Biochemical, Phytochemical Profile and Angiotensin-1 Converting Enzyme Inhibitory Activity of the Hydro-methanolic Extracts of Tulbaghia acutiloba Harv.


  • University of KwaZulu-Natal, School of Laboratory Medicine and Medical Sciences, Discipline of Human Physiology, Durban, 4000, South Africa
  • University of KwaZulu-Natal, School of Chemistry and Physics, Discipline of Chemistry, Durban, 4000, South Africa


Phytotherapeutic treatments have been on the ascendancy over the years as the quest for alternate and easily accessible health care is on the rise. Tulbaghia acutiloba has been used by both traditional healers and the South African population for the management of chronic conditions, but lacks scientific authentication. Hydro-methanolic extracts (roots, rhizomes, leaves and flowers) of the plant were evaluated for their antioxidant activities, biochemical and phytochemical profile. Additionally, the heavy metal content and antihypertensive effects including Angiotensin 1-Converting Enzyme Inhibitory (ACEI) activities were investigated. The antioxidant ability of the hydro-methanolic extracts were determined by 2, 2-diphenyl-1-picryl hydrazyl (DPPH), hydrogen peroxide and nitric oxide scavenging activities. Phytochemical profile was assessed using qualitative and quantitative methods whereas the heavy metal toxicity was determined by using Inductively- Coupled Plasma-Optical Emission Spectrometry (ICP-OES). In vitro ACEI activity was determined by the hydrolysis of the tripeptide, hippuryl –L-Histidyl-L-leucine (Hip-His-Leu). All the extracts showed potent antioxidant activities which was concentration dependent. Phytochemical analysis showed the presence of phenols, amino acids and alkaloids in all the extracts. The leaves showed a relatively higher total phenolic content of 43.26±1.15 mgGAE/g. Gas Chromatography–Mass Spectrometry (GC-MS) analysis showed the presence of major compounds such as α-linolenic acid in the leaves as well as oleic acid and palmitic acid in other parts of the plants. Toxicity of heavy metal was undetected in all extracts of the plant. All the extracts of the plants showed a >50% ACE inhibition at different concentrations with the leaves showing a relatively higher inhibitory activity (76.66 ± 1.65, IC50; 154.23 μg/ml) compared with the other parts of the plants. It is therefore concluded in this study that the biological activities and phytochemical component of the hydro-methanolic extracts of T. acutiloba is indicative of its possible use for the treatment as well as prevention of hypertension and oxidative stressrelated diseases.


Angiotensin 1-Converting Enzyme, Antioxidant, Heavy Metal Toxicity, Tulbaghia acutiloba, Phytochemical

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