Phytochemical composition and antioxidant activity of Cersis siliquastrum

Abstract

The genus Cercis (redbud) belongs to the subfamily Caesalpinioideae of the plant family Fabaceae (Leguminosae). It includes 10 recognized species scattered widely across the warm, north-temperate zones of North America and Eurasia. Cercis siliquastrum is native to Lebanon found in altitudes ranging between 0-800m. The flowers are edible, with sweet to sour taste, used as salad garnish, and can be drunk as tea to relief stomach aches. Flowers are known to be rich in phytochemicals that are strongly associated with reduced risk of developing chronic diseases, such as cancer, diabetes, and cardiovascular diseases. Therefore, our aim of this study is to extract from these flowers’ active phytochemicals. For this purpose, the flowers of Cercis siliquastrum were shade dried, then polyphenols were extracted using the chemical reagents methanol, ethanol,acetone,dichloromethane pre-treated with ammonia, and dichloromethane as a preparatory step. Then these extracts were used to determine the total phenolic content using Follin –Ciocalteu method and their antioxidant activity was assessed using DPPH radical scavenging activity. Whereas for the determination of the total flavonoids we used the Aluminum chloride method. And finally, the total terpenes were determined by Salkowski method. Descriptive statistics were performed in the present study; total phenol, flavonoids, and terpenes contents of the 5 extracts using solvents with different polarities were summarized as mean. To examine the relationship between total phenol, flavonoids and terpenes contents and DPPH radical scavenging activity, Spearman’s correlation coefficients were calculated between total phenol, flavonoids and terpenes contents and DPPH radical scavenging activity. Statistical analyses were carried out using the Statistical Package for Social Sciences (SPSS) version 23. A p-value of < 0.05 was indicative of Statistical significance. Acetone was found to have the highest extraction capacity on phenols (4.825 mg GAE/100mg flower extract). And ethanol for total flavonoid (53 mg QE/100mg flower extract), dichloromethane showed to be the best in extracting terpene with capacity of (192 mg LE/100mg flower extract). In addition, the acetone extract exhibited the highest DPPH scavenging activity (IC50% 41.85 mg/mL). Un-significant negative strong correlations were observed between total flavonoid content and DPPH scavenging activity (r: -0.500 p: 0.391). Further investigation for the antioxidant activity should be performed to identify and isolate the bioactive metabolites responsible for this activity.