title: Vasorelaxation Study and Tri-Step Infrared Spectroscopy Analysis of Malaysian Local Herbs.
abstract: OBJECTIVE
  The aim of this paper is to investigate the activities of Malaysian local herbs (Clinacanthus nutans Lindau, Strobilanthes crispus, Murdannia bracteata, Elephantopus scaber Linn., Pereskia bleo, Pereskia grandifolia Haw., Vernonia amygdalina, and Swietenia macrophylla King) for anti-hypertensive and vasorelaxant activity. An infrared (IR) macro-fingerprinting technique consisting of conventional fourier transform IR (FTIR), second-derivative IR (SD-IR), and two-dimensional correlation IR (2D-correlation IR) analyses were used to determine the main constituents and the fingerprints of the Malaysian local herbs.
  
  
  METHODS
  The herbs were collected, ground into powder form, and then macerated by using three different solvents: distilled water, 50% ethanol, and 95% ethanol, respectively. The potentials of the extracts produced from these herbs for use as vasorelaxants were determined. Additionally, the fingerprints of these herbs were analyzed by using FTIR spectra, SD-IR spectra, and 2D-correlation IR spectra in order to identify their main constituents and to provide useful information for future pharmacodynamics studies.
  
  
  RESULTS
  Swietenia macrophylla King has the highest potential in terms of vasorelaxant activity, followed by Vernonia amygdalina, Pereskia bleo, Strobilanthes crispus, Elephantopus scaber Linn., Pereskia grandifolia Haw., Clinacanthus nutans Lindau, and Murdannia bracteata. The tri-step IR macro-fingerprint of the herbs revealed that most of them contained proteins. Pereskia bleo and Pereskia grandifolia Haw. were found to contain calcium oxalate while Swietenia macrophylla King was found to contain large amounts of flavonoids.
  
  
  CONCLUSIONS
  The flavonoid content of the herbs affects their vasorelaxant activity, and the tri-step IR macro- fingerprint method can be used as an analytical tool to determine the activity of a herbal medicine in terms of its vasorelaxant effect.
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.
authors.forename: Yung Sing
authors.identifier: 0000-0003-4924-9651
authors.initials: YS
authors.lastname: Ch'ng
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.
authors.forename: Chu Shan
authors.initials: CS
authors.lastname: Tan
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.
authors.forename: Yean Chun
authors.initials: YC
authors.lastname: Loh
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.
authors.forename: Mariam
authors.initials: M
authors.lastname: Ahmad
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.
authors.forename: Mohd
authors.initials: M
authors.lastname: Zaini Asmawi
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.
authors.forename: Mun Fei
authors.initials: MF
authors.lastname: Yam
keywords: Malaysian local herbs; tri-step FTIR; vasorelaxation