Evaluation of chemical constituents, antioxidant and anti-inflammatory properties of n-hexane extract of Viscum album L. (Mistletoe) leaves

Abstract Viscum album L. (Mistletoe) is used in ethnomedicine for the management of some ailments ranging from inflammation, pains and oxidative stress. The phytoconstituents, antioxidant and anti-inflammatory properties of n-hexane extract of mistletoe leaves (nHEML) were evaluated in this study. nHEML was obtained from fresh leaves of Viscum album L. using a Soxhlet extractor. Total phenol and flavonoid compositions were assayed using standard colourimetric methods. Gas chromatography-mass spectrometry (GC-MS) analysis was used to ascertain the presence of phytochemicals in the extract. The antioxidant property was determined using 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays, while the anti-inflammatory property was investigated using membrane stabilization (hypotonicity) and heat-induced hemolysis of human red blood cell (HRBC) assays. The results showed a high amount of total phenolic content (37.82 ± 0.22 mg GAE/g) and total flavonoid content (128.85 ± 3.85 mgQE/100mg). GC-MS analysis showed the presence of essential phytoconstituents including phytosterols, vitamin C, fatty acids etc., with known potent biological activities. In vitro, the antioxidant assay showed that DPPH scavenging activity of nHEML was only detected at 400μg/ml with 13.46%, while there was a dose-dependent increase in FRAP activity of nHEML from 50 to 400μg/ml compared to the standard. For the in vitro anti-inflammatory assay, there was a dose-dependent increase in HRBC membrane stabilization and anti-hemolytic activities, which were higher than those of the standards at 200 and 400µg/mL. nHEML contains a significant amount of flavonoids which improved the anti-inflammatory activities against hypotonic and heat-induced inflammation, hence justifying its potential as a possible anti-inflammatory agent. Keywords: Anti-inflammatory activity; antioxidant; DPPH scavenging activity; GC-MS; hemolysis; oxidative stress