Jasminum polyanthum Franch. as a natural source of (−)‐methyl jasmonate: an alternative to the use of the synthetic standard

Introduction – Methyl jasmonate (MJ) contains two chiral centres at C‐3 and C‐7 in its chemical structure, which implies that it can exist in four possible stereoisomeric forms, namely (+)‐MJ, (?)‐MJ, (+)‐epiMJ and (?)‐epiMJ. The absolute configuration of the two side chains of MJ affects the biological activity associated with this compound. Objective – To isolate pure (?)‐MJ from a natural source, Jasminum polyanthum Franch., with the intention of increasing the knowledge about its biological properties, including its effect on the biosynthesis of plant metabolites. Methodology – The method used was based on steam distillation extraction (SDE) as an extraction technique followed by high‐performance liquid chromatography (HPLC) as a purification procedure. The HPLC flow‐rate as well as the number of fractions accumulated were optimised to achieve the concentration and purity required. Results – The employment of 0.3 mL/min as HPLC flow‐rate and the accumulation of three HPLC fractions allowed the required enantiomeric purity (95%) and concentration (0.36 mg/L in each HPLC fraction) to efficiently obtain (?)‐methyl jasmonate from Jasminum polyanthum Franch. to be achieved. Conclusion – The approach proposed may enable the properties and effect of pure (?)‐MJ on plant responses to be studied. The use of a natural source to obtain (?)‐MJ is presented as an alternative to the enantioselective synthesis and enantiomeric resolution from the standard racaemic mixture. Copyright © 2009 John Wiley & Sons, Ltd.