Seasonal Influence on Volatile Organic Compounds from Flowers and Leaves of Lepechinia mutica Extracted by SPME-GC-MS

Lepechinia mutica, an endemic species of the Ecuadorian Andes, was studied to identify the seasonal variation in volatile organic compounds emitted from leaves and flowers in winter and summer using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). A total of 101 and 100 volatile compounds were identified in flowers and leaves, respectively. The main compounds in flowers were β-phellandrene (7.81-17.74%), dictamnol (3.57-31.89%) and 9-epi-(E)-caryophyllene (3.93-14.37%), while in the leaves, they were dictamnol (9.85-34.64%), (Z)-β-ocimene (1.24-29.24%) and δ-3-carene (1.14-11.51%). This is the first report of enantiomeric separation in L. mutica using a capillary column with 2,3-diethyldecyl-6-tert-butyl-dimethylsilyl-β-cyclodextrin, revealing three enantiomerically pure compounds as (S)-(-)-β-pinene, (1S,3R)-(+)-δ-3-carene and (S)-(+)-linalool, while (+) (-) α-pinene, (+) (-) δ-cadinene and (+) (-) α-muurolene were found as racemic mixtures. Principal component analysis confirmed distinct chemical profiles between plant parts and seasons. This result has important implications for the future highlighting its potential as a source of seasonally variables components with applications in fragrance and phytotherapy.