Mechanisms in mediating the anti-inflammatory effects of baicalin and baicalein in human leukocytes.
To evaluate the possible mechanisms responsible for the anti-inflammatory effects of baicalin or baicalein, phorbol-12-myristate-13-acetate (PMA)- or N-formyl-methionyl-leucyl-phenylalanine (fMLP)-activated inflammatory responses of peripheral human leukocytes were studied. Both baicalin and baicalein diminished fMLP- or PMA-induced reactive oxygen intermediates production in neutrophils or monocytes. Neither baicalin nor baicalein prevented the protein kinase C (PKC)-dependent assembly of the NADPH oxidase. Conversely, myeloperoxidase (MPO) activity was inhibited by baicalin or baicalein. fMLP-induced activation of leukocytes, as reflected by increased surface expression of Mac-1 (CD11b/CD18) and Mac-1-dependent neutrophil adhesion, were also inhibited by baicalin or baicalein. Furthermore, baicalein, but not baicalin, impeded fMLP- or AlF(4)(-)-induced Ca(2+) influx. We conclude that impairment of reactive oxygen intermediates production, through scavenging reactive oxygen intermediates by baicalin, or antagonizing ligand-initiated Ca(2+) influx by baicalein, accounts for the inhibition of Mac-1-dependent leukocyte adhesion that confers the anti-inflammatory activity of baicalin or baicalein.
Shen
Yuh-Chiang
YC
National Research Institute of Chinese Medicine, Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Chiou
Wen-Fei
WF
Chou
Yueh-Ching
YC
Chen
Chieh-Fu
CF
D000328:Adult; D017607:Aluminum Compounds / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D044950:Flavanones; D005419:Flavonoids / Q000494:pharmacology*; D005459:Fluorides / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D007962:Leukocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology
D017607:Aluminum Compounds; D000890:Anti-Infective Agents; D044950:Flavanones; D005419:Flavonoids; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; C050992:tetrafluoroaluminate; C038044:baicalin; C006680:baicalein; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019284:Thapsigargin; D009195:Peroxidase; D019255:NADPH Oxidases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D005459:Fluorides; D002118:Calcium