Characterisation and quantification of flavonoids in Iris germanica L. and Iris pallida Lam. resinoids from Morocco.

INTRODUCTION: Iris resinoid obtained from Iris germanica or Iris pallida rhizomes is widely used in the perfume industry but its chemical composition has not yet been reported. Nevertheless, very active compounds have been identified in iris rhizomes including iridals and isoflavones. OBJECTIVE: In this first study concerning iris resinoid composition, flavonoids were qualitatively and quantitatively investigated in I. germanica and I. pallida resinoids. METHODOLOGY: Resinoids were first fractionated by reverse-phase flash chromatography in order to obtain fractions containing all isoflavones. These fractions were analysed by HPLC-DAD (diode array detector) and the fractions containing isoflavones were analysed by HPLC-QTOF (quadrupole time of flight)-MS. Then, the main isoflavones were isolated and identified by NMR and high-resolution mass spectroscopy (HRMS). Finally, total and individual isoflavones were quantified by HPLC-DAD at 265 nm using an external calibration method with irigenin as the external standard. RESULTS: Eight isoflavones were identified in both resinoids (irigenin, iristectorigenin A, nigricin, nigricanin, irisflorentin, iriskumaonin methyl ether, irilone, iriflogenin), one isoflavone only was identified in I. germanica resinoid (irisolidone), whereas one isoflavone (8-hydroxyirigenin), one isoflavanone (2,3-dihydroirigenin) and one benzophenone (2,6,4'-trihydroxy-4-methoxybenzophenone) only were identified in I. pallida resinoid. Isoflavones were quantified in I. germanica and I. pallida resinoids at 180 ± 1.6 mg/g and 120 ± 3.3 mg/g respectively. CONCLUSION: The study shows that I. germanica and I. pallida resinoids are rich in flavonoids and that these two Iris species can be distinguished by simply analysing the polyphenol fraction.

An alternative method for irones quantification in iris rhizomes using headspace solid-phase microextraction.

INTRODUCTION: The essential oil obtained from iris rhizomes is one of the most precious raw materials for the perfume industry. Its fragrance is due to irones that are gradually formed by oxidative degradation of iridals during rhizome ageing. OBJECTIVE: The development of an alternative method allowing irone quantification in iris rhizomes using HS-SPME-GC. METHODOLOGY: The development of the method using HS-SPME-GC was achieved using the results obtained from a conventional method, i.e. a solid-liquid extraction (SLE) followed by irone quantification by CG. RESULTS: Among several calibration methods tested, internal calibration gave the best results and was the least sensitive to the matrix effect. The proposed method using HS-SPME-GC is as accurate and reproducible as the conventional one using SLE. These two methods were used to monitor and compare irone concentrations in iris rhizomes that had been stored for 6 months to 9 years. CONCLUSION: Irone quantification in iris rhizome can be achieved using HS-SPME-GC. This method can thus be used for the quality control of the iris rhizomes. It offers the advantage of combining extraction and analysis with an automated device and thus allows a large number of rhizome batches to be analysed and compared in a limited amount of time.

Intracellular accumulation of rhodamine 110 in single living cells.

To gain a better understanding of the internalization of rhodamines, vital staining of living cells in situ by two different rhodamines, R110 and R123, was studied by microfluorometry. These dyes differ strongly in their lipophilic properties because of differences in charge distribution. Microspectrofluorometry was used to study the fluorescence emission spectra of R110-loaded cells to determine reliable loading conditions. Cell uptake and cell efflux studies of R110 were performed by numerical microfluorescence imaging. A slower uptake was observed for R110 (14 hr) vs R123 (2 hr), but the R110 efflux was much more rapid (30 min) than that of R123 (> 24 hr). Although it appeared in the R110 and R123 co-localization study that R110 was able to accumulate in mitochondria, labeling with R110 was lower than with R123. Our results indicate that, rhodamine 110 in its acid cationic form is able to cross the plasma and mitochondrial membrane and to accumulate in cell compartments as does the cationic rhodamine 123. However, because of its acido-basic properties, R110 should be able to decrease the pH of cell compartments, depending on their ability to regulate pH. In such a model, mitochondrial pH should be more greatly decreased than cytosolic pH, leading to a lower mitochondrial accumulation of R110 than of R123. Surprisingly, these effects, which should affect the energetic state of mitochondria, do not influence cell growth, because no cytotoxic effect was observed.