Anti-obesity activity

Pharmacologically, evodiamine has been widely studied as innovative antiobesity agent and was classified as a full TRPV-1 (transient receptor potential vanilloid-type 1) agonist. This receptor is a nonspecific ion chaimel and is activated by not only chemical compounds containing vanUlyl moiety but also heat (>45 °C) and acid (micromolar range) stimuli. It exhibited binding affinity similar to capsaicin in Chinese hamster ovary cell model. Despite similar in vitro and in vivo anti-obese activities between these compounds, evodiamine has not perceptible taste, including a peppery hot taste [80, 81]. 

Kobayashi Y, Nakano Y, Kizaki M, Hoshikuma K, Yokoo Y, Kamiya T (2001) Capsaicinlike anti-obese activities of evodiamine from fruits of Evodia rutaecarpa, a vanilloid receptor agonist. Planta Med 67(7) 628-633. doi 10.1055/s-2001-17353... 

It is well known that dietary fat is not absorbed from the intestine unless it has been subjected to the action of pancreatic lipase [1], Previously, we found that basic proteins such as protamines, histones and purothionine inhibited the hydrolysis of triolein emulsified with phosphatidylcholine [2], The inhibition of hydrolysis of dietary fat may cause a decrease or delay in the intestinal absorption of fat and reduce blood chylomicron levels, an excess of which is known to induce obesity [3], Therefore, there was a possibility that inhibitory substances toward pancreatic lipase activity may prevent the onset of obesity induced by feeding a high fat diet to mice. Recently, we found that natural products such as tea saponin, platycodi radix saponin, chitin-chitosan and chondroitin sulfate inhibited the pancreatic lipase activity. In the following section, the anti-obesity effects of these natural products will be described in detail. 

It was demonstrated that the anti-obesity effects of oolong tea in high-fat diet-treated mice might be partly due to the inhibitory actions of the saponin fraction in oolong tea on pancreatic lipase activity. In this study, tea saponin prevented the high-fat diet-induced increases in body and parametrial adipose tissue weights by inhibiting the intestinal absorption of dietary fat via inhibition of pancreatic lipase activity, Fig. (5). 

It has been reported that various saponins isolated from foodstuffs have anti-obesity or hypolipidaemic actions [12-16], We found that the crude saponin fractions isolated from Platycodi radix strongly inhibited the pancreatic lipase activity, Fig. (10). 

Serotonin controls the feeling of fullness after eating. The anti-obesity drug fenfluramine was originally prescribed because it increases serotonin levels, thus curing appetite. It turned out, however, that fenfluramine also did but serious damage to the heart and has since been withdrawn from the market. Despite this setback, biochemical research on obesity is one of the most active current research frontiers. 

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