Analysis of Gliricidia sepium Leaves by MALDI Mass Spectrometry Imaging

Abstract

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.

A Guide to MALDI Imaging Mass Spectrometry for Tissues

“…MALDI IMS is a technology that has advanced our understanding of the adaptation, acclimation, and defense responses to environmental stresses of plants, , fungi, and bacteria . Very interesting studies have been published, including the spatial distribution of alkaloids in Erythroxylum coca leaves, the distribution of metabolites within soybean nodules, the symbiotic association between nitrogen-fixing soil bacteria ( Rhizobiaceae ) and plants of the family Leguminosa e (Figure ), and the phytochemical analysis that G. sepium leaves are composed of polyphenols and tannins, investigating the potential use of plants as a raw material for an all-natural cosmetic formulation …”

“…198 Very interesting studies have been published, including the spatial distribution of alkaloids in Erythroxylum coca leaves, 199 the distribution of metabolites within soybean nodules, the symbiotic association between nitrogen-fixing soil bacteria (Rhizobiaceae) and plants of the family Leguminosae (Figure 6), 200 and the phytochemical analysis that G. sepium leaves are composed of polyphenols and tannins, investigating the potential use of plants as a raw material for an all-natural cosmetic formulation. 201 Over the years the increasing number of MALDI IMS publications in microbiology, underlines its popularity, due to its ability to simultaneously detect biomolecules, as well as their spatial distribution, in complex samples. 202−204 The first study showing the metabolic exchange between an organism and the environment, was in 2009 by Yang et al, and they investigated interspecies interactions between B. subtilis and S. coelicolor.…”

Incorporation of Three Different Optical Trains into the IR-MALDESI Mass Spectrometry Imaging Platform to Characterize Artemisia annua

“…Mass Spectrometry Imaging (MSI) is a powerful tool with the ability to acquire spatial and abundance information directly from a sample for visualization of chemical signatures with sample morphology. − Various IR-based MSI platforms have explored endogenous metabolites in diverse mammalian tissues yielding benefits such as high spatial resolution and signal intensities, − but MSI is not as readily employed with plants. Over the years, MSI platforms such as MALDI, DESI, and LAESI have been utilized in plant studies for different biological applications, − although the incorporation of laser optics has been relatively underexplored in the field of plant analysis by MSI. A reflective objective has been integrated into the optical path in a preceding study, but not with comparison to multiple optics.…”