Lan Xiang

Alzheimer’s disease (AD) is a prevalent chronic neurodegenerative disorder; the progression of this disease is driven by cellular determinants such as oxidative stress and dysregulated neurotrophic signaling. Lavender essential oil is traditionally used in aromatherapy for neuronal regulation and neuroprotection, suggesting its potential neuroprotective effects for chronic neurodegenerative disorders like AD. However, the key active constituents responsible for its benefits and the specific molecular pharmacological mechanisms remain unclear. In this study, we isolated myrtenol from lavender essential oil under the guidance of activity evaluation. Its neuroprotective effects were evaluated in PC12 cells via neurite outgrowth, anti-Aβ/H₂O₂ cytotoxicity, and antioxidant assays. Targets and pathways were explored using inhibitor experiments, cell thermal shift assay (CETSA), drug affinity responsive target stability (DARTS), and Western blot. Myrtenol significantly induced neurite outgrowth in PC12 cells and effectively mitigated cytotoxicity and oxidative stress damage induced by Aβ_25–35 and H₂O₂. Mechanistic studies revealed that myrtenol’s effects are associated with the modulation of tyrosine kinase receptor A (TrkA) and insulin-like growth factor-1 receptor (IGF-1R), activating phospholipase C (PLC)/protein kinase C (PKC) and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways to jointly mediate neuroprotection effects against the pathology of AD. This study demonstrates that myrtenol as a highly active component of lavender essential oil possesses NGF-like neuritogenic activity and neuroprotective effects. It provides a foundation for understanding the cellular mechanisms of myrtenol as a small-molecule lead for further investigation in neurodegeneration-related research.

Traditional Chinese medicine plays an important role in human health, but due to the complexity of its active fraction, its therapeutic mechanism still needs further clarification. Polygalae Radix is one of the traditional Chinese medicines, which was recorded in Shennong Classic of Materia Medica with the effect of prolonging life. In the present study, we isolated a small molecule compound with anti-aging effects, 3,6′-disinapoyl sucrose (DISS), from Polygalae Radix under the guidance of the replicative lifespan assay of K6001 yeast strain. It extended the lifespan of yeast and alleviated etoposide-induced aging in 3T3 cells. Furthermore, this compound increased the telomerase activity and the length of telomeres, and targeted the SIRT1 signaling pathway, respectively. In addition, it improved the survival ability of yeast under oxidative stress conditions, decreased ROS and MDA levels, and increased the activity of SOD, CAT and GPx enzymes. Moreover, DISS enhanced autophagic flux, as demonstrated by assay of the YOM38-GFP-ATG8 yeast strain. In conclusion, DISS from Polygalae Radix exerts anti-aging effects by protecting telomeres, regulating the SIRT1/p53/p21 signaling pathway, mitigating oxidative stress and modulating autophagy. Thus, this study provides scientific evidence for the use of Polygalae Radix as an anti-aging herb.

In previous studies, we isolated a series of novel gentisides with nerve growth factor (NGF)-mimic activities from Gentiana rigescens Franch and conducted continuous structure–activity relationship (SAR) studies. Recently, a lead compound named TBG096 was discovered with significant NGF-mimic activity, low toxicity, and ability to pass through the blood–brain barrier (BBB). At the cell level, TBG096 exerts NGF-mimic activity by regulation of heat-shock cognate protein 70 (Hsc70) and downstream proteins. Subsequently, high-fat diet (HFD)-induced Alzheimer disease (AD) mouse models were used to evaluate the anti-AD efficacy of the compound. TBG096 significantly improved the memory dysfunction of AD mice at doses of 0.1, 5, and 20 mg/kg, respectively. In order to elucidate the mechanism of action of the compound against AD, the RNA-sequence analysis of transcriptomics, quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence staining, and Western blot analysis were performed using animal samples. TBG096 significantly increased the expression of the Wnt gene family (Wnt10b, Wnt5a, and Wnt1) and the number of mature neurons and newborn neurons in the hippocampus and cerebral cortex of AD mice, respectively. At the same time, it reduced the activity of microglia, astrocyte cells, and expression of inducible nitric oxide synthase (INOS) in the brain. Moreover, this compound significantly increased phosphorylated-adenosine 5′-monophosphate-activated protein kinase (AMPK), Hsc70, and lysosomal-associated membrane protein 2a (LAMP2A) and decreased the expression of hexokinase 2 (HK2), pyruvate kinase M2 (PKM2), amyloid precursor protein (APP), microtubule-associated protein tau (Tau), phosphoryl-Tau, and β-amyloid (Aβ) at the protein level. These results suggest that TBG096 produced the NGF-mimic activity and the anti-AD effect via promoting neurogenesis and modification of the Hsc70/HK2/PKM2/LAMP2A signaling pathway, proposing a potential novel approach to counteracting cognitive decline by developing small molecules that promote neurogenesis and the Hsc70 signaling pathway.

Gastrodin (gas) has been shown to promote neuroprotection and reverse Alzheimer’s disease (AD) pathology. However, its high effective dose limits its potential in treating AD. In this study, a bioassay system using PC12 cells and the nerve growth factor (NGF)-mimic effect was employed to investigate the structure–activity relationship of gas derivatives. Among the synthesized compounds, GAD037 demonstrated the highest NGF-mimic activity, surpassing gas. Additionally, GAD037 exhibited significant neuroprotective effects, reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels, thereby improving the survival of PC12 cells under oxidative stress. It also protected cells from Aβ-induced toxicity. Target protein identification and mechanistic studies revealed that insulin receptor (INSR) and alpha-actinin-4 (ACTN4) are potential targets of GAD037, confirmed through specific inhibitors, small interfering RNA (siRNA) analysis, a cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS). Moreover, the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) and rat sarcoma (Ras)/protooncogene serine–threonine protein kinase (Raf)/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways were found to be involved in the NGF-mimic activity of GAD037. In conclusion, GAD037 exhibits superior NGF-mimic and neuroprotective activities compared to gas, suggesting its potential as a lead compound for anti-AD applications.

