Characterization of Silybum marianum triacylglycerol regioisomers using accurate mass quadrupole time of flight mass spectrometry

Correlation between secondary metabolites of Iris confusa Sealy and Iris pseudacorus L. and their newly explored antiprotozoal potentials

BACKGROUND

In the last few decades, the use of plant extracts and their phytochemicals as candidates for the management of parasitic diseases has increased tremendously. Irises are aromatic and medicinal plants that have long been employed in the treatment of different infectious diseases by traditional healers in many cultures. This study aims to explore the potential of three common Iris species (I. confusa Sealy, I. pseudacorus L. and I. germanica L.) against infectious diseases. Their in vitro antiprotozoal potency against Plasmodium falciparum, Trypanosoma brucei brucei, T. b. rhodesiense, T. cruzi and Leishmania infantum beside their cytotoxicity on MRC-5 fibroblasts and primary peritoneal murine macrophages were examined.

METHODS

The secondary metabolites of the tested extracts were characterized by UPLC-HRMS/MS and Pearsons correlation was used to correlate them with the antiprotozoal activity.

RESULTS

Overall, the non-polar fractions (NPF) showed a significant antiprotozoal activity (score: sc 2 to 5) in contrast to the polar fractions (PF). I. confusa NPF was the most active extract against P. falciparum [IC50 of 1.08 μg/mL, selectivity index (S.I. 26.11) and sc 5] and L. infantum (IC50 of 12.7 μg/mL, S.I. 2.22 and sc 2). I. pseudacorus NPF was the most potent fraction against T. b. rhodesiense (IC50 of 8.17 μg/mL, S.I. 3.67 and sc 3). Monogalactosyldiacylglycerol glycolipid (18:3/18:3), triaceylglycerol (18:2/18:2/18:3), oleic acid, and triterpenoid irridals (spirioiridoconfal C and iso-iridobelamal A) were the top positively correlated metabolites with antiplasmodium and antileishmanial activities of I. confusa NPF. Tumulosic acid, ceramide sphingolipids, corosolic, maslinic, moreollic acids, pheophytin a, triaceylglycerols, mono- and digalactosyldiacylglycerols, phosphatidylglycerol (22:6/18:3), phosphatidylcholines (18:1/18:2), and triterpenoid irridal iso-iridobelamal A, were highly correlated to I. pseudacorus NPF anti- T. b. rhodesiense activity. The ADME study revealed proper drug likeness properties for certain highly corelated secondary metabolites.

CONCLUSION

This study is the sole map correlating I. confusa and I. pseudacorus secondary metabolites to their newly explored antiprotozoal activity.

Rapid assessment of triacylglycerol fatty acyls composition by LC-APPI+-HRMS using monoacylglycerol like fragments intensities

We present a new analytical approach for the analysis of triacylglycerol fatty acyls distribution by normal phase liquid chromatography (NPLC) coupled with APPI⁺-HRMS. The NPLC method used allows the separation of more than 30 classes of lipids. The energy of the APPI⁺ source enables the formation of low-intensity ions B fragments ([RC = O+74]⁺ <3%), characteristic of lipids with a glycerol esterified by one or more fatty acyls. We found the relative intensities of ions B were close to the fatty acyl distribution. To establish the proof of concept, we decided to focus on the triacylglycerols (TGs) class, the major component of plant oils. By either NPLC or FIA, the TGs class appeared as a single peak. In our experimental conditions, ions B are always present in the mass spectra of TGs and each ion B is specific to a fatty acyl group. The Orbitrap mass spectrometer featured high enough resolution and accuracy to identify ions B and distinguish them from other TG fragment ions. A further adjustment of the fatty acyls relative quantities calculation from ions B intensities was computed using weighting coefficients of ions B response. The methodology was developed and validated using plant oils characterized by a GC-FID reference method. NPLC-APPI⁺-HRMS method offers the advantage of analyzing the fatty acyl composition of complex lipid extracts without the need for sample preparation.