Structural characteristics, antioxidant and immunological activities of polysaccharides from Ficus hirta Vahl based on different extraction methods

Ficus hirta Vahl is a bioactive medicinal plant. However, the structural and functional differences of polysaccharides obtained through various extraction methods remain poorly understood, highlighting the need for further research to explore its potential applications. In this study, four distinct techniques—hot water extraction (HWE), ultrasound-assisted extraction (UAE), enzymatic-assisted extraction (EAE), and fermentation-assisted (FAE) — were used to isolate polysaccharides from Ficus hirta Vahl (FHVP). A comprehensive analysis was performed to evaluate and compare the physicochemical attributes, molecular structures, and free radical scavenging capabilities. These results revealed that the four extraction methods yielded polysaccharides with distinct physicochemical profiles, differing in extraction efficiency, monosaccharide composition, key structural features (FT-IR and NMR), and molecular weight distribution. Specifically, HWE-FHVP and FAE-FHVP displayed enhanced water and oil absorption properties, whereas EAE-FHVP exhibited improved emulsification performance. HWE-FHVP, UAE-FHVP, and EAE-FHVP are resistant to gastric digestion. In contrast, FAE-FHVP is susceptible to gastric degradation. In terms of antioxidant potential, UAE-FHVP exhibited the highest efficacy in neutralizing the DPPH and ABTS radicals. Conversely, HWE-FHVP and FAE-FHVP demonstrated stronger immunostimulatory effects, as evidenced by their ability to upregulate immune enzyme secretion in RAW264.7 cells. These findings underscore the importance of selecting an extraction methodology tailored to the intended application as each technique yields polysaccharides with distinct functional advantages. Concurrently, these findings provide a theoretical basis for the development and utilisation of Ficus hirta Vahl, paving the way for expanding its applications within the nutritional supplement sector and industrial development industry.