Screening of elite germplasms for industrially valuable medicinal crop Stevia rebaudiana for stevioside and rebaudioside A production: An HPTLC-linked chemotaxonomic assessment

Stevia rebaudiana Bertoni (Asteraceae) is a South American perennial herb native to the Paraguay region. It is high-value commercial crop in the food industry because of an array of bioactive diterpenoid glycosides, the most important of which are the steviol glycosides, stevioside (Stev) and rebaudioside A (Reb A). Standardized extract from Stevia leaves, which is high in steviol glycosides, can be used as a high-potency sweetener. The current study proposes a high-performance thin layer chromatography (HPTLC) approach for estimating stevioside and rebaudioside that is rapid, verified, and repeatable. A collection of 32 chemotypes of Stevia rebaudiana were collected from 32 districts across nine Indian states. Stevioside and rebaudioside A content ranged between 1.43 - 5.88 % and 0.77 - 1.95 % respectively across 32 chemotypes of S. rebaudiana. Among all the studied samples, SrP1 chemotype was found to possess the highest quantity of stevioside (5.88 %) and rebaudioside A (1.95 %), followed by SrH11 (5.28 % Stev; 1.89 % Reb A) chemotypes obtained from Jalandhar, Punjab and Palampur, Himachal Pradesh respectively. Chemotype SrWb32 (1.43 % Stev; 0.77 % Reb A) collected from Bardhaman, West Bengal exhibited least amount of stevioside and rebaudioside A. The current fast, reproducible, and validated HPTLC method presents an efficacious toolkit to explore the quantitative variation in the stevioside and rebaudioside A contents in natural S. rebaudiana chemotypes. This methodology may be employed to screen high stevioside and rebaudioside A yielding elite genotypes for future propagation as well as commercialization of these highly potent sweeteners to deal with the ever-expanding demand for alternative yet natural sweeteners in food industries.