The antioxidant activity through b-carotene-linoleate system
of the five extracts and essential oil of M. borneensis at 50
and 100 lg/mL concentrations was compared, respectively,
with butylated hydroxyanisole and it is presented in (Table 4).
The addition of the extracts of M. borneensis and butylated
hydroxyanisole at 50 lg/mL concentrations prevented the
bleaching of b-carotene to different degrees. b-Carotene in this
method undergoes rapid discoloration in the absence of an
antioxidant. This is because of the coupled oxidation of b-carotene
and linoleic acid, which generates free radicals. The linoleic
acid formed free radical upon the abstraction of a
hydrogen atom from one of its diallylic methylene groups,