Anthocyanins content and composition in the fruits of sweet cherries (Prunus avium l.) Infected with Monilinia laxa

Phenolics have long been associated with passive (preinfectional) and active (postinfectional) defence responses of plants to a number of pests and pathogens. Some of these compounds, such as anthocyanins are particularly biologically active, expressing potent antioxidant activity. It has been very well documented in different pathosystems that phenolic compounds can play an important role in disease resistance, being defined as phytoalexins, or acting as a physical barrier, thus preventing plant tissue colonization. The aim of the paper was to investigate the content and composition of anthocyanins in the fruits of nine sweet cherries cultivars, before and after the infection with M. laxa, under the field conditions. Determination of individual compounds was performed using HPLC-DAD analysis, on a Thermo Finnigan Surveyor HPLC system with a diode array detector at 530 nm, on a Gemini C18 (150x4.6 mm) column. Results showed that the anthocyanins content ranged from 0.3 to 26.6 and from 0.02 to 3.52 g kg-1 dry weight in healthy and infected fruits, respectively. The highest content of anthocyanins was detected in „3/Val‟(43.8 g kg-1 dry weight) but this cultivar showed significant decrease in anthocyanins level in fruit, after the infection with M. laxa (10.9 g kg-1 dry weight). The most abundant anthocyanins were cyanidin derivatives (0.08-26.6 and 0.013.7 g kg-1 dry weight in healthy and infected fruits, respectively). „Burlat‟, „Junska rana‟, Merchant‟ and „Summit‟ dominantly had cyanidin-glucoside, while „Priusadebnaja‟ and „Asenova rana‟ accumulated cyanidin-glucoside only after the infection. „Priusadebnaja‟, „Asenova rana‟ and „Lionska‟ had only cyanidinrutinoside. „Lionska‟, „Sue‟ and „Asenova rana‟ had higher cyaniding and peonidin derivative contents in infected fruits (1.2 to 3-fold higher). Peonidine derivatives (peonidin glucoside and rutinoside), as well as 5-carboxypyranocyanidin-rutinoside content mostly decreased after the infection (14.9-97.7%).