Phytochemicals from the Under-utilised fruit Gnetum leptostachyum

Borneo is one of the world’s biodiversity hotspots, which offers a huge diversity of plants that are yet to be explored. Gnetum leptostachyum is a gymnosperm that shares several angiosperm morphologies, indigenous to Borneo. The red fruits are eaten by the native people. In order to investigate the potential health benefits of these underutilized fruits, we probed their underlying chemistry by means of high- resolution tandem LC-mass spectrometry analysis and isolated the chemical constituents using advanced chromatographic techniques. Mass-based molecular networking analysis revealed four main clusters, which are resveratrol monomer-based stilbenes, isoharpontigenin monomer-based stilbenes, alkaloids and flavonoids. Seven stilbenes were successfully purified utilizing recycling HPLC, including resveratrol, isoharpontigenin, gnetin C, gnetin E, gnetin J, gnemonoside M and gnemonol B. The structures were confirmed using high-resolution NMR and accurate mass data. The isolated compounds were tested for α- glucosidase activity and all compounds exhibited promising activity with gnetin J and gnetin E possessing IC₅₀ values of 0.31 μg/mL and 0.32 μg/mL, respectively. Acarbose was used as the positive control (IC₅₀ of 2.2 mg/mL). This work presents for the first time the chemical constituents present in the fruit of G. leptostachyum, which we hope will form a basis for further investigation into its exploitation as a healthy food source.

 

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Publication History

Article published online:
16 November 2023