Anticancer effects of the Melosira nummuloides extract on hepatocellular carcinoma cells through JAK2/STAT3 and MAPK pathway inhibition

Melosira nummuloides , a diatom species recognized for its diverse pharmacological activities , including anti-inflammatory, antioxidant, and anti-obesity effects, has been minimally explored for its anticancer potential. This study investigated the anticancer effects of Melosira nummuloides extracts prepared using various methods: hot water (HW), ethanol (EtOH), methanol (MeOH), chloroform: methanol (2:1, v /v; CM), and supercritical fluid extraction (SFE), against hepatocellular carcinoma (HCC) cells. Among these, the CM extract demonstrated the highest cytotoxicity. Treatment with the CM extract led to concentration-dependent sub-G1 phase accumulation, suppression of JAK2/STAT3 and MAPK (ERK, JNK , and p38) signaling pathways, and caspase-dependent apoptosis in HepG2 and Huh7 cells. GC–MS and GC-FID analyses identified fatty acid compounds as predominant components in the CM extract, with heptadecanoic acid and pentadecanoic acid showing significantly lower IC 50 values and higher concentrations. These fatty acids appear to play key roles in the anticancer activity by promoting apoptosis. This study underscores the potential of Melosira nummuloides extracts, particularly the CM extract, as promising therapeutic agents for HCC, supporting the development of diatom-derived products for cancer treatment. • CM extract of Melosira nummuloides shows high cytotoxicity against HCC cells. • CM extract induces caspase-dependent apoptosis in HepG2 and Huh7 cells. • CM extract inhibits JAK2/STAT3 and MAPK pathways in HCC cells. • Pentadecanoic and heptadecanoic acids are key compounds in CM extract. • CM extract of Melosira nummuloides is a potential natural therapeutic for HCC.