How Astragalus Root Converts Compounds to Boost Health

Jenn Hoskins
25th August, 2024

How Astragalus Root Converts Compounds to Boost Health

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Peking University identified a complete biosynthetic pathway for astragaloside IV from the medicinal plant Astragalus membranaceus
  • The pathway involves four key steps: C-3 oxidation, 6-O-glucosylation, C-3 reduction, and 3-O-xylosylation
  • The study successfully synthesized astragaloside IV in Nicotiana benthamiana, confirming the proposed pathway and highlighting the crucial role of specific enzymes
Astragaloside IV, a bioactive compound derived from the medicinal plant Astragalus membranaceus, has garnered significant attention for its potential therapeutic benefits. Despite previous efforts to identify the enzymes involved in its biosynthesis, the complete pathway remained elusive. A recent study conducted by researchers at Peking University has proposed a comprehensive biosynthetic pathway for astragaloside IV, providing new insights into its production[1]. The researchers identified a sequence of four key steps in the biosynthesis of astragaloside IV from cycloastragenol: C-3 oxidation, 6-O-glucosylation, C-3 reduction, and 3-O-xylosylation. The study highlights the role of a hydroxysteroid dehydrogenase, AmHSD1, which catalyzes both the C-3 oxidation of cycloastragenol to cycloastragenol-3-one and the C-3 reduction of cycloastragenol-3-one-6-O-glucoside to cycloastragenol-6-O-glucoside. Additionally, the glycosyltransferases AmGT8 and AmGT1 were identified as catalyzing the 6-O-glucosylation and 3-O-xylosylation steps, respectively. These findings build upon earlier research that characterized various glycosyltransferases from A. membranaceus. For instance, previous studies identified AmGT1, AmGT5, and AmGT9 as key enzymes involved in the glycosylation of cycloastragenol, contributing to the structural diversity of astragalosides[2]. Another study elucidated the roles of AmUGT15, AmUGT14, AmUGT13, and AmUGT7 in the biosynthesis of cycloastragenol-type glycosides, further clarifying the molecular basis for the structural diversity of these compounds[3]. The study conducted by Peking University researchers successfully synthesized astragaloside IV in transient expression in Nicotiana benthamiana using the combination of AmHSD1, AmGT8, and AmGT1. This achievement supports the proposed four-step biosynthetic pathway and underscores the crucial role of AmHSD1 in the biosynthesis of astragaloside IV within A. membranaceus. The implications of this research are significant, as astragaloside IV has been reported to exhibit protective effects against liver injury and acute liver failure induced by acetaminophen (APAP) overdose. Previous studies have demonstrated that astragaloside IV can protect against APAP-induced hepatotoxicity by activating antioxidant signaling pathways, reducing oxidative stress, and decreasing the expression of pro-inflammatory cytokines[4]. By elucidating the complete biosynthetic pathway of astragaloside IV, this study not only enhances our understanding of its production but also paves the way for the efficient and sustainable synthesis of this bioactive compound. This could potentially lead to the development of new therapeutic agents derived from A. membranaceus, offering alternative treatments for various health conditions. In summary, the identification of the complete biosynthetic pathway for astragaloside IV represents a significant advancement in the field of plant-derived bioactive compounds. The findings from this study, combined with previous research on glycosyltransferases and the protective effects of astragaloside IV, provide a comprehensive framework for the future exploration and utilization of this valuable medicinal compound.

MedicineBiochemPlant Science

References

Main Study

1) A four-step biosynthetic pathway involving C-3 oxidation-reduction reactions from cycloastragenol to astragaloside IV in Astragalus membranaceus.

Published 24th August, 2024

https://doi.org/10.1111/tpj.17001

Related Studies

2) Characterization and protein engineering of glycosyltransferases for the biosynthesis of diverse hepatoprotective cycloartane-type saponins in Astragalus membranaceus.

https://doi.org/10.1111/pbi.13983

3) Functional characterization of a cycloartenol synthase and four glycosyltransferases in the biosynthesis of cycloastragenol-type astragalosides from Astragalus membranaceus.

https://doi.org/10.1016/j.apsb.2022.05.015

4) Astragaloside IV Attenuates Acetaminophen-Induced Liver Injuries in Mice by Activating the Nrf2 Signaling Pathway.

https://doi.org/10.3390/molecules23082032


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