動脈粥狀硬化是導致心血管疾病致死原因之一。動脈粥狀硬化的氧化修飾假說之一即是低密度脂蛋白 (LDL) 的氧化，而 LDL 的氧化是導致早期動脈粥狀硬化的主因。本研究擬從氧化傷害之角度出發，進行體外試驗，利用測定共軛烯酸 (conjugation diene)、硫酸巴比妥酸試驗 (thiobarbituric acid-reactive substances; TBARS)、蛋白質羰基 (protein carbonyl groups) 含量的測定，評估二十種天然藥草植物之水或乙醇萃取物對銅離子誘導 LDL 氧化的影響。結果顯示1.25 μg/mL穿心蓮乙醇萃取物 (ApE) 和海巴戟天葉乙醇萃取物 (LE) 比標準品Trolox 和 rutin (R) 1.25 μg/mL 更能延長遲滯期 (lag phase)。此外，在 LDL 氧化過程時，ApE 可100% 抑制 TBARS 形成，而 LE可60.5% 抑制蛋白質羰基 (carbonyl groups) 的形成。然而，ApE 和 LE 卻在5 μg/mL 產生促氧化現象。虎杖乙醇萃取物 (PcE)、含殻草水萃取物 (CaW)、印度羅勒水萃取物 (OgW) 在1.25 μg/mL 同時可保護脂質過氧化 (低 TBARS 形成) 和蛋白質氧化 (低蛋白質羰基形成)的發生，但對LDL遲滯期是沒有延長效果。雖然，1.25 μg/mL 穿心蓮水萃取物 (ApW)、仙草水萃取物 (McW)、大陸馬鞭草乙醇萃取物 (VoE) 只能減少TBARS 的形成，而1.25 μg/mL香茹乙醇萃取物 (GtE)、仙草乙醇萃取物 (McE）只能減少蛋白質羰基 (carbonyl groups) 的形成，但在5 μg/mL 的ApW、 McW、 VoE、 GtE 和McE 可明顯延長遲滯期。雖然沒有一個萃取物濃度在1.25 μg/mL時，可以同時通過三項抗 LDL 氧化的分析試驗，但整體評估1.25 μg/mL萃取物濃度的試驗結果，以 ApW、CtW、McW、OgW、ApE可能可以有效的抑制銅離子誘導LDL 氧化。此外，當提升萃取物濃度至 5 μg/mL時，ApW 與 McW已同時顯示出有效延長LDL 氧化的遲滯期、減少TBARS與蛋白質羰基的形成。由這些結果顯示穿心蓮與仙草是最值得進一步開發為降低LDL氧化效果的草藥。 Atherosclerosis is the leading cause of death in the cardiovascular disease. One of the oxidative modification hypotheses of atherosclerosis is LDL oxidation. It plays a causative role in early atherogenesis. The in vitro assessment of the antioxidant capacity of aqueous or ethanolic extracts from twenty natural medicinal plants was evaluated by the examination of their ability to inhibit copper (Cu2+)-mediated human low density lipoprotein (LDL) oxidation by using conjugation diene, the thiobarbituric acid-reactive substances (TBARS) and protein carbonyl groups assay. The results indicated that ethanolic extract of Andrographis paniculata (ApE) and Morinda citrifolia (LE) at concentrations 1.25 μg/mL were superior to standards of Trolox and rutin (R) 1.25 μg/mL appeared to have a lengthening in lag phase. In addition, ApE significantly reduced TBARS formation by up to 100% and LE reduced carbonyl formation by up to 60.5% during the course of LDL oxidation. However, ApE and LE at 5 μg/mL were all shown as pro-oxidative effect. Ethanolic extract of Polygonum cuspidatum (PcE), aqueous extract of Centella asiatica (CaW) and Ocimum gratissimum (OgW) at 1.25 μg/mL were simultaneously provided with the protective capacity on lipid peroxidation (lower TBARS formation) and protein oxidation (lower carbonyl formation), but could not prolong the lag phase of LDL. Although aqueous extract of Andrographis paniculata (ApW), aqueous extract of Mesona chinensis (McW), ethanolic extract of Verbena officinalis (VoE) at 1.25 μg/mL could only decrease TBARS formation, and ethanolic extract of Glossogyne tenuifolia (GtE), ethanolic extract of Mesona chinensis (McE) only decreased carbonyl formation at 1.25 μg/mL, ApW, McW, VoE, GtE and McE at 5 μg/mL appeared to have a lengthening in lag phase. Although no extracts at 1.25 μg/mL had all beneficial effects among the three assessment of the antioxidant capacity on LDL oxidation. However, ApW、CtW、McW、OgW and ApE might have showed a potency to inhibit the LDL oxidation induced by copper in overall antioxidative assay at 1.25 μg/mL of extracts. In addition, extracts of ApW and McW at 5 μg/mL could simultaneously prolong the lag phase of LDL, reduce TBARS and carbonyl formation. From the results obtained, the herbs of Ap and Mc deed merited to further development against LDL oxidation.
