PRECURSOR BIOTRANSFORMATION IN IMMOBILIZED PLACENTAL TISSUES OF CAPSICUM-FRUTESCENS MILL .1. INFLUENCE OF FEEDING INTERMEDIATE METABOLITES OF THE CAPSAICINOID PATHWAY ON CAPSAICIN AND DIHYDROCAPSAICIN ACCUMULATION

In order to enhance the levels of capsaicinoids in vitro and to optimi se the suitable precursor, immobilized placental tissues of Capsicum f rutescens were fed with intermediates of the capsaicinoid pathway. Fee ding t-cinnamic acid, p-coumaric acid, caffeic acid or ferulic acid (2 .5 mM final concentration) resulted in a greater accumulation of capsa icin and dihydrocapsaicin than was achieved with the distant precursor s phenylalanine and l-valine. Of all the precursors, coumaric acid was found to be the best for capsaicin and dihydrocapsaicin formation, re sulting in an accumulation. of 2890.8 mu g/culture and 818 mu g/cultur e, respectively, in 5 days of culture. Maximum conversion to capsaicin and dihydrocapsaicin was observed in cinnamic acid treated cultures, which was 82% and 27.5%, respectively. In the present study, a product ion of 1.188 mg capsaicin/g DW of placental tissue/day was achieved wi thout the addition of any precursor and a production of 5.78 mg capsai cin/g DW of placental tissue/day by treating with coumaric acid; this was 11-fold higher than in chilli pepper fruit. These results demonstr ate successful culture of placenta, the site of synthesis of capsaicin , to boost levels of capsaicin and dihydrocapsaicin in vitro.