Antioxidant and anti-inflammatory activites of Clerodendrum leaf extracts collected in Thailand

IntroductionClerodendrum plants have been traditionally used for inflammatory related diseases in Thailand. Crude extracts of Clerodendrum disparifolium and Clerodendrum laevifolium were assessed for antioxidant and anti-inflammatory activities in order to support traditional Thai claims about the therapeutic potential of these plants.MethodsEthanol and hexane extracts of leaves were evaluated for the in vitro antioxidant activity including phenolic content assay using Folin–Ciocalteu method, flavonoid content assay using an aluminium chloride (AlCl3) colorimetric method, 2, 2-Diphenyl-2-picryl-hydrazyl (DPPH) free-radical scavenging activity assay, total reductive capability assay, total antioxidant activity assay using ferric thiocyanate (FTC) and thiobarbituric (TBA) methods. In addition anti-inflammatory activity was assayed against lipoxygenase.ResultsThe phenolic and flavonoid contents, relating with their antioxidant activities, of the extracts ranged from 1167.21–3344.52 GAE/g of dry extract and 9.05–59.91 mg QE/g of dry extract, respectively. Reducing power increased with increasing concentrations of extracts. The lipid peroxidation inhibition was evaluated by ferric thiocyanate (FTC) and thiobarbituric (TBA) methods, which demonstrated the maximum inhibition in ethanol C. laevifolium (55.49%) and C. disparifolium(96.17%) extracts, respectively. Furthermore the ethanol C. laevifolium extract exhibited highest 2, 2-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity (IC50 12.70 μg/mL) and also possessed the greatest anti-inflammatory activity (IC50 14.12 μg/mL).ConclusionsThis study indicated that selected Clerodendrum leaf extracts exhibited potential antioxidant and anti-inflammatory activities, which could be focus of further phytochemical research and may be applicable as natural medicine.