Wan Chunpeng, Yu Yanying, Zhou Shouran, Liu Wei, Tian Shuge, Cao Shuwen
State Key Laboratory of Food Science & Technology, Nanchang University, Nanchang - 330 047, Jiangxi,, China.
Pharmacogn Mag. 2011 Jan;7(25):40-5. doi: 10.4103/0973-1296.75900.
Extraction temperature influences the total phenolic content (TPC), total flavonoid content (TFC) of medicinal plant extracts to a great extend. TPC and TFC are the principle activity constituents present in the plant. The effects of extraction temperature on TPC, TFC and free radical-scavenging capacity of Gynura divaricata leaf extracts are worth to study.
Folin-Ciocalteu and aluminum chloride colorimetric assay were used to determine the TPC and TFC of Gynura divaricata leaf extracts at different temperatures. The antioxidant and free radical-scavenging activity were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and phosphomolybdenum methods.
TPC and TFC were significantly elevated with increasing extraction temperature (from 40°C to 100°C). However, TPC and TFC were not significantly different (P > 0.05) at the extraction temperatures 90°C and 100°C. Also, the extracts obtained at a higher temperature exhibited a significant free radical-scavenging activity compared with extraction at lower temperatures (P < 0.05). The TPCs (13.95-36.68 mg gallic acid equivalent/g dry material) were highly correlated with DPPH (R(2) = 0.9229), ABTS (R(2) = 0.9951) free radical-scavenging capacity, and total antioxidant activity (R(2) = 0.9872) evaluated by phosphomolybdenum method.
The TPC and TFC of G. divaricata leaf was significantly influenced by the extraction temperatures, which were the main antioxidant constituents present in the G. divaricata plant.
提取温度在很大程度上影响药用植物提取物的总酚含量（TPC）和总黄酮含量（TFC）。TPC和TFC是植物中存在的主要活性成分。提取温度对白凤菜叶片提取物的TPC、TFC和自由基清除能力的影响值得研究。
采用福林-酚法和氯化铝比色法测定不同温度下白凤菜叶片提取物的TPC和TFC。通过1,1-二苯基-2-苦基肼（DPPH）、2,2-联氮-双-（3-乙基苯并噻唑啉-6-磺酸）（ABTS）和磷钼酸法测定抗氧化和自由基清除活性。
随着提取温度升高（从40°C至100°C），TPC和TFC显著升高。然而，在90°C和100°C的提取温度下，TPC和TFC无显著差异（P>0.05）。此外，与较低温度下的提取相比，较高温度下获得的提取物表现出显著的自由基清除活性（P<0.05）。TPC（13.95 - 36.68毫克没食子酸当量/克干物质）与DPPH（R² = 0.9229）、ABTS（R² = 0.9951）自由基清除能力以及通过磷钼酸法评估的总抗氧化活性（R² = 0.9872）高度相关。
白凤菜叶片的TPC和TFC受提取温度显著影响，它们是白凤菜植物中主要的抗氧化成分。
