Biosynthesis and Functional Analysis of Steviol Glycosides

Steviol glycosides are diterpenoid sweeteners derived from the leaves of Stevia rebaudiana and represent a family of natural zero-calorie compounds that are 200–300 times sweeter than sucrose. Their biosynthesis commences with the plastidial methylerythritol phosphate (MEP) pathway, leading to the common diterpene precursor geranylgeranyl diphosphate. A series of cytochrome P450 monooxygenases and UDP-glucosyltransferases then catalyse sequential oxidations and glycosylations to yield stevioside, rebaudioside A and other related steviol glycosides. Functional analysis has revealed not only their sensory properties but also a range of physiological activities, including modulation of taste receptor channels, enhancement of insulin secretion, antioxidant effects and influence on lipid and glucose metabolism. Advances in transcriptomics and metabolic engineering have deepened understanding of the gene networks regulating metabolic flux toward steviol glycoside accumulation, enabling strategies to optimise yield and tailor glycoside profiles. Globally, these compounds hold significant potential as natural sweeteners in food and beverage industries, as nutraceuticals in metabolic disease management and as lead structures for novel therapeutic agents.

Research from Nature Portfolio

Recent studies have elucidated molecular targets and developmental regulation of steviol glycoside synthesis. One investigation demonstrated that stevioside, rebaudioside A and steviol act as positive modulators of the TRPM5 ion channel in taste receptor and pancreatic β-cells, potentiating sweet, umami and bitter perception and enhancing glucose-induced insulin release in a Trpm5-dependent manner. This work provides a mechanistic basis for the anti-hyperglycaemic effects of daily stevioside consumption in animal models. Another study employed global transcriptome profiling to dissect developmental phase-dependent reprogramming of biosynthetic genes in leaf tissue. It identified key transcription factors and shifts in metabolic flux between gibberellin and steviol glycoside pathways, and pinpointed candidate UDP-glucosyltransferases and cytochromes P450 for future metabolic engineering to increase desired glycoside content.

Biosynthesis and Functional Analysis of Steviol Glycosides publication trend

The graph below shows the total number of articles in biosynthesis and functional analysis of steviol glycosides across all publications each year (not limited to Nature Index journals).

Technical terms

Steviol glycosides (SGs): Diterpenoid compounds characterised by a steviol aglycone linked to one or more sugar moieties, responsible for intense sweetness.

MEP pathway: Plastidial methylerythritol phosphate route that supplies isoprenoid precursors for diterpene biosynthesis.

UDP-glucosyltransferase (UGT): Enzymes that transfer glucose from UDP-glucose to acceptor molecules, critical for glycosylation of steviol.

TRPM5 channel: Calcium-activated cation channel in taste receptor and pancreatic cells that influences taste perception and insulin secretion.

Transcriptome profiling: Comprehensive analysis of RNA transcripts expressed in a tissue or organism, used to identify genes and regulatory networks.

References

1. Steviol glycosides enhance pancreatic beta-cell function and taste sensation by potentiation of TRPM5 channel activity. Nature Communications (2017).
2. Molecular dissection of transcriptional reprogramming of steviol glycosides synthesis in leaf tissue during developmental phase transitions in Stevia rebaudiana Bert. Scientific Reports (2017).
3. Steviol glycosides from Stevia rebaudiana Bertoni mitigate lipid metabolism abnormalities in diabetes by modulating selected gene expression – An in vivo study. Biomedicine & Pharmacotherapy (2023).
4. Integration of Antioxidant Activity Assays Data of Stevia Leaf Extracts: A Systematic Review and Meta-Analysis. Antioxidants (2024).
5. Synthesis and production of steviol glycosides: recent research trends and perspectives. Applied Microbiology and Biotechnology (2021).