Anticancer Effect of Douchi

Abstract

Douchi is a traditional fermented soybean food with many beneficial health effects. Douchi not only has high nutritional value, it is also a traditional Chinese health food in many previous ancient books throughout the ages. The aim of this study was to determine the in vitro apoptosis-inducing effect of the volatile components of Douchi (VCD) and to examine the relationship between anticancer effects and VCD. After treatment with 0.4, 0.8, and 1.6 mg/mL VCD for 48 h, the proliferation of human nasopharyngeal carcinoma CNE-1 cells was inhibited, and treatment with 1.6 mg/mL VCD had the highest inhibitory effect (84.6%). Treatment with 0.4 and 0.8 mg/mL VCD also showed good inhibitory effects with the apoptosis rates of 29.7% and 55.6%, respectively. The flow cytometry results showed that 36.2% of the 1.6 mg/mL VCD treated CNE-1 cells in the sub-G1 phase. Reversed transcription-polymerase chain reaction (RT-PCR) analysis indicated that VCD could significantly induce apoptosis in CNE-1 cancer cells (P < 0.05) by upregulating cysteine-aspartic acid protease (caspase)-3, caspase-8, caspase-9, Bax, p53, p21, E2F1, p73 and I_kB-\(\alpha\) expression and by downregulating Bcl-2, Bcl-xL, human inhibitor of apoptosis protein (HIAP)-1, HIAP-2 and NF-_kB mRNA expression in a dose-dependent manner. VCD contained 63 chemical compounds that could potentially cause apoptosis in CNE-1 cells. These results showed that VCD had in vitro apoptosis- inducing effects in CNE-1 cells, and this effect was ascribed to the complex chemical composition of VCD. Keeping these compounds by the manufacturing method or cooking changes could enhance the qualities of Douchi in flavor maintaining and functional effects enhancement.