- Superoxide anion radical scavenging activity: Rabdosiin showed potent scavenging activity with an IC₅₀ value of 0.53 ± 0.02 μM (mean ± SD, n=4). This activity was higher than that of ascorbic acid (IC₅₀ = 11.66 ± 2.99 μM) and increased with the number of caffeoyl groups in the compound. [1]
- Hydroxyl radical scavenging activity: Rabdosiin exhibited the highest activity among tested compounds with an IC₅₀ value of 7.40 ± 0.59 μM. Ascorbic acid had an IC₅₀ of 12.70 ± 4.33 μM. [1]
- Hyaluronidase inhibition: Rabdosiin inhibited hyaluronidase activity in a dose‑dependent and caffeoyl number‑dependent manner. Its inhibitory effect was stronger than that of disodium cromoglycate (DSCG), a clinically used anti‑allergic drug. The inhibition increased with the number of caffeoyl groups. (Exact IC₅₀ not reported; see Figure 2 in the paper.) [1]
- β‑Hexosaminidase release inhibition from RBL‑2H3 cells: Rabdosiin inhibited antigen‑induced β‑hexosaminidase release in a dose‑dependent manner. At 2 mM, it achieved more than 90% inhibition (specifically stated as 90% inhibition). The spontaneous release was 3.5 ± 1.2% and stimulated release was 30.5 ± 5.2% (for 2×10⁵ cells/well). Rabdosiin did not inhibit β‑hexosaminidase enzyme activity itself, as confirmed by adding the compound to the extracellular fluid after degranulation (Figure 4). [1]
- Correlation analysis: The superoxide anion radical scavenging activity of rabdosiin showed a linear correlation with its hyaluronidase inhibitory activity (Figure 5). [1]

- Superoxide anion scavenging assay by ESR spin trapping: The assay was performed using the hypoxanthine‑xanthine oxidase system. Hypoxanthine (0.4 mM), diethylenetriamine‑N,N,N′,N′′,N′′‑pentaacetic acid (0.7 mM), and various concentrations of the test compound were dissolved in 100 mM sodium phosphate buffer (pH 7.4). Xanthine oxidase (0.12 units/mL) was added, followed almost immediately by 5,5‑dimethyl‑1‑pyrrole‑N‑oxide (DMPO) at a final concentration of 90 mM. After mixing for 1 minute, ESR spectra were recorded at room temperature (21°C) with a spectrometer at 100 kHz field modulation frequency, 1 G modulation amplitude, and 5 mW output power. The scavenging activity was expressed as the IC₅₀ value (50% inhibition concentration of the compound for superoxide anion radicals generated in this system). Ascorbic acid was used as a positive control. [1]
- Hydroxyl radical scavenging assay by ESR spin trapping: The Fenton system (Fe(II) + H₂O₂) was used. FeSO₄ (22.5 μM), various concentrations of the test compound, and DMPO (90 mM) were mixed. The reaction was started by adding H₂O₂ (22.5 μM). After mixing for 40 seconds, ESR spectra were recorded under the same conditions as above. The scavenging activity was expressed as the IC₅₀ value for hydroxyl radicals generated in the Fenton reaction. Ascorbic acid served as a positive control. [1]
- Hyaluronidase activity assay (Morgan‑Elson method as modified): Hyaluronidase (200 units/mL) was incubated with hyaluronic acid sodium salt (0.4 mg/mL) at 37°C for 40 minutes in 0.1 M acetate buffer (pH 4.0) containing 2.5 mM calcium chloride as an activator. For inhibition studies, hyaluronidase was preincubated with the test compound at 37°C for 20 minutes in 0.1 M acetate buffer (pH 4.0). Then calcium chloride (2.5 mM) was added and incubated at 37°C for 20 minutes. The reaction was started by adding hyaluronic acid sodium salt (0.4 mg/mL) and incubating at 37°C for 40 minutes. Absorbance was measured at 585 nm. The percent inhibition was calculated as: Inhibition(%) = [(A‑B)‑(C‑D)]/(A‑B)×100, where A = absorbance of control (without test compound), B = absorbance of blank (without hyaluronidase) for control, C = absorbance with test compound, D = absorbance of test compound alone. [1]

