Flavonoids analysis and antioxidant, antimicrobial, and anti-inflammatory
activities of crude and purified extracts from Veronicastrum latifolium

A B S T R A C T
Veronicastrum latifolium (V. latifolium) is rich in biologically active flavonoids, and is widely used
in folk medicine. The purpose of this study was to investigate flavonoids of V. latifolium, and
evaluate its antioxidant,antimicrobial, and anti-inflammatory activities. Eight flavonoids including
vitexin, luteolin, wogonoside, apigenin, hispidulin, chrysoeriol, acacetin, and pectolinarigenin were
identified by LC–MS/MS. The purified extract was obtained by enriching crude extract of V. latifolium
through macroporous adsorption resins (MARs). The antioxidant activity of the crude extract and purified
extract was evaluated by (1,1-diphenyl-2-picrylhydrazyl) DPPH, (Ferric ion reducing antioxidant power)
FRAP, and (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) ABTS assay. This study found that the
crude extract and purified extract exhibited ability to scavenge free radicals, and the ability of the purified
extract to scavenge free radicals was stronger than the crude extract in DPPH, ABTS, and FRAP assay. In 
addition, the antimicrobial activity of the crude extract and purified extract against five bacterial strains
(Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Escherichia coli (E.coli), Pseudomonas
aeruginosa (P. aeruginosa), and Acinetobacter baumannii (A. baumannii)), and yeast (Candida albicans
(C. albicans)) was investigated. The crude extract and purified extract displayed bacteriostatic effects
against both gram-positive bacteria and yeast, and the bacteriostatic effects of the purified extract was
stronger compared with the crude extract. The vitro cytotoxicity of the crude extract and purified extract
against isolated rat peritoneal macrophages (RAW264.7) cells was considered that it was not toxic to
RAW264.7 cells at the concentration of 25–300 μg/mL. Anti-inflammatory activity of the crude extract
and purified extract was evaluated by their effects on nitric oxide (NO) production in lipopolysaccharide
(LPS) induced RAW264.7 cells. The crude extract and purified extract significantly inhibited NO production
in RAW264.7 cells at the concentration of 200 μg/mL and 300 μg/mL. This study indicated that V. latifolium
has good antioxidant, antimicrobial, and anti-inflammatory effect.

2.1. Chemicals and reagents

Veronicastrum latifolium was purchased from Medicinal Herbs
Wholesale market (Bozhou, China). Chemicals of the NaNO2, Al(NO3)3,
and NaOH were purchased from Sinopharm Chemical Reagent Co., Ltd.
(Shanghai, China). Acetonitrile, phosphoric acid, methanol, ethanol,
and other solvents used were purchased from J & K Chemical Ltd.
(Beijing, China). Flavonoids standard substances including vitexin (≥
98.0%), luteolin (≥ 98.0%), wogonoside (≥ 98.0%), apigenin(≥
98.0%), hispidulin (≥ 98.0%), chrysoeriol (≥ 98.0%), acacetin (≥
98.0%), pectolinargenin (≥ 98.5%), and rutin (≥ 98.0%) were purchased
from Chengdu Alfa Biotechnology Co., Ltd. (Sichuan, China).