Bridging the Gaps between Plant and Human Health: A Systematic Review of Soyasaponins

Abstract

Saponins, prominent secondary plant metabolites, are recognized for their roles in plant defense and medicinal benefits. Soyasaponins, commonly derived from legumes, are a class of triterpenoid saponins that demonstrate significant potential for plant and human health applications. Previous research and reviews largely emphasize human health effects of soyasaponins. However, the biological effects of soyasaponins and their implications for plants in the context of human health have not been welldiscussed. This review provides comprehensive discussions on the biological roles of soyasaponins in plant defense and rhizosphere microbial interactions; biosynthetic regulation and compound production; immunological effects and potential for therapeutics; and soyasaponin acquisition attributed to processing effects, bioavailability, and biotransformation processes based on recent soyasaponin research. Given the multifaceted biological effects elicited by soyasaponins, further research warrants an integrated approach to understand molecular mechanisms of regulations in their production as well as their applications in plant and human health.

Saponin Biosynthesis in Pulses

“…Saponins display a wide range of biological activities such as anti-microbial or antiinsect repellent activity, being produced as plant defense molecules in response to biotic threats, pathogens and herbivores [9]. Being a part of the antimicrobial defense system of plants, saponins change qualitatively and quantitatively in response to pathogen attacks [6].…”

“…Additionally, saponins confer defensive measures against insects due to their bitter and astringent taste [11]. Given the growing concerns over the widespread use of synthetic pesticides, saponins are suggested to be environmentally friendly alternatives to conventional pesticides to provide crop protection [9]. In addition to being natural pesticides, saponins also enhance the abundance of the plant-beneficial microbes in the rhizosphere.…”

“…In addition to being natural pesticides, saponins also enhance the abundance of the plant-beneficial microbes in the rhizosphere. Accumulating evidence has indicated that soyasaponins in legume root exudates promote the growth of the beneficial microbes that are associated with root nodulation and nitrogen fixation in the rhizosphere, although the composition of secreted soyasaponins is species-dependent and varies between the field and hydroponic culture conditions [9,[12][13][14][15].…”

“…In the context of human health, saponins exhibit a wide spectrum of pharmacological properties, including anti-cholesterolemic, anti-cancer and hemolytic activities [2,4,9,16]. On the other hand, they can cause toxic effects to monogastric animals, and reduce forage palatability and digestibility in ruminants [17].…”

“…Soyasaponins, belonging to the oleanane triterpenoid group, are composed of soyasapogenol and oligosaccharide moieties, and are abundantly present in in the seeds of legumes such as soybean and pulses [2,9]. Four major groups of soyasaponins are distributed in legumes, namely soyasaponins A, B, E and DDMP (2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one), which are categorized by their different substitutions at the C-21 and C-22 positions of the aglycone [23].…”