Catalyzes the transfer of a glucose (Glc) moiety from UDP-Glc to the C-3 position of the oleanane sapogenins oleanolate and hederagenin, and to the C-28 carboxylic group of the lupane sapogenin betulinate (PubMed:23027665). The monoglucosylated hederagenin 3-O-beta-D-glucoside is a feeding deterrent of the yellow-striped flea beetle (Phyllotreta nemorum) (PubMed:23027665). oleanolate + UDP-alpha-D-glucose = H(+) + oleanolate 3-O-beta-D-glucoside + UDP kcat is 0.816 sec(-1) with oleanolate as substrate (PubMed:23027665). kcat is 0.389 sec(-1) with hederagenin as substrate (PubMed:23027665). Optimum pH is 7.9. Belongs to the UDP-glycosyltransferase family.