Compendium of the most significant studies with reference to properties, intake, effects.

Marfil, R., Giménez, R., Martínez, O., Bouzas, P. R., Rufián‐Henares, J. A., Mesías, M., & Cabrera‐Vique, C. (2011). Determination of polyphenols, tocopherols, and antioxidant capacity in virgin argan oil (Argania spinosa, Skeels). European Journal of Lipid Science and Technology, 113(7), 886-893.

Abstract. This study establishes data on polyphenols, tocopherols, and antioxidant capacity (AC) of virgin argan oil. A total of 22 samples from Morocco were analyzed. Total polyphenol content ranged between 6.07 and 152.04 mg GAE/kg. Total tocopherols varied between 427.0 and 654.0 mg/kg, being γ-tocopherol the major fraction (84.68%); α-, β-, and δ-tocopherols represent 7.75, 0.33, and 7.29%, respectively. No influence of oil extraction method on total tocopherols was observed. The AC of argan virgin oils determined by the ABTS method in n-hexane oils dilution ranged between 14.16 and 28.02 mmol Trolox/kg, and by the ABTS, DPPH, and FRAP methods in methanolic oil extracts between 2.31–14.15, 0.19–0.87, and 0.62–2.32 mmol Trolox/kg, respectively. A high correlation was found between ABTS and DPPH methods applied to a methanolic oil extract. Virgin argan oil presents a higher polyphenol and tocopherol content, and total AC than other edible vegetable oils.

Makbal R, Villareal MO, Gadhi C, Hafidi A, Isoda H. Argania Spinosa Fruit Shell Extract-Induced Melanogenesis via cAMP Signaling Pathway Activation. Int J Mol Sci. 2020 Apr 6;21(7):2539. doi: 10.3390/ijms21072539.

Abstract. We have previously reported that argan oil and argan press-cake from the kernels of Argania spinosa have an anti-melanogenesis effect. Here, the effect of argan fruit shell ethanol extract (AFSEE) on melanogenesis in B16F10 cells was determined, and the mechanism underlying its effect was elucidated. The proliferation of AFSEE-treated B16F10 cells was evaluated using the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, while the melanin content was quantified using a spectrophotometric method. The expression of melanogenesis-related proteins was determined by Western blot and real-time PCR, while global gene expression was determined using a DNA microarray. In vitro analysis results showed that the melanin content of B16F10 cells was significantly increased by AFSEE, without cytotoxicity, by increasing the melanogenic enzyme tyrosinase (TRY), tyrosinase related-protein 1 (TRP1), and dopachrome tautomerase (DCT) protein and mRNA expression, as well as upregulating microphthalmia-associated transcription factor (MITF) expression through mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase (ERK) and p38, and the cyclic adenosine monophosphate (cAMP) signaling pathway, as indicated by the microarray analysis results. AFSEE's melanogenesis promotion effect is primarily attributed to its polyphenolic components. In conclusion, AFSEE promotes melanogenesis in B16F10 cells by upregulating the expression of the melanogenic enzymes through the cAMP-MITF signaling pathway.AFSEE may be used as a cosmetics product component to promote melanogenesis, or as a therapeutic against hypopigmentation disorders.

Villareal MO, Kume S, Bourhim T, Bakhtaoui FZ, Kashiwagi K, Han J, Gadhi C, Isoda H. Activation of MITF by Argan Oil Leads to the Inhibition of the Tyrosinase and Dopachrome Tautomerase Expressions in B16 Murine Melanoma Cells. Evid Based Complement Alternat Med. 2013;2013:340107. doi: 10.1155/2013/340107.

