The effect of different hosts on mistletoe (Viscum album) secondary metabolites

  The mistletoes are a significant and diverse group of nasogastric species, which are parasite and have a wide range of hosts and a very wide range of distribution areas in the world. They have high levels of effective compounds. considering the fact that the amount and type of these compounds in plants are highly dependent on environmental and genetic factors, the present study aims at the investigation of the effect of different hosts e.g Persian ironwood (Parrotia persica), hornbeam (Carpinus betulus), alder (Alnus glutinosa) and poplar (Populus euramericana) on the mistletoe secondary metabolites (phenol, flavonoids, antioxidants, Betulin and Betulinic acid) changes. Sampling for this laboratory study was carried out in late September in mistletoe hosted by Persian ironwood, Poplar, Hornbeam and alder, this species in 3 replications in lower points to the middle of the forest of Dr. Bahramnia forestry plantation located in Shast Kalateh forest of Gorgan. Then, Samples were dried, milled and extracted with three ethanol, methanol and acetone solvents. After the extraction, the required test process was performed and the obtained data were analyzed using SAS software. The results showed that different hosts had significant effects on effective compounds of mistletoe. According to the results, the highest levels of antioxidant (95.03% free radical) and phenol (4.45 mg/g dry weight) were related to the stem acetonic extract and leaves ethanolic extract of mistletoes hosted by Persian ironwood, respectively and the highest amount of flavonoids 2.07 mg/g is related to the mistletoe stem ethanolic extract hosted by alder species. The highest amount of betulin (147.3 mg/ml) was measured in the mistletoe leaf hosted by hornbeam species. The highest amount of betulonic acid was found to be 347 mg/ml, which was obtained from the mistletoe stems hosted by the poplar species. The results indicate that the host trees can play a key role in the amount of secondary metabolites and the antioxidant properties of leaf and stem of the mistletoe half-parasite. The presence of these secondary metabolites with medicinal and even industrial value in this plant emphasizes the need for special attention on this valuable species. Due to the fact that two effective anti-cancer agents of betulin and betulinic acid are important and highly costly drugs, the mistletoes hosted with hornbeam and poplar can be used.
Keywords: Betulin, Betulonic acid, Various hosts, Secondary metabolites, Viscum album