Rehabilitating a brain with Alzheimer's: a proposal

Natural products as sources of acetylcholinesterase inhibitors: Synthesis, biological activities, and molecular docking studies of osthole-based ester derivatives

Osthole is a natural coumarin compound which isolated from Cnidium monnieri (L.) Cusson, has extensive pharmacological activities and could be used as a leading compound for drug research and development. In a continuous effort to develop new acetylcholinesterase inhibitors from natural products, eighteen osthole esters were designed, synthesized, and confirmed by ¹H NMR, ¹³C NMR and HRMS. The anti-AChE activity of These derivatives was measured at a concentration of 1.0 mol/mL in vitro by Ellman's method, and the result showed that 4m and 4o had moderate inhibitory activities with 68.8% and 62.6%, respectively. Molecular docking study results further revealed AChE interacted optimally with docking poses 4m and 4o. Network pharmacology also predicted that compound 4m could be involved in Ras signaling pathway, which made it a potential therapeutic target of AD.

Novel Multitarget Directed Tacrine Hybrids as Anti-Alzheimer's Compounds Improved Synaptic Plasticity and Cognitive Impairment in APP/PS1 Transgenic Mice

Alzheimer's disease (AD) is a complex pathological neurodegenerative disease that seriously threatens human health. Therefore, how to effectively improve and treat AD is an urgent problem. In this study, a novel multitarget derivative based on tacrine (named 9i), which could work simultaneously on more than one pathological target, was used to treat AD model APP/PS1 transgenic mice. After 4 weeks of intragastric administration, cognitive function and synaptic plasticity were significantly improved and β-amyloid (Aβ) plaques that are main pathological hallmarks of AD were decreased in the APP/PS1 mice. On the one hand, 9i inhibited the excessive activation of the Raf/MEK/ERK signaling pathway to alleviate the loss of neurons, which provides a foundation for structural integrity. On the other hand, synaptic associated proteins and the density of synaptic spines were increased in APP/PS1 mice treated with 9i, which provides the basis for the improvement of synaptic plasticity and cognitive impairment. Interestingly, 9i also reduced Aβ plaques in the DG region, which is consistent with previous in vitro experiments showing that 9i inhibited the self-assembly of Aβ fibers, thus protecting neurons from Aβ plaque neurotoxicity. Our results suggest that 9i as a novel compound can effectively improve the cognitive function and the pathological changes of AD in APP/PS1 transgenic mice.

Natural Peptides in Drug Discovery Targeting Acetylcholinesterase

Acetylcholinesterase-inhibitory peptide has gained much importance since it can inhibit acetylcholinesterase (AChE) and increase the availability of acetylcholine in cholinergic synapses, enhancing cholinergic transmission in pharmacological treatment of Alzheimer’s disease (AD). Natural peptides have received considerable attention as biologically important substances as a source of AChE inhibitors. These natural peptides have high potential pharmaceutical and medicinal values due to their bioactivities as neuroprotective and neurodegenerative treatment activities. These peptides have attracted great interest in the pharmaceutical industries, in order to design potential peptides for use in the prophylactic and therapy purposes. Some natural peptides and their derivatives have high commercial values and have succeeded in reaching the pharmaceutical market. A large number of peptides are already in preclinical and clinical pipelines for treatment of various diseases. This review highlights the recent researches on the various natural peptides and future prospects for AD management.

Protective effect of rutin on cognitive impairment caused by phenytoin

Objective:

To study the effect of the co-administration of phenytoin (PHT) and rutin in comparison with PHT and piracetam (PIM) on seizure control, cognitive, and motor functions in mice.

Materials and Methods:

Increasing current electroshock seizure (ICES) test was used to evaluate the effect of the co-administration of PHT and PIM on convulsions. Cognitive functions in mice were assessed by a spontaneous alternation in behavior on a plus maze while motor functions were screened using rolling roller apparatus and by counting the number of arms entries on a plus maze. Brain acetyl-cholinesterase (AChE) activity was also estimated.

Statistical Analysis:

The expression of data was done as mean ± standard error of the mean. The normally distributed data were subjected to one-way ANOVA followed by Dunnett's test. P < 0.05 was considered significant.

Results:

The study showed that rutin when co-administered with PHT, significantly reversed PHT-induced reduction in spontaneous alternation without altering the efficacy of PHT against ICES, in both acute and chronic studies. Further, it also reversed PHT-induced increase in AChE activity.

Conclusion:

Rutin alleviated the PHT-induced cognitive impairment without compromising its antiepileptic efficacy.

Validation of the General Practitioner Assessment of Cognition - Chinese version (GPCOG-C) in China

BACKGROUND

To assess the reliability, validity, and diagnostic utility of the Chinese version of General Practitioner Assessment of Cognition (GPCOG-C). The GPCOG, which is specifically designed for use in primary care to screen for cognitive impairment, consists of a patient section testing cognition, and an informant section asking about decline in cognitive and functional abilities.

METHODS

The English version of GPCOG was translated, back-translated, and subsequently revised to determine the final GPCOG-C. Our sample comprised 253 community-dwelling volunteers with memory concerns aged 50 years and over and 103 outpatients of a psychogeriatric clinic with memory complaints. Participants were assessed by one of the four general practitioners or six psychogeriatricians. The Mini-Mental State Examination (MMSE), the Hasegawa's Dementia Scale (HDS), and the GPCOG-C were compared against the DSM-IV-defined dementia diagnosis.

RESULTS

The internal consistency (Cronbach's α) was 0.68 for the GPCOG patient section. The test-retest was 0.98 for the GPCOG-C total. The sequential administration of both components of GPCOG-C had a sensitivity of 97% and a specificity of 89%, with a positive predictive value of 72% and a negative predictive value of 99%. Both the GPCOG-C total and sequential two-stage scoring methods performed at least well as the MMSE and HDS in detecting dementia. The administration time for the two-stage approach was 4.3 ± 2.4 min.

CONCLUSIONS

The GPCOG-C is a valid, time efficient instrument for dementia screening in China.

Toxicological scoring of Alzheimer's disease drug huperzine in a guinea pig model

Huperzine is a secondary metabolite in lycopods Huprzia and an inhibitor of acetylcholinesterase and antagonist of N-methyl-D-apartate receptor. Huperine is a suitable drug for the treatment of Alzheimer's disease as it is a part of traditional Chinese medicine. Currently, it undergoes clinical trials in the European Union and United States. The toxicological data about huperzine are missing and link between huperzine and oxidative stress has not been extensively investigated. For the above mentioned reasons, we organized experiment on a guinea pig model aimed at the investigation of adverse effects caused by huperzine. Guinea pigs were exposed to (-)-huperzine A in doses 5-625 µg/kg. Animals were sacrificed one day after exposure. Ferric reducing antioxidant power, thiobarbituric acid reactive substances, glutathione reductase, caspase 3 activity and selected biochemical markers (e.g. transaminases, blood urea nitrogen and glucose) were assayed. In frontal, parietal, temporal lobes and cerebellum, we found increase of antioxidants, glutathione reductase and oxidative stress markers in a dose dependent manner. Effects on liver, kidney and spleen were milder. We discuss ambivalent action of huperzine in the body and judge the huperzine action owing to recently reported experiments.