Antirheumatoid Arthritis Activities and Chemical Compositions of Phenolic Compounds-Rich Fraction from Urtica atrichocaulis, an Endemic Plant to China

Abstract

Urtica atrichocaulis, an endemic plant to China, is commonly used to treat rheumatoid arthritis even though its pharmaceutical activities and chemical constituents were not studied. Herein, we reported our investigations on the chemical compositions of the phenolic compounds-rich fraction from U. atrichocaulis (TFUA) and their antirheumatoid arthritis activities. We found that the TFUA significantly inhibited the adjuvant-induced rats arthritis, carrageenin-induced rats paw edema, cotton pellet-induced mice granuloma, and the acetic acid-induced mice writhing response. Our phytochemical investigations on the TFUA resulted in the first-time isolation and identification of 17 phenolic constituents and a bis (5-formylfurfuryl) ether. The extensive HPLC analysis also revealed the chemical compositions of TFUA. Our further biological evaluation of the main phenolic components, individually and collectively, indicated that the antirheumatoid arthritis activities of TFUA were the combined effect of multiple phenolic constituents.

Figure 1

Effect of phenolic compounds-rich fraction from Urtica atrichocaulis (TFUA) on the weight of cotton pellet-induced granuloma in mice. Values are expressed as mean ± SD. N  =  10. *P  <  0.05, **P  <  0.01 compared with vehicle control.

Figure 2

The chemical structures of 18 compounds isolated from TFUA. 1: bis (5-formylfurfuryl) ether; 2: scopoletin; 3: (–) olivil; 4: (–) secoisolariciresinol; 5: (–) matairesinol; 6: ferulic acid; 7: p-coumaric acid; 8: caffeic acid; 9: protocatechuic aldehyde; 10: salicylic acid; 11: luteolin; 12: quercetin; 13: gossypetin; 14: kaempferol-3-O-rutinoside; 15: rutin; 16: kaempferol 3, 7-di-O-rhamnopyranoside; 17: phaselic acid; 18: chlorogenic acid.

Figure 3

HPLC profile of phenolic compounds-rich fraction from Urtica atrichocaulis (TFUA). The concentration of TFUA was 1.0 mg/mL and injection volume was 10 μL. The detection wavelength was set at 280 nm and the column was thermostated at 30°C. The eluent was H₂O (containing 0.1% acetic acid)/acetonitrile. A linear gradient solvent system was used, starting from 95% H₂O to 100% acetonitrile during a 40-min period, at the flow rate of 0.8 mL/min. 1: protocatechuic aldehyde; 2: caffeic acid; 3: chlorogenic acid; 4: secoisolariciresinol; 5: rutin; 6: phaselic acid; 7: kaempferol-3-O-rutinoside + kaempferol 3, 7-di-O-rhamnopyranoside; 8: salicylic acid; 9: scopoletin; 10: ferulic acid + gossypetin; 11: quercetin; 12: luteolin.