Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) mediate the degradation of acetylcholine (ACh), a primary neurotransmitter in the brain. Cholinergic deficiency occurs during the progression of Alzheimer's disease (AD), resulting in widespread cognitive dysfunction and decline. We evaluated the potential effect of a natural cholinesterase inhibitor, zerumbone, using in vitro target enzyme assays, as well as in silico docking and ADMET (absorption, distribution, metabolism, excretion, and toxicity) simulation. Zerumbone showed a predominant cholinesterase inhibitory property with IC50 values of 2.74 +/- 0.48 microM and 4.12 +/- 0.42 microM for AChE and BChE, respectively; however, the modes of inhibition were different. Computational docking simulation indicated that Van der Waals interactions between zerumbone and both the cholinesterases were the main forces responsible for its inhibitory effects. Furthermore, zerumbone showed the best physicochemical properties for both bioavailability and blood-brain barrier (BBB) permeability. Together, in the present study, zerumbone was clearly identified as a unique dual AChE and BChE inhibitor with high permeability across the BBB, suggesting a strong potential for its physiological benefits and/or pharmacological e ffi cacy in the prevention of AD.
Morus species, commonly known as mulberry, is widely distributed in China. The mulberry tree is a high-value plant in agriculture. Morus australis is one of the major Morus species growing in Northern China. However, the biological properties of the main constituents of M. australis roots were not well studied. In the present study, through extensive chromatographic and spectral analysis, 12 phenolic compounds were isolated and identified from the M. australis roots. Compounds 1, 2, 8, 9 and 12 were isolated from M. australis roots for the first time. Antitumor activities of these polyphenols were studied on the A549 cell line. Compounds 1, 5 and 6 exhibited cytotoxicity on A549 cells and induced apoptosis in A549 cells via the intrinsic mitochondrial pathway. They also mediated inhibition of autophagic flux contributed cell death via the PI3k/Akt/mTOR pathway. In order to explore more potential bioactivities of these isolates, alpha-glucosidase, acetylcholinesterase and tyrosinase inhibitory activities were studied, and the results demonstrated that the inhibitory activity of these polyphenols on enzymes was not defined by their basic structural skeletons, but by the substituted position.
Title: Bioactive Constituents of F. esculentum Bee Pollen and Quantitative Analysis of Samples Collected from Seven Areas by HPLC Li F, Guo S, Zhang S, Peng S, Cao W, Ho CT, Bai N Ref: Molecules, 24:2705, 2019 : PubMed
Bee pollen contains all the essential amino acids needed by humans. China is the largest producer of bee pollen in the world. In the present study, we identified 11 fatty acids in F. esculentum bee pollen oil by GC-MS analysis, and 16 compounds were isolated from F. esculentum bee pollen by column chromatography and identified. A high-performance liquid chromatography-diode array detector (HPLC-DAD) method was established for the quality control of F. esculentum bee pollen. A validated HPLC-DAD method was successfully applied to the simultaneous characterization and quantification of nine main constituents in seven samples collected from seven different areas in China. The results showed that all standard calibration curves exhibited good linearity (R(2) > 0.999) in HPLC-DAD analysis with excellent precision, repeatability and stability. The total amount in the samples from the seven regions ranged from 23.50 to 46.05 mg/g. In addition, seven compounds were studied for their bioactivity using enzymic methods, whereby kaempferol (3) showed high alpha-glucosidase inhibitory activity (IC50: 80.35 mug/mL), ergosterol peroxide (8) showed high tyrosinase inhibitory activity (IC50: 202.37 mug/mL), and luteolin (1) had strong acetylcholinesterase inhibitory activity (IC50: 476.25 mug/mL). All results indicated that F. esculentum bee pollen could be a nutritious health food.
