Phytochemical analysis and antiradical potential of methanol extracts of Hieracium naegelianum Pančić and H. scheppigianum Freyn underground parts

Abstract

The genus Hieracium L. is autochthonous in Eurasia, North Africa and North America and the vast majority of the taxa are distributed in Europe. Hieracium naegelianum Pančić, belonging to monotypic subendemic section H. sect. Naegeliana Zahn ex Szeląg, is a small, caespitose plant, with long rhizome. It inhabits subalpine and alpine orosubmediterranean screes and mainly is endemic for the mountains in W Balkan, with a single population in S Apennines. Hieracium scheppigianum Freyn is a hybridogenous apomictic species probably originated from H. gymnocephalum Griseb. ex Pant. (H. sect. Pannosa /Zahn (Zahn) and H. bupleuroides C.C. Gmelin, s. l. (H. sect. Drepanoidea Monnier). The species can be found only on screes, rocky places or rocky pastures in subalpine and alpine zone in Dinarides. The underground parts of H. naegelianum and H. scheppigianum were collected on Mt Durmitor, Republic of Montenegro. Dried and powered plant material was macerated with dichloromethane and methanol, successively. Both solvents were evaporated under reduced pressure and dried methanol extracts were used for further investigation. Using LC-MS method, sesquiterpene lactone glycoside of guaianolide type, crepiside E, and six phenolic acids, i.e. chlorogenic acid and five dicaffeoylquinic acids (cynarin, 3,5-, 1,5-, 3,4- and 4,5-dicaffeoylquinic acids) were identified and quantified in both dried methanol extracts. Crepiside E was the most abundant compound (116.58 and 126.88 mg/g), while among phenolic acids, 3,5-dicaffeoylquinic acid (72.86 and 62.01 mg/g) was dominant in both investigated extracts. Radical scavenging activity was estimated using colorimetric DPPH and OH radical assays, and both extracts showed prominent and concentration dependent activity with SC50DPPH of 25.25 and 29.38 μg/mL and SC50OH of 16.09 and 17.50 μg/mL, respectively. This is the first report on secondary metabolites and antiradical potential of underground parts of H. naegelianum and H. scheppigianum