| 摘要: | 本研究主要以小鼠巨噬細胞RAW 264.7為實驗模式，探討大蒜萃取物diallyl sulfide（DAS）、diallyl disulfide（DADS）與allyl methyl sulfide（AMS）對細菌內毒素lipopolysaccharide（LPS）所誘導之發炎相關因子一氧化氮（nitric oxide, NO）、腫瘤壞死因子（tumor necrosis factor-α, TNF-α）、白細胞介素1β（interleukin-1β, IL-1β）、interleukin-6（IL-6）、interleukin-10（IL-10）、前列腺素（prostaglandin E2, PGE2）生成的影響，並進一步瞭解其可能機制。結果顯示，DAS（0.02?10 μM）、DADS（0.01?0.5 μM）與AMS（0.2?20 μM）對細胞皆不會與AMS（2?20 μM）可抑制由LPS所誘導之NO的生成並呈現劑量效應，其中以DADS之作用最為明顯。對細胞激素的結果顯示，較高濃度之DAS可抑制由LPS所誘導之TNF-α、IL-1β、IL-6、IL-10的生成；DADS可抑制由LPS所誘導之TNF-α、IL-10的生成；AMS可抑制由LPS所誘導之IL-1β的生成以及促進IL-10的生成。除此之外DAS可抑制由LPS所誘導之PGE2的生成，DADS和AMS則對LPS所誘導之PGE2的生成無影響。Western blot分析結果指出，DAS、DADS可抑制細胞中iNOS (inducible nitric oxide synthase)蛋白質的表現並呈現劑量關係，且高濃度之DAS亦可抑制細胞中COX-2 (cyclooxgenase-2)蛋白質的表現，這與其抑制NO與PGE2的生成有一相對應關係。除此之外，DAS、DADS、AMS具直接清除NO的作用。綜合以上結果得知，大蒜萃取物DAS、DADS與AMS對LPS所誘導之NO、PGE2及細胞激素的分泌有不同之作用，其中DAS可部分藉由抑制COX-2、iNOS蛋白質的表現而降低由LPS誘導之PGE2、NO的生成，且同時伴隨抑制由LPS所誘導之發炎因子TNF-α、IL-1β、IL-6與IL-10的生成；DADS可部分藉由抑制iNOS蛋白質的表現而抑制由LPS誘導之NO的生成，且同時伴隨抑制因LPS所誘導之發炎因子TNF-α及IL-10的生成；而AMS僅可降低由LPS誘導之NO、TNF-α和IL-1β的生成及促進IL-10的生成。然而，大蒜萃取物本身DAS、DADS與AMS皆可藉由直接清除NO之能力，而降低培養基中NO的生成。
Garlic extracts, including diallyl sulfide (DAS), diallyl disulfide (DADS) and allyl methylsulfide (AMS), are thought to be the bioactive components in garlic. A lot of studies have demonstrated that garlic are effective food of anticancer, and its bioactive components inhibit inflamation. In the present study, we investigated the garlic extracts DAS, DADS and AMS on the inhibition of the nitric oxide, cytokines (TNF-α, IL-1β, IL-6, IL-10) and prostaglandins in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. The results showed that DAS (0.02?10 μM), DADS (0.01?0.5 μM) or AMS (0.2?20 μM) didn’t effect viability of RAW 264.7 cells. The results showed DAS (0.1?10 μM), DADS (0.05?0.5 μM) or AMS (2?20 μM) had a significant dose-dependent inhibition on nitric oxide production in RAW 264.7 cells. DAS had better inhibition than DADS and AMS. Parallel to the NO production, cytokines analysis indicated that DAS (1?10 μM) could inhibit LPS induced the produciotn of TNF-α, IL-1β, IL-6 and IL-10 in a dose-depentdent manner (p<0.05). DADS could inhibit the produciotn of TNF-α and IL-10. AMS could inhibit IL-1β produciotn and induce IL-10 produciotn. Another DAS could inhibit LPS induced PGE2 produciotn, and DADS and AMS had no significantly inhibitory effect. Western blot analysis indicated that high concentration of DAS and DADS could inhibit LPS induced expression of inducible nitric oxide (iNOS) protein. DAS could slightly inhibit expression of cyclooxygenase-2 (COX-2) protein. However, DADS and AMS didn’t have significantly inhibitory effect. This results could parallel to inhibit the production of NO and PGE2. Besides DAS, DADS and AMS itself could inhibit the production of NO in medium. In conclusion, garlic extracts, DAS, DADS and AMS had differential inhibitory patterns on the production of NO, cytokins and PGE2. DAS inhibited LPS induced production of NO, PGE2, TNF-α, IL-1β, IL-6 and IL-10. DADS, to a lesser extent, inhibited LPS induced produciton of NO, TNF-α and IL-10. However, AMS only inhibited the production of NO, TNF-α and IL-1β, but induced IL-10 production. Besides, DAS, DADS and AMS directly lowered NO content in culture medium by their scavenging ability. |
