Antioxidant activity and free radical-scavenging capacity of Gynura divaricata leaf extracts at different temperatures

Chunpeng Wan; Yanying Yu; Shouran Zhou; Wei Liu; Shuge Tian; Shuwen Cao

Articles

Abstract

Pharmacognosy Magazine,2011,7,25,40-45.

DOI:10.4103/0973-1296.75900

Published:January 2011

Type:Original Article

Authors:

Author(s) affiliations:

Chunpeng Wan¹, Yanying Yu², Shouran Zhou³, Wei Liu¹, Shuge Tian⁴, Shuwen Cao⁵
¹State Key Laboratory of Food Science & Technology, Nanchang University, Nanchang - 330 047, Jiangxi, China
²Department of chemistry, Nanchang University, Nanchang - 330 031, Jiangxi, China
³Jiangxi University of Traditional Chinese Medicine, Nanchang - 330 006, Jiangxi, China
⁴Xinjiang Key Laboratory of Famous Prescription and Science of Formulas, Urumqi - 830 011, Xinjiang, China
⁵State Key Laboratory of Food Science & Technology, Nanchang University, Nanchang - 330 047, Jiangxi; Department of chemistry, Nanchang University, Nanchang - 330 031, Jiangxi, China

Abstract:

Background: 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. Materials and Methods: 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. Results: 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 (R² = 0.9229), ABTS (R² = 0.9951) free radical-scavenging capacity, and total antioxidant activity (R² = 0.9872) evaluated by phosphomolybdenum method. Conclusion: 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.