Gastrointestinal bezoar stones: Current knowledge and future perspective on the potential of plant-derived phytobezoar in cancer treatment

Bezoar stone formation is an infrequent event in the gastrointestinal (GI) system due to the chemical reaction between stomach bile and the high intake of nondigestible food materials. There are mainly four types of GI bezoars: trichobezoar, lactobezoar, pharmacobezoar, and phytobezoar, and formations of these bezoars in humans are physical disorders which require clinical treatments. Intriguingly, phytobezoars such as Calculus bovis obtained from ox/cattle have been used in China as medicine since 2000 years ago. Modern science found C. bovis possesses antioxidant and anti-inflammatory properties, and identification of its chemical constituent led to successful synthesis of the artificial medicinal bezoar. Phytobezoars, major type of GI bezoar, can also be found in animals besides ox/cattle, and these bezoars have been traditionally used to treat against poison, and more recently those obtained from porcupines are used by Asian Chinese to treat cancer. However, to date, medicinal values of porcupine bezoars lack scientific proof. Therefore, understanding on the factors that lead to bezoar formation in the GI tract, identification of their chemical composition, and elucidation of underlying physiological mechanism modulated by phytobezoars are important to provide guidance in their usage in treating various ailments including cancer. In this chapter, the development of different bezoar stones in the GI tract is summarized on the pharmacological action of phytobezoars C. bovis, and porcupine bezoar is presented on the medicinal values of these phytobezoars. Moreover, distinct composition and classification of plant materials found in the phytobezoars and their potential benefits in cancer treatment are also discussed.