Evaluation of the Adjuvant Activity of Herniaria glabra Saponin-Based Nanoadjuvants

The increasing use of subunit and recombinant vaccines has created a demand for safe and effective adjuvants capable of enhancing immune responses. Here, we investigated a saponin-rich fraction isolated from Herniaria glabra as a source of novel nanoparticulate vaccine adjuvants. The saponins spontaneously self-assembled with lipid components to form stable nanocomplexes with favorable physicochemical characteristics. In a murine immunization model using viral glycoprotein antigens, these nanocomplexes significantly enhanced antigen-specific immune responses, increasing antibody titers by 8- to 16-fold compared with antigen alone. Their adjuvant activity exceeded that of aluminum hydroxide and approached that of Quillaja saponaria-derived saponin formulations. The nanocomplexes also induced balanced cellular immune responses comparable to those reported for Quil A-based nanosystems. These findings identify H. glabra as a promising alternative source of bioactive saponins and demonstrate the potential of plant-derived nanocomplexes as versatile adjuvant platforms for next-generation vaccines.