Squalene: potential chemopreventive agent

Abstract

Squalene is a triterpene that is an intermediate of the cholesterol biosynthesis pathway and it can be obtained from the diet. Olive oil contains 0.2-0.7% squalene. The average intake of squalene is 30 mg/day in the United States, however, when consumption of olive oil is high, the intake of squalene can reach 200-400 mg/day as observed in Mediterranean countries. The decreased risk for various cancers associated with high olive oil consumption may be due to the presence of squalene. Experimental studies have shown that squalene can effectively inhibit chemically-induced colon, lung and skin tumourigenesis in rodents. The protective effect is observed when squalene is given before and/or during carcinogen treatment. The mechanisms involved for the chemopreventive activity of squalene may include inhibition of Ras farnesylation, modulation of carcinogen activation and anti-oxidative activities. However, several factors must be taken into consideration when the evidence for the inhibition of carcinogenesis by squalene is examined, these include the effective dose used and the time of exposure. The information obtained is from animal bioassays and the long-term effects from consuming increased levels of squalene are not known. Although animal studies have enhanced our understanding of the possible action of squalene in decreasing carcinogenesis, one must apply caution in extrapolating the information obtained in animal studies to humans, because of possible species differences. In order to evaluate the overall implications of squalene to human cancer prevention, further studies are needed to fully identify its protective effects, as well as possible detrimental effects.

Occurrence of squalene and cholesterol in various species of Czech freshwater fish

“…Kayama et al (1969) determined the hydrocarbon contents in six species of sharks; three of these were found to have 33% to 64% of squalene in liver oil. Olive oil is often mentioned as another rich source of squalene (De Leonar-high consumption of olive oil this intake reaches up to 200-400 mg (Smith 2000).…”

“…There exist a number of papers demonstrating the inhibitory effect of squalene after the administration of diverse compounds with established tumorogenicity such as, e.g., sodium arsenite (Shyh-Rong Fan et al 1996), 12-O-tetradecanoylforbol-13-acetate (Murakoshi et al 1992), hydrogen peroxide (O'Sullivan et al 2002), azoxymethane (Rao et al 1998, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanon (Smith 2000) and other substances, or after the application of ionising radiation (Storm et al 1993). These tests were mostly executed using rodents (mice, Norway rats and Chinese hamsters) or model experiments in vitro.…”

“…Mevalonate and farnesylpyrophosphate are the intermediates of this organic synthesis. Squalene is formed of two molecules of farnesylpyrophosphate (Smith 2000). It further cyclises to form lanosterol which changes to cholesterol.…”

Isolation and Identification of Secondary Metabolites from the Ovary of Nelumbo nucifera

“…Cycloartenol which is obtained from Cimicifuga simplex has several biological effects [20]. Squalene was reported to be anti-tumor activity [18].…”

Reaction of Amaranthus hybridus L. (Green) to Telfairia Mosaic Virus (TeMV) Infection

“…In Mozambique and West Africa the leaves are boiled and mixed with a groundnut sauce are eaten as salad (Oliveira and de Carvalho, 1975;Martin and Telek, 1979). This vegetable has also been reported to contain squalene which has beneficial effects on cancers and industry (Rao et al, 1998;Smith, 2000;He et al, 2003).…”