Phytochemical analysis and investigation of antioxidant, antibacterial and anticancerous properties of three medicinal plants of Nepal

Abstract

ABSTRACT The use of plant as medicine started from the prehistoric days and its use is still continuing in different forms whether as synthetic drugs or as complementary medicine. Whole plant was taken as sample in Primula rotundifolia and Potentilla fulgens and bark was used in Rhododendron arboreum. Aqueous, Methanolic and Chloroform extract of three plants Potentilla fulgens, Rhododendron arboreum and Primula rotundifolia were analysed for their total flavonoid, polyphenol content, antioxidant activity, antibacterial and anticancerous activity. Chloroform extract of Primula rotundifolia was found to be highest in flavonoid content i.e. 23±0.71 mg quercetin eqv/gm plant extract. Methanolic extract was also found to be slightly less in flavonoid content than chloroform extract ie. 19±707 mg quercetin eqv/gm plant extract. Polyphenolic content was found to be high in methanolic extract of Potentilla fulgens (448±6 mg gallic acid/gm equivalent) and Rhododendron (449.605±4mg gallic acid/gm equivalent). On contrary chloroform fraction of Primula rotundifolia was rich in phenol content than aqueous and methanolic extract. Antioxidant activity was found to be in good correlation to the total polyphenol content. Methanolic extract of Potentilla fulgens and Rhododendron arboreum showed high scavenging potential with IC50 value at 477.32±5.46 μg/ml and 602±3.11 µg/ml respectively in (2,2-azinobis 3-ethyl-benzothiazoline-6-sulfonic acid) ABTS assay and 340.93±4.09 μg/ml and 517.69±6.33 µg/ml respectively in (2,2-diphenyl-1 picrylhydrazyl) DPPH assay. On contrary in both assays chloroform extract of Primula rotundifolia showed higher free radical scavenging potential with IC50 value at 807.08±3.78 μg/ml in (2,2-diphenyl-1 picrylhydrazyl) DPPH assay and 1420±5.66 μg/ml in (2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) ABTS assay. Antibacterial activity was performed in all extract and chloroform extract of Primula rotundifolia exhibited very impressive result with (Minimum Bactericidal concentration) MBC of 1 mg/ml for Pseudomonas aerugenosa and 800µg/ml for Staphylococcus aureus. Antiproliferative and cytoxicity study was also performed in the extract and Chloroform extract of Primula rotundifolia showed lowest IC50 value at 107.096 μg/ml and low cytotoxicity as well. Methanolic extract of Potentilla fulgens and Rhododendron arboreum showed moderate type of antiproliferative and less cytotoxic property. These findings indicate the possible potential use of these plants as anticancer agent but needs further identification, isolation and purification of the compound responsible. Keywords: Reactive oxygen species (ROS), Flavonoids, antioxidants, Polyphenols, antibacterial, cytotoxicity, Medicinal plants.