The aging population is steadily increasing, with aging and age-related diseases serving as major risk factors for morbidity, mortality, and economic burden. Peanuts, known as the “longevity nut” in China, have been shown to offer various health benefits, with peanut skin extract (PSE) emerging as a key compound of interest. This study investigates the bioactive compound in PSE with anti-aging potential and explores its underlying mechanisms of action. Procyanidin A1 (PC A1) was isolated from PSE, guided by the K6001 yeast replicative lifespan model. PC A1 prolonged the replicative lifespan of yeast and the yeast-like chronological lifespan of PC12 cells. To further confirm its anti-aging effect, cellular senescence, a hallmark of aging, was assessed. In senescent cells induced by etoposide (Etop), PC A1 alleviated senescence by reducing ROS levels, decreasing the percentage of senescent cells, and restoring proliferative capacity. Transcriptomics analysis revealed that PC A1 induced apoptosis, reduced senescence-associated secretory phenotype (SASP) factors, and modulated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. The antioxidative capacity of PC A1 was also evaluated, showing enhanced resistance to oxidative stress in PC12 cells by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and increasing superoxide dismutase (SOD) activity. Moreover, PC A1 induced autophagy, as evidenced by an increase in fluorescence-labeled autophagic compartments and confirmation via Western blot analysis of autophagy-related proteins. In addition, the treatment of an autophagy inhibitor abolished the antioxidative stress and senescence-alleviating effects of PC A1. These findings reveal that PC A1 extended lifespans and alleviated cellular senescence by enhancing oxidative stress resistance and inducing autophagy, positioning it as a promising candidate for further exploration as a geroprotective agent.

Geniposidic 4-isoamyl ester (GENI) with anti-aging effects is a new iridoid glycoside derivative from Gardenia jasminoides Ellis found in our previous study. In this study, to indicate whether this compound has anti-Alzheimer’s disease (AD) effect, the galactose-induced AD mice and naturally aging mice with AD were used to do drug efficacy evaluation. Furthermore, the Western blot, small interfering RNA (siRNA), drug affinity responsive target stability (DARTS), cellular thermal shift assay (CESTA), liquid chromatography-tandem mass spectrometry (LC/MS-MS), adenosine 5′-monophosphate-activated protein kinase (AMPK) mutants and surface plasmon resonance (SPR) analysis were utilized to clarify the mechanism of action and identify target protein of this molecule. GENI exerts anti-AD efficacy in galactose-induced AD mice and naturally aging mice with AD through neuroprotection and modification of autophagy and neuron inflammation. Moreover, AMPK as the target protein of GENI to produce an anti-AD effect is identified and the ASP148, ASP157, and ASP166 of the AMPK α subunit and lysine (LYS)148, aspartic acid (ASP)156, LYS309, and ASP316 in the AMPK γ subunit as binding sites are confirmed. Meanwhile, the AMPK/unc-51-like autophagy-activating kinase 1 (ULK1)/microtubule-associated protein 1 light chain 3 beta (LC3B) and AMPK/mammalian target of rapamycin (mTOR) signaling pathways involved in anti-AD effects of GENI. The findings provide a new perspective on treating neurodegenerative diseases by activating AMPK for the energy metabolism disorder.

Drug development for Alzheimer’s disease (AD) treatment is challenging due to its complex pathogenesis. Tetradecyl 2,3-dihydroxybenzoate (ABG-001), a leading compound identified in our prior research, has shown promising NGF-mimicking activity and anti-aging properties. In the present study, both high-fat diet (HFD)-induced AD mice and naturally aging AD mice were used to evaluate anti-AD effects. Meanwhile, RNA-sequences, Western blotting, immunofluorescence staining, enzyme-linked immunosorbent assay (ELISA), cellular thermal shift assay (CETSA), drug affinity-responsive target stability (DARTS) assay, construction of expression plasmid and protein purification, surface plasmon resonance (SPR) analysis, and 16S rRNA sequence analysis were used to identify the target protein of ABG-001 and clarify the mechanism of action for this molecule. ABG-001 effectively mitigates the memory dysfunction in both HFD-induced AD mice and naturally aging AD mice. The therapeutic effect of ABG-001 is attributed to its ability to promote neurogenesis, activate chaperone-mediated autophagy (CMA), and reduce neuronal inflammation. Additionally, ABG-001 positively influenced the gut microbiota, enhancing the production of indole-3-propionic acid (IPA), which is capable of crossing the blood–brain barrier (BBB) and contributes to neuronal regeneration. Furthermore, our research revealed that IPA, linked to the anti-AD properties of ABG-001, targets the heat shock cognate 70 kDa protein (Hsc70) and regulates the Hsc70/PKM2/HK2/LC3 and FOXO3a/SIRT1 signaling pathways. ABG-001 improves the memory dysfunction of AD mice by modulating autophagy and inflammation through IPA and Hsc70 targeting. These findings offer a novel approach for treating neurodegenerative diseases, focusing on the modification of the gut microbiota and metabolites coupled with anti-aging strategies.