The seeds of Momordica charantia contain two proteins with inhibitory activity on protein synthesis in a cell-free system. One is a high potency protein synthesis inhibitor, momordin. The other is a low potency protein synthesis inhibitor which is also a hemagglutinating lectin.

Momordica charantia (MCL) lectin, isolated from seeds, is a D-galactose-specific lectin. It is a tetrameric glycoprotein wtih a molecular weight of 120 kDa. In vivo growth inhibition at different concentrations (6-24 µg/mL) of MCL is observed against Ehrlich ascites carcinoma (EAC) cells. After lectin treatment, the level of red blood cell and hemoglobin is increased significantly with the decrease of white blood cells. MCL caused cell cycle arrest at G0/G1 phase of EAC cells. MCL showed toxicity against brine shrimp nauplii with an LC50 value of 49.7 µg/mL. Several pathogenic bacteria were agglutinated by MCL in the absence of its inhibitory sugars.