Humulus japonicus attenuates LPS-and scopolamine-induced cognitive impairment in mice

Water extract of Humulus japonicus improves age‑related cognitive decline by inhibiting acetylcholinesterase activity and the acetylcholine signaling pathway

The aging process is associated with a decline in certain cognitive abilities, including learning and memory. This age‑related cognitive decline is associated with a reduction in neurogenesis and alterations in the cholinergic system. Humulus japonicus (HJ), an ornamental plant in the family Cannabaceae, has been reported to exert beneficial effects against neurodegenerative pathophysiologies in mouse models of disorders such as Alzheimer's and Parkinson's disease. Despite the increasingly aging populations of numerous societies, no study has yet investigated the effects of HJ on cognitive decline associated with normal aging. The present study therefore aimed to examine the protective potential of HJ water (HJW) extract against age‑related cognitive decline and scopolamine‑induced cognitive impairment. The analyses revealed that the oral administration of HJW markedly improved novel objective recognition and spatial learning in the novel object recognition and Morris water maze tests, respectively, in aged mice. The administration of 600 mg/kg HJW further increased neurogenesis and CA1 thickness in the hippocampi of aged mice. In scopolamine‑induced cognitive impairment, administration of 400 or 600 mg/kg HJW markedly increased novel object recognition performance in scopolamine‑treated mice. The inhibitory effect of HJW on acetylcholinesterase (AChE) and the activation effects of HJW on the calcium/calmodulin‑dependent kinase (CaMK)IIα‑cAMP response element‑binding protein (CREB) and AKT‑glycogen synthase kinase‑3 β (GSK3β) pathways were further demonstrated. Overall, these results indicate that HJW administration improves cognitive function through the regulation of AChE activity and CaMKIIα‑CREB and AKT‑GSK3β pathways.

Angiotensin-converting enzyme inhibition prevents l-dopa-induced dyskinesia in a 6-ohda-induced mouse model of Parkinson's disease

Parkinson's disease (PD) is characterised by severe movement defects and the degeneration of dopaminergic neurones in the midbrain. The symptoms of PD can be managed with dopamine replacement therapy using L-3, 4-dihydroxyphenylalanine (L-dopa), which is the gold standard therapy for PD. However, long-term treatment with L-dopa can lead to motor complications. The central renin-angiotensin system (RAS) is associated with the development of neurodegenerative diseases in the brain. However, the role of the RAS in dopamine replacement therapy for PD remains unclear. Here, we tested the co-treatment of the angiotensin-converting enzyme inhibitor (ACEI) with L-dopa altered L-dopa-induced dyskinesia (LID) in a 6-hydroxydopamine (6-OHDA)-lesioned mouse model of PD. Perindopril, captopril, and enalapril were used as ACEIs. The co-treatment of ACEI with L-dopa significantly decreased LID development in 6-OHDA-lesioned mice. In addition, the astrocyte and microglial transcripts involving Ccl2, C3, Cd44, and Iigp1 were reduced by co-treatment with ACEI and L-dopa in the 6-OHDA-lesioned striatum. In conclusion, co-treatment with ACEIs and L-dopa, such as perindopril, captopril, and enalapril, may mitigate the severity of L-DOPA-induced dyskinesia in a mouse model of PD.