Determination of secondary metabolites and antioxidant activity of some boraginaceae species growing in Iran

Amir Gharib,Masoud Godarzee

doi:10.4314/tjpr.v15i11.22

Abstract

Purpose: To evaluate the antioxidant potential, flavonoids, and total phenols as well as cyanidin 3- glucoside and delphinidin 3-glucoside contents of some Boraginaceae species that grow in Iran.Methods: The aqueous and ethanol extracts of the plants were prepared. The free radical scavenging activity of the extracts was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method. Total phenolic and flavonoid contents of the extracts were assessed by Folin-Ciocalteu and aluminium chloride colorimetric assays, respectively. Furthermore, cyanidin 3-glucoside and delphinidin 3- glucoside contents of the extracts were determined using high- performance liquid chromatography (HPLC) method.Results: The most powerful free radical scavenging activity with 50 % inhibitory concentration (IC50) of 23.13 ± 1.90 μg mL-1 was exerted by the ethanol extract of Nonea caspica, while the weakest IC50 of 364.38 ± 14.18 μg mL-1 was shown by the aqueous extract of Onosma sericeum. Total phenolic content varied among the plants, ranging from 270.33 ± 2.60 to 3.40 ± 0.28 mg GAE g-1 dry weight. The ethanol extracts of Nonea caspica and Anchusa arvensis displayed the highest total flavonoid content (252.60 ± 1.80 and 29.13 ± 1.05 mg QE g-1 dry weight, respectively). The highest contents of cyanidin and delphinidin 3-glucosides were found in the ethanol extracts of Nonea caspica and Anchusa arvensis, respectively.Conclusion: The results show that some of the plants have potent antioxidant activities which may justify the ethno-therapeutic usage of these plants by traditional healers.Keywords: Boraginaceae, Polyphenol, Antioxidant activity, Cyanidin 3-glucoside, Delphinidin 3- glucoside, Nonea caspica, Onosma sericeum, Anchusa arvensis

Highlights

The Boraginaceae family includes a variety of herbs, shrubs, and trees totaling about 146 genera and 2000 species found in the worldwide [1]
We collected eight species of Boraginaceae family, including Lappula barbata, Onosma bulbotrichum, Rochelia persica, Nonea caspica, Anchusa arvensis, Onosma microcarpum, Onosma sericeum and Trichodesma incanum that according to our knowledge, there were no prior reports on the chemical properties of these plants, and the main aim of this study was to evaluate the polyphenol content and antioxidant activities of these selected species
The highest total phenolic content was observed in the Nonea caspica, whereas the lowest content value was found in the Onosma sericeum

Summary

Introduction

The Boraginaceae family includes a variety of herbs, shrubs, and trees totaling about 146 genera and 2000 species found in the worldwide [1]. The main secondary metabolites of these plants are alkaloids, flavonoids, polyphenols, phytosterols and terpenoids, that some of them showed antioxidant and antibiotic activities [2]. Some Boraginaceae species were used for burns and wounds healing in folk medicine around the world [3]. Wound healing property of this family is related to their antibacterial, antiviral, antioxidant and anti-inflammatory activities, which is directly dependent on their phenolic compounds, such as flavonoids and phenolic acids [2]. A direct relationship between antioxidant activities and phenolic contents of extracts from Boraginaceae species has been established [4]. Many reported biological effects such as antioxidant, anti-inflammatory, antimutagenic and anticancer activities have been attributed to the presence of phenolic and flavonoid compounds, which are widespread in this plant family [5]

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Conclusion