• Food Science of Animal Resources
• /
• v.23 no.3
• /
• pp.193-199
• /
• 2003

In order to investigate the meat tenderizing effects of pear, pineapple and kiwifruit, crude protease was prepared from each fruit and treated with actomyosin in a single manner or mixed type in several combination. Actomyosin was incubated with various proteases for 24 hrs under three different pH condition, and its degrading performance was evaluated by the SDS-PAGE. Pear extract showed an active degrading activity for actomyosin at pH 5.3 and 7.0. But, little actomyosin degradation was observed at pH 8.0. Actomyosin was strongly degraded by the treatment of protease from pineapple at all different pHs(5.3, 7.0 and 8.0). Kiwifruit protease extract has shown actomyosin degradation activity 1hr after treatment at pH 5.3 and pH 7.0. Meanwhile, the mixture of pear and pineapple extracts(l:l, w/w) showed much more degradation than the results of singular manner treatment at pH 5.3 and 7.0. When the pear protease was mixed with kiwifruit protease(l:l, w/w), the performance of actomyosin degradation was similar to the results of each single protease treatment. When the mixture was made of pineapple and kiwifruit extracts, actomyosin degradation was almost the same as the result of treatment of pineapple protease only. When those three proteases were mixed together(l:l:l, w/w/w), actomyosin degrading activities was in time dependent manner at pH 5.3. In summary, pear protease can be used potentially as a meat tenderizer when it was mixed with pineapple or kiwifruit rendering proper tenderization of the meat.

• Applied Biological Chemistry
• /
• v.49 no.3
• /
• pp.233-237
• /
• 2006

In the present study, we compared the functional analysis of pear extracts cultured in conventional and environment-friendly conditions in primary cultured rat hepatocytes. ATP synthesis significantly increased by the treatment with environment friendly cultured pear powder but not by conventional group. In addition, cell proliferation using $[^3H]$-thymidine incorporation was also stimulated by environment-friendly cultured pear extract compared to conventional group. Moreover, the expressions of CDK-2 and CDK-4 were increased but p21WAF1/Cip1 and p27 Kip1 decreased by environment-friendly cultured pear extract but not by conventional group. In conclusion, environment-friendly cultured pear powder has stimulatory effect on cell proliferation compared to conventional group in primary cultured rat hepatocytes.

• Korean Journal of Pharmacognosy
• /
• v.33 no.3 s.130
• /
• pp.230-237
• /
• 2002

Prickly pear(Opuntia ficus-indica var saboten Makino, Cactaceae) is widely used as folk medicine for burned wound, edema and indigestion. To confirm the hypolipidemic action of the extract from Cactus stem and fruit in dietary hyperlipidemic rats, variations of the lipid- or cholesterol-related components were investigated. As results these changes were significantly prevented by treatments with Cactus extracts. The effects of the extract of fruit was better than those of stem.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1998.11a
• /
• pp.187-187
• /
• 1998

The objective was to verify biological activities of fruit and stem of prickly pear(Opuntia ficus indica L. var, saboten Makino). We have determined inhibitory activities on enzymes, such as dopamine ${\beta}$-hydroxylase(DBH), monoamme oxidase A and B(MAO-A, B), and antioxidant activity, in vitro. We purchased dried stem powder and lyophilized fruit powder of prickly pear from CheJu Island, and prepared the extracts with 80% of methanol. The fruit extract showed stronger inhibitory effects on MAO-A and -B and antioxidant activity compared. to the stem extract, on fractionation with hexane, ethyl acetate, butanol and water. Both the stem and the fruit extracts with ethyl acetate showed stronger enzyme inhibitory and antioxidant activities than other extracts. Now we are isolating active principles from both ethyl acetate extracts.

