Diosmin/essential oil combination for dermal photo-protection using a lipoid colloidal carrier

Solar irradiation induces skin inflammatory processes causing deleterious effects like premature ageing. In this study, the designed lipoid colloidal carrier (LCC) was loaded with Diosmin in combination with different essential oils, to be used as a topical photo-protective preparation. To investigate the ability of the essential oils to potentiate Diosmin effects, the Diosmin/essential oil-loaded LCCs (LCC2, LCC3 and LCC4) were compared to the Diosmin-loaded LCC (LCC1). The incorporated essential oils were those of Rosmarinus officinalis, Zingiber officinale or Vitis vinifera in LCC2, LCC3 and LCC4, respectively. All the LCCs had particle size (PS) values ranging from 121.1 to 144.3 nm with uniform distribution and, zeta potential (Z) values around 30 mV. Also, they all had high drug encapsulation efficiencies. LCC1 had the lowest anti-oxidant and in-vitro sun-blocking effect (p < 0.05). In-vivo photo-protective studies showed that all the formulated LCCs had a skin protective effect when compared to the positive control (p < 0.05); however LCC1 had the lowest anti-erythemal and anti-wrinkling effect. Histological studies proved the efficacy of the designed LCCs as skin anti-photoageing, with LCC1 showing the lowest anti-inflammatory and anti-wrinkling effect, while LCC2 had the highest anti-wrinkling effect. These results indicated that the suggested Diosmin/essential oil combinations improved the anti-oxidant, sun-blocking and anti-photoageing effects of Diosmin. After one year of storage, the LCCs showed satisfactory physical stability. This study presents the designed LCCs as safe and effective nano-structured dermal care products containing 'all-natural' components.