Neuroprotective effect of Bryophyllum pinnatum flavonoids against aluminum chloride-induced neurotoxicity in rats.

Toxic metals such as aluminum accumulation in the brain have been associated with the pathophysiology of several neurodegenerative disorders. Bryophyllum pinnatum leaves contain a vast array of polyphenols, particularly flavonoids, that may play a role in the prevention of toxic and degenerative effects in the brain. This study assessed the neuro-restorative potential of leaves of B. pinnatum enriched flavonoid fraction (BPFRF) in aluminum-induced neurotoxicity in rats. Neurotoxicity was induced in male Wistar rats by oral administration of 150 mg/kg body weight of aluminum chloride (AlCl3) for 21 days. Rats were grouped into five (n = 6); Control (untreated), Rivastigmine group, AlCl3 group and BPFRF group (50 and 100 mg/kg b.wt.) for 21 days. Neuronal changes in the hippocampus and cortex were biochemically and histologically evaluated. Expression patterns of acetylcholinesterase (AChE) mRNA were assessed using semi-quantitative reverse-transcription-polymerase chain reaction protocols. Molecular interactions of BPFRF compounds were investigated in silico. The results revealed that oral administration of BPFRF ameliorated oxidative imbalance by augmenting antioxidant systems and decreasing lipid peroxidation caused by AlCl3. BPFRF administration also contributed to the down-regulation of AChE mRNA transcripts and improved histological features in the hippocampus and cortex. Molecular docking studies revealed strong molecular interactions between BPFRF compounds, catalase, superoxide dismutase and glutathione peroxidase Overall, these findings suggest the neuroprotective effect of Bryophyllum pinnatum against aluminum-induced neurotoxicity.

UPLC-PDA-ESI-QTOF-MS/MS fingerprint of purified flavonoid enriched fraction of Bryophyllum pinnatum; antioxidant properties, anticholinesterase activity and in silico studies.

CONTEXT: Bryophyllum pinnatum (Lam.) Oken (Crassulaceae) is used traditionally to treat many ailments. OBJECTIVES: This 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 METHODS: Methanol 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). RESULTS: UPLC-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 CONCLUSIONS: BPFRF 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.

Evaluation of 6-Gingerol and its modified analogues as therapeutic candidates against Schistosoma mansoni phosphofructokinase

The African most prevalent tropical disease after malaria is schistosomiasis and this disease in the developing countries is a massive socio-economic and public health burden. The disease also caused over 200,000 deaths. The development and design of new and novel antischistosomal drugs is now very important, as there are no vaccines currently and there is only one drug at the moment for the treatment of schistosomiasis. In this article, 6-gingerol was docked against the Schistosoma mansoni phosphofructokinase and the docking result was compared to those obtained from the docking of its modified analogues against the same enzyme. The chemical structure of 6-gingerol was obtained from the PubChem database while the modified analogues were designed using the ChemAxon software. The molecular docking procedure was carried out with the aid of the AutoDock Vina software while polar interactions which were eventually used in predicting the amino acid residues at the Schistosoma mansoni phosphofructokinase active site were visualized using the Pymol software. The Schistosoma mansoni phosphofructokinase 3D crystallized structure was modeled using the Swiss Model server. The molecular docking result showed that the modifications made on 6-gingerol had a positive effect on the binding energy of the compound to the enzyme active site as an appreciable increase was observed. 6-Gingerol and its modified analogues also violated none of the Lipinski's rule with suggests that the experimental compounds are drug-like. The C2H5 analogue of 6 gingerol was selected as the ideal therapeutic agent based on the pharmacokinetics study and the exhibited binding energy(AU)

La enfermedad tropical con más prevalencia en África después de la malaria es la esquistosomiasis; en los países en vías de desarrollo constituye una carga socio-económica y de salud pública enorme. La enfermedad ha ocasionado más de 200.000 muertes anuales. El desarrollo y diseño de nuevas y novedosas drogas antiesquistosomales es muy importante, ya que actualmente no existe vacuna disponible y solo hay una sola droga licenciada para su tratamiento. En esta investigación, el compuesto 6-gingerol se acopló a la enzima fosfofructoquinasa de Schistosoma mansoni y se comparó con los resultados obtenidos a partir de las interacciones de sus análogos modificados a la misma enzima. La estructura química del 6-gingerol se obtuvo de la base de datos PubChem, mientras que los análogos modificados se diseñaron utilizando el software ChemAxon. El procedimiento de acoplamiento molecular se llevó a cabo con la ayuda del software AutoDockVina, mientras las interacciones polares eventualmente utilizadas para predecir los residuos de aminoácidos en el sitio activo de la enzima fosfofructoquinasa de Schistosoma mansoni se visualizaron empleando el software Pymol. La estructura cristalizada tridimensional de la enzima fosfofructoquinasa de Schistosoma mansoni se modeló utilizando el programa Swiss Model. Se demostró que las modificaciones realizadas en el 6-gingerol tuvieron un efecto positivo en la energía de unión del compuesto al sitio activo de la enzima, tras observarse un aumento apreciable de dicha energía. El compuesto 6-Gingerol y sus análogos modificados tampoco violaron ninguna de las reglas de Lipinski, lo que sugiere que estos compuestos experimentales tienen propiedades similares a los medicamentos. El análogo C2H5 de 6-gingerol se seleccionó como el agente terapéutico ideal, basados en el estudio de farmacocinética y la energía de enlace demostrada(AU)

Structural and spectroscopic characterisation of a heme peroxidase from sorghum.

A cationic class III peroxidase from Sorghum bicolor was purified to homogeneity. The enzyme contains a high-spin heme, as evidenced by UV-visible spectroscopy and EPR. Steady state oxidation of guaiacol was demonstrated and the enzyme was shown to have higher activity in the presence of calcium ions. A Fe(III)/Fe(II) reduction potential of -266 mV vs NHE was determined. Stopped-flow experiments with H2O2 showed formation of a typical peroxidase Compound I species, which converts to Compound II in the presence of calcium. A crystal structure of the enzyme is reported, the first for a sorghum peroxidase. The structure reveals an active site that is analogous to those for other class I heme peroxidase, and a substrate binding site (assigned as arising from binding of indole-3-acetic acid) at the γ-heme edge. Metal binding sites are observed in the structure on the distal (assigned as a Na(+) ion) and proximal (assigned as a Ca(2+)) sides of the heme, which is consistent with the Ca(2+)-dependence of the steady state and pre-steady state kinetics. It is probably the case that the structural integrity (and, thus, the catalytic activity) of the sorghum enzyme is dependent on metal ion incorporation at these positions.