α-Synuclein (α-syn) fibrils and Bax protein. Molecular docking studies suggest that aegeline binds to the pathogenic peptide site (residues 45-54) of α-synuclein fibrils, interacting with His50 and Val48 residues via π-π stacking and hydrogen bonding, respectively. It also binds to the BH4 domain of Bax, interacting with residues E44 and G39 via hydrogen bonds. [1]

Rescue of α-Synuclein-Induced Growth Arrest: In yeast cells expressing 2 copies of human α-synuclein, aegeline at 10 μM restored growth to 26.5 ± 3% above basal level. In cells expressing 3 copies of wild-type α-synuclein, it restored growth to 43.0 ± 6% above basal level; in cells expressing 3 copies of the A53T mutant α-synuclein, it restored growth to 93 ± 8% above basal level. Even at 2.5 μM concentration, aegeline rescued growth of yeast cells expressing 3 copies of α-synuclein on galactose-containing SG agar plates. [1]
Inhibition of α-Synuclein-Induced Apoptotic Markers: In yeast cells expressing 3 copies of α-synuclein, aegeline significantly reduced reactive oxygen species (ROS) production, prevented loss of mitochondrial membrane potential (MMP), and reduced nuclear DNA fragmentation (apoptosis). ROS levels were reduced from high levels observed in α-synuclein-expressing cells to near control levels; MMP loss was similarly abrogated; DNA fragmentation decreased from 42% to 11%. [1]
Rescue of Bax-Induced Growth Arrest: In yeast cells expressing a single copy of human Bax, aegeline at 2.5 μM restored growth in galactose-containing SG liquid medium, with an EC₅₀ value of 850 ± 10 nM for growth restoration. [1]
Inhibition of Bax-Induced Apoptotic Markers: In yeast cells expressing Bax, aegeline significantly reduced ROS production (from 4.3-fold increase to near basal levels), prevented loss of MMP (from 45% reduction to near control levels), and reduced nuclear DNA fragmentation (from 34% to 13%). [1]
Antioxidant Activity: Aegeline exhibited antioxidant activity in both DPPH and ABTS free radical scavenging assays at 20 μM concentration, comparable to vitamin C. [1]

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Additionally, in cells expressing the highly pathogenic A53T alpha-synuclein mutant, aegeline avoids growth arrest. Inhibiting increased ROS levels, loss of mitochondrial membrane potential, and nuclear DNA fragmentation—apoptotic characteristics observed in cells expressing α-synuclein or Bax—restores cell proliferation [1]. While thapsigargin successfully suppressed histamine release from RPMC, aegeline had a mild inhibitory impact on histamine release from the cell [2].

DPPH Radical Scavenging Assay: The ability of aegeline to scavenge free radicals was assessed using the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. Aegeline at 20 μM was observed to be as effective as vitamin C in scavenging DPPH radicals. [1]
ABTS Radical Scavenging Assay: The antioxidant activity of aegeline was also evaluated using the ABTS (2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid) assay. At 20 μM concentration, aegeline demonstrated antioxidant activity comparable to vitamin C. [1]

Yeast Growth Rescue Assay: Yeast strains expressing 2 or 3 copies of human α-synuclein or a single copy of human Bax were grown in 96-well microtiter plates containing minimal SG medium (with 2% galactose and 0.2% glucose). Aegeline was added at concentrations ranging from 2.5 to 10 μM (final DMSO concentration 0.5%). Plates were incubated at 30°C with shaking at 200 rpm for 72 hours. Cell growth was monitored by measuring optical density at 600 nm (OD₆₀₀). Percentage growth restoration was calculated relative to control cells grown without compound. Fisetin and quercetin were used as positive controls. [1]
Reactive Oxygen Species (ROS) Detection: Yeast cells were grown in SG medium with or without aegeline to induce α-synuclein or Bax expression. Cells were harvested and stained with dihydroethidium, which is oxidized to fluorescent ethidium upon reaction with superoxide. Fluorescence intensity was measured to quantify ROS levels. Cells grown in glucose-containing SD medium (repressed expression) served as controls. [1]
Mitochondrial Membrane Potential (MMP) Measurement: Yeast cells were grown in SG medium with or without aegeline to induce α-synuclein or Bax expression. Cells were stained with JC-10 dye, which exhibits potential-dependent accumulation in mitochondria and shifts fluorescence from green to orange-red with increasing membrane potential. Fluorescence ratios were used to assess MMP loss. Cells grown in SD medium served as controls. [1]
Nuclear DNA Fragmentation (Apoptosis) Detection: Yeast cells were grown in SG medium with or without aegeline to induce α-synuclein or Bax expression. Cells were subjected to TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) staining to detect fragmented DNA, a hallmark of apoptosis. The percentage of apoptotic cells was quantified by fluorescence microscopy. Cells grown in SD medium served as controls. [1]
Western Blot Analysis: Protein lysates from yeast strains were separated by SDS-PAGE, transferred to membranes, and probed with specific antibodies to confirm co-expression of α-synuclein, Bax, and ySec22p or hBcl-xL proteins. This confirmed that growth rescue was due to functional suppression rather than reduced expression of the toxic proteins. [1]

The compound was used in yeast cell assays at concentrations up to 10 μM, and no adverse effects on yeast cell growth were noted at these concentrations. [1]

[1].Aegeline, a natural product from the plant Aegle marmelos, mimics the yeast SNARE protein Sec22p in suppressing α-synuclein and Bax toxicity in yeast. Bioorg Med Chem Lett. 2019 Aug 15;29(16):2437-2438.

[2]. Effects of aegeline, a main alkaloid of Aegle Marmelos Correa leaves, on the histamine release from mast cells. Pak J Pharm Sci. 2011;24(3):359‐367.

(+/-)-Aegeline is a member of the methoxybenzene class of compounds.

C18H19NO3

297.34836

297.136

C, 72.71; H, 6.44; N, 4.71; O, 16.14

456-12-2

15558419

White to off-white solid powder

1.2±0.1 g/cm3

567.7±50.0 °C at 760 mmHg

180 °C

297.1±30.1 °C

0.0±1.6 mmHg at 25°C

1.612

2.45

2

3

6

22

355

0

COC1=CC=C(C=C1)C(CNC(=O)/C=C/C2=CC=CC=C2)O

QRFDENJATPJOKG-KPKJPENVSA-N

InChI=1S/C18H19NO3/c1-22-16-10-8-15(9-11-16)17(20)13-19-18(21)12-7-14-5-3-2-4-6-14/h2-12,17,20H,13H2,1H3,(H,19,21)/b12-7+

(E)-N-[2-hydroxy-2-(4-methoxyphenyl)ethyl]-3-phenylprop-2-enamide

(+-)-Aegeline; RefChem:390686; DTXSID101318019; DTXCID801747811; ...; 456-12-2;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~336.30 mM)

Solubility in Formulation 1: 2.5 mg/mL (8.41 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (8.41 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)