Vaccines have a tremendous role to combat acute and chronic infectious diseases, and to improved human health. Modern subunit vaccines are produced by using recombinant or synthetic antigens to create therapeutic and prophylactic vaccines rather than live or attenuated microbes used in traditional vaccines. Although subunit vaccines offer improved safety and more specific targeting, they are poorly immunogenic and often require multiple doses for protection.¹ As such, these vaccines are usually co-administered with (vaccine) adjuvant to enhance immunogenicity.² Vaccine adjuvants not only improve the immunogenicity of the subunit vaccines but also improve the efficacy of vaccines and reduce the amount of required rare and expensive antigens.³ Though in last few decades several vaccine adjuvants have been developed, they suffer from various limitations like high toxicity, significant side effect and less effective adjuvanticity.
In this regard carbohydrate vaccine adjuvants are good alternative as they possess minimal toxicity, readily biodegradable and high biocompatibility. QS-21, a natural product, isolated from Quillaja saponaria tree, is one such promising carbohydrate vaccine adjuvant.⁴ Despite the promise of QS-21 it has several drawbacks associated with its clinical use such as limited supply, laborious and very low yielding isolation process, and chemical instability for long term storage.⁵ Hence, there is a huge demand to develop novel carbohydrate vaccine adjuvants with suitable and effective adjuvanticity, but has the minimal toxicity, stable for long-term storage and cost effective synthesis for more supply. Initial studies showed that Lablaboside F and Soyasaponins (A1, A2, I, III) could be a suitable alternative as those exhibited negligible hemolytic toxicity, while maintaining potent immunopotentiating properties compared to QS-21.⁶ Thus herein we describe an easy and step economic synthetic rout to achieve the Lablaboside F with good yield and extraction of Soyasaponins from soybean.

Jayanta Ghorai

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