Phytochemical screening and biological studies of leaf extract of Nerium oleander L.
Gita Khadka, Dharma Prasad Khanal

Nerium oleander L. has long been recognized for its healing properties among various ethnic groups and traditional healers and has a broad-spectrum of medicinal benefits, including cardio tonic, analgesic, antidiabetic, anti-inflammatory, antibacterial, antineoplastic, antifungal, antidepressant and antimitotic. To begin the study, leaves extracts were prepared through maceration in non-polar solvent n-hexane and polar solvent ethanol. Total Phenolic Content and Total Flavonoid Content of the extracts were evaluated utilizing Folin-Ciocalteu method and standard chemical assay procedures respectively. To assess the antioxidant activity of the extract, a reducing power assay and a DPPH radical scavenging assay were employed. In order to evaluate the antibacterial activity, the borehole method using Staphylococcus aureus and Escherichia coli was performed. Furthermore, the GC-MS analysis of the ethanolic extract showed 23 major peaks, while the n-hexane extract contained 10 major peaks. The ethanolic leaf extract exhibited a Total Phenolic Content value of 87.1 mg GAE per gm and a Total Flavonoid Content value of 727.5 mg QE/g. Moreover, the reducing power assay demonstrated a linear graph, illustrating antioxidant properties of the plant. The DPPH radical scavenging assay showed an IC50 value of 15.276 ug/mL, meanwhile the standard ascorbic acid had an IC50 value of 6.72 ug/mL. Additionally, the ethanolic leaves extract displayed some antibacterial activity against E. coli.

Keywords: Nerium oleander, GC-MS, antibacterial