Identification of proanthocyanidins from litchi (Litchi chinensis Sonn.) pulp by LC-ESI-Q-TOF-MS and their antioxidant activity

PLoS One. 2015 Mar 20;10(3):e0120480. doi: 10.1371/journal.pone.0120480. eCollection 2015.

Abstract

Content of total proanthocyanidins as well as total phenolics, flavonoids, antioxidant activities were evaluated for litchi (Litchi chinensis Sonn.) pulp of 32 cultivars. One cultivar, Hemaoli, showed the highest total proanthocyanidins and total phenolics, and DPPH or ABTS radical scavenging activities. ESI-MS and NMR analysis of the Hemaoli pulp crude extracts (HPCE) showed that procyandins composed of (epi)catechin unites with degree of polymerization (DP) of 2-6 were dominant proanthocyanidins in HPCE. After the HPCE was fractionated by a Sephadex LH-20 column, 32 procyanidins were identified by LC-ESI-Q-TOF-MS in litchi pulp for the first time. Quantification of individual procyanidin in HPCE indicated that epicatechin, procyanidin B2, procyanidin C1 and A-type procyanidin trimer were the main procyanidins. The radical scavenging activities of different fractions of HPCE as well as six procyanidins standards were evaluated by both DPPH and ABTS assays. HPCE fractions showed similar antioxidant activities with those of Vc and six individual procyanidins, the IC50 of which ranged from 1.88 ± 0.01 to 2.82 ± 0.10 μg/ml for DPPH assay, and from 1.52 ± 0.17 to 2.71 ± 0.15 μg/ml for ABTS assay. Such results indicate that litchi cultivars rich in proanthocyanidins are good resources of dietary antioxidants and have the potential to contribute to human health.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Free Radical Scavengers / chemistry*
  • Free Radical Scavengers / pharmacology
  • Litchi / chemistry*
  • Mass Spectrometry
  • Plant Extracts / chemistry*
  • Plant Extracts / pharmacology
  • Proanthocyanidins / chemistry*
  • Proanthocyanidins / pharmacology

Substances

  • Free Radical Scavengers
  • Plant Extracts
  • Proanthocyanidins

Grants and funding

This work was supported by the National Project of Scientific and Technical Supporting Programs Funded by the Ministry of Science & Technology of China (2012BAD33B08) and the Program for New Century Excellent Talents in University of Ministry of Education of China. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.