Coffee To Go – Coffee’s Aroma Kick-starts Genes In Rat Brain
Drink coffee to send a wake-up call to the brain? Or just smell its rich, warm aroma? An international group of scientists is reporting some of the first evidence that simply inhaling coffee aroma alters the activity of genes in the brain.
In experiments with laboratory rats, they found that coffee aroma orchestrates the expression of more than a dozen genes and some changes in protein expressions, in ways that help reduce the stress of sleep deprivation.
Han-Seok Seo and colleagues point out that hundreds of studies have been done on the ingredients in coffee, including substances linked to beneficial health effects. “There are few studies that deal with the beneficial effects of coffee aroma,” they note. “This study is the first effort to elucidate the effects of coffee bean aroma on the sleep deprivation-induced stress in the rat brain.”
In an effort to begin filling that gap, they allowed lab rats to inhale coffee aroma, including some rats stressed by sleep deprivation. The study then compared gene and protein expressions in the rats’ brains. Rats that sniffed coffee showed different levels of activity in 17 genes. Thirteen of the genes showed differential mRNA expression between the stress group and the stress with coffee group, including proteins with healthful antioxidant activity known to protect nerve cells from stress-related damage.
ASAP J. Agric. Food Chem., ASAP Article, 10.1021/jf8001137
Web Release Date: June 3, 2008
Effects of Coffee Bean Aroma on the Rat Brain Stressed by Sleep Deprivation: A Selected Transcript- and 2D Gel-Based Proteome Analysis
Han-Seok Seo, Misato Hirano, Junko Shibato, Randeep Rakwal, In Kyeong Hwang, and Yoshinori Masuo§
The aim of this study was 2-fold: (i) to demonstrate influences of roasted coffee bean aroma on rat brain functions by using the transcriptomics and proteomics approaches and (ii) to evaluate the impact of roasted coffee bean aroma on stress induced by sleep deprivation. The aroma of the roasted coffee beans was administered to four groups of adult male Wistar rats: 1, control group; 2, 24 h sleep deprivation-induced stress group (the stress group); 3, coffee aroma-exposed group without stress (the coffee group); and 4, the stress with coffee aroma group (the stress with coffee group). Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of some known genes responsive to aroma or stress was performed using total RNA from these four groups. A total of 17 selected genes of the coffee were differently expressed over the control. Additionally, the expression levels of 13 genes were different between the stress group and the stress with coffee group: Up-regulation was found for 11 genes, and down-regulation was seen for two genes in the stress with coffee group. We also looked to changes in protein profiles in these four samples using two-dimensional (2D) gel electrophoresis; 25 differently expressed gel spots were detected on 2D gels stained by silver nitrate. Out of these, a total of nine proteins were identified by mass spectrometry. Identified proteins belonged to five functional categories: antioxidant; protein fate; cell rescue, defense, and virulence; cellular communication/signal transduction mechanism; and energy metabolism. Among the differentially expressed genes and proteins between the stress and the stress with coffee group, NGFR, trkC, GIR, thiol-specific antioxidant protein, and heat shock 70 kDa protein 5 are known to have antioxidant or antistress functions. In conclusion, the roasted coffee bean aroma changes the mRNA and protein expression levels of the rat brain, providing for the first time clues to the potential antioxidant or stress relaxation activities of the coffee bean aroma.