Secondary Metabolites of Medicinal Plants. Bharat Singh

an MS medium, supplemented with BAP and NAA or IAA, and then were incubated in the dark for 10–12 days for germination. Leaf explants excised from four-week-old aseptic seedlings were cultured on an MS medium supplemented with hormones BAP, kinetin (Kin), and the combination of BAP + Kin, BAP with NAA, and BAP with IAA. The BAP with NAA media was observed to be more suitable for callus formation. The highest number of regenerated shoot buds was obtained when shoot explants were cultured on an MS medium supplemented with BAP and IAA (Swamy et al. 2014). Capsaicinoids are acid amides of C9–C11 branched-chain fatty acids and vanillylamine. Moreover, it has been suggested that these compounds play an ecological role in seed dispersal. Recent progress has been made on the biosynthetic pathway, and several of the genes coding for biosynthetic enzymes have been cloned and expression studies performed. With regard to catabolism, cumulative evidence supports that capsaicinoids are oxidized in the pepper by peroxidases. Peroxidases are efficient in catalyzing in vitro oxidation of both capsaicin and dihydrocapsaicin. These enzymes are mainly located in placental and the outermost epidermal cell layers of pepper fruits, as occurs with capsaicinoids and some peroxidases are present in the organelle of capsaicinoid accumulation, i.e. the vacuole. Hence, peroxidases are in the right place for this function. The products of capsaicin oxidation by peroxidases have been characterized in vitro, and some of them have been found to appear in vivo in the Capsicum fruit (Díaz et al. 2004).

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