The Inhibitory Effect of Panax Ginseng Extract on Amyloid-like Fibril Formation of Trypsin in Aqueous Ethanol.

BACKGROUND: In case of several chronic diseases, prevention is could be more effective than treatment. Functional foods that contain significant amounts of bioactive components gained considerable attention not only in traditional but in modern medicine as well. We have investigated how P. ginseng extract inhibits the in vitro formation of amyloid-like fibrils of phenylmethylsulfonyl- trypsin (PMS-trypsin) in 60% ethanol at pH 7.0. The model system used is non-physiological, but it is capable of detecting the anti-amyloidogenic effect of the various agents.

OBJECTIVE: The main objective of this study was to examine the possible inhibitory effect of ginseng extract on amyloid-like fibril formation of trypsin in aqueous ethanol.

METHODS: The amyloid formation and aggregation kinetics of PMS-trypsin was studied by turbidity measurements, Congo Red (CR) binding assays, size exclusion chromatography and Electronic Circular Dichroism (ECD) measurements and the shapes of amyloid fibrils became visible by Transmission Electron Microscopy (TEM).

RESULTS: In the presence of 500-fold diluted P. ginseng extract in the incubation mixture, the absorption at 350 nm decreased to 47.1% after incubation for 24 h, compared relative to the sample which contained no additives. CR binding experiments suggested that the aggregates in our samples have amyloid-like properties, and P. ginseng extract inhibits the amyloid-like fibril formation of PMS-trypsin depending on concentration. Our results show that the ginseng extract does not bind to the fibrils. In the absence of P. ginseng extracts large sized colloid aggregates were abundant. Adding P. ginseng extracts to our samples decreased the light dispersion of the solution. This is due to the decrease of the rate of the aggregation or to the smaller size of the aggregates evolved. Our results show that the presence of ginseng extract helps to maintain the native structure of the protein. In the presence of 500-fold diluted P. ginseng extract, TEM images demonstrated, that P. ginseng extract has inhibitory effect on the formation of amyloid-like fibrils of PMS-trypsin.

CONCLUSION: The results indicated that P. ginseng extract significantly inhibits the formation of amyloid-like fibrils of PMS-trypsin in aqueous ethanol, and helps to maintain the native structure of the protein. The rate of inhibition depends on concentration. P. ginseng extract is an efficient antiamyloidogenic agent.