Bitter Melon , also known as Karela or Momordica Charantia is a herb that helps regulate blood sugar levels and keeps body functions operating normally. It contains Gurmarin, a polypeptide considered to be similar to bovine insulin, which has been shown in experimental studies to achieve a positive sugar regulating effect by suppressing the neural response to sweet taste stimuli. Karela's principle constituents are lectins, charantin and momordicine. The fruits have long been used in India as a folk remedy for diabetes mellitus. Lectins from the bitter gourd have shown significant antilipolytic and lipogenic activities.

The fruits and leaves of the plant contain two alkaloids, one of them being momordicine. The plant is reported to contain a glucoside, a saponin-like substance, a resin with an unpleasant taste, an aromatic volatile oil and a mucilage. The seeds contain an alkaloid (m.p. 236?) and an anthelmintic principle in the germ; they also contain urease. The fruits, leaves and extracts of Momordica charantia possess pharmacological properties and medicinal uses. It is useful as an emetic, purgative, in bilious affections, burning soles of the feet, as an anthelmentic, in piles, leprosy, jaundice, as a vermifuge, astringent in hemorrhoids, as a stomachic, antispasmodic, antioxytocic, hypoglycemic, antipyretic, mild hypotensive, anorectic and for the potentiation of ACh, histamine and BaCI2 induced contractions and inhibition of ACh of skeletal muscle.