Title
Biotransformation characteristics of Loranthus tanakae by Rhodopseudomonas palustris
Authors
HUANHUAN DENG HONGYU YAN LEI BI ZIYING GENG XIAOMIN WU and GUANE YANG

Received May 22, 2014
Published Volume 50 Issue 7-8 July-August
Keywords Loranthus tanakae, photosynthetic bacteria (PSB), Rhodopseudomonas palustris, biotransformation, orthogonal experimental design

Abstract
The orthogonal experiment design and the variation of the transformation time were used to determine the optimal translation conditions and biotransformation characteristics of Loranthus tanakae by Rhodopseudomonas palustris. High performance liquid chromatography (HPLC) and liquid chromatography – mass spectrometry (LC-MS) were used to analyse the test results. In vitro DPPH radical scavenging activity assays were applied to evaluate the antioxidant activities of the converted products. The optimal translation conditions were found to be as follows: pH 8, without conventional medium, and nutrient solution with 10 g/100 mL extract of L. tanakae (content of L. tanakae extract). Upon the biotransformation of L. tanakae by R. palustris, the presence of four new chemical components was revealed, indicating that R. palustris should have some hydrolytic enzymes to convert four glycosides into four aglucons. In vitro, the biotransformation liquid and the contrast liquid offered moderate DDPH radical scavenging activity with IC50 values of 45.48 and 67.82 µg/mL, respectively.