Clinical evaluation of a dioic acid‐based formulation on facial skin in an Indian population

Abstract

The aim of this work was to investigate the effects of 1,18-octadecen-9-dioic acid (dioic acid) and a Rumex occidentalis extract complex for their skin-lightening action in an Indian population. Prior to the clinical study, the efficacy of dioic as an inhibitor of melanogenesis was confirmed on dark-pigmented human melanocytes. As part of a 12-week vehicle-controlled clinical study, the skin-lightening effect of a test product containing 1% dioic acid, 2% of a Rumex occidentalis extract and sunscreens (SPF 15) was assessed on the facial skin of 71 Indian female volunteers. Change in skin colour was monitored by (A) Chroma Meter® measurement (L*, a*, b*) and Individual Typology Angle (ITA˚) calculation and (B) Visual grading of standardized photographs by a dermatologist. Colorimetric measurements on volunteers' cheeks showed a significant increase of L* and ITA˚ compared to baseline after 4, 8 and 12 weeks of test product application. For both L* and ITA˚ measurements, changes were significantly different than the SPF 15-containing vehicle at weeks 4 and 12. These results were confirmed by the dermatological visual grading. The overall skin-lightening action of the test product was beyond the one observed with the SPF 15 vehicle. These findings show that a dioic acid and Rumex occidentalis complex deliver a significant skin-lightening effect on facial skin in an Indian population.

The melanogenesis and mechanisms of skin‐lightening agents – existing and new approaches

“…Moreover, synergistic effect of octadecenoic acid and plant extract of Rumex Occidentalis has been reported in reconstructed tanned epidermis [102], where the Rumex extract showed direct inhibition of tyrosinase activity [103].…”

“…Suppression of melanin formation on purified tyrosinase and in melanocytes [108] Clinical study using magnesium-L-ascorbyl-2-phosphate cream resulted in lightening effect in 19 of 34 patients with chloasma or senile freckles [108] octadecenedioic acid Reduction in tyrosinase mRNA and protein expression concomitant with inhibition of melanogenesis [101] Studies on octadecenedioic acid resulted in a more even skin tone and overall lighter skin colour [102,142] ª POMC-related peptides [112], it is likely that alternative pathways can activate intracellular cAMP and induce melanogenesis. One alternative cAMP-dependent pathway that has been proposed to be active and turn on melanogenesis in these mice is the adrenergic receptor, especially since the POMC-deficient mice was shown to have an abnormally large adrenal gland [112,113].…”

Clinical evidences of benefits from an advanced skin care routine in comparison with a simple routine

“…While countless vehicle‐controlled studies have demonstrated about the benefit of actives over a vehicle alone and/or vs gold standard ingredients, clinical evidence about the benefits of a skin care routine remains scarce, despite the claimed benefits of using products as part of a regimen. Reported efficacy of regimens is available in the dermatological field, to address skin conditions such as acne, atopic dermatitis, or rosacea .…”

Facial skin-lightening benefits of the tetrapeptide Pro-Lys-Glu-Lys on subjects with skin types V-VI living in South Africa

“…9 Typical actives include retinoids, [10][11][12] niacinamide, [13][14][15][16] kojic acid, 17 arbutin and derivatives, 18,19 bisabolol, 20 soybean trypsin inhibitors, 21 azelaic acid, 22 licorice derivatives such as Glabrene and isoliquiritigenin, 23 vitamin C derivatives and other antioxidants, 24 N-acetyl glucosamine, 25,26 N-undecy-10-enoyl-L-phenylalanine, 27 hydroxyacids 28,29 and octadecenedioic acid. [30][31][32] To develop new potential ingredients for skin-lightening products, we have focused on the inflammatory pathways involved in skin pigmentation. 33 Recently, it has been shown that a peptide comprising Lys-Glu-Lys (KEK), which was further modified with a proline attached to its N-terminus (PKEK) to stabilize its structure, reduces interleukin-6 and 8, tumor necrosis factor-a and cyclo-oxygenase gene expression in ultraviolet (UV) light-stimulated keratinocytes in vitro and in vivo.…”

“…Traditional routes include the use of sunscreens, but inhibition of melanocyte activity, reduction in melanosome transfer and dendricity together with the accelerated removal of melanin by inducing epidermal proliferation are typical 9 . Typical actives include retinoids, 10–12 niacinamide, 13–16 kojic acid, 17 arbutin and derivatives, 18,19 bisabolol, 20 soybean trypsin inhibitors, 21 azelaic acid, 22 licorice derivatives such as Glabrene and isoliquiritigenin, 23 vitamin C derivatives and other antioxidants, 24 N‐acetyl glucosamine, 25,26 N‐undecy‐10‐enoyl‐L‐phenylalanine, 27 hydroxyacids 28,29 and octadecenedioic acid 30–32 …”