Effects of avocado and soya bean lipidic non‐saponifiables on the components of skin connective tissue after topical application in the hairless rat: biophysical and biomechanical determination

Abstract

Synopsis The non-saponifiable lipidic fractions of avocado and soya bean applied percutaneously to hairless rats for 15 days had been shown to produce biochemical modifications of dermal connective tissue components: increases of soluble collagen and of the ratio soluble collagen/insoluble collagen. In this present study, we tried to show whether these biochemical modifications could be confirmed by biophysical analytical methods and could affect the biochemical properties of the skin. The experiments were carried out on three groups of rats treated by application to the dorsal skin, either with 0.9% NaCl (control), or sweet almond oil (vehicle), or with a mixture of 2/3 soya bean and 1/3 avocado in solution at 5% of sweet almond oil (treated group). After 15 days treatment, the rats were killed and the skin of the treated area dissected. X-ray diffraction diagrams were recorded by varying the position of previously dried samples in controlled conditions. Results indicated that the vehicle decreased the orientation degree of collagen fibres, acting on their reticulation. The addition of the non-saponifiable fraction did not significantly add to the vehicle effect. The study of thermostability of the cutaneous collagen by differential scanning calorimetry showed that non-saponifiables increased the slope of the rise of temperature of denaturation. The quantity of heat absorbed during the denaturation (enthalpy variation) reached around 0.04 J mg(-1) of collagen in the control groups and did not exceed 0.03 J mg(-1) of collagen in the treated ones. Taken in conjunction with previous work it is probable that the non-saponifiables increase the proportion of soluble collagen. The elasticity of whole skin, determined by a static method using an Instron exten-siometer was significantly modified by treatment with non-saponifiables. They produced a decrease of the elasticity module. These results correspond to a decrease of collagen reticulation degree.

Avocado Oil: Characteristics, Properties, and Applications

“…In addition to an increase in the solubility of collagen, behavior that is attributed to a decrease in the activity of lysyl oxidase was observed [66]. A similar conclusion was proposed by Lamaud et al [71], stating that the mixture of soybean and avocado oils decreased the degree of collagen cross-linking, a process that has been associated with a delay in wound healing. However, Oliveira et al [53] indicated that the healing activity of a semi-solid formulation of avocado oil (50/50 Vaseline) and avocado pulp oil promoted the increase of collagen synthesis and decreased the number of inflammatory cells during the process of wound healing.…”

Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils

“…Research has been conducted on the effect of topical administration of avocado fruit extract on wound models in rats, revealing faster re-epitheliazation and higher hydroxyproline content of the repaired wound [ 95 ]. The topical application of avocado oil in rats has also been shown to increase collagen synthesis and decrease the numbers of inflammatory cells during the WH process [ 94 , 96 ].…”

Vegetable butters and oils in skin wound healing: Scientific evidence for new opportunities in dermatology

“…The oil was dermally applied once a day for 14 days. The results showed that avocado oil, used alone or in a dermal formulation (50% avocado oil in petrolatum), increased collagen synthesis and reduced the number of inflammatory cells throughout the wound‐healing process (de Oliveira et al, ; Lamaud et al, ).…”

“…Vegetable butters and oils have shown promising results in in vitro and in vivo studies. They affect phases of the wound‐healing process through their bacteriostatic, antimicrobial, anti‐inflammatory, and antioxidative activities and by promoting cell proliferation, increasing collagen synthesis, stimulating dermal reconstruction, and repairing the skin's lipid barrier function (Cornily et al, ; de Oliveira et al, ; Lamaud, Huc, & Wepierre, ; Lewinska, Zebrowski, Duda, Gorka, & Wnuk, ; T.‐K. Lin, Zhong, & Santiago, ; Mandawgade & Patravale, ; Nasopoulou, Karantonis, Detopoulou, Demopoulos, & Zabetakis, ; Shinagawa, de Santana, Torres, & Mancini‐Filho, ; Vaughn, Clark, Sivamani, & Shi, ).…”