Red Potato Extract Protects fromD-Galactosamine-induced Liver Injury in Rats

Abstract

The protective effects of red potato extract (RPE) as to liver damage were determined in D-galactosamine (GalN)-intoxicated rats. Increases in serum aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase activities, all of which were induced by GalN injection, decreased in RPE administered rats, suggesting that RPE acts as a functional food showing anti-hepatotoxicity.Key words: colored potato; anthocyanin; D-galactosamine; hepatotoxicity; rat It is well-known that polyphenols originating from various fruits and vegetables have a wide range of biological effects such as antioxidant, anti-inflammatory, and anti-carcinogenic activities.1,2) Generally, potato has not been regarded as a food rich in antioxidants, but several researchers have found that depending on the genetic variety, some potato contain considerable amounts of polyphenols, flavonoids, and anthocyanins.3,4) Furthermore, recently new varieties of potato have been developed around the world to find new uses, as these are rich in antioxidants. Among new potatoes, the colored potato especially has attracted special interest in many countries due to its color appeal, such as yellow, purple, or red. The pigments of colored potatoes have been identified as anthocyanin derivatives.3-6) Like natural antioxidants from other plants, antioxidants from potato are believed to behave as an important functional food, 4) but little information is available. Recently, we found that purple potato extract (PPE, Hokkai no.92) attenuates the liver damage induced by D-galactosamine (GalN) in rats, 7) but it has not yet been reported that different colored potato extracts have analogous health benefits. Hence in this study we investigated the hepatoprotective effects of red potato extract (RPE, Hokkai no.91) against GalNinduced liver injury in rats.RPE was prepared according to our previous report. 7)Briefly, pared potato was homogenized with 5% formic acid and centrifuged at 2;000 Â g for 20 min at 4 C. Finally, the supernatant fraction was lyophilized and dissolved in 70% ethanol or distilled water (RPE). The total polyphenol content in the ethanol solution was determined by the Folin-Ciocalteu method.8) Absorbance was measured at 750 nm using a spectrophotometer (Shimadzu 1600-UV, Kyoto, Japan). The flavonoid content in the ethanol solution was determined according to the report of Jia et al., 9) using standards based on the known (+)-catechin concentration. Briefly, 200 ml of a known concentration of extract was mixed with 1.25 ml of distilled water and 75 ml of 5% NaNO 2 , and then 150 ml of 10% AlCl 3 was added 6 min later. Next, 500 ml of 1 N NaOH was added, and the total was made up to 2.5 ml with distilled water. Absorbance was measured at 510 nm using a spectrophotometer. The monomeric anthocyanin content in aqueous solution was measured by a pH differential method using a spectrophotometer.10) It was calculated using the molar extinction coefficient of pelargonidin-3-glucoside (31,600 l cm À1 mg À1 ), a molecular weight of 433.2 g mol À...

Anthocyanin-Rich Red Potato Flakes Affect Serum Lipid Peroxidation and Hepatic SOD mRNA Level in Rats

“…Although the various signaling routes responsible for Mn-SOD expression are still being identified, it is believed that an increased level of Mn-SOD is cytoprotective. 27) Therefore, it is likely that the present data might support our previous report, 7) which showed that red potato extract protects against D-galactosamine-induced hepatic toxicity in rats.…”

“…RPF were prepared according to our previous report. 7) Red potatoes were thoroughly washed with water and air dried on filter paper. Then they were peeled, sliced, steam-heated, mashed, dried in a drum dryer, and ground to flour.…”

Influence of alpha lipoic acid on antioxidant status in D-galactosamine-induced hepatic injury

“…At the course of liver injury, the transport function of hepatocytes is distressed which can result in the leakage of plasma membrane thereby causing an increase in serum marker enzymes such as AST, ALT, ALP, and LDH (Drotman and Lawhorn, 1978;Mukherjee, 2003). GalN administration in rats disrupts the membrane permeability of the plasma membrane causing leakage of the enzymes from the cell, which leads to elevation in levels of marker enzymes (Han, et al, 2006). In our study, the rise in AST, ALT, ALP, and LDH levels induced by GalN administration was significantly reduced by ALA pretreatment suggesting that its hepatoprotective activity might be due its effect against cellular leakage and loss of functional integrity of the cell membrane in hepatocytes.…”

A comparative transcriptome analysis of a wild purple potato and its red mutant provides insight into the mechanism of anthocyanin transformation

“…Potatoes with anthocyanins have benefits on health. The studies with rats demonstrate anthocyanins extracted from potatoes can significantly increase SOD activity and antioxidant capacity, and protect from injury [ 3 , 4 ]. Anthocyanins in potatoes exert an anti-bacterial activity against different bacterial strains and a slight activity against three fungal strains [ 5 ].…”