Chemometrics of the composition and antioxidant capacity of essential oils obtained from six Cupressaceae taxa.

Essential oils (EOs) are complex and susceptible to environmental conditions, they have a wide range of biological activities and are often used to differentiate between similar species. In this study, gas chromatography-mass spectrometry (GC-MS) coupled with chemometric analysis was applied to systematically analyse and evaluate EOs constituents and antioxidant activity of six Chinese Cupressaceae taxa (Platycladus orientalis Franco, P. orientalis Franco 'Sieboldii', P. orientalis Franco 'Aurea', Juniperus chinensis Roxb., J. chinensis Roxb. 'Kaizuca', and J. sabina L.) under identical conditions. The antioxidant activity of the EOs was evaluated using 2,2 -diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and ferric reducing power (FRAP), and the total phenolic content (TPC) of the EOs was determined by Folin-Ciocalteau reagent. In total, seventy individual constituents were identified with the main components being α-pinene, sabinene, D-limonene, bornyl acetate, δ-3-carene and ß-myrcene. Principal component analysis (PCA) and hierarchal cluster analysis (HCA) successfully discriminated the six taxa into three chemotypes and the unique chemotype revealed that J. chinensis 'Kaizuca' may be a species rather than a cultivar of J. chinensis. The results of OPLS-DA analysis showed that the three compounds screened, namely, α-pinene, sabinene, and δ-3-carene, can completely distinguish Platycladus spp. from Juniperus spp. The DPPH assay results ranged from 576.14 (J. chinensis 'Kaizuca') to 1146.12 (J. sabina) µmol eq Trolox/mL EO, while the ABTS values ranged from 1579.62 (P. orientalis 'Aurea') to 5071.82 (J. sabina) µmol eq Trolox/mL. In the FRAP assay, the values ranged from 1086.50 (J. chinensis 'Kaizuca') to 1191.18 (J. sabina) µmol eq Trolox/ml and the TPC of the EOs studied ranged from 15.17 (J. chinensis 'Kaizuca') to 39.37 (J. sabina) mg GAE/mL EO. The results consistently showed that J. sabina possessed the strongest antioxidant activity and can be preferentially used as a rich source of potentially natural antioxidants.

An integrated strategy for quality control of Pseudobulbus Cremastrae seu Pleiones based on Q-marker.

Pseudobulbus Cremastrae seu Pleiones (PCsP), a traditional Chinese medicine known as ‶Shan-Ci-Gu″, possesses properties for clearing heat, counteracting toxicity, dissipating phlegm, and resolving masses. As a TCM with multiple bases, the dried pseudobulbs of Pleione bulbocodioides (PB), Pleione yunnanensis (PY) and Cremastra appendiculata (CA) are considered to be the official sources of PCsP. Additionally, several unofficial substitutes are also available in the market. To enhance the quality control of PCsP, an integrated strategy based on Q-marker was proposed. Initially, a study of integrating plant metabolomics, target isolation, structure identification, and activity testing afforded five Q-markers, including three new compounds. Furthermore, a quality evaluation method using a single standard to determine multi-components (SSDMC) based on Q-marker was established, which could effectively distinguish PB from CA and the counterfeit herbs. Finally, the transitivity of Q-markers was explored through a representative Chinese compound prescription containing PCsP. The results indicated that the identified Q-markers together with the established analysis methods could be effectively applied for quality control of PCsP and its preparations.