A recent study measured and compared the chemical compositions, antioxidants and anti-aging activities of Cortex Moutan (CM), from different collection periods and producing areas, aiming to obtain excellent CM extracts. 

It examined the bioactivities of CM extracts by an in vitro antioxidant method and an ultraviolet B (UVB) irradiated human dermal fibroblast (HDF) model. Further, it obtained the phytochemical properties from ultra-fast liquid chromatography quadrupole time-of-flight mass spectrometry (UFLC-Q-TOF-MS) before the multivariate statistical analysis. 

The observations were as follows:

• The extracts of Heze CM (HZCM) and Luoyang CM (LYCM) collected in June showed better in vitro antioxidant activities, markedly boosted the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and decreased the content of malondialdehyde (MDA), compared to other CM extracts.
• HZCM and LYCM extracts increased the relative expression of SOD and GSH-Px mRNA.
• The extract of HZCM obtained in June markedly repressed matrix metalloproteinase 1 (MMP-1) production and improved procollagen type I (PCOL)-I production in UVB irradiated HDF.
• Overall, the study identified or tentatively identified 50 compounds, including 17 monoterpenoids, 19 flavonoids, 13 phenols and 1 amino acid in the CM extracts.
• It found gallic acid, p-hydroxybenzoic acid, oxypaeoniflorin, paeoniflorin, 1,2,3,4,6-O-pentagalloyl glucose and paeonol as the chief compounds in the CM extracts. 

Overall, the study indicates that CM collected from April to September possesses better antioxidant and anti-aging effects for external usage.

Source: Yang S, Liu X, He J, et al. Insight into seasonal change of phytochemicals, antioxidant, and anti-aging activities of root bark of Paeonia suffruticosa (Cortex Moutan) combined with multivariate statistical analysis. Molecules. 2021;26(20):6102.