Chemical constituents from Agrimonia pilosa Ledeb. and their chemotaxonomic significance

Abstract Phytochemical investigation of the ethanol extract from the whole plant of Agrimonia pilosa led to the isolation of 31 compounds, including 16 flavonoids (1–16), 5 triterpenes (17–21), 1 isocoumarin (22), 5 phenolic acids (23–27), 1 ceramide (28), 2 agrimols (29–30) and 1 fatty acid (31). Their structures were determined by various spectroscopic analyses. Compounds 5, 7 and 20 were firstly isolated from the genus Agrimonia, and compounds 6, 10–11, 15, 26, 28 and 31 were isolated from the family Rosaceae for the first time. Moreover, the chemotaxonomic significance of these compounds was summarised.


Introduction
The species of the genus Agrimonia (Rosoideae) are perennial herbaceous flowering plants, mainly distributed in the temperate regions of the Northern Hemisphere (Kato et al. 2010). The aerial parts of Agrimonia pilosa were also listed in the Chinese Pharmacopoeia as a kind of haemostatic drug for treating urinary, respiratory, digestive system diseases, and various kinds of bleeding such as bloody dysentery (Xu et al. 2005;Wang et al. 2012a). Pharmacological studies showed that A. pilosa exhibits antihaemorrhagic, antioxidant, hepatoprotective, anticancer and α-glucosidase inhibitory activities (Kubínová et al. 2016).
Previous scientific investigations focused on hypoglycaemic (Gray & Flatt 1998), coronary (Correia et al. 2006), anti-tumour (Nho et al. 2011), antioxidant (Kubínová et al. 2016) and other activities of ethanol extracts and water extracts of genus Agrimonia. However, there are few researches on the active components of the species from Agrimonia, not to say the systematic research on the chemical composition. Therefore, we aimed to investigate the chemical constituents of A. pilosa by modern chromatographic techniques and separation methods, and then summarise their chemotaxonomic significance.

Phytochemical research
Phytochemical investigation of the ethanol extract from the whole plant of A. pilosa led to the isolation of 31 compounds. The structures of the compounds (see Figure S1 in Supplemental file) were determined on the basis of various spectroscopic data including 1D-NMR and 2D-NMR, and by comparison with the literature. The isolated compounds were identified as tiliroside (1) (Chen et al. 1978), agrimol D (30) (Chen et al. 1978), and tianshic acid (31) (Yuan et al. 2008).

Chemotaxonomic significance
In recent years, phytochemistry research showed that there are many kinds of chemical constituents in the plants of this family, including flavonoids and their glycosides Liu et al. 2014), sterols and their glycosides (Bilia et al. 1994), triterpenoids (Bilia et al. 1993;An et al. 2005;Liu et al. 2014), and tannins (Okuda et al. 1984). From all the isolates in this study, compounds 5, 7 and 20 were firstly obtained from the genus Agrimonia, and compounds 6, 10-11, 15, 26, 28 and 31 were firstly isolated from the family Rosoideae.

Disclosure statement
No potential conflict of interest was reported by the authors.

Funding
This study was financially supported by the National Natural Science Foundation of China [grant number 31500277] and the Open Fund of Guangxi Key Laboratory of early Prevention in Regional High incidence Cancer [grant number GK2015-TKF02].