Phytochemical discrimination of Pinus species based on GC-MS and ATR-IR analyses and their impact on Helicobacter pylori.

INTRODUCTION: The leaves and cones of Pinus plants as well as their essential oils have been used in traditional medicine for the treatment of several ailments.
OBJECTIVES: Phytochemical discrimination of Pinus species and investigation of their anti-Helicobacter pylori activity in vitro and in silico.
MATERIALS AND METHODS: Gas chromatography-mass spectrometry (GC-MS) and attenuated total reflectance infrared (ATR-IR) metabolic profiling of the essential oils of Pinus species. Principal component analysis (PCA) and hierarchal cluster analysis (HCA) were applied for discrimination and segregation of Pinus species.
RESULTS: GC-MS revealed the presence of 76 constituents, where monoterpenes represented the major class with the dominance of α-pinene (72%) followed by β-pinene (16%) for P. canariensis. β-Pinene was the dominant component in P. pinea (24%) followed by terpinolene (11%). α-Pinene (17%) and caryophyllene (12%) were the major components in P. halepensis, while, 3-carene (33%) and α-pinene (17%) represented the major constituents of P. roxburghii oil. By applying PCA and HCA on GC-MS and ATR-IR data analysis, ATR-IR displayed much better discrimination for Pinus species. The pine oils showed promising inhibitory effects on Helicobacter pylori. Furthermore, in silico molecular modelling was carried out where the calculated free binding energies of phytochemicals identified ranged from -33.71 to -19.67 kcal/mol for urease and -41.18 to -16.57 kcal/mol for shikimate kinase. This suggests favourable binding of pine essential oil components to both enzymes, thus explaining their potential inhibitory activity on H. pylori.
CONCLUSION: GC-MS and ATR-IR based metabolic analyses could discriminate between Pinus species. Pine essential oils can be used as promising therapeutic drugs to protect against H. pylori infection.