Evaluation of Diversity in some Phytochemical Characteristics and Antibacterial Effects of Extract of Iranian Cultivars of Chrysanthemum (Dendranthema morifolium Ramat.)

Introduction  Due to their pleasant and soothing taste and odor, attractive colors, and medicinal purposes, Chrysanthemum morifolium flowers have been widely used as food, tea, ornamentation, and medicine. It has been reported that C. morifolium can reduce hyperactivity of the liver, improve eyesight and regulate cellular immunity. Pharmacological investigations have shown that Flo's chrysanthemum exhibits antibacterial, antioxidant, anti-inflammatory, and heart-protective characteristics. Previous phytochemical studies on caffeic acid derivatives, flavonoids, triterpenoids, glycosides and alkaloids have been isolated from Flo's chrysanthemum. In this study, chrysanthemum cultivars were evaluated in terms of having secondary compounds and desirable medicinal properties, as well as antibacterial effects to introduce superior cultivars and purposeful planning for breeding research. The purpose of the present study, 25 cultivars of C. morifolium were compared in terms of essential oil content, leaves total phenolic, flavonoid and antioxidant activity. Materials and Methods  In this experiment, 25 chrysanthemum cultivars were studied in terms of essential oil percentage, antioxidant index, total phenol and flavonoid content and antibacterial effects in a randomized complete block design in Lorestan University research farm in the year 2016. Essential oil was extracted from dried flowers in the shade using a Clevenger apparatus for 3 hours. Evaluation of antioxidant activity of the extract was measured by DPPH method based on the method of Kulisic et al. (2004). The amount of flavonoids was measured by aluminum chloride and total phenol by Folin - Ciocalteu reagent colorimetric. Ward analysis was done to classify the cultivars. Results and Discussion The results of analysis of variance showed that the studied chrysanthemum cultivars had significant differences in terms of all studied phytochemical traits. According to the obtained results, among different cultivars, the total amount of phenolic compounds is between 14.52-47.90 mg/g dry weight, the total flavonoid content is between 11.59-55.62 mg/g DW and IC50 index varied between 83.92 and 257.43 μg/ml. The highest amount of total phenol was present in Avadis and Dila cultivars (45.86-47.90 mg/g dry weight), while Yasamin cultivar (14.52 mg/g DW) had the lowest amount. Also, in terms of total flavonoid content, Golnar and Farahnaz cultivars had the highest total flavonoid content with 55.62 and 53.01 mg quercetin/g DW, respectively. Cluster analysis divided all studied cultivars into five groups. The percentage of essential oil among different cultivars varied between 0.41 to 0.62% and a high variability was observed in terms of the amount of essential oil in the studied cultivars. The highest percentage of essential oil was related to Farhnaz and Elmira2 cultivars. In general, the results showed high antioxidant activity of most cultivars. Therefore, chrysanthemum extract can be introduced as a suitable source of natural antioxidants. Also in this study, Paridokht, Sana and Ashraf cultivars were studied in terms of antioxidant and antibacterial index and Farahnaz and Elmira 2 cultivars appeared superior to other cultivars in terms of essential oil production. Hedaei et al. (2018) studied evaluation of some bioactive compounds and antioxidant activity of leaf methanolic extract and flower essential oil content from different cultivars of Chrysanthemum morifolium, in this review, total phenol and flavonoid contents and IC50 values in different cultivars were ranged from 17.63-33.20 mg/g DW, 12.62-53.17 mg quercetin/g, and 54-228 μg/ml respectively. The highest phenolic content was in cultivar “Poya3” (33.20 mg/g DW), whereas the cultivar “Sahand2” (17.63 mg/g DW) contained the lowest value. Also, in terms of total flavonoid content, cultivars “Marmar” and “Sahand 2” had the highest and the lowest flavonoids with 53.17 and 12.62 mg quercetin per gram, respectively.  Conclusion  The results of the present study indicate a significant difference between different cultivars in terms of the total amount of phenolic, flavonoid and antioxidant compounds that the existence of such diversity can be the role of cultivar and genetics in the production of these compounds. According to the results of this study, chrysanthemum cultivars with desirable levels of phenolic and flavonoid compounds can be used as a source of natural antioxidants as an alternative to synthetic antioxidants. In this study, Sana, Paridokht and Ashraf cultivars appeared superior to the existing genotypes in terms of phytochemical and antibacterial traits. The results of this study can be used to select the correct parents for purposeful crosses in subsequent chrysanthemum breeding programs in order to improve the phytochemical traits of existing cultivars.