Aspalathin: a rare dietary dihydrochalcone from Aspalathus linearis (rooibos tea)

Abstract

Aspalathin (2′,3,4,4′,6′-pentahydroxy-3′-C-β-D-glucopyranosyldihydrochalcone) is a natural C-linked glucosyl dihydrochalcone present in Aspalathus linearis (Burm.f.) R.Dahlgren (rooibos), a South African endemic plant, popularly consumed globally as a herbal tea. Aspalathin is reported to possess potent anti-oxidant properties that are believed to be responsible for the health benefits of rooibos. Other pharmacological properties ascribed to the molecule include antidiabetic, antimutagenic, anti-inflammatory, antithrombotic, and xanthine oxidase inhibitory activities. The role of aspalathin in limiting the progression of metabolic disorders and preventing diabetes-induced cardiovascular complications has been reported. The aforementioned potential health benefits of aspalathin have rendered it a popular natural ingredient that is incorporated in various nutraceutical and cosmeceutical products for protection against different conditions. Percutaneous permeation studies revealed some degree of absorption through the skin, supporting its use in cosmetic preparations. To perform an in-depth assessment of the scientific literature available on aspalathin, a bibliometric analysis was carried out on publications for the period 1965–2020, using the Scopus database. A total of 140 articles were retrieved, indicating that South African authors are major contributors to aspalathin research. The most common areas of investigation were identified as anti-oxidation, chemistry/chemical profiling, antidiabetic and anti-inflammatory activities. A comprehensive literature search showed that there are currently only two available reviews on aspalathin. Hence, the present review aims to explore the history and fill gaps with regards to collating aspects of the synthesis, quality control, metabolism and various biological activities of the molecule.