Antioxidant Activities of Dialium indum L. Fruit and Gas Chromatography-Mass Spectrometry (GC-MS) of the Active Fractions

Abstract

The fruit of Dialium indum L. (Fabaceae) is one of the edible wild fruits native to Southeast Asia. The mesocarp is consumed as sweets while the exocarp and seed are regarded as waste. This study aimed to evaluate the antioxidant activities of the fruit by using four assays, which measure its capabilities in reducing phosphomolybdic-phosphotungstic acid reagents, neocuproine, 2,2-diphenyl-picrylhydrazyl (DPPH), and inhibiting linoleic acid peroxidation. The active fractions were then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the seed methanol fraction (SMF) exhibited the strongest antioxidant activity with significantly higher (p < 0.05) gallic acid equivalence (GAE), total antioxidant capacity (TAC), and DPPH radical scavenging activity (IC50 31.71; 0.88 µg/mL) than the other fractions. The exocarp dichloromethane fraction (EDF) was the discriminating fraction by having remarkable linoleic acid peroxidation inhibition (IC50 121.43; 2.97 µg/mL). A total of thirty-eight metabolites were detected in derivatized EDF and SMF with distinctive classes of phenolics and amino acids, respectively. Bioautography-guided fractionation of EDF afforded five antioxidant-enriched subfractions with four other detected phenolics. The results revealed the antioxidant properties of D. indum fruit, which has potential benefits in pharmaceutical, nutraceutical, and cosmeceutical applications.

Antioxidant Activity of Polyphenolic Plant Extracts

“…The observed bioactivities of O. ficus-indica extracts were probably attributed to its polyphenolic content, especially to piscidic acid, eucomic acid, isorhamnetin derivatives, and rutin [31]. Moreover, Osman et al [32] identified by GC-MS the polyphenols of Dialium indum L. fruit and assessed in vitro their antioxidant properties. D. indum is native to Southeast Asia and its fruit is edible [32].…”

“…Moreover, Osman et al [32] identified by GC-MS the polyphenols of Dialium indum L. fruit and assessed in vitro their antioxidant properties. D. indum is native to Southeast Asia and its fruit is edible [32]. The results showed that the D. indum fruit contains phenolics, amino acids, saccharides, fatty acids, sesquiterpene, polyols, and dicarboxylic acids [32].…”

“…The results showed that the D. indum fruit contains phenolics, amino acids, saccharides, fatty acids, sesquiterpene, polyols, and dicarboxylic acids [32]. Interestingly, it was also demonstrated for the first time that the exocarp of D. indum fruit contains thirteen phenolic antioxidants (i.e., vanillic acid, syringic acid, ferulic acid, isoferulic acid, sinapic acid, vanillin, syringic aldehyde, p-hydroxybenzaldehyde, coniferyl aldehyde, p-hydroxybenzoic acid, homovanillic acid, p-coumaric acid, and sinapic aldehyde) [32]. Averrhoa bilimbi is another plant that has been used in traditional medicine of Asian countries [33].…”

In vivo antiplasmodial and toxicological studies of Dialium angolense Welw. Ex Oliv. (Fabaceae) leaves extracts, a medicinal plant from Eastern Congo

“…In comparison with some species of the genus Dialium, this activity appears to be much greater. Indeed, the antioxidant activity on DPPH, expressed as IC50 in μg / mL, of several species of the genus Dialium is reported in the literature, D. indum, 181.6 ± 0.4 [33,34], D. guineense, 50.23 ± 0.15 [35], D. corbisieri, 14.44 ± 0.12 and D. gossweileri, > 500 [36], D. cochinchinensis, 65.01 ± 0.12 [37]. This interesting antioxidant activity observed in D. angolense would be linked to the presence of phenolic compounds mainly flavonoids, identified and quantified within the plant during this study (table 2), as well as several previous studies which testify to the antioxidant activity of flavonoids [38][39][40][41][42].…”

Analytical Methods for Exploring Nutraceuticals Based on Phenolic Acids and Polyphenols

“…Hence, GC methods for the determination of polyphenols rely on derivatization procedures to reduce the polarity of analytes. In this regard, silylation has been successfully applied to the identification and quantification of phenolic compounds in plant and fruit extracts [66][67][68][69].…”