HPLC–DAD–MS/MS profiling of standardized rosemary extract and enhancement of its anti-wrinkle activity by encapsulation in elastic nanovesicles

The anti-wrinkle activity of defatted rosemary extract (DER) was assessed, and its effect was optimized by encapsulation in transferosomes (TFs). DER was standardized to a rosmarinic acid content of 4.58 ± 0.023 mg% using reversed-phase high performance liquid chromatography (Rp-HPLC), and its components were identified by HPLC-diode array detection-tandem mass spectrometry. In vitro free radical scavenging assays showed DER had high free radical scavenging activity against 2,2-diphenyl-2-picryl hydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and superoxide radicals. DER also inhibited bleaching of β-carotene with high Fe(III) and Fe(II) chelating ability. In vivo anti-wrinkle activities of topically applied DER (20, 50, and 100 mg) and a TF formulation (TF4, 20 mg of DER) were evaluated in UVB-irradiated mice using a wrinkle scoring method, metalloproteinase (MMP) expression, and histopathology. Among the nanovesicles, TF4 was the most deformable, and had an acceptable size and encapsulation efficiency and enhanced permeation of DER through rat skin compared with unencapsulated DER. DER (50 and 100 mg) and TF4 significantly inhibited MMP-2 and MMP-9 expression and improved wrinkle scores. DER and TF4 moderately decreased epidermal thickness without pigmentation. DER is a potent natural antioxidant for combating skin aging. Moreover, encapsulation of DER in TFs will enhance its skin permeation and anti-wrinkle activity.