Simultaneous treatment of the cells with arabinosylcytosine and the extract as well as the OeB, leads to an additional enhancement of NEP activity.
O-phthalalaldehyde was obtained from Merck, dihydrotestosteron (DHT) from Fluka and arabinosylcytosine (AC) from Ferak.
Effect of the combination of Epilobium aqueous extract and oenothein B with arabinosylcytosine (AC) on specific NEP activity and cell proliferation Specific cellular NEP Concentration activity in % Cell proliferation % Control 100[+ or -]5 100[+ or -]4 25 [micro]g/ml AC 167[+ or -]9* 53[+ or -]4** 25 [micro]g/ml AC + 199[+ or -]7* 54[+ or -]4** 50 [micro]g/ml extract 25 [micro]g/ml AC + 176[+ or -]6* 57[+ or -]3** 100 [micro]g/ml extract 25 [micro]g/ml AC + 216[+ or -]12* 56[+ or -]2** 20 [micro]M oenothein 25 [micro]g/ml AC + 198[+ or -]17* 52[+ or -]3** 40 [micro]M oenothein *Significant difference to the specific enzymatic activity of the controls.
The treatment of the cells with arabinosylcytosine and green tea extract results in a strong enhancement of cellular NEP activity whereas cellular ACE activity was not changed significantly, indicating a green tea extract-specific regulation of NEP expression.
L-Leucine-p-nitroanilide, Suc-L-Ala-L-Ala-L-Phe-7-amido-3-methylcoumarin (SAAP-AMC), Aminopeptidase N (APN), arabinosylcytosine, epigallocatechin gallate and phosphoramidon were obtained from Sigma; Hip-L-His-L-Leu was purchased from Bachem; lisinopril was a gift of Schering & Plough (USA); the cell culture media and fetal calf serum (FCS) were obtained from Biochrom; green tea extract (EFLA[R]85942) was obtained from Emil Flachsmann AG (Switzerland).
For this purpose we treated the cells with arabinosylcytosine and different concentrations of green tea extract.
Arabinosylcytosine is the most potent selective inhibitor of DNA synthesis (Beranek, 1986) and induced only the cellular NEP activity, not the ACE activity.