| 摘要: | 桑枝是桑科植物（Morus alba L.）之乾燥嫩枝。桑枝成分有maclurin、rutin、isoquercitrin、scopoletin、umbelliferone、resveratrol與morin 等。本研究以這七種為指標成分，進行市售品的定量與抗氧化研究，並比較其區段沖堤物的體外抗氧化活性。利用逆相 HPLC 分析方法，沖提系統之流動相(A) 為60 mM KH2PO4 及 5% H3PO4 (pH 4.4)，流動相(B) 為水/氰甲烷/甲醇=（20/40/40）(V/V)。分離管柱為5C18-AR，偵測波長在 254 nm。結果可在 70 分鐘內，成它a分離7個指標成分，並完成其成分的定量。結果顯示：maclurin、rutin、morin、isoquercitrin、scopoletin、umbelliferone、resveratrol，含量約為65.6~326.5mg/g，其自由基清除試驗以maclurin及morin為最好，可達72~80%。自由基清除效應試驗中，區段J、K、L樣品濃度為30 ppm時清除率皆大於90%；在Trolox當量抗氧化能力方面樣品濃度為8 ppm時，區段J、K、L高達90%；在還原力測定，區段J、K、L樣品濃度100 ppm時還原能力相當於20 ppm維他命C；抑制脂質過氧化試驗中，區段K、L、M之抑制率皆大於80%；鐵螯合能力，區段E、F樣品濃度200 ppm時螯合能力約40%；清除超氧陰離子能力試驗中，區段K樣品濃度15 ppm時清除能力51.16%；在樣品濃度為7.5 ppm時，區段K抑制酪胺酸酶活性達89.28%。本研究在體外抗氧化活性與美白測定中證實桑枝區段K較佳，推測是含有maclurin與rutin二種成分有關，值得深入研究。
Mulberry branch is dried tender branch of the plant (Morus alba L.). Maclurin, morin, rutin, isoquercitrin, scopoletin, umbelliferone and resveratrol are marker compounds of the mulberry branch. Several commercial products were subjected to analyze the contents of the seven marker compounds by HPLC and evaluate the antioxidant activity. The RP-LC method was carried out within 70 minutes by using cosmosil C18-AR column and a gradient solvent system of phosphate and acetonitrile at 254 nm. The effects of phosphate concentration, pH value and organic modifier concentration of the mobile phase on the separation of the analytes were also studied.
In results, the contents of eight marker compounds in the commercial products are about 65.6~326.5mg/g.The data shows that maclurin and morin have the best free radical scavenge avtivity .And the in vitro antioxidant activity of different eluents of Mulberry branch were measured and compared with above commercial products. In 30 ppm of sample concentration, fractions J, K and L show more than 90% scavenging activity in DPPH assay, and possess 90% trolox equivalent antioxidant capacity while using 8.0 ppm in the assay. Besides, 100ppm sample concentration of the three fractions have the same potassium ferricyanide red＝ucing activity as 20ppm of vitamin C in the assay. In liposome assay system, three fractions shown more than 80% inhibition activity are fractions K, L and M. However, fraction E and F, show more than 40% scavenging activity in chelating activity on ferrous ions assay, while the sample concentration amount to 200 ppm. When sample concentration is 15 ppm, Fraction K have scavenging ability approximately 51.16% in SOD-like assay. Finally, in 7.5 ppm of sample concentration, Fraction J, K and L have more than 89.28% tyrosinase inhibition activity. This research demonstrates that Fraction K of different eluents of Mulberry branch reveals the remarkable achievement in antioxidation activity and the whitening assay in-vitro, and conjectures that it has related to maclurin and rutin, and is worth thoroughly studying. |
