Dioscorea hispida (D.hispida) is the most well-known starchy tuber in Malaysia and called 'ubi gadong'. Despite concerns over toxicity effects, the tuber is known to possess therapeutic values due to the presence of bioactive compounds such as saponins. This study was performed to identify the changes in gene expression profiles associated with hepatoxicity in pregnant rat treated with D.hispida using RT² Profiler PCR Array. The identification of steroidal saponins from D.hispida was carried out by UHPLC/MS method. Treatment of D.hispida caused mortality when dosage above 2000 mg/kg b.w. was given to pregnant rats. The PCR array showed that several genes were significantly up and down-regulated upon treatment with D.hispida. Treatment of D.hispida at 2000 mg/kg b.w leads to significant upregulation of several genes such as Btg2, Gsr, L2hgdn, S100a8, Slc17a3, Bhmt, Cd68, Cyp1a2 whereas several genes were downregulated such as Abcb1a, Aldoa, Cdc14b, Icam1, Krt18, Hpn and Maob. The consumption of D.hispida extract when taken at lower dosage of 2000 mg/kg may not be harmful to rats. D.hispida extract given at the highest dosage to pregnant rats caused alterations of several genes categorized in different hepatotoxic group functions such as necrosis, cholestasis and phospholipodisis.
3',4'-Dihydroxycinnamic acid (aka caffeic acid) is a common dietary component found in a variety of plant-derived food products either in a free form or esterified as in chlorogenic acids such as 5-O-caffeoylquinic acid. The dihydroxycinnamate is produced principally by hydrolysis in the colon of 5-O-caffeoylquinic acid and other caffeoylquinic acid esters, and is catabolised by the resident microbiota prior to absorption. In the present study 3',4'-dihydroxycinnamic acid was incubated in vitro, with or without glucose, under anaerobic conditions with faecal slurries obtained from five volunteers. The main resultant catabolites to accumulate were 3-(3',4'-dihydroxyphenyl)propanoic acid (aka dihydrocaffeic acid), 3-(3'-hydroxyphenyl)propanoic acid and phenylacetic acid. Both the rate of degradation of the hydroxycinnamate substrate and the catabolite profile varied between the faecal samples from the individual volunteers. Overall there was no clear cut effect when glucose was added to incubation medium.