• Nutrition Research and Practice
• /
• v.11 no.3
• /
• pp.198-205
• /
• 2017

BACKGROUND/OBJECTIVES: The anti-diabetic activity of pear through inhibition of ${\alpha}-glucosidase$ has been demonstrated. However, little has been reported about the effect of pear on insulin signaling pathway in obesity. The aims of this study are to establish pear pomace 50% ethanol extract (PPE)-induced improvement of insulin sensitivity and characterize its action mechanism in 3T3-L1 cells and high-fat diet (HFD)-fed C57BL/6 mice. MATERIALS/METHODS: Lipid accumulation, monocyte chemoattractant protein-1 (MCP-1) secretion and glucose uptake were measure in 3T3-L1 cells. Mice were fed HFD (60% kcal from fat) and orally ingested PPE once daily for 8 weeks and body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and serum lipids were measured. The expression of proteins involved in insulin signaling pathway was evaluated by western blot assay in 3T3-L1 cells and adipose tissue of mice. RESULTS: In 3T3-L1 cells, without affecting cell viability and lipid accumulation, PPE inhibited MCP-1 secretion, improved glucose uptake, and increased protein expression of phosphorylated insulin receptor substrate 1 [p-IRS-1, ($Tyr^{632})$)], p-Akt, and glucose transporter type 4 (GLUT4). Additionally, in HFD-fed mice, PPE reduced body weight, HOMA-IR, and serum lipids including triglyceride and LDL-cholesterol. Furthermore, in adipose tissue, PPE up-regulated GLUT4 expression and expression ratio of p-IRS-1 ($Tyr^{632})/IRS$, whereas, down-regulated p-IRS-1 ($Ser^{307})/IRS$. CONCLUSIONS: Our results collectively show that PPE improves glucose uptake in 3T3-L1 cells and insulin sensitivity in mice fed a HFD through stimulation of the insulin signaling pathway. Furthermore, PPE-induced improvement of insulin sensitivity was not accompanied with lipid accumulation.

• Food Industry And Nutrition
• /
• v.9 no.2
• /
• pp.53-59
• /
• 2004

• Proceedings of the Korean Nutrition Society Conference
• /
• 2003.05a
• /
• pp.229.2-229.2
• /
• 2003

• The Korea Journal of Herbology
• /
• v.30 no.1
• /
• pp.51-57
• /
• 2015

Objectives : The effect of pear extract with Daekumeumjagami and vitamin C medication(PDV) on alcohol metabolism and hepatic injury was assessed following hepatic injury induced by alcohol in mice. Methods : The model of alcoholic hepatic injury was established by orally administration with 3 g/kg 25% alcohol in mice. PDV was orally administrated once a day for 5 days. Mice were randomly divided into 5 groups : normal group, control group, and PDV groups (PDV-A, PDV-B and PDV-C). The activities of aspartate amino transferase (AST) and alanine amino transferase (ALT) and alcohol dehydrogenase (ADH) in serum, superoxide dismutase (SOD) and catalase in liver were determined after alcohol exposure. Results : Compared with control group, treatment with PDV-B and PDV-C significantly elevated activities of ADH. Moreover, the index of hepatic injury in serum was significantly decreased by treatment with PDV-B and PDV-C in ALT activity and PDV-C in AST activity. Additionally, enhanced catalase activities in liver was found in PDV-C treated mice after exposure to alcohol. Also, WBC in blood was significantly lower by treatment with PDV-B and PDV-C. Conclusions : This study suggests that PDV treatment could enhance alcohol metabolism, and prevent hepatic injury after alcoholic hepatic injury and that this effect is likely related to its modulation on the alcohol metabolizing and antioxidant enzymes.

• Korean Journal of Food Science and Technology
• /
• v.47 no.2
• /
• pp.254-260
• /
• 2015

The effect of the extraction solvent on the physiological properties of the peel of the Korean pear (Pyrus pyrifolia cv. Niitaka) was evaluated. The total phenol content was highest in the 80%(wt) methanol extract, whereas flavonoid content was highest in the 80% ethanol extract. The antioxidant activities of the extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging abilities, and their reducing power. The water and 80% methanol extracts of the pear peel had highest DPPH and ABTS radical scavenging activities, and reducing power, respectively. The inhibition of ${\alpha}$-glucosidase was highest in the 80% methanol extract, and alcohol dehydrogenase activity was highest in the water extract. All three extracts had similar antimicrobial activity. Because water, 80% ethanol, and 80% methanol extracts exhibited high activities in different assays of physiological properties, each solvent could be used for specific purposes.

• Food Science of Animal Resources
• /
• v.29 no.2
• /
• pp.157-163
• /
• 2009

This study was conducted for the isolation, purification, and characterization of a protease from Korean pear, to see its proteolytic activity on chicken actomyosin and to find the optimum pH and temperature of activity on chicken actomyosin. The protease was isolated from crude extract of Korean pear by ammonium sulfate precipitation. Further purification was done by DEAE-Sepharose ion-exchange chromatography, Mono-Q and Mini-Q column chromatography. The purified enzyme gave a single protein band on SDS polyacrylamide gel electrophoresis and the molecular weight was found to be 38 kDa. The specific activity of purified enzyme was 34,907 unit/mg with 25 fold purification and the yield was 2%. The purified enzyme incubated with chicken actomyosin showed high activity. The optimum pH and temperature for enzyme activity on chicken actomyosin were 6.5 and $70^{\circ}C$, respectively. A protease was purified from Korean pear for the first time and characterized. It was found to be promising for meat tenderization.