Constituents of Chamaecrista diphylla (L.) Greene Leaves with Potent Antioxidant Capacity: A Feature-Based Molecular Network Dereplication Approach

Abstract

Chamaecrista diphylla (L.) Greene (Fabaceae/Caesalpiniaceae) is a herbaceous plant that is widely distributed throughout the Americas. Plants from this genus have been used in traditional medicine as a laxative, to heal wounds, and to treat ulcers, snake and scorpion bites. In the present study, we investigated the chemical composition of Chamaecrista diphylla leaves through a mass spectrometry molecular network approach. The oxygen radical absorbance capacity (ORAC) for the ethanolic extract, enriched fractions and isolated compounds was assessed. Overall, thirty-five compounds were annotated for the first time in C. diphylla. Thirty-two of them were reported for the first time in the genus. The isolated compounds 9, 12, 24 and 33 showed an excellent antioxidant capacity, superior to the extract and enriched fractions. Bond dissociation energy calculations were performed to explain and sustain the antioxidant capacity found. According to our results, the leaves of C. diphylla represent a promising source of potent antioxidant compounds.

Keywords: Chamaecrista diphylla; antioxidants; bioactive molecules; dereplication; molecular networking.

Figure 1

Selected clusters and putative identified compounds from the molecular network in negative ion mode for the ethanolic extract (EE), methanolic (Fr-MeOH) and ethyl acetate (Fr-OAcEt) fractions of Chamaecrista diphylla leaves. Numbers inside the nodes correspond to the accurate mass (m/z) for the [M–H]^– for each precursor. Node pie charts represent the proportion of each feature in EE (red), Fr-MeOH (blue) and Fr-OAcEt (green). Square shapes correspond to the isolated compounds. Octagonal shapes correspond to a match against an experimental or in silico MS².

Figure 2

Oxygen radical absorbance capacity comparison for the ethanolic extract (EE), Fr-MeOH, Fr-OAcEt and the 8 isolated compounds from the leaves of Chamaecrista diphylla. The Kruskal–Wallis non-parametric test (equivalent to ANOVA) and Dunn’s post-test were applied [60]. The tests were based on the statistical requisites available in the literature [61] performed in the software R v. 4.03. Different letters refer to significant differences between the eleven samples (EE, Fr-MeOH, Fr-OAcEt, 9, 12, 17, 20, 24, 26, 29, and 33) at a level of p < 0.05.