乳酸菌胞外多醣之抗氧化活性及抗腫瘤研究

Study on the antioxidant and anti-tumor effects of Lactic acid bacteria exopolysaccharides

林薏文(Yi-Wen Lin)

指導教授 ： 王瑜琦

義守大學/醫學院/生物科技學系/碩士(2020年)

摘要

乳酸菌 (Lactic acid bacteria) 胞外多醣 (Exopolysaccharides) 具有許多潛在的生物活性，如抗氧化活性、抗腫瘤、抗潰瘍、降低膽固醇活性和免疫刺激活性，由不同乳酸菌產生的胞外多醣可以表現出不同的生物學和物理化學特徵。
本研究從人類胃部分離篩選出四株乳酸菌菌株，並探討其耐酸性、膽鹽耐受性、抗菌能力及抗生素敏感等特性。進一步從這四株乳酸菌上清液中分別粗萃出胞外多醣，針對這些乳酸菌生產之胞外多醣進行定量分析，並利用DPPH自由基清除率、羥基自由基清除率以及還原力來評估這些胞外多醣之抗氧化能力。此外，也探討這些胞外多醣對兩種癌細胞株及正常細胞株生長的影響。
實驗結果顯示，此四株乳酸菌具有耐酸、耐膽鹽、抗病原菌及對抗生素敏感等特性。四株乳酸菌粗萃之胞外多醣均具有良好的抗氧化能力，在濃度為4.0 mg/mL時，其DPPH自由基清除率均可達50% 以上。在清除羥基自由基試驗中，乳酸菌930B及932B生產之胞外多醣具有較高之清除能力，分別可達47.2% 及45.6%。在體外對癌細胞的影響結果顯示，乳酸菌胞外多醣可以降低癌細胞生存率，其中以乳酸菌922B 胞外多醣在濃度4.0 mg/mL時，抑制癌細胞存活的效果最佳，對人類胃癌細胞及結腸癌細胞的存活率，分別可以降低至51.4% 及33.3%。而四株乳酸菌的胞外多醣在濃度4.0 mg/mL時，對於正常細胞株(人類皮膚纖維母細胞及小鼠纖維母細胞)的存活率影響，維持在至少90% 的存活率。

關鍵字

胞外多醣 ； 乳酸菌 ； 抗氧化活性 ； 抗腫瘤

並列摘要

Lactic acid bacteria (LAB) Exopolysaccharides (EPS) has many potential biological activities, such as antioxidant activity, anti-tumor, anti-ulcer, cholesterol-lowering activity and immune-stimulatory activity. EPS produced by different LAB strains can exhibit different biological and physicochemical characteristics.
In this study, four LAB strains were isolated from the human stomach and their tolerance to acid and bile salt, anti-bacterial activity against pathogenic bacteria and susceptibility to antibiotics were investigated. In addition, EPS were crudely extracted from the supernatant of these four LAB strains, and these EPS produced by LAB were quantitatively analyzed and were evaluated their anti-oxidant ability using free radical DPPH scavenging assay, hydroxyl scavenging assay and reducing power assay. On the other hand, the study also investigated the effects of EPS produced by LAB on the viability of two cancer cell line and two normal cell line.
The results of this study showed that four strains of LAB had acid and bile salts resistance, anti-pathogenic bacterial activity and sensitive to several antibiotics. The crude EPS extracted from LAB exhibited relatively high antioxidant activitiy. EPS showed more than 50% DPPH scavenging activity at the concentration of 4.0 mg/mL. In the hydroxyl scavenging assay, the EPS produced by 930B and 932B have a high scavenging activity to 47.2% and 45.6%. In the cell viability, the results showed that EPS can reduce the survival rate of cancer cells and EPS from 922B strain at 4.0 mg/mL had the best inhibitory effects (51.4 % and 33.3% respectively) on AGS cells and Caco-2 cells. However, EPS at 4.0 mg/mL form all LAB strains can maintain normal cell line (Hs68 cells and NIH-3T3 cells) 90% survival rate.

並列關鍵字

Exopolysaccharides ； Lactic acid bacteria ； Antioxidant activity ； Anti-tumor

參考文獻

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