Antioxidant and α-glucosidase inhibitory activities of eight neglected fruit extracts and UHPLC-MS/MS profile of the active extracts

The 70% ethanolic extracts from eight neglected fruits; Muntingia calabura, Leucaena leucocephala, Spondias dulcis, Syzygium jambos, Mangifera caesia, Ardisia elliptica, Cynometra cauliflora and Ficus auriculata were evaluated for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, α-glucosidase inhibitory activities as well as total phenolic content. The results of this study revealed that M. caesia fruit extract demonstrated the most potent radical scavenging activity. Among the fruits examined for α-glucosidase inhibitory activity, M. calabura and F. auriculata exhibited strong activity with no significant difference. The Pearson correlation indicated that the activities of M. caesia and F. auriculata contributed by phenolic compounds. A total of 65 metabolites were tentatively identified by using ultra-high-performance liquid chromatography tandem mass spectrometry (UHLPC-MS/MS). These findings suggested that the possible application of M. caesia and F. auriculata as a functional food with antioxidant and α-glucosidase inhibitory properties.

NMR-based metabolomics for elucidating the bioactive compounds from Mangifera caesia Jack and Ficus auriculata lour

Mangifera caesia and Ficus auriculata are neglected fruits found in Malaysia and are locally known as "buah binjai" and "buah ara", respectively. To profile the metabolites for both fruits, we conducted a robust ¹ H-nuclear magnetic resonance (NMR)-based metabolomics approach. Principal component analysis (PCA) and partial least square (PLS) analyses were applied to distinguish the metabolites variations of M. caesia and F. auriculata fruits extracted with different ethanol ratios (0, 70, and 100%). In total, 34 metabolites were identified in M. caesia and F. auriculata fruits. The 70% ethanol extracts of both fruits displayed the highest antioxidant and α-glucosidase inhibitory activities, as well as notable with the highest phenolic content, compared with the other samples. The present metabolomics study shows that the polarities of solvent extractions play a crucial role in the assessment and recovery of the metabolites for the high value of natural antioxidants and α-glucosidase inhibitors in M. caesia and F. auriculata fruits. PRACTICAL APPLICATIONS: Antioxidant and antidiabetic agents from fruit sources are increasingly becoming popular due to its potential contributions to human health, by protecting against infections and degenerative diseases. However, some of these fruits were neglected where the scientific data on their potential benefits and biochemical contents are lacking. The information gained from this study provides valuable knowledge on M. caesia and F. auriculata fruits as natural antioxidant and α-glucosidase inhibitors agents that might be beneficial to consumers, further promote the usage of neglected fruits as functional food and natural supplements.

Biological Activities of Selected Plants and Detection of Bioactive Compounds from Ardisia elliptica Using UHPLC-Q-Exactive Orbitrap Mass Spectrometry

Plants and plant-based products have been used for a long time for medicinal purposes. This study aimed to determine the antioxidant and anti-α-glucosidase activities of eight selected underutilized plants in Malaysia: Leucaena leucocephala, Muntingia calabura, Spondias dulcis, Annona squamosa, Ardisia elliptica, Cynometra cauliflora, Ficus auriculata, and Averrhoa bilimbi. This study showed that the 70% ethanolic extract of all plants exhibited total phenolic content (TPC) ranging from 51 to 344 mg gallic acid equivalent (GAE)/g dry weight. A. elliptica showed strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) scavenging activities, with half maximal inhibitory concentration (IC₅₀) values of 2.17 and 49.43 μg/mL, respectively. Most of the tested plant extracts showed higher inhibition of α-glucosidase enzyme activity than the standard, quercetin, particularly A. elliptica, F. auriculata, and M. calabura extracts with IC₅₀ values of 0.29, 0.36, and 0.51 μg/mL, respectively. A total of 62 metabolites including flavonoids, triterpenoids, benzoquinones, and fatty acids were tentatively identified in the most active plant, i.e., A. elliptica leaf extract, by using ultra-high-performance liquid chromatography (UHPLC)–electrospray ionization (ESI) Orbitrap MS. This study suggests a potential natural source of antioxidant and α-glucosidase inhibitors from A. elliptica.