Ethanol Extract of Magnolia officinalis Prevents Lipopolysaccharide‐Induced Memory Deficiency via Its Antineuroinflammatory and Antiamyloidogenic Effects

Abstract

Magnolia bark contains several compounds such as magnolol, honokiol, 4-O-methylhonokiol, obovatol, and other neolignan compounds. These compounds have been reported to have various beneficial effects in various diseases. There is sufficient possibility that ethanol extract of Magnolia officinalis is more effective in amyloidogenesis via synergism of these ingredients. Neuroinflammation has been known to play a critical role in the pathogenesis of Alzheimer's disease (AD). We investigated whether the ethanol extract of M. officinalis (10 mg/ kg in 0.05% ethanol) prevents memory dysfunction and amyloidogenesis in AD mouse model by intraperitoneal lipopolysaccharide (LPS, 250 µg/ kg/day for seven times) injection. We found that ethanol extract of M. officinalis prevented LPS-induced memory deficiency as well as inhibited the LPS-induced elevation of inflammatory proteins, such as inducible nitric oxide synthase and cyclooxygenase 2, and activation of astrocytes and microglia. In particular, administration of M. officinalis ethanol extract inhibited LPS-induced amyloidogenesis, which resulted in the inhibition of amyloid precursor protein, beta-site amyloid-precursor-protein-cleaving enzyme 1 and C99. Thus, this study shows that ethanol extract of M. officinalis prevents LPS-induced memory impairment as well as amyloidogenesis via inhibition of neuroinflammation and suggests that ethanol extract of M. officinalis might be a useful intervention for neuroinflammation-associated diseases such as AD.

Honokiol improves learning and memory impairments induced by scopolamine in mice

“…Moreover, honokiol could also significantly decrease beta-amyloid (Aβ)-induced neuronal death, via inhibiting the reactive oxygen species (ROS) production, intracellular calcium elevation, and caspase-3 activity (Hoi et al, 2010). Extract of M. officinalis containing honokiol could not only ameliorate SCOP-induced memory impairment via inhibition of AChE activity (Lee et al, 2009), but also prevent lipopolysaccharide (LPS)-induced memory deficiency via its antineuroinflammatory and antiamyloidogenic effects (Lee et al, 2012). Therefore, we hypothesized that honokiol may have potential benefit in the treatment of AD.…”

Water extract of Magnolia officinalis cortex inhibits osteoclastogenesis and bone resorption by downregulation of nuclear factor of activated T cells cytoplasmic 1

“…M. officinalis cortex is a key ingredient of several traditional medicines such as Pyengwisan and Banhahubaktang that are commercially available and widely prescribed at traditional medicine clinics in Korea 11, 12. Previous studies have shown that M. officinalis extracts have antibacterial, 13 antiatherogenic, 14 antineuroinflammatory, 15 and anticancer effects 16 . Moreover, M. officinalis cortex has several biological active components, including magnolol and honokiol, to have beneficial effects on ligature-induced periodontitis or arthritis by inhibiting osteoclastogenesis, suggesting an inhibitory potential of M. officinalis cortex on inflammatory-induced bone disease 17, 18.…”

Amelioration of Cognitive Dysfunction in APP/PS1 Double Transgenic Mice by Long-Term Treatment of 4-O-Methylhonokiol

“…Although we did not demonstrated anti-neuroinflammatory properties of 4- O -methylhonokiol in this investigation, previous studies revealed that this compound had a potent anti-neuroinflammatory activity which was associated with cognitive enhancement in the AD animal models (Lee et al ., 2012a; Lee et al ., 2013). We suggested that the anti-inflammatory activity was mediated by diminishing NF-κB signaling pathway.…”