Safflower (Carthamus tinctorius), a thistlelike annual, is one of the oldest cultivated crops, its use dating back to ancient Egypt. It was traditionally grown for its seeds, which were used in foods and folk medicine. Safflower is now primarily cultivated for its vegetable oil, which is extracted from its seeds. Safflower oil has been found to exert notable health benefits when consumed through the diet and also when used in topical formulations.
Linoleic acid is a primary constituent of safflower seeds, and is the component to which the oil’s cutaneous benefits are typically ascribed. In fact, safflower oil is one of the richest sources of linoleic acid, which is necessary for the endogenous production of ceramides, key components of the epidermal layer that play a crucial role in barrier function and help the skin retain water.
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Although safflower oil is rich in the essential omega-6 fatty acid linoleic acid and is known to confer health benefits via diet, there is a dearth of data on the use of safflower for dermatologic purposes.
In skin care products, safflower oil is incorporated in moisturizing agents for its occlusive properties. Occlusive agents coat the stratum corneum to slow transepidermal water loss. Typically, such substances have the capacity to dissolve fats and are therefore used in many skin care cosmetics.
Research on Topical Applications
In an early study on the antiproliferative potential of C. tinctorius extracts, Yasukawa et al., in 1996, isolated erythro-alkane-6,8-diols from the flowers of C. tinctorius and applied the tumor-promoting agent 12-O-tetradecanoylphorbol-13-acetate (TPA) to the ears of mice (1 mcg/ear) to induce inflammation. The investigators reported that five of the eight alkane-6,8-diols assayed suppressed inflammation, and the mixture of erythro-alkane-6,8-diols significantly inhibited TPA-induced skin tumor formation in mice after initiation with 7,12-dimethylbenz[a]anthracene (Oncology 1996;53:133-6).
In 2004, Roh et al. investigated the melanogenesis-suppressing activity of safflower seeds to develop a novel skin-whitening agent. They reported that an 80% aqueous methanol extract and ethyl acetate fraction from the seeds significantly inhibited mushroom tyrosinase, and the researchers identified three active constituents [N-feruloylserotonin, N-(p-coumaroyl)serotonin, and acacetin]. Of these, N-feruloylserotonin and N-(p-coumaroyl)serotonin were found to more potently suppress the melanin synthesis of Streptomyces bikiniensis and B16 melanoma cells than arbutin, a well-known inhibitor of melanogenesis (Biol. Pharm. Bull. 2004;27:1976-8).
In 2005, Solanki et al. conducted a short, randomized controlled study in a tertiary-care neonatal intensive care unit (NICU) of a large teaching hospital, to assess the transcutaneous absorption of oil traditionally used in massage of newborns, and to compare the effects of safflower oil and coconut oil on fatty acid profiles of massaged babies. The investigators randomly assigned 120 babies to three groups – safflower oil, coconut oil, or no-oil controls (40 in each group). The babies were massaged with 5 mL of oil four times daily for 5 days. Blood triglyceride levels were significantly elevated in all groups, though much more so in the noncontrol groups. Significant increases in essential fatty acids (linolenic and arachidonic) were seen in the safflower oil group, and similar increases in saturated fats were seen in the coconut oil group, with changes more evident in term babies. The researchers concluded that topically applied oil is absorbed in neonates and is likely available nutritionally. Consequently, they deemed the fatty acid constituents of the massage oils significant in potentially impacting the fatty acid profiles of patients (Indian Pediatr. 2005;42:998-1005). Safflower oil is rich in essential fatty acids, and coconut oil is rife with saturated fat.
Potential Dietary Benefits
Safflower oil has also been found, as has olive oil, to confer dietary benefits on diabetic pregnant rats and their embryos, preventing diabetes-induced developmental harm during early organogenesis (Mol. Hum. Reprod. 2010;16:286-95). Supplementation with either oil has also been demonstrated to prevent excessive activity by matrix metalloproteinases (specifically MMP-2 and MMP-9) in the placenta of diabetic rats, with salubrious effects manifesting in the sera (Placenta 2012;33:8-16). In addition, in a recent study, safflower oil and folic acid supplementations were shown to interact, protecting rat embryos from diabetes-induced harm through reductions in proinflammatory mediators (Mol. Hum. Reprod. 2012;18:253-64).
As mentioned above, safflower oil is available in several topical products, but it is more likely beneficial through diet. Topically, safflower oil, as found in a Neutrogena bath oil, for example, contains linoleic acid and may be useful when added to bathwater or applied to wet skin. Of course, oils in general are not suitable for all skin types. Safflower oil is indicated for individuals with dry or damaged skin.
Conclusion
Safflower oil, rich in the essential omega-6 fatty acid linoleic acid, is known to confer health benefits via diet. It is also included in skin care products, such as bath oils, which anecdotally appear to be effective. Nevertheless, there is a dearth of data on the use of safflower oil for dermatologic purposes. Much more research is necessary, including randomized controlled clinical trials in humans, to establish the potential for more extensive uses of safflower oil for skin health.