Natural accumulation of terpene trilactones in Ginkgo biloba leaves:: variations by gender, age and season

Ginkgo terpene trilactones (TTLs) are a group of biologically active compounds in Ginkgo leaf extracts. The contents of TTLs in Ginkgo leaves directly affects the qualities of the related phytopharmaceutical products. In this study, the natural occurrence of TTLs in Ginkgo leaves within one vegetative season was investigated. The leaves were collected from six sampled trees with different age and gender at monthly intervals from June to November in Madison, WI. The contents of TTLs were quantified by RP-HPLC/RI procedure, validated by LC/sonic spray ionization-mass spectrometer (SSI-MS) assay, and the data were analyzed statistically. The natural accumulation of total TTLs in Ginkgo leaves fluctuated significantly with seasons with a peak appearing in August. The total amounts of TTLs accumulated in leaves from younger trees were higher than those from older trees; total TTLs in female trees were higher than in male trees. This survey on the natural occurrence of TTLs was expected to ensure the quality of Ginkgo product from the stage of incoming material with rich and consistent bioactive value in terms of Ginkgo terpene trilactones.