Comprehensive metabolite profile of multi-bioactive extract from tree peony (Paeonia ostii and Paeonia rockii) fruits based on MS/MS molecular networking.

Tree peony seed, traditionally used for edible oil production, is rich in α-linolenic acid. However, little attention is given to the fruit by-products during seed oil production. The present work aimed to comprehensively investigate the phytochemical constituents and multiple biological activities of different parts of tree peony fruits harvested from Paeonia ostii and Paeonia rockii. 130 metabolites were rapidly identified through UPLC-Triple-TOF-MS on the basis of MS/MS molecular networking. Metabolite quantification was performed through the targeted approach of HPLC-ESI-QQQ-MS. Eight chemical markers were screened via principal component analysis (PCA) for distinguishing species and tissues. Interestingly, two dominant compounds, paeoniflorin and trans-resveratrol, are specially localized in seed kernel and seed coat, respectively. Unexpectedly, the extracts of fruit pod and seed coat showed significantly stronger antioxidant, antibacterial, and anti-neuroinflammatory activities than seed kernel from both P. ostii and P. rockii. Our work demonstrated that tree peony fruit is promising natural source of bioactive components and provided its potential utilization in food and pharmaceutical industries.

Bioactive components, antioxidant and antimicrobial activities of Paeonia rockii fruit during development.

In last ten years, much attention focused on tree peony fruit (TPF) for edible oil production despite other potential utilization. The present study identified and quantified 29 bioactive components by liquid chromatography-electrospray ionization-triple quadrupole-mass spectrometry (LC-ESI-QqQ-MS) targeted approach during the development of TPF. Trans-resveratrol, benzoic acid, luteolin, and methyl gallate were selected as predominant chemical markers between seeds and pods through principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA). Extremely high levels of paeoniflorin (1893 mg/100 g) and trans-resveratrol (1793 mg/100 g) were observed at stage 2 (S2) and S6 in seeds, respectively. Antioxidant activities determined by ABTS+•, DPPH•, and FRAP assays showed significant correlations with total phenolic content (TPC) and total flavonoid content (TFC). The strongest antibacterial effects of pod and seed against Staphylococcus aureus and Proteus vulgaris occurred at initial stages and maturation stages. TPF could be a potential source of bioactive compounds with functional properties.