Original sentence: These are often split into two groups: 1) Rb1 group protopanaxadiol: Rb1, Rb2, Rc and Rd) and 2) Rg1 group (propanaxatriol: Rg1, Re, Rf, and Rg2)
Edited sentence: These are often split into two groups: the Rb1 group (characterized by the protopanaxadiol presence : Rb1, Rb2, Rc and Rd) and the Rg1 group (propanaxatriol: Rg1, Re, Rf, and Rg2)