Capsicum an amide of vanillylamine with a fatty
(hot red peppers) is the most widely used spicy material in the preparation of foods
and is also reported to have medicinal applications. Capsaicinoids and capsinoids are two different classes
of lipophilic alkaloids present in capsicum
(Kobata et al. 1998). Capsaicin, is an
amide of vanillylamine with a fatty acid, is responsible for the pungent nature
of the fruits of red pepper (Kawada et al. 1986). Capsinoids, on the other hand
are the nonpungent ester analogue of capsaicinoid. Another
two related compounds of coniferyl esters, capsiconiate coniferyl (E)-8-methylnon-6-enoate, and
dihydrocapsiconiate coniferyl 8-methylnonanoate have been isolated from Capsicum baccatum L. var. praetermissum (Fig. 1). Capsiconinoids possess similar
biological activities like capsaicinoids and capsinoids (Kobata et al. 2008;
Tanaka et al. 2009). However, their pungency was found to be much weaker than
that of capsaicin, which has been attributed to the presence of double bond
next to the aromatic ring (Walpole et al. 1993). These food compounds were
found to be involved in the obesity prevention (Watanabe and Yerada 2015).
of the coniferyl esters of fatty acids were already isolated in the literature.
Coniferyl esters of palmitic and oleic acids were isolated from Platycodon grandiflorum A. Decandolle
roots. The antioxidant activities of these two compounds were found to be as
high as butylated hydroxytoluene (BHT) or butylated hydroxyanisole (BHA) (Lee
et al. 2004). Appendino et al. (2004)
isolated coniferyl stearate along with several furano- and
dihydrofuranocoumarins from the roots and seeds of the poisonous tree, named Opopanax chironium L.
to the low pungency of the coniferyl esters with potential biological and
antioxidant activity, it would be interesting to study the synthesis and
evaluation of a series of coniferyl esters which was not studied earlier. Lipase
catalyzed synthesis of capsiconinoid analogues would be more favorable in the preparation
of such biologically important molecules over chemical catalysis. In addition
lipases offer selectivity towards alcohols over phenols with mild reaction
conditions which lead to high product yields and purity (Adlercreutz 2000; Kaki
et al. 2012). Therefore, the present work aims at the enzymatic synthesis of
linear analogues of capsiconinoids and their evaluation for antioxidant
activities, which has not been reported earlier.