Inhibition of In Vitro Copper-Induced Oxidation
of LDL. In the present study, the antioxidative
effect of guava peel and pulp extracts were studied in a
system containing 50 µg protein mL-1 of human LDL
which was oxidized in vitro by 5 µM of CuCl2. In this
system, LDL peroxidation was estimated in terms of the
formation of conjugated dienes. It is clear from these
experiments that the different portions of guava fruit
tested prolonged the lag phase in a concentrationdependent
manner. Table 3 shows the CLT50 index. The
Psidium guajava peel extract exhibited high inhibition
of in vitro copper-induced LDL oxidation.
Results of the LDL oxidation test suggest that guava
extracts were an efficient antioxidant for LDL in vitro.
Guava fruits may have potential health effects on the
prevention of atherosclerosis development (29) and may
be related to in vivo antioxidant activity of guava
components.
The evaluated parameters showed that guava fruit
is a good source of both natural antioxidants and
antioxidant dietary fiber. The generation of these
products at pilot plant scale has been recently undertaken
by our group (30).
The same two portions of a wild variety of Psidium
(Psidium acutangulum) were analyzed for dietary fiber
content and indigestible fraction (Table 2). Polyphenol
contents and antioxidant activity by three methods werealso measured (Table 4). These values implicate that
this variety could be also considered a suitable source
of AODF.