Pectic polysaccharide from corn (Zea mays L.) effectively inhibited multistep mediated cancer cell growth and metastasis

Corn pectic polysaccharide (COPP) inhibited galectin-3 mediated hemagglutination at Minimum
Inhibitory Concentration (MIC) of 4.08 lg/mL as opposed to citrus pectin (25 lg/mL), a well known galectin-
3 inhibitor and lactose (4.16 lg/mL) – sugar specific to galectin-3. COPP effectively (72%) inhibited
invasion and metastasis in experimental animals. In vivo results were substantiated by modulation of
cancer specific markers such as galectin-3, which is a key molecule for initiation of metastatic cascade,
vascular endothelial growth factor (VEGF) that enhances angiogenesis, matrix metalloproteinases 2
and 9 that are required for invasion, NF-jB, a transcription factor for proliferative potency of tumor cells
and a phosphoglucoisomerase (PGI), the activity of which favors cancer cell growth. Structural characterization
studies indicate the active component (relatively less acidic, 0.05 M ammonium carbonate,
160 kDa fraction) which showed antimetastatic potency in vitro with MIC of 0.09 lg/mL, and �45 fold
increase in the activity when compared to that of COPP. Gas liquid chromatographic analysis indicated
the presence of rhamnose (1%), arabinose (20%), xylose (3%), mannose (4%), galactose (54%) and uronic
acid (10%) in different proportions. However, correlative data attributed galectin-3 inhibitory activity
to enhanced levels of arabinose and galactose. FTIR, HPLC and NMR spectroscopic analysis further highlights
that COPP is an arabinogalactan with methyl/ethyl esters. It is therefore suggested that the blockade
of galectin-3 mediated lung metastasis appears to be a result of an inhibition of mixed functions
induced during metastasis. The data signifies the importance of dietary carbohydrate as cancer-preventive
agent. Although pectin digestibility and absorption are issues of concern, promising in vivo data provides
evidence for the cancer preventive property of corn. The present study reveals for the first time a
new component of corn, i.e., – corn pectin with cancer preventive activity apart from corn starch that
has been in wide use for multipurpose health benefits.