Abstract. Argan (Argania spinosa L.) oil has been used for centuries in Morocco as cosmetic oil to maintain a fair complexion and to cure skin pimples and chicken pox pustules scars. Although it is popular, the scientific basis for its effect on the skin has not yet been established. Here, the melanogenesis regulatory effect of argan oil was evaluated using B16 murine melanoma cells. Results of melanin assay using B16 cells treated with different concentrations of argan oil showed a dose-dependent decrease in melanin content. Western blot results showed that the expression levels of tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and dopachrome tautomerase (DCT) proteins were decreased. In addition, there was an increase in the activation of MITF and ERK1/2. Real-time PCR results revealed a downregulation of Tyr, Trp1, Dct, and Mitf mRNA expressions. Argan oil treatment causes MITF phosphorylation which subsequently inhibited the transcription of melanogenic enzymes, TYR and DCT. The inhibitory effect of argan oil on melanin biosynthesis may be attributed to tocopherols as well as the synergistic effect of its components. The results of this study provide the scientific basis for the traditionally established benefits of argan oil and present its therapeutic potential against hyperpigmentation disorders.

Berrougui H, Alvarez de Sotomayor M, Pérez-Guerrero C, Ettaib A, Hmamouchi M, Marhuenda E, Herrera MD. Argan (Argania spinosa) oil lowers blood pressure and improves endothelial dysfunction in spontaneously hypertensive rats. Br J Nutr. 2004 Dec;92(6):921-9. doi: 10.1079/bjn20041293. 

Abstract. Traditionally hand-pressed argan oil, obtained from Argania spinosa seeds, is eaten raw in south-west Morocco; its rich composition of tocopherols, MUFA and PUFA make a study of its actions on risk factors for CVD, such as hypertension, interesting. The effects of 7 weeks of treatment with argan oil (10 ml/kg) on the blood pressure and endothelial function of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats were investigated. Systolic blood pressure and heart rate were measured every week by the tail-cuff method and endothelial function was assessed by carbachol (10(-8) to 10(-4) M)-induced relaxations of aortic rings and small mesenteric arteries pre-contracted with phenylephrine. Argan-oil administration reduced the mean blood pressure of SHR after the fifth week of treatment (P<0.05) and increased (P<0.01) the endothelial responses of arteries from SHR. The NO synthase inhibitor, L-N-omega-nitroarginine (3 x 10(-5) M) revealed a greater participation of NO in the relaxant effect after the treatment. When cyclooxygenase (COX) was blocked with indomethacin (10(-5) M), an involvement of COX products in the endothelium-dependent response was characterized. Enzyme immunoassay of thromboxane B2 showed a significant decrease (P<0.05) in the release of thromboxane A2 in both aorta and small mesenteric artery after argan-oil treatment of SHR. Experiments in the presence of the thromboxane A2-prostaglandin H2 receptor antagonist ICI 192,605 (10(-5) M) confirmed this result. Results after incubation with the antioxidants superoxide dismutase and catalase suggested that a decreased oxidative stress might contribute to explain the beneficial effects of argan-oil treatment.

Chafchaouni-Moussaoui I, Charrouf Z, Guillaume D. Triterpenoids from Argania spinosa: 20 years of research. Nat Prod Commun. 2013 Jan;8(1):43-6. 

Abstract. During the last two decades, the argan tree has been the subject of intensive phytochemical investigation. If argan oil is the most known argan derivative, argan saponins are frequently considered as molecules presenting a strong economic potential. This review presents an update of the current research efforts on argan saponins from around the world. Research evidence suggests that arganine C can be considered as a lead compound for new antivirals.

El Monfalouti, H., Charrouf, Z., Belviso, S., Ghirardello, D., Scursatone, B., Guillaume, D., ... & Zeppa, G. (2012). Analysis and antioxidant capacity of the phenolic compounds from argan fruit (Argania spinosa (L.) Skeels). European journal of lipid science and technology, 114(4), 446-452.

Abstract. Polyphenol composition of the shell, pulp, and roasted and unroasted kernels of the argan fruit was qualitatively and quantitatively determined by HPLC coupled with electrospray negative ionization ion trap MS (HPLC-ESI-MS). Eleven phenolic compounds were identified. Unroasted kernels and shell contained various polyphenols but the pulp was characterized by a very high amount of total polyphenols (75.78 mg of gallic acid equivalent/g). The radical scavenging (DPPH. method) and antioxidant activity (ABTS method) of each fruit part was also determined. Argan fruit pulp showed the highest radical scavenging activity (0.17 ± 0.005 µM Trolox equivalent (TE)/mg) and antioxidant activity (0.375 ± 0.07 µM TE/mg). Therefore, argan fruit polyphenols are good candidates to be exploited as health supplements and nutraceuticals.

