Chemical-activity-based quality marker screening strategy for Viscum articulatum.

Viscum articulatum Burm. f. is a parasitic plant rich in flavonoids, triterpenoids, and catechins and has a high nutritional value. It has been reported that consuming V. articulatum can prevent cardiac diseases. In this study, six bioactive compounds, including catechins, triterpenoids, and phenylpropanoid glycosides, were determined in alcohol extracts of the plant using HPLC. The anti-inflammatory and antioxidant activities of three catechins, two triterpenoids, and three combination drugs were measured in cardiomyocytes, and the results showed that the anti-inflammatory activity was significantly enhanced while retaining strong antioxidant activity when epicatechin and ursolic acid were used in combination. The main quality markers epicatechin and ursolic acid were screened based on the specificity of the genuine herb and a potent synergistic effect, and the lowest limitation contents of V. articulatum which could discriminate it from some other taxonomically similar materials were accordingly determined. This self-built lowest limitation content of the two screened quality markers could quickly and accurately reflect the efficacy in terms of chemical composition and reverse the disorderly market use of nongenuine herbs or confusing species for adulteration. This study is of some significance for market regulation, drug development, and clinical medication.

Assessment of extracts from mistletoe (Viscum album) for herb-drug interaction by inhibition and induction of cytochrome P450 activities.

Three commercially available extracts from mistletoe (Viscum album L.) grown on ash tree (abnobaVISCUM(®) Fraxini 20 mg), on fir (abnobaVISCUM(®) Abietis 20 mg), and on pine (abnobaVISCUM(®) Pini 20 mg) were tested in vitro for their potential to interfere with the major drug metabolizing cytochromes P450 by hepatocyte viability, by inhibition of cytochromes P450 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1 and 3A4, and by the induction of cytochromes P450 1A2, 2B6, 2C9, 2E1 and 3A4. As the three extracts are produced from mistletoe plants belonging to three different subspecies of Viscum album L. they have explicit differences in the content and spectrum of various active ingredients, e.g. mistletoe specific lectins. Cytotoxic effects on liver cells were observed for abnobaVISCUM(®) Fraxini with a high lectin content with an EC(50) value of 2.56 µg/mL, for abnobaVISCUM(®) Abietis with a moderate lectin content with an EC(50) value of 5.79 µg/mL and for abnobaVISCUM(®) Pini with a low lectin content with an EC(50) value of 30.86 µg/mL. The induction of cytochromes P450 was tested on human liver cells from three donors. Inhibition of cytochromes P450 was carried out on human liver microsomes. No or minor induction and inhibition was observed for all three extracts. The data indicate no or minor potential for herb-drug interactions by interference with cytochromes P450 by any of the three mistletoe extracts.