Accumulation of anthocyanins and flavonols in black currants (Ribes nigrum L.) by pre-harvest methyl jasmonate treatments

[Background] Chemical elicitation is one of the most effective methods currently used to enrich plant foods in bioactive compounds. Methyl jasmonate (MJ) has been described as a very useful elicitor of some plant compounds, polyphenols among them. The objective of this study was to determine the effects of pre-harvest MJ application on the increase of the main flavonoids and the antioxidant properties of black currant (Ribes nigrum) cultivars.
[Results] Significant enhancement of individual and total anthocyanins was measured after elicitation with MJ, particularly when 0.2 mM concentrations were used. Total anthocyanins increased from 28288.74 ± 253.65 mg kg−1 to 43561.08 ± 145.87 mg kg−1 in Ben Hope black currants after elicitation with 0.2 mM MJ. Similarly, increases from 35986.04 ± 287.98 mg kg−1 to 41320.22 ± 145.87 mg kg−1 were estimated in Ben Alder cultivar. Black currant flavonols were not individually affected by the treatment; however, total flavonols increased from 3115.21 ± 12.11 mg kg-1 to 3268.41 ± 145.87 mg kg-1 in Ben Hope and from 3016.38 ± 10.07 mg kg-1 to 3110.95 ± 8.57 mg kg-1 in Ben Alder. Antioxidant properties of black currants as measured by DPPH and ABTS assays improved proportionally to the increase of flavonoid content after MJ elicitation.
[Conclusion] The pre-harvest elicitation with MJ is proposed as an useful tool to enhance contents of anthocyanins and flavonols as well as free radical scavenging activity of black currants. The functional black currants here obtained can be interesting for industry for consumption as fresh fruits and for production of juice and jam.
Authors thank the Comunidad Autónoma of Madrid (Spain) and European funding from FEDER program (research project S2013/ABI-3028, AVANSECAL-CM) for financial support. We acknowledge SCRI for supplying and treating the samples and Mikaela Herranz Pascual for her hep in the experimental work. Dr. Gema Flores thanks CSIC for her JAE-Doc contract.