Norsteroid
Norsteroids are a structural class of steroids that have had an atom or atoms removed, biosynthetically or synthetically, from positions of branching off of rings or side chains, or from within rings of the steroid ring system. Norsteroids are systematically classified into four categories, A-, B-, C-, and D-norsteroids depending on ring if modified. Natural sources of norsteroids include but are not limited to sponges, corals, terrestrial plants, fungi, and bacteria. For instance, 19-norsteroids constitute an important class of natural and synthetic steroids derived by removal of the methyl group of the natural product progesterone; the equivalent change between testosterone and 19-nortestosterone is illustrated below.
Examples
Norsteroid examples include: 19-norpregnane, desogestrel, ethylestrenol, etynodiol diacetate, ethinylestradiol, gestrinone, levonorgestrel, norethisterone, norgestrel, norpregnatriene, quinestrol, 19-norprogesterone, nomegestrol acetate, 19-nortestosterone, and norethisterone acetate.
Ganonorsterone A
In 2023 under the guidance of the Zhao research group from the Henan [University of Chinese Medicine], in Zhengzhou, China, they discovered the compound ganonorsterone A. Obtained as a colorless oil, this compound was proved to be a dicyclic norsteroid. Using analysis of nuclear magnetic resonance data along with high-performance liquid chromatography, and electronic circular dichroism it was concluded the formula of the compound to be. This compound exhibited moderate inhibition on nitric oxide production in macrophages demonstrating potential anti-inflammatory activity; however, no cytotoxicity, or the ability to damage or kill cells, was discovered against five human cancer cell lines including but not limited to HL-60, SMMC-7721, A549, MCF-7, and SW-480.