INVESTIGATION OF IMMUNOLOGICAL ADJUVANT ACTIVITIES OF PANAX GIENSENG SAPONINS IN MOUSE MODEL

Abstract

The development of effective vaccines hinges upon the inclusion of an appropriate immunopotentiator or adjuvant to enhance both cellular and humoral immune responses. Adjuvants are compounds designed to augment vaccine efficacy, and there exists an imminent need for the creation of novel and improved adjuvants. Saponins, classified as amphipathic glycosides, have garnered significant attention due to their multifaceted biological activities and their ability to stimulate immune responses when paired with antigens like ovalbumin. In this investigation, Panax ginseng roots were purchased from Hyolim Agriculture Farming in North Korea, for saponin extraction. Methanol and n-butanol extraction protocol were employed for saponin extraction, and their profiles were meticulously characterized through Flash Chromatography (FC), TLC and HPLC. Two primary fractions, designated as PS-1 (Panax ginseng-1) and PS-2 (Panax ginseng-2), were isolated and subjected to evaluation as adjuvants in a mouse model, alongside ovalbumin. Over the course of 20 days, four groups of mouse were immunized with varying doses of PS-1 and PS-2, encompassing fractions such as PS-1±40, PS-1±60, PS-2±80, and PS-2±100. The adjuvant activity was subsequently compared with QuilA saponin (QuilA±100), while a sixth group of mouse immunized ovalbumin alone. Immunization responses were assessed at primary and secondary stages on the 10th and 20th days, respectively, by quantifying IgG, IgG4 subclass antibodies, and Interleukin-6 (IL-6) concentrations through ELISA. The findings revealed that increasing doses of Panax ginseng saponins led to heightened levels of IgG and IgG4 subclass antibodies in mouse serum, concurrently with the induction of IL-6 responses discerned from spleen cell cultures. Remarkably, the PS-2±100 saponin dose exhibited a substantial upsurge, elevating IgG antibody concentration by 96.26%, IgG subclass antibody concentration by 85.19%, and triggering a notable increase in IL-6 levels (246.67 pg/l on the 20th day), as evidenced by a 0.51 optical density (OD) value post-immunization. In conclusion, Panax ginseng saponins, particularly the PS-2±100 fraction, demonstrate potent adjuvant capabilities, significantly enhancing both humoral and cellular immune responses when administered alongside ovalbumin. This research contributes valuable insights into the exploration of natural saponins as promising vaccine adjuvants, highlighting their substantial immunostimulatory potential and their prospective role in vaccine formulations.