Isolated from cotton seeds. It causes infertility in a variety of cotton pests and spermatogenesis arrest in humans. Gossypol also has antimalarial properties, preventing the growth of P. falciparum at low micromolar concentrations. It inhibits aldose reductase (Ki = 0.5 µM). Gossypol also acts as an anti-cancer agent, inhibiting cell growth in various cancer cell lines, in part by blocking the anti-apoptotic functions of Bcl-2 and Bcl-xL, again at low micromolar concentrations. Also acts as a non-selective competitive inhibitor of NADH binding to LDH, with K(i) values of 1.9, 1.4, and 4.2 µM for LDH-A4, -B4, and -C4, respectively.