Chemical and physiological aspects of isomers of conjugated fatty acids (original) (raw)

2010, Food Science and Technology (Campinas)

Lifestyle factors, including diet, influence the development of many non transmissible chronic diseases such as cancer, atherosclerosis, inflammation, and obesity (PARK; PARIZA, 2007). The human diet contains saturated, monounsaturated and omega-3 and omega-6 polyunsaturated fatty acids (YANG et al., 2009). In addition, two types of structurally related conjugated octadecaenoic acids, namely, conjugated linoleic acids (CLAs) and conjugated linolenic acids (CLNAs), are also present in the human diet although in small quantities (YANG et al., 2009). It has been noted that the quality of dietary lipids could be an important modulator in terms of the morbidity and mortality of these diseases (NAGAO; YANAGITA, 2005). Polyunsaturated fatty acids (PUFAs), such as linoleic acid (LA, 18:2, ω-6), α-linolenic acid (LNA, 18:3, ω-3), and arachidonic acid (20:4, ω-6) are important for the maintenance of biofunctions in mammals. It should be also noted that other polyunsaturated fatty acids of omega-series such as eicosapentaenoic acid (EPA, 20:5, ω-3) and docosahexaenoic acid (DHA, 22:6, ω-3) are correlated with a reduced risk of cancer and cardiovascular disease in clinical and animal studies (NAGAO; YANAGITA, 2008). Recently, many studies are focused on 'conjugated fatty acids' (CFAs), which is the general term for a set of positional and geometric isomers of polyunsaturated fatty acids with conjugated double bonds (YUAN, G. F.; YUAN, J. Q.; LI, 2009; YUAN et al., 2009a). Interest in health benefits of CFAs is increasing since they have been shown to possess antioxidant, antitumor, immunomodulatory, and serum lipid-lowering activity (CAO et al., 2009). According to Tran et al. (2010), CFAs are known to have pharmacologic activities relevant to the prevention and treatment of atherosclerosis, obesity, cancer, and hypertension. CFAs occur naturally as diene, triene, and tetraene compounds (YUAN, G. F.; YUAN, J. Q.; LI, 2009; YUAN et al., 2009a, c). Theoretically, several CFA isomers are possible with multiple combinations of numerical, positional, and geometrical configurations of conjugation in double bonds Resumo Ácido graxo conjugado (AGC) é o termo geral usado para descrever os isômeros posicionais e geométricos dos ácidos graxos poliinsaturados com duplas ligações conjugadas. Os AGCs do ácido linoléico (ALCs) são encontrados naturalmente em alimentos derivados de animais ruminantes, carnes e produtos lácteos. Os AGCs do ácido α-linolênico (ALNCs) são encontrados exclusivamente em óleos de sementes de vários tipos de plantas. Desenvolvem-se muitas investigações com o objetivo de avaliar os efeitos do consumo de AGCs para a saúde, já que estes têm sido associados a processos fisiológicos relacionados com doenças crônicas não transmissíveis como câncer, aterosclerose, inflamação e obesidade. Estudos conclusivos sobre os efeitos dos AGCs no organismo humano ainda são raros e mais pesquisas sobre sua atuação em processos fisiológicos são necessárias. O objetivo desta revisão é discutir a influência dos ácidos graxos conjugados sobre os processos fisiológicos. Palavras-chave: ácido linoléico conjugado (ALCs); ácido α-linolênico conjugado (ALNCs); efeitos à saúde; análises.