Metabolites profiling of Mimusops caffra leaf via multiplex GC-MS and UPLC-MS/MS approaches in relation to its antioxidant and anti-inflammatory activities

Abstract

Mimusops caffra is a small to medium-sized fruit-producing tree belonging to the Sapotaceae family with potential commercial, medicinal, and nutritional value. The main goal of the current study is to profile the phytochemical composition of M. caffra leaf targeting both volatile and non-volatile metabolites using gas chromatography and mass spectrometry (GC-MS) and ultrahigh performance liquid chromatograpy coupled with mass spectrometry (UPLC-MS/MS), respectively. A total of 62 secondary metabolites were annotated via UPLC-MS/MS belonging to organic acids, phenolic acids, flavonoids, triterpenes, fatty acids and their derivatives, and sphingolipids. Moreover, 50 volatile compounds were detected by using GC-MS classified as monoterpene, aliphatic and aromatic hydrocarbons, alcohols, phenols, fatty acids/esters, and triterpenes. The antioxidant and anti-inflammatory activities of the crude methanol extract, ethyl acetate, n-butanol fractions were evaluated using DPPH radical scavenging capacity and nitric oxide inhibition activity, respectively. The crude methanol extract exhibited the strongest antioxidant activity as compared to ethyl acetate, n-butanol fractions and ascorbic acid (used as a reference antioxidant). The IC₅₀ values of the crude methanol extract, ethyl acetate, n-butanol fractions in DPPH assay were 9 ± 0.37 µg/ml, 22.1 ± 0.79 µg/ml and 42.2 ± 1.65 µg/ml, respectively, compared to 12.5 ± 0.7 µg/ml for ascorbic acid. Furthermore, NO inhibition assay revealed that most of tested extracts exhibited marked inhibition (78-88%) at a dose of 1280 µg/mL, the crude methanol extract showed the most potent anti-inflammatory activity with IC₅₀ of 137 µg/ml. Overall, these findings suggest that the crude methanol extract, n-butanol and ethyl acetate fractions of M. caffra contain potential antioxidant compounds highlighting their therapeutic potential.

Keywords: Mimusops caffra; Anti-inflammatory; Antioxidant activity; GC-MS; Sapotaceae; UHPLC-MS.

Fig. 1

GC-MS Chromatogram of M. caffra leaves n-hexane extract, 5: Decane 12: undecane, 22: Dodecane, 31: 2-phenyl undecane and 48: 24-Norursa-3,12-diene.

Fig. 2

Chemical composition of M. caffra leaves hexane extracts.

Fig. 3

Mimusops caffra tree and its leaves and pie charts of different volatile metabolites classes.

Fig. 4

Base peak chromatogram of M. caffra leaf extract (A) analysis in negative mode (B) Positive mode.

Fig. 5

The radical DPPH scavenging activity, represented by percentage of inhibition, of the three different solvent extract compared to ascorbic acid. (A) Percentage of inhibition of total extract; (B) percentage of inhibition of n-butanol extract; (C) percentage of inhibition of ethyl acetate extract and finally; (D) percentage of inhibition of ascorbic acid.

Fig. 6

The radical NO scavenging activity, represented by percentage of inhibition, of the three different solvent extract compared to ascorbic acid. (A) Percentage of inhibition of total extract; (B) percentage of inhibition of n-butanol; and (C) percentage of inhibition of ethyl acetate extract.