“In the western world, dietary fats can account for 40% of energy intake, with triacylglycerol (TAG) being the major component (Mu & Høy, 2004). Pancreatic lipase plays an important role in the hydrolysis of TAG with only 10–30% of hydrolysis occurring before the duodenal phase (Hamosh & Scow, 1973). Pancreatic lipase has become a valid target in the treatment of obesity with the development of Tetrahydrolipstatin (orlistat®) (Drent & Vanderveen, 1993). Orlistat inhibits pancreatic lipase by covalently
modifying the active site, reducing the hydrolysis of TAG (Borgstrom, 1988 and Hadvary et al., 1988). When taking orlistat, high throughput screening compounds the level of ingested fat excreted in the faeces can be increased from 5% to 32% when compared to a placebo group (Zhi et al., 1994). In the UK, 98% of all prescriptions for
the treatment of obesity in 2010 were for buy BIBW2992 orlistat, the remaining 2% was for Sibutramine (withdrawn 2010) (The NHS Information Centre, 2012). Gastrointestinal side effects associated with orlistat treatment can often cause problems with patient compliance to the treatment regime, with below 50% compliance, even with pharmacist intervention (Gursoy et al., 2006 and Malone and Alger-Mayer, 2003). However, the gastrointestinal side effects of orlistat may be reduced if taken concomitantly with natural fibres, such as Psyllium mucilloid ( Cavaliere, Floriano, & Medeiros-Neto, 2001). Alginates are dietary fibres consisting of a linear polymer containing two epimers of uronic acid, mannuronic (M) and guluronic acid (G) (Haug & Smidsrod, 1967). Alginates can be extracted from the cell walls of brown seaweed or from certain bacteria. For example, alginates are the major constituents of the vegetative capsule of the rigid and desiccation resistant
walls of metabolically dormant cysts in the soil bacteria Azotobacter vinelandii ( Haug & Smidsrod, 1967). Certain polymers have been shown to have an effect on triacylglycerol hydrolysis, such as chitin–chitosan mixtures and polydextrose with diethylaminoethyl groups attached (Han et al., 1999 and Tsujita et al., 2007). Both of these polymers potentially affect the substrate and the interface between substrate and enzyme. Alginates have previously Adenosine triphosphate been shown to have an inhibitory effect on gastrointestinal enzymes. In 2000 Sunderland et al., showed that alginates reduced the activity of pepsin by an average of 52% in vitro ( Sunderland, Dettmar, & Pearson, 2000). The work identified the characteristics of alginates that correlated with the level of pepsin inhibition ( Sunderland, Dettmar, & Pearson, 2000). The molecular weight of the alginate was key to the level of pepsin inhibition achievable ( Strugala et al., 2005 and Sunderland et al., 2000). The previously shown bioactivity of alginate can be altered by both sugar residue composition and molecular weight.