Phytochemical Profile and Bioactivity of the Methanolic Leaf and Root Extracts of South African Bulbine frutescens

Abstract

Bulbine frutescens is an indigenous succulent medicinal plant in South Africa. The plant is commonly used traditionally for the treatment of skin related ailments. B. frutescens has been reported to possess antioxidant, anti-viral and antimicrobial properties. To date, most studies have been conducted on the leaves, while limited reports have been documented on the roots, as well as comparative analyses between both plant parts. The aim of this study was to determine the phytochemical content, antioxidant and antibacterial activities in the leaves and roots of B. frutescens. Methanolic extracts of each plant part were assessed on the phytochemical analysis, antioxidant (DPPH, hydrogen peroxide, metal chelating) and antibacterial activity against S. aureus and E. coli. The results from the phytochemical screening showed that the leaves contained more phytochemical groups than the roots. The roots displayed higher total phenolics (991.7 ± 54.1 mg GAE/g), total flavonoid (285.8 ± 60.6 mg QE/g) and total tannin contents (1698.75 ± 28.15 mg GAE/g) than the leaves. The roots also showed a stronger antioxidant activity in DPPH (3.43 ± 0.16 mg/ml) and metal chelating (0.54 ± 0.01 mg/ml) assays, compared to the leaves, which only showed a higher scavenging power against hydrogen peroxide radicals (1.48 ± 0.02 mg/ml) than the roots. Both plant parts showed intermediate zones of inhibition (10-19 mm) against both bacterial strains, with the exception of the leaves which had a 20.67 ± 0.67 mm inhibition against S. aureus. These results validate the uses of both leaves and roots of B. frutescens in traditional medicine and further suggests for the application of the roots in pharmaceutical and cosmetic industries.Bulbine frutescens is an indigenous succulent medicinal plant in South Africa. The plant is commonly used traditionally for the treatment of skin related ailments. B. frutescens has been reported to possess antioxidant, anti-viral and antimicrobial properties. To date, most studies have been conducted on the leaves, while limited reports have been documented on the roots, as well as comparative analyses between both plant parts. The aim of this study was to determine the phytochemical content, antioxidant and antibacterial activities in the leaves and roots of B. frutescens. Methanolic extracts of each plant part were assessed on the phytochemical analysis, antioxidant (DPPH, hydrogen peroxide, metal chelating) and antibacterial activity against S. aureus and E. coli. The results from the phytochemical screening showed that the leaves contained more phytochemical groups than the roots. The roots displayed higher total phenolics (991.7 ± 54.1 mg GAE/g), total flavonoid (285.8 ± 60.6 mg QE/g) and total tannin contents (1698.75 ± 28.15 mg GAE/g) than the leaves. The roots also showed a stronger antioxidant activity in DPPH (3.43 ± 0.16 mg/ml) and metal chelating (0.54 ± 0.01 mg/ml) assays, compared to the leaves, which only showed a higher scavenging power against hydrogen peroxide radicals (1.48 ± 0.02 mg/ml) than the roots. Both plant parts showed intermediate zones of inhibition (10-19 mm) against both bacterial strains, with the exception of the leaves which had a 20.67 ± 0.67 mm inhibition against S. aureus. These results validate the uses of both leaves and roots of B. frutescens in traditional medicine and further suggests for the application of the roots in pharmaceutical and cosmetic industries.