Title: Chemical characterization of main bioactive constituents in Paeonia ostii seed meal and GC-MS analysis of seed oil Tian X, Guo S, Zhang S, Li P, Wang T, Ho CT, Pan MH, Bai N Ref: J Food Biochem, :e13088, 2019 : PubMed
The seeds of tree peony (Paeonia ostii) are promulgated as emerging edible oil crops. However, biological properties of principal constituents of peony seeds were not well studied. Fifteen main constituents including suffruticosols A and B, trans-epsilon-viniferin, ampelopsin E, resveratrol, trans-resveratrol-4'-O-beta-d-glucopyranoside, paeoniflorin, luteolin, luteolin-4'-O-beta-d-glucopyranoside, apigenin, kaempferol, oleanic acid, betulinic acid, hederagenin, and caffeic acid were isolated and identified. Their cytotoxicity against human tumor cell lines (COLO205, HT-29, HepG2, AGS, and HL-60) were evaluated. Among them, trans-epsilon-viniferin showed the most potent cytotoxicity against HL-60 cells (IC50 5.6 muM); ampelopsin E exhibited the most obvious antiproliferative properties on COLO205 (IC50 78.1 muM) and HT-29 (IC50 4.2 muM) cells, and betulinic acid showed the strongest growth inhibitory effects on HepG2 (IC50 6.6 muM) and AGS (IC50 5.4 muM) cells. Three enzymes (tyronsinase, alpha-glucosidase, and acetylcholinesterase) inhibitory activities of 12 compounds were also screened. Stilbene compounds, especially suffruticosols A and B, showed a significant inhibitory activity on all three enzymes. PRACTICAL APPLICATIONS: The cytotoxicity of 15 main constituents from peony seeds against COLO205, HT-29, HepG2, AGS, and HL-60 cells were evaluated. Among them, trans-epsilon-viniferin showed the most potent cytotoxicity against HL-60 cells (IC50 5.6 muM); ampelopsin E exhibited the most obvious antiproliferative properties on COLO205 (IC50 78.1 muM) and HT-29 (IC50 4.2 muM) cells, and betulinic acid showed the strongest growth inhibitory effects on HepG2 (IC50 6.6 muM) and AGS (IC50 5.4 muM) cells. Collectively, these results suggested that Paeonia ostii seed (POS) extracts are potential candidates for anticancer agents.
SCOPE: The aim of this research was to explore whether the tea-polyphenol (-)-epigallocatechin-3-gallate (EGCG) could be used as a potential agent for blocking smoking (nicotine, Nic)- or hormone (estradiol, E2)-induced breast cancer cell proliferation through inhibition of a common signaling pathway. METHODS AND RESULTS: To explore whether Nic (>0.1 muM, 24 h) and E2 (>1 nM, 24 h) significantly increased alpha9-nicotinic acetylcholine (alpha9-nicotinic acetylcholine receptor (nAChR)) mRNA and protein expression levels, real-time PCR and immunoblotting analysis experiments were performed in human breast cancer (MCF-7) cells. Luciferase promoter activity experiment was performed to test the alpha9-nAChR promoter activity affected by Nic, E2 or EGCG. The results indicate that treatment with EGCG (1 muM) profoundly decreases Nic- and E2-induced MCF-7 proliferation by down regulating alpha9-nAChR expression. The alpha9-nAChR promoter activity is significantly induced by 24-h treatment with Nic (10 muM) or E2 (10 nM) (>1.8 and approximately 2.3-fold, respectively) in MCF-7 cells. Pretreatment with EGCG eliminated the Nic- and E2-induced alpha9-nAChR promoter-dependent luciferase activity. We further demonstrate that combined treatment with EGCG profoundly inhibits [3H]-Nic/ alpha9-nAChR binding activity in breast cancer cells. CONCLUSIONS: We found that the EGCG could be used as an agent for blocking smoking (Nic)- or hormone (E2)-induced breast cancer cell proliferation by inhibiting of alpha9-nAChR signaling pathway. This study reveals the novel antitumor mechanisms of EGCG, and these results may have significant applications for chemopreventive purposes in human breast cancer.
Large-scale epidemiological cohort studies performed in the United States indicate that breast cancer risk is associated with active and passive smoking. As of yet, however, there is no direct evidence of antitumor effects by agents that block the effect of tobacco compound nicotine (Nic) on relevant nicotinic receptors (nAChR) involved in breast tumorigenesis. In the present study, the expression profiles of different nAChR subunits in the human breast cancer cell line (MDA-MB-231) were characterized by RT-PCR. Nic (>0.1 microM, 6 h) significantly increased alpha9-nAChR mRNA and protein expression levels in human breast cancer cells (MDA-MB-231 cells). On the other hand, combined treatment with luteolin (Lut, 0.5 microM) and quercetin (Que, 0.5 microM) profoundly decreased MDA-MB-231 proliferation by down-regulating alpha9-nAChR expression. MDA-MB-231 cells were cultured in soft agar to evaluate anchorage-independent colony formation; combined treatment of Lut+Que inhibited Nic-induced MDA-MB-231 colony formation. Interestingly, the number of colonies formed was profoundly reduced in alpha9-nAChR knockdown (Si alpha9) cells in the combined (Lut+Que)-treated group as compared to the relevant control groups. Such results show that Lut- or Que-induced antitransforming activities were not limited to specific inhibition of the alpha9-nAChR receptor. Both alpha5- and alpha9-nAChR appear to be important molecular targets for Lut- and Que-induced antitumor effects in human breast cancer cells.
