In vitro evaluation of free flavonoids in Cassia fistula Linn. calli of different ages under varying concentrations of plant growth regulators (PGRs)

Abstract

Cassia fistula Linn, a paramount medicinal plant consumed by huge population all over the world. Its bioactive metabolites include flavonoids, phenolics, and polyphenols. Major objective of current study is to find right media combination and age of callus for maximum accumulation of free flavonoids in Cassia fistula cultures. In this study, the calli were induced in MS + 1.0 mg/L 2,4-D + 0.05 mg/L BAP with 50 mg/L ascorbic acid. These calli were then transferred to basic MS medium with 1.0 mg/L 2,4,5-T and varied BAP concentrations. Four and 8 weeks old calli were used to find out the right concentration of BAP and age for upscaling of free flavonoids. The samples were extracted and HPTLC analyzed for free flavonoids at 260 nm along with the leaf explants. The study revealed that the amount and number of free flavonoids in 4 weeks old calli increased as the amount of cytokinin (0.5 to 1.0 mg/L BAP) increased but decline with further addition of BAP (2.0 mg/L BAP). In aged calli number and amount of free flavonoids exhibit a tremendous increase when compared to the calli in the same medium at 4 weeks. This is inferred that accruing age of callus, reduced quantities of plant growth regulators (optimized for callus growth) accumulate free flavonoids. The best medium for free flavonoid production is MS + 1.0 mg/L 2,4,5-T with 1.0 mg/L BAP may be recommended for producing a high amount of free flavonoids in C. fistula in vitro. The results were justified with the results of quantification.