METHODOLOGY: Three sodium-fluoride(NaF) concentration(0.01%w/v,0.1%w/v and 0.5%w/v respectively)and two poly-γ-glutamic acid(PGGA)concentration(1%w/v and 2%w/v respectively)were prepared in 0.1 M acetic acid(pH4.0)and deionized distilled water.For de/re-mineralisation study, tooth samples (18 teeth varnished, leaving a 2 mm2 window on the mid-buccal surfaces) were immersed in respective acidified NaF and PGGA solutions. The Ca2+ release/uptake was monitored with ISE over 72-hr with increasing pH every 24-h from 4.0 to 6.0.These teeth were later subjected to cross-sectional microhardness to determine integrated mineral recovery of enamel on increasing pH of respective acidified solution.In order to determine mechanism of PGGA,two concentrations of PGGA in deionized-water-solutions were used for tooth samples immersion followed by overnight drying then later subjected to Fourier Transform Infra-Red(FT-IR) analysis.The FT-IR analysis was also carried out on PGGA powder.For control,the experiment was repeated using hydroxyapatite(HAp)pellets.The density of PGGA solutions(1%and2%)was also measured to determine their dynamic viscosities.
RESULTS: The ISE and microhardness testing revealed statistically significant (ρ ≤ 0.05) dissolution inhibition and remineralisation potential for tooth sample treated with acidified 2%PGGA. From the FT-IR spectra, it was observed that the profiles of the enamel and HAp surfaces treated with 1%-and 2%-PGGA solutions were similar to those of PGGA powder.It was found that the viscosity of PGGA increases with increasing concentration.
CONCLUSION: The study implies that 2% PGGA is more effective than NaF as forms a coating layer to protect from demineralisation and promote remineralisation of the tooth surface.
AIM OF THE STUDY: This study is designed to investigate the vasorelaxant effect of Chen pi and to study its pharmacology effects.
MATERIALS AND METHODS: The vasorelaxant effect of water extract of Chen pi (CRW) were evaluated on thoracic aortic rings isolated from Sprague Dawley rats. The fingerprint of Chen pi and the extracts were developed with quantification of hesperidin content by HPTLC.
RESULTS: CRW exhibited the strongest vasorelaxant activity. CRW caused the relaxation of the phenylephrine pre-contracted aortic rings in the presence and absence of endothelium as well as in potassium chloride pre-contracted endothelium-intact aortic ring. The incubation of propranolol (β-adrenergic receptor blocker), atropine (muscarinic receptor blocker), Nω-nitro-L-arginine methyl ester (NO synthase inhibitor), ODQ (sGC inhibitor), indomethacin (COX inhibitor), 4-aminopyridine (KV blocker), barium chloride (Kir blocker), and glibenclamide (KATP blocker) significantly reduced the vasorelaxant effects of CRW. CRW was also found to be active in reducing Ca2+ releases from the sarcoplasmic reticulum and suppressing the voltage-operated calcium channels.
CONCLUSION: The vasorelaxant effect of CRW on rat aorta involves NO/sGC, calcium and potassium channels, muscarinic and β-adrenergic receptors.