title: Cytochrome P450 inhibitory potential and RP-HPLC standardization of trikatu--a Rasayana from Indian Ayurveda.
abstract: BACKGROUND
  Trikatu is a very well known 'Rasayana' in Ayurveda and widely used as a polyherbal ayurvedic formulation in India. It consists of three well known plants, viz., Piper longum (PL), Piper nigrum (PN) and Zingiber officinale (ZO) in equal ratio. Trikatu has been prescribed for cough, cold, fever, asthma, respiratory problems and improvement of digestive disorders. The aim of the present study was to investigate the effect of individual ingredients of trikatu namely PL, PN, and ZO and formulations [Marketed formulation (MF) and laboratory formulation (LF)] on drug metabolizing enzymes (CYP3A4 and CYP2D6), to assess its herb-drug interaction potential through cytochrome P450 inhibition assays. Further this work was aimed to develop an RP-HPLC method for the identification and quantification of piperine and 6-gingerol in the crude drug trikatu.
  
  
  METHODS
  Enzyme inhibition effect of LF, MF, PL, PN and ZO was explored through CYP450-CO complex assay using rat liver microsomes (RLM) and a fluorescence screening method using individual isoenzymes (CYP3A4 and CYP2D6). The RP-HPLC method was developed for the identification and quantification of piperine and 6-gingerol in LF, MF and individual plant materials at the concentration of 1mg/mL.
  
  
  RESULTS
  RP-HPLC analysis confirmed the presence of piperine and 6-gingerol in LF and MF [Piperine: 7.89±2.12% (w/w) (MF), 6.70±2.13% (w/w) (LF)]; [6-gingerol: 5.3±1.21% (w/w) (MF), 4.95±2.34% (w/w) (LF)]. Inhibitory potential of MF and LF in CYP450-CO complex assay was found to be 37.54±3.12% (MF) and 35.12±2.31% (LF) and against CYP2D6 and CYP3A4 was estimated to be IC50 251.30±3.98 and 245.23±1.92μg/mL and IC50 225.50±1.02 and 223.254±0.92μg/mL respectively.
  
  
  CONCLUSIONS
  Different concentrations of the trikatu formulation and its individual components showed significantly (p<0.001) less inhibitory activity on individual isoenzymes as compared to the positive control. The crude drug exhibited inhibitory potential against the CYP450 enzymes in a concentration dependent manner. Outcome of the present study demonstrated that trikatu has less interaction potential with drug metabolizing enzymes.
authors.affiliation: School of Natural Product Studies, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Ranjit K
authors.initials: RK
authors.lastname: Harwansh
authors.affiliation: School of Natural Product Studies, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Kakali
authors.initials: K
authors.lastname: Mukherjee
authors.affiliation: School of Natural Product Studies, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Santanu
authors.initials: S
authors.lastname: Bhadra
authors.affiliation: School of Natural Product Studies, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Kar
authors.affiliation: School of Natural Product Studies, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India.
authors.forename: Shiv
authors.initials: S
authors.lastname: Bahadur
authors.affiliation: National Research Institute of Ayurvedic Drug Development, Central Council for Research in Ayurvedic Sciences, Department of AYUSH, Kolkata 700091, India.
authors.forename: Achintya
authors.initials: A
authors.lastname: Mitra
authors.affiliation: School of Natural Product Studies, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India. Electronic address: naturalproductm@gmail.com.
authors.forename: Pulok K
authors.initials: PK
authors.lastname: Mukherjee
mesh_terms: D000475:Alkenes / Q000494:pharmacology*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism*; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism*; D065607:Cytochrome P-450 Enzyme Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D041743:Herb-Drug Interactions; D008862:Microsomes, Liver / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats
chemical_list: D000475:Alkenes; D065607:Cytochrome P-450 Enzyme Inhibitors; D010880:Piperidines; C540456:trikatu; D019389:Cytochrome P-450 CYP2D6; D051544:Cytochrome P-450 CYP3A
keywords: Ayurveda; Cytochrome P450; Herb–drug interaction; Rasayana; Spices; Trikatu