Isolation and Identification of Antioxidant Compounds from Ligularia fischeri

Abstract

The plant Ligularia fischeri var. spiciformis Nakai, a well-known edible medicinal herb in Korea, has been used to treat maladies such as jaundice, scarlet fever, rheumatoid arthritis, and hepatic function failure. In this research, 4 major antioxidant compounds were detected from this plant's leaves using an on-line high-performance liquid chromatography (HPLC)-ABTS screening system, which can determine the antioxidant activity based on a decrease in absorbance at 734 nm after postcolumn reaction of HPLC-separated antioxidants with the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radicals (ABTS(*)). In order to isolate these active compounds, a preparative HPLC was applied and their chemical structures were identified as 5-O-caffeoylquinic acid (5-CQA), 3,4-di-O-caffeoylquinic acid (3,4-DCQA), 3,5-di-O-caffeoylquinic acid (3,5-DCQA), and 4,5-di-O-caffeoylquinic acid (4,5-DCQA) by ESI/MS(n) and (1)H NMR. These 4 isomers comprised over 10% of the dried leaves, with 3,5-DCQA being the most abundant compound. The radical scavenging activity of each isomer was also evaluated simultaneously through the on-line HPLC-ABTS method, which showed 94% antioxidant activity of the ethanol extract derived from caffeoylquinic acids. Among these isomers, 3,4-DCQA contained the most strong antioxidant activity while 3,5-DCQA accounted for the highest radical scavenging capacity due to having the highest content.

Effects of Various Cooking Methods on Content, Oxygen Radical Absorbance Capacity, and Bioaccessibility of Caffeoylquinic Acids in Ligularia fischeri (Ledeb.) Turcz, Gom-Chi

“…The amount of 5-CQA, 4-CQA, 3-CQA, and 3,4-di-CQA was 136.72, 2144.44, 16.81, and 421.93 μg/g fresh weight of fresh Gom-chi, respectively. Different constituents of CQAs in fresh Gom-chi were previously identified by other investigators (Shang et al, 2010;Kim et al, 2012). Kim et al (Kim et al, 2012) reported that methanol extract of air dried Gom-chi contained 5-CQA, 3,4-di-CQA, 3,5-di-CQA, and 4,5-di-CQA.…”

“…Kim et al (Kim et al, 2012) reported that methanol extract of air dried Gom-chi contained 5-CQA, 3,4-di-CQA, 3,5-di-CQA, and 4,5-di-CQA. Shang et al, (Shang et al, 2010) found that four major components including 5-CQA, 3,4-di-CQA, 3,5-di-CQA, and 4,5-di-CQA were identified from 70% ethanol extract of air-dried Gom-chi. Compared to the results of our study, those studies detected several di-CQA including 3,4-di-CQA, 3,5-di-CQA, and 4,5-di-CQA rather than others in air-dried Gom-chi.…”

“…Ligularia fischeri (Ledeb) Turcz known as 'Gom-chi' in Korea, a member of the compositae, is stably supplied and mostly consumed in Korea (Shang et al, 2010). It is also a perennial vegetable plant and cultivated in moist, shady areas in various countries in Europe and eastern Korea (Shang et al, 2010;Kim et al, 2012).…”

“…It is also a perennial vegetable plant and cultivated in moist, shady areas in various countries in Europe and eastern Korea (Shang et al, 2010;Kim et al, 2012). Gom-chi has been recognized as plant predominantly contains caffoylquinic acids .…”

“…These are known to provide diverse biological functions such as a scavenging of free radicals, reacting to enzymatic browning, preventing fungal pathogens, and resisting pathogenic insects . Owing to various functions of CQAs, Gom-chi is known to contain a significant amount of CQAs and has been used as a traditional medicine for the treatment of jaundice, scarlet fever, rheumatoid arthritis, and liver injury (Shang et al, 2010). As consumption of Gom-chi has increased in recent years, many easy cooking methods including blanching, pan frying, and microwaving has been introduced (Pellegrini et al, 2010).…”