Preliminary Phytochemical Screening an D Antibacterial Activities of Methanolic Extracts of Selected Mistletoes from Kathmandu Valley

Abstract

Mistletoes are hemi-parasitic plant belongs to Sandalwood family (Santalaes), that exploit and (or) parasitize a wide range of host plants. Nepal harbors about 19 species of mistletoes ranges from tropical to temperate with different host plants. However, only 15 specimens were found at National Herbarium and Plant Laboratories (KATH). On the basis of deposited specimens distribution range of mistletoes has been identified. The minimum elevation recorded was 125 m a.s.l and maximum at 3500 m a.s.l. In this study, methnolic extract of seven mistletoes were subjected to phytochemical analysis and determination of antioxidant activity and antibacterial activity. Sonication method was used for extraction process. The highest yield % was obtained for Viscum album (24.26 %) and lowest for Scurrula parasitica (11.86 %). Phytochemical analysis showed the presence almost all major phytochemicals such as saponin, flavonoid, steroid, terpenoid, glycosides, alkaloids and phenol. The total flavonoid and phenol content were determined by Aluminium chloride colorimetric method and Folin-Ciocalteu reagent respectively. Viscum album (31.45 ± 2.32 mg QE/g) showed highest flavonoid content whereas Macrosolen cochinchinensis (24.90 ± 2.26 mg QE/g) showed lowest. Similarly, highest phenolic content was found in Scurrula parasitica (32.90 ± 2.46 mg GAE/g) and lowest in Viscum album (20.60 ± 2.06 mg GAE/g). The antioxidant activity was measured by DPPH (2, 2- Diphenyl-1- picryhydrazyl) radical scavenging assay (RSA) and ascorbic acid was taken as standard. Scurrulaparasitica showed best antioxidant activity with lowest IC₅₀ (26.04 ± 0.71 µg/ml). Viscumalbum showed low antioxidant activity with highest IC₅₀ value (199.0 ± 1.25 µg/ml). The IC₅₀ value for DPPH radical scavenging activity of methanolic extract of selected mistletoes was statistically negatively correlated with the total phenolic content and positively correlated with the total flavonoid content in this study. For antibacterial screening, four different ATCC culture gram positive bacteria Staphylococcus aureus and Staphylococcus epidermidis and gram negative bacteria Escherichia coli, Pseudomonas aeroginosa were used. Gentamycin was used as positive control. Agar well diffusion technique was used for antibacterial screening and zone of inhibition was observed. Antibacterial screening showed that Helixanthera ligustrina and Viscum articulatum were effective against all bacterial strains. Scurrula parasitica was only effective for gram positive bacteria Staphylococcus aureus and Staphylococcus epidermidis. Macrosolen cochinchinensis showed antibacterial activity against all bacterial strain except Staphylococcus aureus. Similarly, Macrosolen cochinchinensis was highly effective against Pseudomonas aeroginosa. Scurrula elata Viscumalbum and Viscum articulatum var.liquidambaricolum did not show any result against all tested bacteria. On the basis of above result, the selected mistletoe plant can be used for making drugs against different human diseases after detailed investigation. Additionally, the above study showed that there may be probability of finding similar phytochemicals in other remaining mistletoes species, which must be encouraging for further research.