Analysis of nordihydroguaiaretic acid in Larrea divaricata Cav. extracts by micellar electrokinetic chromatography.

Introduction: Larrea divaricata Cav. is a common shrub used in folk medicine to treat a variety of diseases. The main product extracted from this bush is nordihydroguaiaretic acid (NDG), which is a potent antioxidant.

Objective: In this paper we propose a novel method for the quantification of NDG in different extracts of Larrea divaricata. The concentration of NDG in two different aqueous extracts (I and D) and an ethanolic extract (Eet) was analysed, in order to evaluate the safe use of the extracts for pharmacological purposes.

Methodology: Micellar electrokinetic chromatography (MEKC) was performed under the following conditions: the background electrolyte used consisted of 20  mm phosphate buffer (pH 7.5), 10  mm sodium dodecyl sulphate and 10% acetonitrile.

Results: The limits of detection and quantitation of NDG were 4.54 × 10(-4) and 10.6 × 10(-4)   mg/mL, respectively. The concentration of this acid in both aqueous extracts was within the safe levels. However, the decoction must be used carefully because the concentration of the acid was almost over the recommended limit. In the case of ethanolic extracts, the amount of NDG was above the safe concentration, which is in agreement with the solubility of the active compound in ethanol.

Conclusions: The conclusions of this study demonstrate that most of these plant extracts should be used with care, especially those which are used with medicinal purposes. This is the first research on the quantification of NDG using MEKC in jarilla extracts.