1-Naphthylacetic acid (0.7-14 μM) has an IC50 of 13.16 μM and a Ki of 6.87 μM, respectively, which means that it inhibits PLA2 activity [1].

Absorption, Distribution and Excretion
After oral administration /0.1-1.0 mg/ ...of (14)C-naphthaleneacetic acid /(14)C-NAA/ to rats ...83-90% ...was excreted in urine, mostly in 24 hr and 3-10% in feces in 48 hr. After larger doses, excretion of (14)C in urine was prolonged and more was excreted in feces. Thus, after dose of about 100 mg /(14)C-NAA/ rat excreted 55% in 24-hr urine, 16% in 2nd day and 21% in 48-hr feces, whereas, after dose of about 250 mg, rat excreted 25% in 24-hr urine, 42% in 2nd day, 10% in 3rd day, and 18% in 48-hr feces and 3% in 3rd day.
Experiments in rats with cannulated bile ducts showed that fecal /(14)C-naphthaleneacetic acid/ was probably due to material excreted in bile. In rat receiving a lower dose (about 0.1 mg), excretion in urine (38%) was 4-fold more than in bile (9%), whereas in rat receiving a higher dose (about 100 mg), excretion in bile (12%) was 3-fold more than in urine (4%). The pattern applied whether bile was collected for 2 or 6 hr. The portion of /(14)C-NAA/ excreted in bile was greater than that excreted in feces suggesting that entero-hepatic circulation occurred thus, (14)C-compound excreted in bile were partly reabsorbed from intestines (after possible modification, such as deconjugation of conjugates) to be excreted by kidneys. Thus, naphthaleneacetic acid was rapidly and completely absorbed after oral dose to rats and its excretion was dose-dependent, but was rapid after lower doses.
Thin apple and pear blossoms: foliar absorption characteristics: surplus washes off easily; physiological action results from absorbed and translocated portion. Translocation characteristics: mobile; accumulates in meristems.

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Metabolism / Metabolites
When naphthaleneacetic acid was incubated with aspergillus niger, major metabolite was found to be 5-hydroxy analog. 4- and 6-hydroxy analogs were also observed.
A metabolic product of naphthaleneacetic acid from wheat coleoptiles was identified as the 5-hydroxy analog.
When kinnow mandarin fruits were dipped in aq soln of naphthaleneacetic acid, 4 metabolites were formed. Two of these were not identified. Other two, in larger amt, were identified as the Alpha-NAA-aspartate and alpha-naphthylacetyl-beta-d-glucose (na-glucose).
Hydrolysis of the methyl ester of naphthaleneacetic acid was observed during storage of treated potatoes. When winesap and stayman cultivars were exposed to naphthaleneacetic acid ...some decarboxylation occurred and 6 conjugates were formed. Pea roots exposed to NAA produced NAA-aspartate... .
After single oral doses ... /to/ rats, 4 metabolites were found in urine. Two were identified as naphthaceturic acid and naphthacetylglucosiduronic acid. 3rd compound was apparently as a sulfate, indicating possible hydroxylation. The 4th was unidentified.

[1]. Crystal structure of phospholipase A 2 in complex with 1-naphthaleneacetic acid. IUBMB Life. 2018 Oct;70(10):995-1001.

[2]. Effect of 1-naphthaleneacetic acid on organic acid exudation by the roots of white lupin plants grown under phosphorus-deficient conditions. J Plant Physiol. 2014 Sep 15;171(15):1354-61.

1-naphthaleneacetic acid is a naphthylacetic acid substituted by a carboxymethyl group at position 1. It has a role as a synthetic auxin. It is a conjugate acid of a 1-naphthaleneacetate.
1-Naphthylacetic acid has been reported in Humulus lupulus, Rehmannia glutinosa, and other organisms with data available.

C12H10O2

186.21

186.068

86-87-3

1-Naphthaleneacetic acid potassium salt;15165-79-4

6862

White to off-white solid powder

1.2±0.1 g/cm3

373.2±11.0 °C at 760 mmHg

141-143 °C(lit.)

270.1±14.4 °C

0.0±0.9 mmHg at 25°C

1.652

2.74

1

2

2

14

212

0

PRPINYUDVPFIRX-UHFFFAOYSA-N

InChI=1S/C12H10O2/c13-12(14)8-10-6-3-5-9-4-1-2-7-11(9)10/h1-7H,8H2,(H,13,14)

2-naphthalen-1-ylacetic acid

alpha Naphthylacetic acid; alphaNaphthylacetic acid; alpha-Naphthylacetic acid

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)

MEthanol : ~125 mg/mL (~671.29 mM)
DMSO : ≥ 100 mg/mL (~537.03 mM)
H2O : ~0.1 mg/mL (~0.54 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (13.43 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 (13.43 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 (13.43 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.)