- Cell culture: RBL‑2H3 cells were maintained in minimum essential medium supplemented with 15% heat‑inactivated fetal bovine serum in a humidified atmosphere of 5% CO₂. Cells were subcultured three times per week and removed from plates using a cell scraper. [1]
- β‑Hexosaminidase release assay: Cells were plated at 2×10⁵ cells per well in 24‑well culture plates and cultured overnight with DNP‑specific IgE (0.5 μg/mL) to sensitize. The supernatants were discarded, and cells were washed three times with Pipes‑buffered saline (25 mM Pipes pH 7.2, 125 mM NaCl, 2.7 mM KCl, 5.6 mM glucose, 1 mM CaCl₂, 0.1% BSA). Cells were then preincubated at 37°C for 15 minutes in the presence of various concentrations of rabdosiin. Stimulation was performed by adding DNP‑BSA (10 ng/mL) for 20 minutes. Aliquots (10 μL) of the medium and cell lysate (obtained by adding 0.1% Triton X‑100) were incubated with 10 μL of 1 mM p‑nitrophenyl‑N‑acetyl‑β‑D‑glucosaminide in 0.1 M sodium citrate (pH 4.5) at 37°C for 1 hour. The reaction was stopped by adding 250 μL of carbonate buffer (0.1 M Na₂CO₃ and 0.1 M NaHCO₃, pH 10), and absorbance due to p‑nitrophenol formation was measured at 405 nm. Net percent release was calculated as: Net% release = [(A‑C)/(B‑C)]×100, where A = amount of β‑hexosaminidase in extracellular fluid, B = total content in cells, C = amount in extracellular fluid from non‑stimulated cells. Inhibition (%) = [1‑(Net% release with test compound / Net% release of stimulated cells)]×100. Rabdosiin at 2 mM gave >90% inhibition. The compound did not affect β‑hexosaminidase enzyme activity when added to the extracellular fluid of degranulated cells (Figure 4). [1]

[1]. Antiallergic activities of rabdosiin and its related compounds: chemical and biochemical evaluations. Bioorg Med Chem. 1998 Jul;6(7):1051-6.

- The superoxide anion radical scavenging activity of rabdosiin correlated linearly with its hyaluronidase inhibitory activity (Figure 5). [1]
- Unlike disodium cromoglycate (which did not inhibit β‑hexosaminidase release in this cell line at 10 mM), rabdosiin and caffeic acid inhibited release >80% at 2 mM, suggesting a different mechanism of action. [1]
- The study proposes that rabdosiin is a candidate for a therapeutic agent for allergy due to its potent scavenging of active oxygen species, hyaluronidase inhibition, and β‑hexosaminidase release inhibition. [1]

C36H30O16

718.613811969757

718.153

263397-69-9

101064233

Off-white to yellow solid

3.9

10

16

13

52

1320

4

C1=CC(=C(C=C1C[C@@H](C(=O)O)OC(=O)[C@@H]2[C@H](C3=CC(=C(C=C3C=C2C(=O)O[C@H](CC4=CC(=C(C=C4)O)O)C(=O)O)O)O)C5=CC(=C(C=C5)O)O)O)O

VKWZFIDWHLCPHJ-ZLESDFJESA-N

InChI=1S/C36H30O16/c37-21-4-1-15(7-24(21)40)9-29(33(45)46)51-35(49)20-11-18-13-27(43)28(44)14-19(18)31(17-3-6-23(39)26(42)12-17)32(20)36(50)52-30(34(47)48)10-16-2-5-22(38)25(41)8-16/h1-8,11-14,29-32,37-44H,9-10H2,(H,45,46)(H,47,48)/t29-,30+,31+,32+/m1/s1

(2S)-2-[(1S,2R)-3-[(1R)-1-carboxy-2-(3,4-dihydroxyphenyl)ethoxy]carbonyl-1-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1,2-dihydronaphthalene-2-carbonyl]oxy-3-(3,4-dihydroxyphenyl)propanoic acid

Rabdosiin

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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 (~139.16 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (3.48 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (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 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 (3.48 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (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 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (3.48 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.)