Saponins from the roots of Chenopodium bonus-henricus L. with neuroprotective and anti-α-glucosidase activities

Six saponins of phytolaccagenin, bayogenin, medicagenic acid, 2β-hydroxygypsogenin, and 2β-hydroxyoleanoic acid from the roots of Chenopodium bonus-henricus L. were investigated for neuroprotective and anti-α-glucosidase activities. All tested saponins (10 µM) showed statistically significant neuroprotective activities on isolated rat brain synaptosomes using a 6-hydroxydopamine in vitro model. They preserved synaptosome viability as well as the reduced glutathione level. The bayogenin glycoside (Chbhs-05) possessed the most prominent neuroprotective effect. The anti-α-glucosidase activity of the tested saponins was established by measuring the levels of the released 4-nitrophenol using LC-MS. Bonushenricoside B (Chbhs-07) showed the highest inhibitory effect against α-glucosidase (44.1%) compared to the positive control acarbose (36.3%) at a concentration of 625 µM.

The Mechanism Of Action Of Polyphenol On Changes In The Dynamics Of Calcium In The Synaptosomes Of The Rat Brain Against The Background Of Glutamate

The manuscript shows a short data used using fluorescent probes to study the effect of polyphenol PС-7 on changes in the dynamics of intracellular Ca2+ content in rat brain synaptosomes, depending on the site of glutamate binding on calcium channels by a specific mediator with glutamate. To measure the amount of cytosolic Ca2+ synaptosomes, we calculated using the Grinkevich equation. It has been shown that polyphenol PС-7 binds to the β1-subunit of the voltage-gated calcium channel and allosterically changes its conformation so that the conductivity for Ca2+ ions increases through the channel, the blocking effect of polyphenol PС-7 can be explained by its binding to voltage-gated calcium channels and activating them.

Neuroprotective and antioxidant activities of saponins’ mixture from Astragalus glycyphylloides in a model of 6-hydroxydopamine-induced oxidative stress on isolated rat brain synaptosomes

The aim of the study was to investigate the possible neuroprotective and antioxidant activity of purified saponins’mixture (PSM), isolated from Astragalus glycyphylloides (Fabaceae), in a model of 6-hydroxydipamine (6-OHDA)-induced oxidative stress on isolated rat brain synaptosomes. Synaptosomes were incubated with 3 different concentrations of PSM: 60 µg/mL; 6 µg/mL; 0.6 µg/mL. The effects of PSM were compared to those of silymarin (S), at the same concentrations. The main parameters, characterized functional and metabolic status of synaptosomes, were investigated: viability (MTT-test) and level of reduced glutathione (GSH). At isolated rat brain synaptosomes, in conditions of 6-OHDA-induced oxidative stress (150 μМ), PSM revealed statistically significant, concentration-dependent, neuroprotective and antioxidant effects, compared to those of silymarin. Effects were most prominent at concentration 60 µg/mL. These neuroprotective effects of PSM might be due to the possible activity as scavenger of reactive oxygen species (ROS), produced by p-quinone (toxic metabolite of 6-OHDA).

Local protein synthesis is a ubiquitous feature of neuronal pre- and postsynaptic compartments

There is ample evidence for localization of messenger RNAs (mRNAs) and protein synthesis in neuronal dendrites; however, demonstrations of these processes in presynaptic terminals are limited. We used expansion microscopy to resolve pre- and postsynaptic compartments in rodent neurons. Most presynaptic terminals in the hippocampus and forebrain contained mRNA and ribosomes. We sorted fluorescently labeled mouse brain synaptosomes and then sequenced hundreds of mRNA species present within excitatory boutons. After brief metabolic labeling, >30% of all presynaptic terminals exhibited a signal, providing evidence for ongoing protein synthesis. We tested different classic plasticity paradigms and observed distinct patterns of rapid pre- and/or postsynaptic translation. Thus, presynaptic terminals are translationally competent, and local protein synthesis is differentially recruited to drive compartment-specific phenotypes that underlie different forms of plasticity.