Isolation and biological evaluation of a novel steroid from Sagina japonica (Sw. ex Steud.) Ohwi

A previously undescribed steroidal compound (1), together with seven known metabolites (2–8), were isolated from the 70% ethanol extract of Sagina japonica (Sw. ex Steud.) Ohwi. Structural characterisation of all compounds was achieved through spectroscopic methods, including HR-ESI-MS, UV, IR, and NMR. Notably, compounds 1–2 and 4–8 are newly recorded in the genus Sagina. Biological activity evaluation revealed that compounds 5 and 8 inhibited α-glucosidase, with acarbose as the positive control. Compounds 4 and 8 demonstrated anti-inflammatory effects relative to dexamethasone (DEX). Additionally, using cisplatin (DDP) as the reference compound 6 showed inhibitory activity against both HepG2 and Hs 683 cell lines, while 4–5 and 7 displayed anti-proliferative effects in HCT-15 cells.