forsythiaside and caffeic-acid

The present study aimed to investigate the metabolism of Forsythoside A (FTA) by human fecal bacteria to clarify the relationship between its intestinal metabolism and its pharmacological activities. FTA was incubated with human fecal microflora in vitro to investigate its metabolic process, and highly sensitive and specific ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was performed using MetaboLynx software for metabolite analysis. Caffeic acid (CA) and hydroxytyrosol (HT) were obtained by hydrolysis of FTA, and CA was further hydrogenated to form 3,4-dihydroxybenzenepropionic acid (DCA). The anticomplementary, antimicrobial and antiendotoxin activities of FTA and its metabolites by human fecal microflora were evaluated in vitro with a hemolysis assay, the agar disc-diffusion method, the MIC value and the gel clot LAL assay, respectively. The metabolites showed higher biological activity than FTA, especially HT and DCA. Orally administered FTA may be metabolized to HT and DCA, and the pharmacological effects of FTA may be dependent on intestinal bacterial metabolism.

Topics: Adult; Animals; Anti-Infective Agents; Caffeic Acids; Chromatography, High Pressure Liquid; Complement Inactivating Agents; Feces; Female; Glycosides; Guinea Pigs; Humans; Male; Mass Spectrometry; Microbiota; Middle Aged; Molecular Structure; Phenylethyl Alcohol; Young Adult

Caffeic acid, chlorogenic acid and forsythiaside are active components of Chinese herbs and have diverse biological activities. As the similar compounds, they all include 3, 4-dihydroxy-phenyl in their structures. In this paper, the fluorescence and UV spectra of the caffeic acid, chlorogenic acid and forsythiaside were studied in different pH. The spectra properties of fluorescence and UV were further discussed in view of the phenol hydroxyl states, free, dissociative and protonated. It is found that the luminescence intensity, the peak shape and peak wavelength change with pH. Experimental results also indicate that caffeic acid, chlorogenic acid and forsythiaside can emit fluorescence in wide range of pH (2-12), and fluorescent intensity is enhanced as the dissociation of 4-phenol hydroxyl. On the other hand, fluorescent intensity may be quenched as the dissociation of 3-phenol hydroxyl. Furthermore, in strong acidic or in strong basic media, the fluorescence is quenched partly, and the shape of UV spectra changed greatly in strong basic media, meaning that their molecular structures are changed considerable.

Topics: Anti-Infective Agents; Caffeic Acids; Chlorogenic Acid; Drugs, Chinese Herbal; Glycosides; Hydrogen-Ion Concentration; Luminescence; Molecular Structure; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet