Food Science and Preservation (한국식품저장유통학회지)

The Korean Society of Food Preservation (한국식품저장유통학회)
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Effects of Green Tea Extract on Intestinal Mucosal Esterification of $^{14}C$-Oleic Acid in Rats

녹차 추출물이 흰쥐 소장세포의 지방 에스테르화 과정에 미치는 영향

  • Seo, Yun-Jung (Department of Food and Nutrition, Changwon National University) ;
  • Noh, Sang-K. (Department of Food and Nutrition, Changwon National University)
  • 서윤정 (국립창원대학교 식품영양학과) ;
  • 노상규 (국립창원대학교 식품영양학과)
  • Published : 2008.06.30
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Abstract

Previously, we have shown that green tea extract lowers the intestinal absorption of cholesterol, fat, and other fat-soluble compounds. We conducted this study to determine whether green tea extract affects the rate of $^{14}C$-oleic acid esterification into various lipids in the intestinal mucosa of rats. Male Sprague-Dawley ruts were had free access to a nutritionally adequate AIN-93G diet and deionized water. Initially, the rat's mucosal content of total lipids was measured following 1 mL olive oil administration with (green tea group) or without (control group) 100 mg green tea extract powder. At 1 h and 5 h, intestinal segments were extracted for total lipid analysis. Secondly, to measure mucosal esterification rates of lipids, an abdominal incision was made along the midline, and a 10-cm long jejunal segment of the small intestine was ligated in situ. Then, micellar solutions with or without green tea extract were injected into the ligated jejunal segments and incubated for 10 mill. The micellar solution contained $200.0\;{\mu}$ Ci $^{14}C$-oleic acid, $200.1\;{\mu}mol$ unlabelled oleic acid, $66.7\;{\mu}mol$ 2-monooleoylglycerol, $66.7\;{\mu}mol$ palmitoyl-sn-glycero-3-phosphocholine, 2.2 mmol glucose, $50.0\;{\mu}mol$ albumin, and 16.5 mmol Na-taurocholate per L of phosphate buffered saline (pH, 6.3) with or without 8.87 g green tea extract powder. At 10 min, each rat was sacrificed by cervical dislocation under anesthesia and the segment was removed for lipid analysis. Significant differences were observed in mucosal triglyceride content at 1 h and 5 h in ruts given green tea extract. Significant differences in the rate of $^{14}C$-oleic acid esterification into triglycerides and phospholipids fractions were observed between control and green tea groups. However, There were no significant differences in other lipid fractions. These results indicate that the lowered esterification rates of $^{14}C$-oleic acid into triglycerides and phospholipids fractions is attributable to presence of green tea extract. This may be associated with an inhibitory effect of green tea catechin on the mucosal processes of lipids, leading to the inhibition of intestinal absorption of lipids.

이 실험은 녹차추출물이 흰쥐 소장mucosa에서 $^{14}C$-oleic acid의 에스테르화 과정에 어떤 영향을 미치는지를 조사하기 위해서 설계되었다 먼저, olive oil을 구강으로 강제 투여했을 때, 1시간 그리고 5시간 후에, 녹차 성분의 변수에 의해서 소장 mucosa 내에 축적된 중성지방이 얼마나 감소하는지를 조사하였다. 그리고 소장세포 내에서 녹차 성분에 의해서 각종 지방으로 $^{14}C$-oleic acid의 분배비율이 영향을 받는지 조사하였다. 이 실험에 사용된 micelle 용액은 $200.0\;{\mu}Ci$ $^{14}C$-oleic acid, $200.1\;{\mu}mol$ oleic acid, $200.1\;{\mu}mol$ 2-monooleoylglycerol, $66.7\;{\mu}mol$ palmitoyl-sn-glycero-3-phosphocholine, 2.2 mmol glucose, $50.0\;{\mu}mol$ albumin, 그리고 16.5 mmol Na-taurocholate per L of phosphate buffered saline (pH, 6.3)를 기본으로 하며, 실험군의 micelle 용액은 녹차추출물 분말(green tea extract powder)이 8.87 g/L의 농도로 추가되었다. Ligament of Treitz 부위 에 연결된 소장 부위의 양 끝을 살균 처리된 suture silk(4-0 Silk)로 느슨하게 매듭처리 한 후, $800.0\;{\mu}L$ micelle 용액을 매듭 처리된 소장의 윗매듭 속으로 주입하여, 장기 및 부속기관을 원위치시켰다. 10분 후에, cervical dislocation 방법으로 희생시킨 후 매듭된 소장 부위를 꺼내어 장내용물(luminal content)의 잔존 $^{14}C$-oleic acid를 측정하였다. 획득된 소장 벽에서 각종 지방으로 $^{14}C$-oleic acid의 분배율을 측정하였다. 소장 mucosa에서 총지방량은 녹차추출물에 의해서 영향을 받지 않았으나, 이중 중성지방의 비율은 유의적으로 감소되었다. 또한 소장 벽에서 각종지방으로 $^{14}C$-oleic acid의 분배율은 녹차추출물에 의해서, 중성지방과 인지질 분획에서 유의적인 감소현상을 보였다. 이 실험은, 이전 동물실험들에서 누차 보고되었던, 녹차추출물에 의한 소장 지방 흡수 억제 현상은 $^{14}C$-oleic acid의 에스테르화 비율과 상관성이 있는 것으로 제시하고 있다.

Keywords

References

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