Physiological Functions of Freshwater Clam Extracts and the Exploration of Their Bioactive Compounds

Freshwater clams (Corbicula spp.), commonly known as shijimi in East Asia, have long been valued for their functional and nutritional properties. In this review, we summarise the physiological effects of hot water extracts derived from Taiwanese freshwater clams (FCE), particularly in relation to metabolic syndrome and other lifestyle-related disorders. Traditionally, shijimi has been used to alleviate hepatic dysfunction and symptoms associated with alcohol consumption. FCE significantly suppresses galactosamine-induced increases in serum aspartate aminotransferase and alanine aminotransferase. In addition, FCE reduces alcohol-induced hepatic lipid accumulation and lowers hepatic cholesterol levels. FCE also influences alcohol metabolism: animals receiving FCE exhibit lower blood alcohol concentrations and a faster rate of alcohol clearance following ethanol administration. These findings suggest that shijimi may protect against alcohol- or drug-induced liver damage, potentially by enhancing alcohol metabolism. Beyond its role in liver protection, shijimi has been associated with the alleviation of jaundice, possibly through increased bile secretion linked to improved cholesterol homeostasis. Supporting this, studies using models of exogenous hypercholesterolemia show that FCE lowers both serum and hepatic cholesterol levels in a dose-dependent manner. Overall, traditional claims regarding the hepatoprotective effects of shijimi are increasingly supported by mechanistic and molecular evidence. This is the first clarified review of the various effects of shijimi.