以 Caco-2 細胞株探討維生素 C 影響鐵吸收之新作用機制並評估某些市售食品之鐵生物利用率

Novel Mechanism of Ascorbic Acid on Iron Absorption and Evaluation of Iron Bioavailability of Some Commercial Food Products Using Caco-2 Cells.

陳翠英(Tsui-ying Chen)

指導教授 ： 蕭寧馨

國立臺灣大學/生命科學院/微生物與生化學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.10259

摘要

缺鐵為我國的營養問題之一，可藉由提升鐵生物利用率來改善。本實驗目的在於利用Caco-2細胞模式，探討維生素 C促進鐵吸收之新作用機制，並評估新型鐵劑及食品對鐵生物利用率的影響，作為應用於人體之參考。Caco-2細胞在滿盤後13天進行攝鐵實驗，其條件為apical site 添加100μM Fe處理6小時，測量細胞內鐵蛋白作為攝鐵能力之指標。
探討維生素 C作用機制時，Caco-2細胞培養於雙層培養皿，控制組為apical site 提供鐵源，實驗組則分別在apical site或basolateral site添加維生素C。控制組Ferric reductase 活性為13 ± 1 μM Fe2+/hr.well，鐵蛋白含量為69 ± 8 ng/mg protein。結果顯示，當維生素C添加在apical site時，ferric reductase 活性及鐵蛋白含量增加分別為控制組的7-8及5倍，反之，當維生素C 添加在basolateral 時則分別為控制組的3-4及4倍，在此証實維生素C除了在apical site和鐵進行化學性還原反應外，還有參與細胞內還原三價鐵能力來促進鐵吸收。
Caco-2細胞評估不同食品的鐵生物利用率中，發現Ferrous bis-glycine (FBG) 在碳酸飲料中鐵生物利用率和FeSO4相似Relative biological value (RBV) 139，但在四物萃取液中FBG鐵生物利用率高於FeSO4 (RBV 192)；蜆精對細胞鐵蛋白合成量無影響，但雞精則會抑制，FBG 在雞精中可發揮其高鐵生物利用率的優勢 (RBV 209)；果寡糖對 FeSO4、FBG、FeCl3 (RBV 95-102) 的鐵生物利用率不會造成影響。

關鍵字

鐵生物利用率 ； Caco-2 細胞 ； 維生素C

並列摘要

Iron deficiency is a nutritional disorder in our country. This high prevalence of iron deficiency could be improved by increasing dietary iron bioavailability. Caco-2 cell model was used to study the effect of ascorbic acid on iron absorption and to evaluate iron bioavailability of a novel iron supplement and commercial food products, which might act as references in further clinical study. In the iron uptake experiments, Caco-2 cells were conducted after 13d post-confluence and treated with 100 μM of Fe for 6h. Cellular ferritin level was assayed to be an indicator of iron status in Caco-2 cells.
To assess the effect of ascorbic acid on iron absorption, Caco-2 cells were seeded in insert plate and iron was added in apical site (Control group). Effects of Ascorbic acid in either apical or basolateral site were then monitored (Experimental group). Basal cellular ferric reductase activity and ferritin level were 13 ± 1 μM Fe2+/hr.well and 69 ± 8 ng/mg protein, respectively. However, compared to the control group, ferric reductase activity and ferritin level showed respective 7- to 8-fold and 5-fold increase when ascorbic acid was added in apical site, otherwise 3- to 4-fold and 4-fold increase of ferric reductase activity and ferritin level respectively were observed when added in basolateral site. This study demonstrated not only ascorbic acid could perform chemical reduction reaction with iron in apical site, but participate intracellular conversion of reduced ferric iron to ferrous iron which promoted iron absorption.
The iron bioavailability of Ferrous bis-glycine (FBG) and FeSO4 added in soft drink were similar Relative biological value (RBV) 139. However, FBG in four agents extract was higher in iron bioavailability than FeSO4 in four agents extract (RBV 192). The Flashwater clam essences had no effects on intracellular ferritin levels after FeSO4 and FBG addition, but chicken essences decreased it (RBV 209). Besides, FBG compared to FeSO4 had higher iron bioavailability in chicken essences. No significant iron bioavailability change was observed after adding FeSO4、FBG、FeCl3 to oligofructose (RBV 95-102).

並列關鍵字

Caco-2 cells ； ascorbic acid ； iron bioavailability

參考文獻

林佩錦 (1995) 以體外消化法及貧血老鼠血紅素再生法評估紫菜鐵質之生體可用率。國立台灣大學農業化學研究所碩士論文。

何素珍、蕭寧馨 (2002) 健康食品之補鐵功能評估方法草案。

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