In this study, P. divaricatum (Piperaceae) plants were subcultured by cuttings and cell tissue in order to carry out a comparison of the volatile profile, phenolic compounds, and antioxidant activity. Propagation by cuttings used vermiculite substrate and Murashige-Skoog (MS) medium in the absence of growth regulators and rooting started at 15 days of growth providing a higher number of plants after 90 days. In vitro propagation was performed using shoot apices as explants in MS media supplemented with 0.5 mg mL-1 BA (6-benzyladenine). Volatile profiles analyzed by gas chromatography-mass spectrometry (GC-MS) showed as main compounds methyl eugenol, E-β-ocimene, and β-elemene in the in vivo and in vitro cultures. Phenolic contents determined by the Folin-Ciocalteu method had no significant difference at the end of 90 days of growth displaying a good linear correlation with antioxidant activity and phenylpropanoids amounts (r > 0.7). However, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging was higher for in vitro plants grown in comparison to in vivo plants cultured.

Ocimum gratissimum oil is used for various medicinal, food and cosmetic applications due to its high chemical variability. Local businesses have considered the economic exploitation of this plant. A specimen sampled at São Luís, MA, Brazil, with thymol and derivatives oil, was subjected to seasonal and circadian study, and to antifungal and antioxidant assays. It was possible to observe that the weather conditions showed a direct influence on the oil yield and variation of its constituents, mainly oxygenated monoterpenes and monoterpene hydrocarbons, with the predominance of thymol, γ-terpinene, and p-cymene. Principal component analysis (PCA) was able to justify the oil chemical variability of the seasonal (70%) and circadian (86%) study. Oil displayed inhibition for the fungus Corynespora cassiicola at a concentration above 0.3 µL mL-1, and it showed a more significant activity by comparison to thymol. Using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, the oil antioxidant activity was about 75% of thymol.