Effects of extraction solvents on the recovery of bioactive compounds from Platycladus orientalis Leaves of different tree ages: a comparative metabolomics approach

Platycladus orientalis foliage, referring to the dried twigs and leaves of the Cupressaceae plant P. orientalis, is a traditional Chinese medicine known for its anti-inflammatory and sedative properties. The composition and concentration of metabolites in P. orientalis foliage vary depending on extraction solvents and the age of the tree, which makes the selection of efficient solvents and appropriate tree age crucial.

This study evaluated solvent extraction efficiency for bioactive compounds from P. orientalis foliage and analyzed metabolic variations across trees aged 5-3000 years. Acetic acid (AcOH) achieved the highest extraction yield (14.17%), while Ethanol (EtOH) yielded the lowest (9.60%). EtOH extracts exhibited the highest total phenolic and flavonoid contents, with flavonoids increasing with tree age. Water and EtOH showed stronger DPPH scavenging than AcOH; water excelled in ·OH scavenging, whereas AcOH led in ABTS scavenging and total antioxidant activity. Older trees consistently outperformed younger ones in antioxidant assays. Both EtOH and AcOH inhibited E. coli and S. aureus; AcOH’s effect against E. coli strengthened with tree age. Water and essential oil showed no antibacterial effects, though all extracts, especially essential oil, inhibited Aspergillus niger. GC-MS identified 88 metabolites and 14 bioactive compounds. β-pinene and geraniol characterized trees under 1000 years, while caryophyllene oxide and α-terpineol accumulated in super-aged trees. These compounds exhibited multi-target pharmacological synergy via anti-tumor, analgesic, anti-inflammatory, and neuroprotective pathways. UHPLC-QE-MS suggested upregulated phenylpropanoid and flavonoid biosynthesis in 3000-year-old trees, leading to accumulation of key antioxidants like isoeugenol, coniferin, myricetin, and quercetin.

These findings confirm that even at 3000 years of age, P. orientalis maintains a robust capacity to synthesize active metabolites, underscoring its considerable potential as a valuable resource for pharmaceutical research and development. This study highlights the synergistic effects of solvent and tree age on the bioactive compounds in P. orientalis foliage, providing a theoretical basis for optimizing extraction processes and developing high-value natural products. It also underscores the unique value of ancient tree resources in pharmaceutical applications, offering new strategies for plant-derived drug development.