Chemical composition characteristics and monthly variation patterns of oleoresins from five introduced pine species

In order to effectively utilize the oleoresin resources of introduced pine species, the monthly variation patterns of the chemical composition of oleoresin from Pinus elliottii Engelm. (S), Pinus taeda L. (H), Pinus caribaea var. bahamensis (Griseb.) W. H. Barrett & Golfari (PCB), Pinus caribaea var. caribaea Morelet (PCC) and Pinus caribaea var. hondurensis (Sénécl.) W. H. Barrett & Golfari (PCH) were analyzed by gas chromatography-mass spectrometry and gas chromatography. The results showed that the oleoresin from the five introduced pine species was similar in compound types and mainly composed of monoterpenes and diterpenes. The types of compounds remained stable across different months. Oleoresin from five introduced pine species could be easily and quickly distinguished based on the differences in the relative contents of the main compounds (α-pinene, β-pinene, β-phellandrene and isopimaric acid). The relative contents of the main compounds in the oleoresin fluctuated in different months. In months with a significant temperature decrease, both the number of oleoresin-secreting individual plants decreased and the fluctuation range of the main compounds’ relative contents increased. In December, the number of oleoresin-secreting individual of PCB decreased from 30 to 23. In January of the following year, the number of oleoresin-secreting individual of S, H, PCC and PCH decreased from 30 to 16, 21, 19 and 21 respectively. The relative contents of α-pinene, β-pinene, and β-phellandrene in the oleoresin of PCB, PCC, and PCH reached their minimum values in February; conversely, those in the oleoresin of S and H reached their maximum values the in February. This work has important guiding significance for the identification of oleoresin sources, the selection of oleoresin raw materials, the breeding of superior individual plants, and the determination of the optimal resin-tapping time in actual forestry production.