α amyrin

All solvents: chloroform, diethyl ether, methanol, and chemicals: CH₃COOH, KOH, NaOH (purchased from Chempur, Piekary Śląskie, Poland), used for extraction and analysis were of analytical grade. Authentic standards of α-amyrin and ursolic acid methyl ester were purchased from Roth (Karlsruhe, Germany); β-amyrin, lupeol, uvaol, oleanolic acid, campesterol, sitosterol and stigmasterol were purchased from Sigma-Aldrich (Steinheim, Germany).

All solvents used for extraction and analysis, i.e., chloroform, diethyl ether, and methanol (purchased from Chempur, Piekary Śląskie, Poland), were of analytical grade. Authentic standards of α-amyrin and ursolic acid methyl ester were purchased from Roth (Karlsruhe, Germany), and β-amyrin, lupeol, uvaol, betulinic acid, oleanolic acid, campesterol, sitosterol, and stigmasterol were purchased from Sigma-Aldrich (Steinheim, Germany).

The following plant metabolites used in our study were ordered: (−)-caryophyllene oxide, (+)-nootkatone, zerumbone, β-amyrin, crocetin dialdehyde, saffron stigma (Sigma-Aldrich, St. Louis, MO, USA), α amyrin (Carl Roth, Karlsruhe, Germany) and taraxasterol acetate (Biorbyt, Cambridge, UK) (Figure 1). All compounds were dissolved in dimethyl sulfoxide (DMSO) in order to be used in the assays. Saffron threads were incubated in DMSO for 1 h on a rotary shaker (100 rpm); then, the supernatant was collected and used in the work. A C₇-C₃₀ saturated alkanes standard solution was also obtained from Sigma-Aldrich to calculate the GC retention indices of the sesquiterpenes formed by A. thaliana. The liquid standards used were β-elemene, ordered from Abcam plc (Cambridge, UK) and (−)-trans-caryophyllene (sum of enantiomers, purity: ≥98.0%) and (−)-α-cedrene (sum of enantiomers, purity: 96.4%) purchased from Sigma-Aldrich.