Preliminary screening of Nicotiana glauca extracts for determination of antioxidant activity by different methods

Abstract

Nicotiana glauca (Solanaceae), or tree tobacco, is found in dry arid climates of North America, Africa and Europe. It has been reported to have both toxic and medicinal properties. The main aim of this study was to analyze the phytochemical screening and quantitative estimation of polyphenols, flavonoids and flavonols of crude extracts from the leaves of Nicotiana glauca and to evaluate its in vitro antioxidant properties. Three different solvents were used to extract bioactive compounds from powdered leaves of Nicotiana glauca: dichloromethane (DCM), ethyl acetate (AE) and n-buthanol (n-BuOH). The three extracts were then subjected to qualitative phytochemical screening using standard procedures. Total phenolics, total flavonoids and total flavonols contents of the extracts were measured by Folin Ciocalteu and Aluminium chloride methods respectively. Furthermore, the antioxidant capacity evaluation was performed using the DPPH, ABTS, DMSO alcalin, Phenantroline, FRAP and CUPRAC methods. The three extracts were then subjected to qualitative phytochemical screening using standard procedures. These methods showed the presence of polyphenols and comarines in all extracts. Moreover, flavonoids, tannins, steroids and quinones were reported in the AE and n-BuOH extracts. In addition, alkaloids were seen to be present in DCM extract, while saponines and phlobatannins were absent in all extracts. The antioxidant capacity evaluation was performed using the DPPH, ABTS, DMSO alcalin, Phenantroline, FRAP and CUPRAC methods.

Keywords

• nicotiana glauca
• antioxidant activity
• screening