Antioxidant Activity of Anacardic Acids - Natural Antioxidants and Biocides from Wild Medicinal Plants - page 137

9 Antioxidant Activity
of Anacardic Acids

Noriyoshi Masuoka, Kuniyoshi Shimizu and Isao Kubo*
Department of Environmental Science, Policy and Management,
University of California, Berkeley, USA

9.1 Introduction

removing the cashew kernel from the nut.
The processes used are mainly hot-oil and
roasting in which the CNSL oozes out from
the shell and the liquid obtained is about
30-35% from the shell. Subsequently, the
diverse biological activities of anacardic
acids including antioxidant activity have
been described (Masuoka and Kubo, 2004;
Ha and Kubo, 2005; Kubo et al. , 2006).
Antioxidant activity is associated with a
lowered incidence of some forms of cancer
and cardiovascular diseases (Diplock et al. ,
1998). Anacardic acids have thus recently
also been advocated for use in functional
food formulations (Trevisan et al. , 2006).
These data have, however, been reported as
a result of sporadic research, so it is timely
to review and synthesize all that is currently
known.
The oxidation of unsaturated fatty acids
in biological membranes leads to a decrease
in the membrane fluidity (Dobrestova et al .,
1977) and disruption of membrane struc-
ture and function (Machlin and Bendich,
1987; Slater and Cheeseman 1987). Cellular
damage owing to lipid peroxidation is asso-
ciated with carcinogenesis (Yagi, 1987) and
other diseases (Garewal, 1997). Inhibition of
membrane peroxidation has been shown to
have a protective effect in the initiation and

In recent years the cashew Anacardium
occidentale L. (Anacardiaceae) apple has
increased in value, especially in the coun-
tries where it is grown, such as Brazil. There
is no doubt that the nut (true fruit) is the
most important product of the cashew tree.
However, this tree also yields the pear-
shaped 'apple' (pseudo fruit) to which the
nut is attached. A number of processes have
now been developed for converting the
cashew apple into various products such as
juice, jam, syrup, chutney and beverage.
Cashew apple juice is, in fact, one of the
most popular juices in Brazil today. In our
continuing efforts concerning the utiliza-
tion of 'cashew nut shell liquid' (CNSL)
from A. occidentale as a starting material for
preparation of useful compounds, anacardic
acids and 6-alk(en)ylsalicylic acids were
isolated and characterized from the cashew
apple and nut. Anacardic acids can be
obtained in large quantities from the CNSL
(reviewed by Tyman, 1979). Although the
CNSL is available in greater tonnage, it is
neglected in commercial terms, and there is
thus considerable potential for its further
exploitation. CNSL is traditionally obtained
as a by-product during the process of

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