Evaluation of Crocus sativus L. Stigma Phenolic and Flavonoid Compounds and Its Antioxidant Activity

Abstract

Saffron (Crocus sativus L.) belongs to the Iridaceae family. The stigma of saffron has been widely used as spice, medicinal plant, and food additive in the Mediterranean and Subtropical countries. Recently, attention has been paid to the identification of new sources of safe natural antioxidants for the food industry. The antioxidant activities of spices are mainly attributed to their phenolic and flavonoid compounds. Saffron is one of the spices believed to possess antioxidant properties, but information on its antioxidant activity and phenolic, flavonoids compound are rather limited, therefore this research was carried out to evaluate the antioxidant activity of saffron stigmas extracted with different solvents. The phenolic and flavonoid compounds of saffron were also examined using reversed phase (RP)-HPLC. Results showed that saffron stigma possess antioxidant activity. The free radical scavenging and ferric reducing power activities were higher for the methanolic extract of saffron stigma at a concentration of 300 μg/mL, with values of 68.2% and 78.9%, respectively, as compared to the corresponding boiling water and ethanolic extracts, but the activities were lower than those of antioxidant standards such as BHT and α-tocopherol. The obtained total phenolics value for methanolic saffron extract was 6.54 ± 0.02 mg gallic acid equivalent (GAE)/g dry weight (DW), and for total flavonoids, 5.88 ± 0.12 mg rutin equivalent/g DW, which were also higher than values obtained from the ethanolic and boiling water extracts. In addition, the RP-HPLC analyses indicated the presence of gallic acid and pyrogallol as two bioactive compounds. In summary, saffron stigmas showed antioxidant activity and methanol appeared to be the best solvent to extract the active components, among which the presence of gallic acid and pyrogallol might contribute towards the stigma’s antioxidant properties. Hence, saffron stigma could be applied as a natural antioxidant source for industrial purposes.

Evaluation of antioxidant activities of bioactive compounds and various extracts obtained from saffron (Crocus sativus L.): a review

“…3). Effect of the use of water and different organic solvents such as ethanol or methanol at various concentrations on the total polyphenol content and antioxidant activity was studied for saffron (Makhlouf et al 2011;Karimi et al 2010). Makhlouf et al (2011) have been studied the different conditions for extraction of saffron components.…”

“…The following extracts were obtained from saffron soaked and boiled and extracted with water and methanol 50 % (v/v) using maceration method. Karimi et al 2010 prepared saffron extracts using three different solvents of ethanol 80 % (v/v), methanol 80 % (v/v) and boiling water by shaking conventional method. In another study, the extraction yield of saffron components with water and 80 % (v/v) ethanol using a following maceration step (5 days at 4°C) was respectively increased to 71.0 % and 58.4 % (Amin et al 2011).…”

“…A high correlation between polyphenol content and antioxidant activity of saffron extracts was observed (Makhlouf et al 2011;Amin et al 2011;Karimi et al 2010;Chen et al 2008). Change in solvent polarity alters its ability to dissolve a selected group of antioxidant compounds and influences the antioxidant activity estimation.…”

“…Several researches have shown that spices containing phenolic and flavonoid compounds indicated antioxidant activities, so they are frequently used as antioxidant food supplements (Rahaiee et al 2012;Karimi et al 2010;Martinez-Tome et al 2001). The antioxidant property of C. sativus stigma could be credited to its phenolic content as well as to its active ingredients such as safranal, crocin, crocetin and carotene, all of which have been reported to have antioxidant properties (Karimi et al 2010).…”

“…Interest in the impact of saffron carotenoids on human health is due to their high antioxidant capacity which was investigated by many researchers (Makhlouf et al 2011;Asdaq and Inamdar 2010;Karimi et al 2010;Bathaie and Mousavi 2010;TavakkolAfshari et al 2008;Kanakis et al 2007;Soeda et al 2007;Magesh et al 2006;Ochiai et al 2004;Selim et al 2000;Verma and Bordia 1998;Nair et al 1995). One of hypothesis for the modes of anti carcinogenic and anti tumor actions of saffron has been proposed the inhibitory effect on free radical chain reactions (Makhlouf et al 2011).…”