RESUMEN
Interactions between viscum album (Iscador) and DNA were studies by amplification of specific human pepsinogen A gene promoter sequences by polymerase chain reaction (PCR). Gel retardation assays showed no binding of Viscum album to these promoter sequences. Incubation of plasmid constructs consisting of human pepsigen A promoter fragments coupled to thechloramphenicol acetyl-transferase (CAT) reporter gene with Iscador had no effect on transcriptional activity. Promoter sequences incubated with Iscador became insensitive to methylation by specific DNA methyltransferases by destruction of DNA methyltransferase activity
Asunto(s)
Viscum album , Metilación , ADN (Citosina-5-)-Metiltransferasas , Pepsinógeno A , Reacción en Cadena de la PolimerasaRESUMEN
The protective effect of extracts of mistletoe Viscum album (Iscador) with reference to carcinogenesis was tested on in vitro cultured porcine gastric chief cells. Putative protection against in vitro methylation of lambda DNA by N-methyl-N-nitro-N-nitrosoguanidine (MNNG) was studied with restriction endonucleases. Preparations of Iscador from mistletoe grown on oak as host tree had a high cytotoxic effect on gastric chief cells, with an LC50 after 24hrs that ranged between 0.01 and 0.03 mg/ml. At 0.01 mg/ml, Iscador was also found to protect lambda DNA from methylation or destruction by MNNG. During the course of this study a high variability was found both in cytotoxicity and protection rate against methylation which we attribute to batch to batch differences. Thus the LC50 for Iscador MH86L12 was 0.005 mg/ml, while for MH87 D24 it was 0.05 mg/ml after 24hrs. The Iscador batch W frf 50 mg/ml, which was made from a fresh plant extract at the Hiscia Institute, showed less variability. Results are therefore given for this batch of Iscador only
Asunto(s)
Animales , Técnicas In Vitro , Viscum album/farmacología , Desnaturalización de Ácido Nucleico , ADN , Metilnitronitrosoguanidina , Técnicas de Cultivo , Investigación Homeopática Básica , Carcinógenos , PorcinosRESUMEN
The effects of several preparations of Iscador, a commercially obtainable extract of mistletoe, Viscum album L., on cell proliferation and cell viability was studied. Iscador Quercus was shown to inhibit cell proliferation of: human fibroblast cell lines, mouse tumour cell lines, human carcinoma tumour cell lines and a human lymphoblastic tumour cell line. Iscador Quercus, Iscador Ulnus and Iscador Malus were about equally cytostatic to mouse 3T3 fibroblasts. Iscador Pinus was somewhat less cytostatic. Iscador Quercus had a very direct cytotoxic effect on MOLT4 tumour cells as assessed by trypan blue dye exclusion. The cytostatic and cytotoxic properties of Iscador could be annulled by heating Iscador form 30 min. at 90 "graus"C. Iscador reduced the cloning efficiency of ASG experiments it can be concluded that a small percentage of CHO cells is insensitive to high concentrations of Iscador at short incubation times. The importance of these findings in relation to the cytostatic and cytotoxic compounds possibly present in Iscador is discussed