Biosynthesis of Capsaicin in Callus Cultures derived from Fruit Explants of Capsicum annuum L.

Biosynthesis of capsaicin (8-methyl-N-vanillyl-6-noneamide) was compared in callus cultures obtained from different explants (placenta and pericarp) of Capsicum annuum L var. HC-44 and Pusajwala fruits. MS medium supplemented with 2,4- D (2mg l-1) and kinetin (0.5 mg l-1) induced better callus formation. Capsaicin accumulation and phenylalanine ammonia-lyase (PAL) activity was 2-fold higher in placenta-derived callus culture than in pericarp-derived callus culture (with peak activity at 12 day of subculturing). Phosphate depleted medium showed a marginal increase in capsaicin content and PAL activity in both placenta and pericarp-derived callus cultures of two varieties. Whereas, nitrogen depleted medium showed about 10-fold increase in capsaicin content with corresponding 2-fold increase in PAL activity in callus cultures derived from both explants. Addition of ferulic acid (2mM) increased the capsaicin content by 2 and 1.3 folds in placenta and pericarp-derived callus cultures, whereas phenylalanine (2mM) when added to medium increased capsaicin marginally and 2 folds respectively. On the other hand streptomycin sulphate (3.4 �M) increased capsaicin content upto 2 folds in pericarp-derived callus cultures of both the varieties. Between the two varieties HC-44 derived callus cultures showed higher capsaicin content than Pusajwala derived callus cultures. The varietal variation, explant sources and composition of culture medium determine the capacity of callus cultures to synthesize capsaicin.