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Questions About Lectins

Fruit Lectins and E.Coli

Lectins in fruits having gastrointestinal activity: their participation in the hemagglutinating property of Escherichia coli O157:H7.

Arch Med Res 2001 Jul-Aug;32(4):251-7

Coutino-Rodriguez R, Hernandez-Cruz P, Giles-Rios H.

In fruits with therapeutic properties for antidiarrheal and laxative uses, the presence of lectins may be the bioactive properties that interfere with bacterial adhesion, thought to be competition for glycoside signal sites in the attachment. METHODS: This study identifies lectins in crude extracts from fruits such as Tamarindus indica (tamarind), Spontia vulgaris (plum), Psidium guava (guava), Mangifera indica (mango), Cydonia vulgaris (quince), and Crataegus mexicanus (tejocote). To verify the procedures, extracts from Ricinus communis (castor bean), Glycine max (soybean), Phaseolus vulgaris (beans), Vicia fava (fava bean), and Solanum tuberosum (potato) were used as controls for lectin activity. Both sources of lectins were analyzed to determine their participation in the host-parasite interaction, using as a model the hemagglutinating properties of Escherichia coli O157:H7 CONCLUSIONS: In summary, guava has a galactose-specific lectin that prevents adhesion of E. coli O157:H7 to red cells; this lectin is mediated by galactose. Prevention could also be due to their capacity of agglutinating E. coli by guava lectins.


Guava lectin is a galactose-specific lectin that may be useful in the prevention of E. coli infection of the gut. This may be particularly true and useful for group Os and group B non-secretors.

Many plant and animal lectins possess anti-microbial activity. For example, the lectins in">Helix pomatia (Roman snail; escargot) and soybean are capable of agglutinating Baccilus anthracis ('Anthrax'). Griffonia simplicifolia lectin, from the bean used to produce the 5HT supplement, also used as a 'natural mood elevator' has also been shown to agglutinate B. anthracis, however it is uncertain whether the lectin is in the nutritional supplement.

1. Cole HB, Ezzell JW Jr, Keller KF, Doyle RJ. Differentiation of Bacillus anthracis and other Bacillus species by lectins. J Clin Microbiol. 1984 Jan;19(1):48-53.

2. Doyle, R.J., Keller, K.F. and Ezzell, J.W. (1985) In: Manual of Clinical Microbiology (Lennette, E.H., Balows, A., Hausler,W. J., Shadomy, H.J eds.), pp. 211-215 (Washington DC, USA).

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