Abstract
Plectranthus neochilus Schltr. is an aromatic species, commonly used for
digestive, antispasmodic, and analgesic purposes. Although many studies have
reported the chemical composition of its essential oil, variations in the
volatile profile were observed, which may be due to multiple factors linked to
growth and field conditions. In order to detect metabolic variations in this
species, we employed a GC-MS-based untargeted metabolomics approach analyzing
samples of four P. neochilus individuals collected over a year. From all
analyses, 24 mass features were detected and 21 were identified according to
their respective chromatographic peaks. All features varied among samples,
particularly (2E)-hexenal, 3-octanone and δ-3-carene,
which showed the highest coefficient of variation percentage in our study.
Although the four individuals presented the same peaks in the chromatograms,
significant differences in the intensity of specific mass features were detected
between individuals throughout the year. Time of sampling did not affect P.
neochilus volatile composition; the chemical profile remained constant
throughout the day. Seasonal trends were observed for the species. Winter months
coincided with a drop in the intensity of most components. Air temperature
showed a positive correlation with some feature intensities, while myrcene and
α-thujene resulted in a positive and a negative correlation
with rainfall, respectively. This study was the first attempt to correlate
metabolic variation and environmental factors in P. neochilus. Our
approach was successful in identifying the composition and variation of the
headspace volatiles of P. neochilus leaves.
Key words
medicinal plants -
Plectranthus neochilus
- Lamiaceae - plant metabolomics - volatile composition - headspace solid-phase microextraction
