Induction of Anthocyanin Production in Established Callus Cultures of Roselle (Hibiscus sabdariffa L.) Using Yeast Extract

Abstract

Aims: Hibiscus sabdariffa var. sabdariffa (Malvaceae), a shrub locally known as roselle has been valued for its vibrant red colored calyces that are used as food colorant and health drink. Its anthocyanin content has been known to have health promoting effects like antioxidant activity, antimicrobial and anti-cancer, among others. This study was done to establish callus cultures of roselle which are capable of producing anthocyanins. Study Design: An experimental study was done to look into the effects of different factors such as explant source and growth hormone concentration on the induction of roselle callus cultures. The effect of different concentrations of yeast extract as elicitor of anthocyanin production was also tested. Place and Duration of Study: The study was conducted at the Biotechnology Laboratory for Natural Products, Institute of Biological Sciences, University of the Philippines Los Baños from June 2011 to May 2014. Methodology: Callus induction was done using aseptically grown seedlings of the Thailand accession at MS medium with different combinations of growth hormones (T1: 0.5ppm 2,4-D and 1ppm kinetin; T2: 1ppm 2,4-D and 1ppm kinetin; T3: 1ppm 2,4-D and 2ppm kinetin). Established cultures were subjected to anthocyanins elicitation using yeast extract (Y1: 8g/L, Y2: 4g/L, Y3: 1g/L and Yc: no extract) as a biotic elicitor. Results: Callus formation and ephemeral anthocyanin production were observed 2 weeks after inoculation. Addition of yeast extract increased the growth rate up to 10-fold (4g/L) but difference among treatments was not statistically significant. Callus cultures produced anthocyanins 2 weeks after transferred back to a growth medium without yeast extract. Conclusion:  Anthocyanin production was unstable and temporary but the calli proved competent for anthocyanin production. Yellow calli were also observed after exposure to yeast extract, TLC profile showed presence of chlorogenic acids which are possible precursors for anthocyanin production.