Planta Med 2009; 75 - PC12
DOI: 10.1055/s-0029-1234471

Juglans nigra green husks as a source of bioactive phytochemicals

L Rodrigues 2, A Paranhos 1, 2, T Amaral 1, 2, J Canhoto 2, T Batista 1, 2
  • 1Laboratório de Farmacognosia, Faculdade de Farmácia, Pólo Ciências da Saúde, Azinhaga de Santa Comba, 3000–548 Coimbra, Portugal
  • 2Centro Estudos Farmacêuticos, Universidade de Coimbra, Pólo Ciências da Saúde, Azinhaga de Santa Comba, 3000–548 Coimbra, Portugal

Juglans spp. (Juglandaceae) have been used in folk medicine for thousands of years to treat a wide range health disorders. Recently, a correlation between phenolic contents and antioxidant activity was established for J. regia L. leaves [1]. The present work evaluates the antioxidant properties of J. regia L. and J. nigra L. husks and assesses the biological and chemical potential of the Juglans nigra L., which is economically less valued.

Green husks from both species were extracted with 70% aqueous ethanol using an Ultra-Turrax homogeniser. Total phenols were evaluated by Folin-Ciocalteu method. Antioxidant assessment was carried out with the DPPH method and the assay based on the superoxide-driven reduction of NBT by photochemically reduced riboflavin. Phenolic profiles were established by HPLC-PDA-ESI/tandem MS, in negative ion mode. A higher phenolic content was verified for J. nigra (83.1±0.16mg of gallic acid equivalents/g dry plant) relatively to J. regia (15.7±0.03mg/g). In addition, reactivity for DPPH and superoxide anion was also higher for J. nigra extract (Table 1). Different phenolic profiles were observed and significant quantities of ellagic acid and its derivatives were detected in J. nigra extract.

Table 1: Free radicals scavenging activity of the Juglans spp. green husk extracts.

70% Aqueous ethanol extracts

DPPHa

Superoxide aniona

Juglans nigra L.

11.0224±0.0309

5.5270±0.3702

Juglans regia L.

54.1366±0.0281

8.1987±0.5814

a EC50 expressed in µg dry extract/mL in the reaction mixtures. Each value is the mean±SD of three replicates.

The importance of the ellagic acid as antioxidant, preventing oxidative DNA damage [2], suggests the J. nigra green husks as a potential source of bioactive compounds involved in the degenerative diseases prevention.

Acknowledgements: FCT and POCTI/FEDER for financial support and LEM/UC integrated in RNEM of Portugal for the HPLC/MS analyses.

References: [1] Kulisic-Bilusic, T. et al. (2008) Food Technol. Biotechnol. 46:368–375.

[2] Aiyer, H.S. et al. (2008)J. Mol. Sci. 9:327–341.