti-apoptotic Bcl-2 expression during the time course of the study. However, phospho-p38 mitogen-activated protein kinase (p-p38 MAPK) and phospho-c-Jun amino-terminal kinase (p-JNK) expression increased at 8–24 h. Caspase-3 and caspase-8 activities also increased at 8–48 h and 12–48 h, respectively, in the same manner as p-p38 MAPK and p-JNK expression. These results indicate that ECH induced apoptotic changes in rat epididymides and that the apoptotic cell death may be related more to the MAPK pathway than to the mitochondrial pathway.

Monitoring of Commercial Red Pepper Powders for Their Irradiation Status

Ten commercially available red pepper powders were investigated using photostimulated-luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) analyses to confirm their irradiation status. The application of PSL, TL, and ESR analyses was also confirmed by in-house irradiation. In PSL-based screening, all samples gave negative photon counts (<700 PCs). The PSL calibration dose (1 kGy) showed a low sensitivity of 4 samples, while the others provided reliable screening results. TL glow curves demonstrated maximum peaks after 250 o C for the 6 samples; however 4 samples gave complex TL glow curves with maximum peaks in the range of 185-260 o C (radiation-specific), which could be the effect of an irradiated component in low concentration as the TL ratios of all samples were <0.1. Radiation-specific ESR features were absent in the all commercial samples. Variable irradiation detection properties were found; where the TL analysis showed the possible presence of an irradiated component in 4 samples requiring further monitoring and investigation.

Antioxidant and ACE Inhibitory Activity of Cultivated and Wild Angelica gigas Nakai Extracts Prepared Using Different Extraction Conditions.

The purpose of this study was to investigate the biological activities of cultivated Angelica gigas Nakai (CAG) and wild Angelica gigas Nakai (WAG) extracts prepared by extraction with water, 30% ethanol, 60% ethanol, or 90% ethanol. The electron donating ability of the WAG extracts was higher than that of the CAG extracts and 0.1% and 1.0% solutions of the comparative substance, L-ascorbic acid. The superoxide dismutase-like activity of the CAG extracts was higher than that of WAG extracts. Superoxide dismutase-like activity was highest (33.95%) in the CAG water extract. The total polyphenol content was highest in the 60% ethanol extracts of WAG. The nitrite scavenging ability of the CAG and WAG extracts was highest at a pH of 1.2. The tyrosinase inhibitory effect was highest (43.72%) in the water extract of WAG. The angiotensin converting enzyme inhibitory activity was highest (83.84%) in the 60% ethanol extract of WAG. The results of the present study will be useful for understanding the antioxidant and angiotensin-converting enzyme inhibitory activities of Angelica gigas Nakai extracts.

Development of antihypertensive natural seasoning using beef hydrolyzate

Natural seasoning with antihypertensive effect was developed using beef hydrolyzate. Quality of the natural seasoning product was compared with five concentrations of beef hydrolyzates at 0, 5, 10, 15, and 20%. Optimum conditions of beef hydrolyzate were determined to be Alcalase 2.4 L 1%, beef concentration 5%, and 4 h of hydrolysis. Angiotensin-converting enzyme (ACE) inhibitory activity of beef hydrolyzate was increased by 70.2% as compared to that of control under the same condition. Sensory evaluation results showed that natural seasoning with 15% beef hydrolyzate was acceptable with salty and savory taste. ACE inhibitory activity of the seasoning with 15% beef hydrolyzate was increased by 41.7% compared to control. Amino acid compositions of natural seasoning in 15% beef hydrolyzate were taurine (511.3mg%), glutamine (846.2mg%), glycine (120.6mg%), and ammonia (NH3) (105.7 mg%). Optimal composition of the seasoning product was: 15% beef hydrolyzate mixed with 1.7% red pepper powder, 4.25% crab water extract, 10.2% kelp powder, 1.7% garlic powder, 10.2% anchovy powder, 10.2% short-necked clam powder, 12.75% shrimp powder, 17% beef powder, 12.75% shiitake powder, and 4.25% freeze-dried pollock powder. The seasoning with 15% beef hydrolyzate may have antihypertensive effects with high consumer acceptability.