Insulin-sensitizing and Anti-proliferative Effects of Argan Oil

Samira Samane, Josette Noe, Zoubida Charrouf6, Hamid Amarouch5 and Pierre Selim Haddad1

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The argan tree (Argania spinosa) is a thorny evergreen tree that plays an essential ecological and socio-economic role in southwestern parts of Morocco. A program aimed to increase the industrial value of Argania spinosa is currently carried out in Morocco (1,2). All the parts of the tree have value. Specially, the almond oil is largely used for cooking or in traditional medicine and represents the argan tree’s most important product.

Various biological properties largely known by traditional medicine have received some scientific supports. It is notably the case for the traditional uses of almond oil to decrease blood cholesterol and hypertension (3–5), to treat skin diseases such as juvenile acne and chicken pox pustules (2), or for other beneficial effects of saponin derivatives, notably analgesic and anti-inflammatory (6), anti-microbial (2) and lipolytic properties (2).

Chemical analysis revealed that argan oil is particularly well balanced in terms of fatty acid composition (2,7). Argan oil isrich (80%) in unsaturated fatty acids, 43% of which are monounsaturated fatty acids (especially oleic acid). Essential fatty acids represent 36% (especially linoleic acid) (8). Studies with the unsaponifiable fraction of the oil highlighted antioxidant compounds present in relatively high concentrations (mainly tocopherols). Argan oil is also known to contain phenolic constituents like caffeic, vanillic and ferulic acids, as well as tyrosol, and sterols like schottenol, spinasterol and finally squalene (2,8,9).

Recently we became aware of claims for a potential antidiabetic action of Argania spinosa almonds that has not been scientifically validated to date (Z. Charrouf, unpublished data). Diabetes has become a worldwide epidemic disease with over 170 million people suffering from it (10). The vast majority of cases are of the so-called Type 2 Diabetes Mellitus (T2DM). There exists a genetic predisposition to the disease that is precipitated by environmental factors such as a sedentary lifestyle and unhealthy eating habits, obesity being one of the most prominent risk factors. T2DM is characterized by an insensitivity of peripheral tissues to the action of insulin, termed insulin resistance.

Binding of insulin to its specific cell surface receptor induces receptor autophosphorylation that triggers the activation of two main intracellular signaling pathways: the phosphatidyl-inositol-3-kinase (PI3K) pathway involved in glucose transport and glycogen synthesis, and the extracellular regulated kinase (ERK) pathway involved in gene expression and cell proliferation mechanisms (11). Resistance to insulin can appear at various levels of these signaling pathways (11).

We therefore explored the claimed anti-diabetic potential of argan seeds by examining the effects of various extracts on an insulin-responsive cell line. More specifically we looked at the potential of our argan extracts to increase the in vitro PI3K and ERK responses to insulin in HTC cells, a cell line of hepatic origin. One of the saponin extracts had a stimulatory effect on the PI3K cascade, compatible with an anti-diabetic potential. However we observed an inhibitory action specifically on ERK for a majority of the extracts. This unexpected result prompted us to explore the anti-proliferative effect of pertinent argan seed extracts on transformed cells of human and canine origin.View full article >