Metabolite Profiling of Manilkara zapota L. Leaves by High-Resolution Mass Spectrometry Coupled with ESI and APCI and In Vitro Antioxidant Activity, α-Glucosidase, and Elastase Inhibition Assays

Abstract

High-resolution mass spectrometry equipped with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) sources was used to enhance the characterization of phytochemicals of ethanol extracts of Manilkara zapota L. leaves (ZLE). Sugar compounds, dicarboxylic acids, compounds of phenolic acids and flavonoids groups, and other phytochemicals were detected from the leaves. Antioxidant activity and inhibition potentiality of ZLE against α-glucosidase enzyme, and elastase enzyme activities were evaluated in in vitro analysis. ZLE significantly inhibited activities of α-glucosidase enzyme at a lower concentration (IC50 2.51 ± 0.15 µg/mL). Glucose uptake in C2C12 cells was significantly enhanced by 42.13 ± 0.15% following the treatment with ZLE at 30 µg/mL. It also exhibited potential antioxidant activities and elastase enzyme inhibition activity (IC50 27.51 ± 1.70 µg/mL). Atmospheric pressure chemical ionization mass spectrometry (APCI–MS) detected more m/z peaks than electrospray ionization mass spectrometry (ESI–MS), and both ionization techniques illustrated the biological activities of the detected compounds more thoroughly compared to single-mode analysis. Our findings suggest that APCI along with ESI is a potential ionization technique for metabolite profiling, and ZLE has the potential in managing diabetes by inhibiting α-glucosidase activity and enhancing glucose uptake.

High Resolution Mass Spectroscopy-Based Secondary Metabolite Profiling of Nymphaea nouchali (Burm. f) Stem Attenuates Oxidative Stress via Regulation of MAPK/Nrf2/HO-1/ROS Pathway

“…Moreover, phenolic acid produced its characteristic product ion by losing the neutral mass of hydroxyl (−18 Da), methyl (−15 Da), or carboxylic (−44 Da) moiety [ 13 ]. Compound 1, 2, 3, 4, and 5 yielded a molecular ion peak [M-H] − at m/z 135.0444, 137.0227, 153.0186, 167.0344, and 169.0134 and fragmentation ions at m/z 91.05, 93.03, 106.02, 123.01, and 125.02, respectively, because of neutral loss of CO 2 confirmed the presence of methyl benzoic acid, salicylic acid, protocatechuic acid, vanillic acid, and gallic acid, respectively [ 12 , 13 , 14 ]. Compound 6 produced a precursor ion peak [M-H] − at m/z 183.0290 and diagnostic ions at m/z 139.0401 and 123.0088 by losing a CO 2 and CH 3 group and was identified as methoxygallate [ 15 ].…”

“…Compound 29, 30, and 32, with a molecular ion peak [M-H] − at m/z 117.0175, 133.0124, and 1610450 and fragmentation ions at m/z 99.00, 115.00, and 143.03 from loss of H 2 O and m/z 73.03, 89.02, and 99.05 from a neutral loss of CO 2 confirmed the presence of succinic acid, malic acid, and hydroxyadipic acid, respectively [ 12 ]. Compound 31 had a precursor ion [M-H] − at m/z 147.0292, generating characteristic ions at m/z 133.01 ([M-H-CH 3 ] − and further produced the MS 2 daughter ion peak at 115.00 and 87.00 from loss of H 2 O and COOH, respectively.…”

“…Compounds 33, 35, 36, and 37 with quasi-molecular ions [M-H] − at m/z 129.0916, 143.1061, 195.1384, and 199.1697, were identified as fatty acids including methylcaproic acid, caprylic acid, dodecadienoic acid, and dodecanoic acid, respectively, by comparison with the literature [ 2 , 11 , 12 ].…”

“…They were identified as ethyl-β-hydroxybutyric acid and α-amino-β-hydroxybutyric acid, respectively [ 28 ]. Compound 39 was designated pyroglutamic acid as it generated a monoisotopic peak [M-H] − at m/z 128.0336 and a characteristic peak at m/z at 82.0298 from a loss of 46 Da ([M-H-2H-COO]) [ 12 ].…”

“…Three different stepped normalized collision energies (NCE = 10, 30, and 40) were used to perform MS/MS experiments with the same instrument. The instrument was operated in (−) mode, and the other operative parameters for MS/MS experiments were as follows: sheath gas flow rate of 10, auxiliary gas flow rate of 0 (arbitrary units), spray voltage of 3.50 kV, capillary temperature of 320 °C, and an S-lens Rf level of 50 [ 2 , 12 ].…”