TLC Profiles of Selected Cirsium Species with Chemometrics in Construction of Their Fingerprints

Comparative Contents of Polyphenolic Compounds in Aerial Parts of Cirsium esculentum, C. serratuloides, and Ancathia igniaria (Asteraceae)

Because Ancathia igniaria (Spreng.) DC. (Cirsium igniarium Spreng.) has been segregated as a monotypic genus from the genus Cirsium on the basis of phylogenetic data, chemotaxonomic differences are of interest to detect in the composition of polyphenolic components of aerial plant parts. Phenolic compounds are of chemotaxonomic significance in a number of genera and families. The polyphenolic profile of aerial parts was therefore compared for Cirsium esculentum (Siev.) C.A. Mey., Cirsium serratuloides (L.) Hill, and A. igniaria. The last two species were for the first time examined in this context. The compounds were identified against known standard via high-performance liquid chromatography (HPLC). The species of the genus Cirsium were found to have similar compositions of simple phenols, but differ in the set of flavonoids. Six to eight phenolic compounds were detected in the species, and three simple polyphenols (syringin, chlorogenic acid, and ethyl gallate) proved to be common. The flavonoid profiles of aerial parts included rutin in both Cirsium species. Cymaroside and quercetin-3-O-β-D-diglucoside-O-α-L-rhamnoside were species specific for C. serratuloides; salipurposide and hyperoside, for C. esculentum. An extract of A. igniaria aerial parts contained cinaroside (like in C. serratuloides), chrysin 7-O-glucoside, and eriodictyol. A greater difference in flavonoid composition was observed between the genera Cirsium and Ancathia. Data on phenolic compound composition are of importance for chemosystematics and use of plants as medicinal raw materials. The total content of coumarins, aglycones, and flavonoid glycosides in the species was determined by a spectrophotometric method. The contents of flavonoids and coumarins in C. esculentum and C. serratuloides were comparable and exceeded their contents in A. igniaria. Thus, A. igniaria proved to differ from the genus Cirsium in the quantitative and qualitative composition of phenolic compounds.

Antioxidant Effects and Phytochemical Properties of Seven Taiwanese Cirsium Species Extracts

In the present investigation, we compared the radical-scavenging activities and phenolic contents of seven Taiwanese Cirsium species with a spectrophotometric method. We further analyzed their phytochemical profiles with high-performance liquid chromatography–photodiode array detection (HPLC–DAD). We found that the flower part of Cirsium japonicum var. australe (CJF) showed the best radical-scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and the hypochlorite ion, for which the equivalents were 6.44 ± 0.17 mg catechin/g, 54.85 ± 0.66 mmol Trolox/g and 418.69 ± 10.52 mmol Trolox/g respectively. CJF also had the highest contents of total phenolics (5.23 ± 0.20 mg catechin/g) and phenylpropanoids (29.73 ± 0.72 mg verbascoside/g). According to the Pearson’s correlation coefficient, there was a positive correlation between the total phenylpropanoid content and ABTS radical-scavenging activities (r = 0.979). The radical-scavenging activities of the phenylpropanoids are closely related to their reducing power (r = 0.986). HPLC chromatograms obtained in validated HPLC conditions confirm that they have different phytochemical profiles by which they can be distinguished. Only CJF contained silicristin (0.66 ± 0.03 mg/g) and silydianin (9.13 ± 0.30 mg/g). CJF contained the highest contents of apigenin (5.56 ± 0.09 mg/g) and diosmetin (2.82 ± 0.10 mg/g). Among the major constituents, silicristin had the best radical-scavenging activities against DPPH (71.68 ± 0.66 mg catechin/g) and ABTS (3.01 ± 0.01 mmol Trolox/g). However, diosmetin had the best reducing power and radical-scavenging activity against the hypochlorite anion (41.57 ± 1.14 mg mmol Trolox/g). Finally, we found that flavonolignans (especial silicristin and silydianin) and diosmetin acted synergistically in scavenging radicals.