Determination of antioxidant activity, total phenolics and fatty acids in essential oils and other extracts from callus culture, seeds and leaves of Argania spinosa (L.) Skeels

Abstract

Argan (Argania spinosa (L.) Skeels) is an endangered and endemic agroforestry species of Morocco highly appreciated for its nutraceutical properties. Herein, the antioxidant activity, total phenolic content and fatty acids were evaluated in different extracts obtained from callus culture, seeds and leaves of four argan genotypes: G25, G36, G41 and G84. Callus induction, proliferation and morphology varied depending on genotype and explant type. The highest callus induction rate (97.5%) was observed in the cotyledon explants of genotype G84. The radical scavenging activity values ranged from 76.5 to 98.1%. The essential oils extracted from calli induced from seedling-derived leaves exhibited a slightly higher radical scavenging activity (91.7%) than those extracted from field-grown leaves (90–91.1%). The total phenolic content ranged from 0.72 mg/g dry weight gallic acid equivalent in the methanolic extracts of G84 callus obtained from seedling-derived leaves to 198.26 mg/g dry weight gallic acid equivalent in the essential oils of G84 seeds. The fatty acid composition varied significantly among the different samples. The essential oils extracted from seeds and callus obtained from cotyledon explants have high contents in oleic and linoleic acids (26–37.9% and 25–36.8%, respectively), while the major fatty acid found in the essential oils of leaves and callus obtained from seedling-derived leaves was eicosenoic acid (18.8–45.4%). The present study showed that argan callus culture could be envisaged for sustainable and continuous production of bioactive compounds, and that each extract analyzed had unique and distinct characteristics. The essential oils and other extracts obtained from argan callus induced in vitro were characterized and were compared with those obtained from seeds and field-grown leaves