The Effect of the Ethanolic Extracts from Syzygium aromaticum and Syzygium nervosum on Antiproliferative Activity and Apoptosis in HCT116 and HT-29 Cells

Colorectal cancer (CRC) is the third most diagnosed cancer worldwide, and p53 dysfunction plays a significant role in its pathogenesis by impairing cell cycle control and apoptosis. This study aimed to elucidate the phytochemical composition and anticancer potential of extract of residue from clove hydrodistillation (<i>Syzygium aromaticum</i>, SA) and seed extract from <i>Syzygium nervosum</i> (SN). LC-DAD-MS/MS analysis identified gallic acid (2.68%) and ellagic acid (6.70%) as major constituents in SA, while SN contained gallic acid (0.26%), ellagic acid (3.06%), and 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) as major constituents. Both extracts exhibited potent antioxidant effects as evidenced by DPPH and ABTS assays. In vitro assays showed that SA and SN significantly inhibited the proliferation of HCT116 (p53 wild-type) colorectal cancer cells, with minimal effects on HT-29 (p53 mutant) cells. Apoptosis was confirmed in HCT116 via Annexin V-FITC/PI staining and increased caspase-3/7 activity. Cell cycle analysis revealed sub-G1 accumulation, accompanied by upregulated p21 and concurrently downregulated cyclin D1 expression, both hallmarks of p53-mediated checkpoint activation. These molecular effects were not observed in HT-29 cells. In conclusion, SA and SN extracts selectively induce apoptosis and cell cycle arrest in p53-functional CRC cells, likely mediated by their phenolic constituents. These findings support their potential as promising plant-derived therapeutic agents for targeted colorectal cancer treatment.