Antioxidant activities of seed extracts from Dalbergia odorifera T. Chen

Abstract

The heartwood or root of Dalbergia odorifera T. Chen is an important traditional Chinese medicine. Antioxidant activities of seed extracts from D. odorifera T. Chen were first investigated in this study. Ethanolic extracts were suspended in distilled water and partitioned successively with petroleum ether, ethyl acetate, n-butanol (n-BuOH) and water, yielding four extracts named as PE, EE, BE and WE, respectively. The EE exhibited the highest total phenolic, total flavonoid, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, linoleic acid and lard peroxidation inhibition, but lowest chelating ability. Liquid chromatography mass spectrometry (LC/MS) analysis of EE revealed that there was a predominant component with negative molecular ion [M-H]^- at m/z 373.2, a fragment at m/z 343.2 and UV λ_max at 263 and 297nm. The mechanisms of antioxidant activities of seed extracts were exploited. Positive linear correlations were observed between reducing power and DPPH radical scavenging activity (R2 = 0.836), and linoleic acid peroxidation inhibition (R² = 0.920), respectively. Similarly, high positive linear correlations of the total phenolic and total flavonoid with DPPH radical scavenging activity, reducing power and linoleic acid peroxidation inhibition were observed. This study therefore suggests that seeds of D. odorifera T. Chen have the potential to be used as natural antioxidants in food or pharmaceutical industry.

Key words: Antioxidant activity, Dalbergia odorifera T. Chen, seed, liquid chromatography mass spectrometry (LC/MS).