Structural and physicochemical characterization and purity assessment of myrsinoic acids A and B, active compounds isolated from Rapanea ferruginea barks

Abstract

The present study provided a chemical, physical and physicochemical characterization of myrsinoic acids A (MAA) and B (MAB) isolated from stem bark of Rapanea ferruginea Mez (Myrsinaceae). In previous pre-clinical studies these compounds have shown important antiinflammatory, anticholinesterasic and antimicrobial activities. A gradient stability-indicating LC-UV method was developed, and a forced degradation study was carried out. Purity, log P, solubility, and pK a were determined. Thermal analysis (DSC/TG) was conducted for both compounds. MAB was characterized by X ray powder diffraction (XRPD) and scanning electron microscopy (SEM). When submitted to stress conditions, both markers showed degradation, with MAA presenting higher lability. The purity of MAA (oil) was 76.20%, while that of MAB (powder) was 98.90%. MAA and MAB exhibited log P values of 3.30 and 3.22, respectively. MAA was very slightly soluble in methanol and acetonitrile, while MAB was slightly soluble in both solvents. Both were practically insoluble in water. MAA and MAB showed pK a of 4.5 and 4.8, respectively. In the SEM analysis, MAB showed a semi-crystalline morphology and high purity when analyzed by XRPD and DSC. This data will contribute to the development, quality control and standardization of pharmaceuticals using MAA and MAB. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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“…2b, peaks I, II, III and IV), as well as a decrease in the markers peaks. The UV absorption profiles of these peaks were similar to found for isolated MAA and MAB 20 , indicating its possible degradation products by hydrolysis, what requires further studies for structural elucidation. The degradation in oxidative media (Fig.…”

“…The gradient elution was programmed as follows: 0-2 min (25:5:70), 2-5 min (25:30:45), 5-10 min (25:60:15), 10-12 min (20:70:10), 12-15 min (15:75:10) and 15-20 min (15:84:1) than return to the initial condition until 30 min of analysis. The analysis was monitored at 260 nm for MAA and at 270 nm for MAB.As described by Zermiani et al 20 for isolated MAA and MAB.…”

3,4-dimethoxychalcone novel ultraviolet-A-protection factor in conventional sunscreen cream

“…The wavelength was set in 200–400 nm to determination using UV-Vis spectrophotometry (Hitachi, UV-3200, Japan). [ 10 ]…”

Nanoemulsion as a carrier to improve the topical anti-inflammatory activity of stem bark extract of <em>Rapanea ferruginea</em>

“…MAB marker showed a faster release from the conventional formulation than from nanoemulsion, which could be explained by its lower hydrophobicity. 28 Higher capacity of the nanoemulsion for retaining the markers in the internal phase is probably due to the degree of organization at the nanoemulsion interface, as well as the higher affinity of the markers with the internal phase.…”

“…The differences in the values of the zeta potential can be due to the acidic characteristic of the SE markers. According to Zermiani et al,28 the pKa value of MAA and MAB is 4.5 and 4.8, respectively, and pH value of nanoemulsions was 5.2, therefore myrsinoic acids are ionized as anionic substances. The in vitro irritation potential of the nanoemulsions was at a moderate level.…”