Background: Caffeic acid (CA) and ellagic acid (EA) are phenolic acids naturally occurring in many plant foods. Cardiac protective effects of these compounds against dyslipidemia, hypercoagulability, oxidative stress and inflammation in diabetic mice were examined. Methods: Diabetic mice were divided into three groups (15 mice per group): diabetic mice with normal diet, 2% CA treatment, or 2% EA treatment. One group of non-diabetic mice with normal diet was used for comparison. After 12 weeks supplement, mice were sacrificed, and the variation of biomarkers for hypercoagulability, oxidative stress and inflammation in cardiac tissue of diabetic mice were measured. Results: The intake of CA or EA significantly increased cardiac content of these compounds, alleviated body weight loss, elevated plasma insulin and decreased plasma glucose levels in diabetic mice (p < 0.05). These treatments also significantly enhanced plasma antithrombin-III and protein C activities (p < 0.05); and decreased triglyceride content in cardiac tissue and plasma (p < 0.05), in which the hypolipidemic effects of EA were significantly greater than that of CA (p < 0.05). CA or EA significantly lowered cardiac levels of malondialdehyde, reactive oxygen species, interleukin (IL)-beta, IL-6, tumor necrosis factor (TNF)-alpha and monocyte chemoattractant protein (MCP)-1 (p < 0.05); and retained cardiac activity of glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (p < 0.05). These compounds also significantly up-regulated cardiac mRNA expression of GPX1, SOD and catalase; and down-regulated IL-1beta, IL-6, TNF-alpha and MCP-1 mRNA expression in diabetic mice (p < 0.05). Conclusion: These results support that CA and EA could provide triglyceride-lowering, anti-coagulatory, anti-oxidative, and anti-inflammatory protection in cardiac tissue of diabetic mice. Thus, the supplement of these agents might be helpful for the prevention or attenuation of diabetic cardiomyopathy.

The antibacterial effects of roselle calyx aqueous and ethanol extracts and protocatechuic acid against food spoilage bacteria Salmonella typhimurium DT104, Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus were examined. Minimal inhibitory concentrations of roselle calyx aqueous and ethanol extracts and protocatechuic acid against these bacteria were in the range of 112–144, 72–96, and 24–44 μg/mL, respectively. Protocatechuic acid content in roselle calyx aqueous and ethanol extracts was 2.8 ± 0.7 and 11.9 ± 1.2 mg/g, respectively. Antibacterial activity of roselle calyx ethanol extract and protocatechuic acid was not affected by heat treatments from 25° to 75°C and 25° to 100°C, respectively. After 3 days storage at 25°C, the addition of roselle calyx extracts and protocatechuic acid exhibited dose-dependent inhibitory effects against test bacteria in ground beef and apple juice, in which the roselle calyx ethanol extract showed greater antibacterial effects than the aqueous extract. These data suggest that roselle calyx ethanol extract and protocatechuic acid might be potent agents as food additives to prevent contamination from these bacteria.