Study of the flavonoids and secondary metabolites of the Argan tree (Argania spinose L.)

The separation and identification of the main phenolic compounds present in the co-product of the Argan tree (Argania spinosa) were carried out using high performance liquid chromatography techniques coupled with mass spectrometry (LC-ESI-MS/MS).The study was based on the retention times of the peaks of the phenolic compounds in samples and was compared to those of the controls (reference compounds) and supplemented by an analysis of the fragmentations of the molecules by mass spectrometry. Phenolic compounds in the pulp of the Argan namely such as catechin (2.8%), epicatechin (14.7%), procyanidin (2.7%), quercetin (1.6%), luteolin (0.2%) and naringenin (0.07%) were found. Phenolic acid is consisted of gallic acid (5%) and protocatechuic acid (21.1%). These compounds are more dominant than flavonoids. The flavonoids-O-rhamnoglucosides the most dominant compounds is isorhoifoline (7.2%) and hesperidin (4.5%) against rutin (0.1%) and rhamnetin-O-rutinoside (0.5%) are less dominant. The main compounds are the hyperoside (13.4%) and isoquercetin (10%). On the other hand, naringenin-7-O-glucoside constituted the most minority compound of this type of flavonoid in the pulp of the fruit of the Argan tree (the percentage of naringenin-7-O-glucoside and quercetin-3-O-arabinose is 15.3%). There are other phenolic compounds in the pulp of the Argan namely such as catechin (2.8%), epicatechin (14.7%), procyanidin (2.7%), quercetin (1.6%), luteolin (0.2%) and naringenin (0.07%). The main flavonoids found in the leaves of the Argan tree are Quercetin (21.73%), Myricetin (54.34%), Hyperoside (8.69%), and also Myricetin-3-Ogalactoside (9.78%). Argan cake is rich in flavonoids. Among these, epicatechin (110 mg/kg), catechin (11 mg/kg), protocatechic acid (15.2 mg/kg), vanillic acid (16.3 mg/kg) and 4-hydroxybenzyl alcohol (8.6 mg/kg) are higher in Argan cake. Argan oil is richer in tocopherol (597 to 775 mg/kg), Argan oil is rich in gamma tocopherol (631 mg/kg), and that make Argan valuable nutraceutical. The study of the secondary metabolites and especially the flavonoids of the Argan tree was undertaken with the aim of identifying new metabolites making it possible to increase the industrial than commercial value of the Argan tree.