Phytochemical analysis and biological activities of various parts of Bulbine natalensis (Baker): A comparative study

Introduction: Bulbine natalensis is a succulent plant native to South Africa, used to treat various skin conditions. The purpose of this investigation was to analyse the phytochemical content, as well as antioxidant and antibacterial activities of various parts of B. natalensis. Methods: Phytochemical screening tests were performed to investigate the presence of ten compounds from B. natalensis methanol extract. Total phenolic, flavonoid, tannin, and proanthocyanidin content assays were followed to determine their concentrations in B. natalensis. The ۲,۲-diphenyl-۱-picrylhydrazyl (DPPH), hydrogen peroxide (H۲ O۲ ), and iron chelating assays were used to assess the antioxidant activity. To determine the antibacterial properties of B. natalensis against Staphylococcus aureus and Escherichia coli, the agar-well diffusion method was adopted. Results: The phytochemical screening revealed more compounds present in the leaves. The underground stems yielded higher concentrations of total phenolics (۱۹۰۹.۲ ± ۴.۸ mg gallic acid equivalent [GAE]/g), total flavonoids (۲۵۹.۷ ± ۲۷.۲ mg quercetin equivalent [QE]/g), and total proanthocyanidins (۸۵۸.۳ ± ۱.۷ mg catechin equivalent [CE]/g) in comparison to the leaves and roots. The roots showed stronger DPPH (۰.۳۶ ± ۰.۰۲ mg/mL) and H۲ O۲ (۰.۲۴ ± ۰.۰۴ mg/mL) scavenging activities. Only the underground stems and roots showed inhibition against S. aureus with the values of ۱۵.۳۳ ± ۰.۶۷ mm and ۱۵.۶۷ ± ۰.۳۳ mm, respectively, whereas the leaves displayed the highest inhibition against E. coli (۱۸.۳۳ ± ۰.۸۸ mm). Conclusion: The methanolic extracts of B. natalensis leaves, underground stems, and roots possess significant phytochemical content, in conjunction with antioxidant and antibacterial activities.