Assessment of non-invasive techniques and herbal-based products on dermatological physiology and intercellular lipid properties

Abstract

Skin is the largest external organ of the human body. It acts as a barrier to protect the human body from environmental pollution, mechanical stress, and excessive water loss. The defensive function resides primarily on top of the epidermis layer commonly known as stratum corneum (SC). Human SC consists of three major lipids, namely ceramide, free fatty acid, and cholesterol that comprise approximately 50%, 25%, and 25% of the total lipid mass, respectively. The optimal composition of SC lipids is the vital epidermal barrier function of the skin. On the other hand, skin barrier serves to limit passive water loss from the body, reduces chemical absorption from the environment, and prevents microbial infection. In contrast, epidermal lipids are important to maintain the cell structure, growth and differentiation, cohesion and desquamation as well as formation of a permeability barrier. Multiple non-invasive in vivo approaches were implemented on a regular basis to monitor skin physiological and intercellular lipid properties. The measurement of different parameters such as transepidermal water loss (TEWL), hydration level, skin elasticity, collagen intensity, melanin content, sebum, pH, and tape stripping is essential to evaluate the epidermal barrier function. Novel non-invasive techniques such as tape stripping, ultrasound imaging, and laser confocal microscopy offer higher possibility of accurate and detailed characterisation of skin barrier. To date, these techniques have also been widely used to determine the effects of herbal plants in dermatology. Herbal plants have been traditionally used for ages to treat a variety of skin diseases, as reported by the World Health Organisation (WHO). Their availability, lower cost, and minimal or no side effects have created awareness among society, thus increase the demand for natural sources as the remedy to treat various skin diseases. This paper reviews several non-invasive techniques and evaluations of herbal-based product in dermatology.

Oleogel Formulations for the Topical Delivery of Betulin and Lupeol in Skin Injuries—Preparation, Physicochemical Characterization, and Pharmaco-Toxicological Evaluation

“…Important changes of skin parameters were obtained in the first 10 days due to the exposure to UV radiation: transepidermal water loss, erythema, and melanin levels have grown a lot, while the skin hydration has dropped. Erythema, skin hydration, and transepidermal water loss are the main parameters that can be associated with some skin pathological aspects, including skin injury, inflammation, or in some cases, infection [65].…”

Melissa officinalis L. Aqueous Extract Exerts Antioxidant and Antiangiogenic Effects and Improves Physiological Skin Parameters

“…Mouse skin presents several differences in thickness and in the number of cells but not the layers of cells in dermis and epidermis as compared to human skin [70]. Still, mouse skin is considered a relevant model for the evaluation of compounds that act on skin by the means of non-invasive measurements [71]. The in vivo results obtained in this study indicate the benefits of aqueous MO leaves extract at skin level characterized by reduced values of erythema and enhanced values of skin moisture (both parameters are significantly modified compared to the other groups).…”

“…The main pigments that influenced these parameters are hemoglobin, bilirubin and mostly melanin. Erythema is associated with some skin pathological aspects, including skin injury, inflammation or in some cases infection [71]. The aqueous extract protects and hydrates the mice skin.…”

“…It can be determined non-invasively by using a Corneometer. Hydrolipid film is an indicator for healthy skin [71].…”

Effect of Evening Primrose Oil Supplementation on Selected Parameters of Skin Condition in a Group of Patients Treated with Isotretinoin—A Randomized Double-Blind Trial

“…Measurements and assessments of skin condition parameters were performed at baseline and after 9 months of intervention. Non-invasive methods such as a Tevameter (TM 210 ELECTRONIC) for assessing transepidermal water loss, a Sebumeter (SM 810 ELECTRONIC, Koln, Germany) for assessing sebum content and a Corneometer (CM 825 ELECTRONIC, Koln, Germany) for assessing transepidermal skin hydration were used to evaluate the biophysical properties of facial skin [ 53 ]. All skin measurements were taken in a sitting position, in a room with a temp of 20–25 °C and relative humidity of 40–60%.…”