Matrix-assisted laser
desorption/ionization imaging mass spectrometry
(MALDI IMS) can determine the chemical identity and spatial distribution
of several molecules in a single analysis, conserving its natural
histology. However, there are no specific studies on the spatial distribution
of alkaloids in Erythroxylum coca leaves by MALDI
IMS, preserving the histology of the monitored compounds. Therefore,
in this work, positive-ion mode MALDI Fourier-transform ion cyclotron
resonance imaging mass spectrometry (MALDI(+)FT–ICR IMS) was
applied to identify and analyze the distribution of alkaloids on the
surface of coca leaves, evaluating the ionization efficiency of three
matrices (α-cyano-4-hydroxycinnamic acid (CHCA), 2-mercaptobenzothiazole
(MBT), and 2,5-dihydroxybenzoic acid (DHB)). The last was chosen as
the best matrix in this study, and it was studied in five concentrations
(0.5, 1.0, 2.0, 4.0, and 8.0 mg·mL–1), where
2 mg·mL–1 was the most efficient. The washing
of coca leaves with the organic solvents (acetonitrile, methanol,
toluene, and dichloromethane) tested did not improve the performance
of the ionization process. Finally, a tissue section, 50 μm
thick, was used to study the inner part of the leaf tissue, where
alkaloids and flavonoid molecules were detected.
The consumption of design drugs, frequently known as new psychoactive substances (NPS), has increased considerably worldwide, becoming a severe issue for the responsible governmental agencies. These illicit substances can be defined as synthetic compounds produced in clandestine laboratories in order to act as analogs of schedule drugs mimetizing its chemical structure and improving its pharmacological effects while hampering the control and making regulation more complicated. In this way, the development of new methodologies for chemical analysis of NPS drugs is indispensable to determine a novel class of drugs arising from the underground market. Therefore, this work shows the use of high-resolution mass spectrometry Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) applying different ionization sources such as paper spray ionization (PSI) and electrospray ionization (ESI) in the evaluation of miscellaneous of seized drugs samples as blotter paper (n = 79) and tablet (n = 100). Also, an elucidative analysis was performed by ESI(+) MS/MS experiments, and fragmentation mechanisms were proposed to confirm the chemical structure of compounds identified. Besides, the results of ESI(+) and PSI(+)-FT-ICR MS were compared with those of GC-MS, revealing that ESI(+)MS showed greater detection efficiency among the methodologies employed in this study. Moreover, this study stands out as a guide for the chemical analysis of NPS drugs, highlighting the differences between the techniques of ESI(+)-FT-ICR MS, PSI(+)-FT-ICR MS, and GC-MS.
When investigating
the potential use of plants as a raw material
for an all-natural cosmetic formulation, the main parameters are the
chemical composition, antioxidant potential, antimicrobial action,
and toxicity. Additionally, the production of natural cosmetics should
also consider the availability of primary materials and the environmental
and socioeconomic impact. Gliricidia sepium is a
species that produces a large amount of plant material, being cultivated
in the agroforestry system. However, studies of phytochemical composition
and chemical spatial distribution are scarcely using the MALDI MS
(matrix-assisted laser desorption ionization mass spectrometry) and
MALDI MSI (mass spectrometry imaging) techniques. A methodology was
developed to optimize ionization parameters and analysis conditions
by evaluating the efficiency of three matrices: α-cyano-4-hydroxycinnamic
acid, 2,5-dihydroxybenzoic acid (DHB), and 2-mercaptobenzothiazole
in MALDI MS analysis. All results were compared to ESI MS (electrospray
ionization mass spectrometry), and afterward, MALDI MSI analysis was
performed on the leaf surface. This study showed through phytochemical
analysis that G. sepium leaves are composed of polyphenols
and tannins, concluding that the methanolic extract had a higher amount
of flavonoid content. Four compounds were identified on the leaf surface,
and their spatial distribution was analyzed by MALDI MS using DHB
as a matrix. Kaempferol, isorhamnetin, and some fatty acids showed
potential applicability for cosmetical use. All the extracts presented
antioxidant activity or antimicrobial action and no cytotoxicity.
Therefore, extracts of G. sepium could be used as
raw materials in cosmetics.
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