Antioxidant activity and pigment contents in Argentinean rose petals

BAIBUCH SABRINA; GABILONDO JULIETA; CARMEN A. CAMPOS; LAURA MALEC

Nanchang

Simposio; International Symposium on Phytochemicals in Medicine and Food; 2021

International Association of Dietetic Nutrition and Safety (IADNS), Phytochemical Society of Europe (PSE) and the Phytochemical Society of Asia (PSA).

The petals of flowers of the Rose genus are a valuable source of phenolic compounds withantioxidant activity [1]. Some of these compounds are also responsible of petal colors. Duringthe flower growth process, several blooms occur that are discarded, becoming a waste fromthe floral industry. The aim of this work was to analyze and compare the antioxidant activityand pigment contents of Argentinian roses of different colors. The petals of fifteen cultivarswere dried by air at 65 ºC for 1.3 h. The compounds were obtained by a solid-liquidextraction carried out with ethanol / water (38/62) and ultrasound assistance (275 W, 50/60Hz) for 30 min at 75 ºC. The antioxidant activity was measured through the Ferric reducingantioxidant power (FRAP) and DPPH methods. The concentration of pigments such asanthocyanins and flavonoids were measured by colorimetric methods. Total phenolics weremeasured according to the Folin-Ciocalteu method. Extractions were made in duplicate andall analysis were performed in triplicate (n=6). Data were analyzed by ANOVA andsignificant differences were evaluated by the Tukey test (p < 0.05). The content of allcompounds varied within a wide range, and the cultivars with darker colors showed thehigher values. The DPPH values ranged between 752.44 ± 5.51 and 204.71 ± 3.62 mg Trolox/ g dry weight (dw) and those of FRAP between 848.40 ± 10.67 and 275.15 ± 9.12 mg Trolox/ g dw. Europeana, with more intense red color, presented the highest values of the evaluatedparameters, while Iceberg (white color) the lowest. Total phenolics varied between 218.03 ±4.87 and 78.83 ± 3.23 mg gallic acid (GA) / g dw. The darker colored cultivars, Oklahomaand Papa Mellian, presented the highest contents of anthocyanins (5.77 ± 0.11 and 5.56 ±0.13 mg cianidyn 3 glucoside (C3G)/ g dw, respectively) and flavonoids (125.88 ± 6.50 and114.28 ± 1.27 mg quercetin (Q) / g dw, respectively). Mentioned values are comparable to thehigher ones previously reported for other flowers or even other rose cultivars [1-3]. Anexcellent correlation was observed between total phenolics and antioxidant activity (DPPHmethod, R2 = 0.9234 and FRAP, R2 = 0.9769), indicating that phenolic compounds areprimary responsible for the antioxidant activity of the extracts. Results indicate that darkerrose petals are a promising source of natural antioxidants and pigments that could be used asfood additives to replace the synthetic ones. It also turns out to be a good way to useagro-industrial waste, contributing to the circular economy.