Untargeted Metabolomics and Targeted Quantitative Analysis of Temporal and Spatial Variations in Specialized Metabolites Accumulation in Poria cocos (Schw.) Wolf (Fushen).

Mei Yang,Zhengyang Yang,Huasheng Peng,Rui Xu,Yujiao Zhao,Yuejian Qin

doi:10.3389/fpls.2021.713490

Abstract

Poria cocos (Schw.) Wolf is a saprophytic fungus that grows around the roots of old, dead pine trees. Fushen, derived from the sclerotium of P. cocos but also containing a young host pine root, has been widely used as a medicine and food in China, Japan, Korea, Southeast Asian countries, and some European countries. However, the compound variations at the different growth periods and in the different parts of Fushen have not previously been investigated. In this study, an untargeted metabolomics approach based on ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) and targeted quantitative analysis was utilized to characterize the temporal and spatial variations in the accumulation of specialized metabolites in Fushen. There were 119 specialized metabolites tentatively identified using the UPLC-Q/TOF-MS. The nine growth periods of Fushen were divided into four groups using partial least squares discrimination analysis (PLS-DA). Four different parts of the Fushen [fulingpi (FP), the outside of baifuling (BO), the inside of baifuling (BI), and fushenmu (FM)] were clearly discriminated using a PLS-DA and orthogonal partial least squares discrimination analysis (OPLS-DA). Markers for the different growth periods and parts of Fushen were also screened. In addition, the quantitative method was successfully applied to simultaneously determine 13 major triterpenoid acids in the nine growth periods and four parts. The quantitative results indicated that the samples in January, March, and April, i.e., the late growth period, had the highest content levels for the 13 triterpenoid acids. The pachymic acid, dehydropachymic acid, and dehydrotumulosic acid contents in the FM were higher than those in other three parts in March, whereas the poricoic acid B, poricoic acid A, polyporenic acid C, dehydrotratrametenolic acid, dehydroeburicoic acid, and eburicoic acid in FP were higher beginning in October. These findings reveal characteristics in temporal and spatial distribution of specialized metabolites in Fushen and provide guidance for the identification of harvesting times and for further quality evaluations.

Highlights

Poria cocos (Schw.) Wolf is a saprophytic fungus that grows around the roots of old, dead pine trees (Committee for the Pharmacopoeia of PR China, 2020)
The detected and identified compounds were numbered according to their elution order, and the characterization of the specialized metabolites identified in the negative ion mode is shown in Table 1, and those identified in the positive ion mode are shown in Supplementary Table 3
Triterpenoid acids are the main specialized metabolites of Fushen, which are biosynthesized via the mevalonic acid pathway, share numerous common skeletons and modifications (Zou et al, 2019)

Summary

Introduction

Poria cocos (Schw.) Wolf is a saprophytic fungus that grows around the roots of old, dead pine trees (Committee for the Pharmacopoeia of PR China, 2020). Some taxonomists have proposed that the synonym Pachyma hoelen should be used rather than P. cocos as the name of the Chinese cultivar (Wu et al, 2020a). P. cocos has been widely used as a medicine and food in China, Japan, Korea, Southeast Asia, and some European countries (Zhu et al, 2020). In traditional Chinese medicine, it is used to treat edema with less urine, restlessness, and insomnia with palpitations (Committee for the Pharmacopoeia of PR China, 2020). P. cocos has been shown to contain the triterpenoid acids, polysaccharides, sterols, and other active ingredients. Triterpenoid acids are the main specialized metabolites, and, to date, more than 100 have been identified (Feng et al, 2018)

Methods

Results

Conclusion