Bowman-Birk inhibitors from legumes as colorectal chemopreventive agents

Table 2 Preclinical studies showing colorectal chemopreventive properties of Bowman-Birk inhibitor-like proteins from several legume species

Species (common name)	Model system (carcinogen)	Effect and/or mechanisms of action	Ref.
Glycine max (soy)	Rodent colon carcinogenesis (DMH)	Soybean BBI is effective at concentrations as low as 10 mg/100 g diet in reducing the incidence and frequency of colorectal tumors. Its ability to inhibit serine proteases is required for their chemopreventive properties. No adverse effects are observed in treated animals	[52,53]
	Mouse colorectal carcinogenesis (DMH)	Soybean BBI, when simultaneously treated with DMH, prevent the development of neoplastic lesions and protect against the onset of severe inflammatory processes	[79]
	Mouse colon inflammation (DSS)	A soybean Bomwan-Birk inhibitor concentrate reduces colon inflammation in mice with induced ulcerative colitis. Lower mortality rates and delayed onset of mortality are observed	[58]
	Colon cancer cell proliferation	The antiproliferative properties of BBI isoinhibitors, IBB1 and IBBD2, reveal that both trypsin- and chymotrypsin–like proteases involved in carcinogenesis should be considered as potential targets
			[26]
Lens culinaris (lentil)	Colon cancer cell proliferation	Lentil BBI is able to inhibit the growth of HT29 colon cancer cells at concentrations as low as 19 μmol/L, in a concentration-dependent manner; by contrast, colonic fibroblast CCD-18Co cells are unaffected	[30]
Pisum sativum (pea)	Colon cancer cell proliferation	TI1B, a major pea protease inhibitor, affect in a dose-dependent manner the growth of HT29 colon cancer cells whereas an inactive mutant did not show any significant effect	[55]
Vicia faba (field bean)	Mouse stomach carcinogenesis (benzopyrene)	BBI proves to be biologically active, under acidic conditions, in suppressing benzopyrene-induced forestomach carcinogenesis in mice following oral treatment; the oncopreventive properties are related to its protease inhibitory activity	[93]

DMH: Dimethylhydrazine; DSS: Dextran sulphate sodium; BBI: Bowman-Birk inhibitor.