UPLC-PDA-ESI-QTOF-MS/MS fingerprint of purified flavonoid enriched fraction of Bryophyllum pinnatum; antioxidant properties,anticholinesterase activity and in silico studies |
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| Authors: | Joyce Oloaigbe Ogidigo Chioma Assumpta Anosike Parker Elijah Joshua Collins U Ibeji Daniel Emmanuel Ekpo Bennett C Nwanguma Okwesili Fred Chiletugo Nwodo |
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| Institution: | aDepartment of Biochemistry, Faculty of Biological Sciences, University of Nigeria, Nsukka, Nigeria;bBioresources Development Centre, National Biotechnology Development Agency, Abuja, Nigeria;cDepartment of Pure and Industrial Chemistry, Faculty of Physical Sciences, University of Nigeria, Nsukka, Enugu State, Nigeria;dDepartment of Biochemistry, Mkar University, Benue State, Nigeria |
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| Abstract: | ContextBryophyllum pinnatum (Lam.) Oken (Crassulaceae) is used traditionally to treat many ailments.ObjectivesThis study characterizes the constituents of B. pinnatum flavonoid-rich fraction (BPFRF) and investigates their antioxidant and anticholinesterase activity using in vitro and in silico approaches.Materials and methodsMethanol extract of B. pinnatum leaves was partitioned to yield the ethyl acetate fraction. BPFRF was isolated from the ethyl acetate fraction and purified. The constituent flavonoids were structurally characterized using UPLC-PDA-MS2. Antioxidant activity (DPPH), Fe2+-induced lipid peroxidation (LP) and anticholinesterase activity (Ellman’s method) of the BPFRF and standards (ascorbic acid and rivastigmine) across a concentration range of 3.125–100 μg/mL were evaluated in vitro for 4 months. Molecular docking was performed to give insight into the binding potentials of BPFRF constituents against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE).ResultsUPLC-PDA-MS2 analysis of BPFRF identified carlinoside, quercetin (most dominant), luteolin, isorhamnetin, luteolin-7-glucoside. Carlinoside was first reported in this plant. BPFRF significantly inhibited DPPH radical (IC50 = 7.382 ± 0.79 µg/mL) and LP (IC50 = 7.182 ± 0.60 µg/mL) better than quercetin and ascorbic acid. Also, BPFRF exhibited potent inhibition against AChE and BuChE with IC50 values of 22.283 ± 0.27 µg/mL and 33.437 ± 1.46 µg/mL, respectively compared to quercetin and rivastigmine. Docking studies revealed that luteolin-7-glucoside, carlinoside and quercetin interact effectively with crucial amino acid residues of AChE and BuChE through hydrogen bonds.Discussion and conclusionsBPFRF possesses an excellent natural source of cholinesterase inhibitor and antioxidant. The material could be further explored for the potential treatment of oxidative damage and cholinergic dysfunction in Alzheimer’s disease. |
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| Keywords: | Alzheimer’ s diseases acetylcholinesterase butyrylcholinesterase carlinoside docking studies lipid peroxidation |
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