Thanks to charactin and momordicin, the essential substances in karera (also known as Biter Melon or Bitter Gourd), diabetics can find relief from high blood sugar. These two substances are useful anti-oxidants in normalizing blood pressure as well as warding off diabetes complications. Diabetics. Karela has two very essential compounds called charactin and momordici. Their seeds contain plant-based insulin known as polypeptide-P, which act like the insulin made in pancreas, and lowers your sugar levels. So, whether you decide to consume Karela or drink its extract, your diabetic condition will be reversed and especially if you suffer from insulin-dependent Type 2 diabetes as well as toxemia conditions.