Drissi A, Girona J, Cherki M, Godàs G, Derouiche A, El Messal M, Saile R, Kettani A, Solà R, Masana L, Adlouni A. Evidence of hypolipemiant and antioxidant properties of argan oil derived from the argan tree (Argania spinosa). Clin Nutr. 2004 Oct;23(5):1159-66. doi: 10.1016/j.clnu.2004.03.003. 

Abstract. Background: Virgin argan oil is of interest in cardiovascular risk prevention due to its fat composition and antioxidant compounds. Aims: We investigated with Moroccan subjects the effect of regular virgin argan oil consumption on lipid profile and antioxidant status and the in vitro effect of argan oil minor compounds (tocopherols, sterols and polyphenols) on LDL peroxidation....Conclusions: Our findings suggest for the first time that regular consumption of virgin argan oil induces a lowering of LDL cholesterol and has antioxidant properties. This oil offers an additional natural food to reducing cardiovascular risk.

Cayuela, J.A., Rada, M., Pérez‐Camino, M.D.C., Benaissa, M., Abdelaziz, E. and Guinda, Á., 2008. Characterization of artisanally and semiautomatically extracted argan oils from Morocco. European Journal of Lipid Science and Technology, 110(12), pp.1159-1166.

Abstract. The present study was conducted to know the possible influence of the seed treatment, method of extraction and geographical origin on the quality and chemical composition of argan oil. Artisanally and semiautomatically extracted argan oils, from roasted and unroasted seeds, from interior and coast areas, were studied. The quality parameters analyzed were acid value, peroxide value, K232 and K270, triacylglycerols and fatty acid composition, polar compounds, total phenols, tocopherol content and oil stability index (OSI). Seed treatment and extraction method showed a higher influence on quality parameters than geographical area; the quality parameters of the different oils were discussed. The total phenolic content in all analyzed samples was lower than 10 ppm. γ-Tocopherol was the major tocopherol (84.4–86.4%) with a high contribution to the total tocopherol content (383–485 ppm). The OSI of the argan oil samples were well correlated (R = 0.97) with the tocopherol contents. The argan oil samples obtained from roasted seeds presented higher stability (26–38 h) than the oils from unroasted seeds (16–32 h).

Benaouf Z, Benbahi I, Djorf O, Souidi Z, Kechairi R. Importance of Argan Oil in Human Health According to the Dosage of Antioxidants in the Algerian Argan Fruits (Argania spinosa). Avicenna J Med Biotechnol. 2020 Jan-Mar;12(1):66.

Abstract. The chemistry and a few pharmacological aspects of argan oil have been studied; there are still no strong clinical data available that provide evidence of the efficacy of argan oil in humans. That argan oil constituents have pharmacological properties in vitro is not sufficient to ascertain the clinical potential of whole argan oil (Figure 1). More studies are necessary to determine its impact on human health. In Tindouf (Algerian area) and Morocco, the position of argan oil as a natural product with strong consumer expectations resulting from traditional claims of activity that are insufficiently supported by scientific proof is shared by several other plant extracts or products. Such a trend is likely to continue in view of the strong current demand for food supplements. This demand justifies pharmacological studies on these products 1,2. Argan oil has a high level of oleic and linoleic acids and antioxidant compounds which has impact on cardiovascular diseases 3. Minor compounds of argan oil, such as sterols, may be involved in its cholesterol-lowering effect 4. The antidiabetic effect of argan oil has been claimed for a long time in traditional medicine; however, the mechanism of regulation of the level of glucose in the blood remains unknown 5. The antihypertensive effect of argan oil and its mechanism of action have been studied by Berrougui et al. Our results show that the phenolic fractions studied have remarkable antioxidant properties. Although the composition of the phenolic fraction of fruits can evolve over the years, they deserve a better valuation in the pharmacological, cosmetic and agro-food fields because of their antioxidant properties.