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Determination of the Juglone Content of Juglans regia Leaves by GC/MS.

Determination of the Juglone Content of Juglans regia Leaves by GC/MS.

Natural product communications (2015-09-29)

Irena Matławska, Wiesława Bylka, Ewa Widy-Tyszkiewicz, Beata Stanisz

ABSTRACT

The constituents of walnut (Juglans regia L.) leaves are represented by tannins, phenolics, and naphthoquinones, the characteristic compound being juglone. The content of juglone in the methanolic extract of the leaves determined by the GC/MS method was 9.9 ± 0.2 mg/100 g; small amounts (1.3 ± 0.02 mg/100 g) were recorded in the infusion, whereas in the decoction it was not detected. As some studies indicate toxicity of juglone, only decoctions should be recommended for therapeutic use.

MATERIALS

Product Number

Brand

Product Description

Sigma-Aldrich

Toluene, SAJ first grade, ≥99.0%

Sigma-Aldrich

Toluene, JIS 300, suitable for residue analysis, ≥99.8%

Sigma-Aldrich

Sodium hydroxide-¹⁶O solution, 20 wt. % in H₂¹⁶O, 99.9 atom % ¹⁶O

Sigma-Aldrich

Ethyl formate, SAJ special grade, ≥97.0%

Sigma-Aldrich

Toluene, JIS 1000, suitable for residue analysis, ≥99.8%

Sigma-Aldrich

Toluene, JIS special grade, ≥99.5%

Sigma-Aldrich

Ethyl formate, ≥97%, FCC, FG

Sigma-Aldrich

5-Hydroxy-1,4-naphthoquinone, 97%

Sigma-Aldrich

Ethyl formate, natural, ≥95%, FG

Sigma-Aldrich

Hydrogen chloride, ReagentPlus^®, ≥99%

Sigma-Aldrich

Toluene, anhydrous, 99.8%

Sigma-Aldrich

Ethyl formate, reagent grade, 97%

Supelco

Toluene, HPLC grade, 99.8%

Sigma-Aldrich

Methanol solution, suitable for NMR (reference standard), 4% in methanol-d₄ (99.8 atom % D), NMR tube size 3 mm × 8 in.

Sigma-Aldrich

Toluene, suitable for HPLC, ≥99.9%

Supelco

Methanol solution, contains 0.10 % (v/v) formic acid, UHPLC, suitable for mass spectrometry (MS), ≥99.5%

Sigma-Aldrich

Hydrogen chloride solution, 3 M in cyclopentyl methyl ether (CPME)

Sigma-Aldrich

Methanol, SAJ special grade

Sigma-Aldrich

Methanol, suitable for HPLC

Sigma-Aldrich

Chloroform, suitable for HPLC

Sigma-Aldrich

Hydrogen chloride – ethanol solution, 0.1 M in ethanol

Sigma-Aldrich

Sodium hydroxide, JIS special grade, ≥96.0%

Sigma-Aldrich

Methanol, JIS 300, ≥99.8%, suitable for residue analysis

Sigma-Aldrich

Hydrochloric acid solution, 12 M

Sigma-Aldrich

Hydrochloric acid solution, 0.05 M

Sigma-Aldrich

Sodium hydroxide solution, 0.01 M

Sigma-Aldrich

Sodium hydroxide solution, 0.1 M

Sigma-Aldrich

Hydrochloric acid solution, 0.5 M

Sigma-Aldrich

Hydrochloric acid solution, 6 M

Sigma-Aldrich

Chloroform, SAJ first grade, ≥99.0%, contains 0.4-0.8% ethanol