Current Cosmetic Science - Volume 1, Issue 2, 2022

The toxic metal content of cosmetics causes worry because of the daily and repeated use of these products, which are placed over thin and sensitive areas of the skin such as the face, eyelids, and lips.

Toxic metals like Fe, Cr, Hg, Cu, Cd, Ni, and As are found in various types of cosmetics such as colour cosmetics, hair cosmetics, body and face care products, and herbal cosmetics. Previous studies estimate that in commercial cosmetics, toxic metals might be present in high amounts, causing a risk to human health.

Many analysis methods used for determining toxic metals in cosmetics were established. The instruments involving FAAS, ICP-AES, ICP-MS, hydride generation, cold vapor, and CE spectrometers with many novel methods were described in this review. Green analytical methods should be developed for determining toxic metals in cosmetics, particularly during the preparation of analytical cosmetic samples.

The tools mostly used for assessing analytical protocols related to green analytical chemistry are GAPI (green analytical procedure index). GAPI provides use full information on the safety of analytical chemistry procedures, depending on the five pentagrams shaped with three color symbols (green, yellow, and red), referring to low, medium to high impact, respectively.

This review offers an overview of analytical chemistry methods and instruments used for the estimation of toxic metals in cosmetics and their GAPI assessment.

Polyphenols are natural compounds that show bioactive properties such as antioxidants. Therefore, their application in the cosmetic industry may be considered.

Tannic acid and gallic acid were used as an additive for emulsion preparation. The microscope observation was carried out to study the formation of the droplets. In addition, the polyphenols release from the emulsion, their antioxidant activity, and the color parameters were studied.

The results showed that the addition of polyphenols decreased the droplets’ diameter. Each emulsion demonstrated antioxidant activity, but the version with a 5% gallic acid addition was the most effective. The addition of tannic acid and gallic acid alters the color characteristics of the formulation under investigation.

In this study, we confirmed that tannic acid and gallic acid might be potentially used as additives in cosmetics formulations.

Glabridin (Glab) is a polyphenolic flavonoid of licorice acclaimed for its skin whitening properties. However, its poor solubility, low physicochemical stability and inefficient percutaneous penetration create hurdles in the best use of this agent in dermo-cosmetic application. The purpose of the present work was to prepare and evaluate Glabridin-loaded nanostructured lipid carrier (Glab NLC) in order to enhance its skin permeation, and hence, promote its skin-whitening potential in cosmetic formulations. Nanostructured lipid carrier (NLC) has already proven its potential for drug delivery via the skin by offering various benefits, like high tolerability, biocompatibility, high drug loading, improved stability, and close contact with stratum corneum, leading to rich skin penetration and protection of bioactive from degradation.

NLC was prepared by solvent emulsification diffusion technique and was evaluated for particle size, zeta potential, polydispersity index, drug loading and encapsulation, and in vitro drug release. Optimized formulation was incorporated into a cream base, and its skin whitening activity was evaluated. Glycerol monostearate (GMS) and olive oil were chosen as solid and liquid lipids for NLC formulation.

The particle size, PDI, zeta potential, entrapment efficiency, and drug release of optimized formulation were found to be 189 nm, 0.259, -14.5mV, 94.56%, and 98.86 ± 0.80%, respectively. The optimized NLC was incorporated into a suitable cream base and evaluated. The skin whitening activity of Glabridin NLC cream was determined by performing tyrosinase inhibition activity. The percentage inhibition value of GlabNLC loaded cream and Kojic acid against mushroom tyrosinase was found to be 60.31% and 52.61%, respectively.

The obtained results advocate lipid particles as an appropriate carrier of Glabridin for skin whitening cosmetic cream.

Hyperpigmentation is a common disorder characterized by brown patches, differential skin tone, and sunburns on the area of exposure. Hydroquinone (HQ) is considered the most effective agent in the treatment of pigmentation but exhibits skin irritation and local toxicity at higher concentrations. Hence, HQ-encapsulated nanostructured lipid carriers (NLCs) were designed and assessed as an alternative for the treatment of pigmentation to reduce skin irritation without exhibiting toxicity.

The objective of this study was to formulate and evaluate hydroquinone-encapsulated NLCs in the cream base as a treatment for hyperpigmentation.

The present formulation aimed to encapsulate adequate hydroquinone in NLCs for potential application of depigmentation. Hydroquinone was formulated utilizing melt-emulsification ultrasound dispersion technique, in which the aqueous phase consists of water and Tween 80, whereas the lipid phase is prepared with oleic acid and glyceryl monostearate. The characteristics of the final formulation were analyzed by surface morphology, percentage entrapment efficiency, ex-vivo release, in-vitro release, and cell line studies.

Hydroquinone-encapsulated lipid nanocarriers demonstrated promising results within the size range of 22 ± 1.22 nm to 164 ± 0.75 nm and encapsulation efficiency of 78 ± 5.05% in a partially crystallized lipid-based state. The system displayed enhancement in absorption and penetration with zeta potential of -10.2 ± 1.86 mV to -24.6 ± 0.45 mV, and presented a substantial decrease in water loss as a result of packet formation.

The results indicated hydroquinone-encapsulated NLCs as safe and effective for the treatment of pigmented skin, reducing the appearance of dark patches and improving the skin texture.

Phytochemicals utilization in cosmetics is the current trend in the beauty and fashion industry. Most women prefer cosmetics derived from natural products over synthetic chemicals, as natural products are devoid of undesirable side effects. Skin protection is important not only from an aesthetic point of view but also for optimal health. Therefore, exploring the use of phytochemicals in cosmetic dermatology is essential.

In the current in vitro studies, we investigated the skin-protection properties of capsanthin 50%w/w crystals (CAP-50CR) and capsanthin 1.5% w/w soft extract (CAP-1.5SE) obtained from red bell pepper fruits, out of which, one is an industrial by-product effective for sunburn, melanin inhibition, tyrosinase inhibition, anti-fungal activity, and gene expression of Aquaporin 3 (AQP-3) in the human keratinocyte cell line.

Two extracts were obtained by solvent extraction, supercritical extract purification, and saponification, and were characterized and examined for their dermatological activities.

Capsanthin 50%w/w crystals (CAP-50CR) showed a sun protection factor (SPF) value of 34.44, whereas capsanthin 1.5% w/w soft extract (CAP-1.5SE) showed a value of 20.63. Minimal inhibitory concentration (MIC) of CAP-50CR against Malassezia furfur was 0.625 mg/mL and 5mg/mL for CAP-1.5 SE. Both CAP-50CR and CAP-1.5SE showed the same MIC values against Candida albicans, which is 2.5 mg/mL. In the MTT assay on mouse skin melanoma cells (B16F10), the test substance CAP-50CR showed a CTC50 value of 98.44±2.55 µg/mL, whereas the test substance CAP-1.5SE exhibited a CTC50 value greater than 1000 µg/mL. Further, the non-toxic concentrations of the test items were evaluated for forskolin-induced melanin inhibition activity. For CAP-50CR, the non-toxic concentration of 7 and 3 µg/mL showed melanin inhibition of 48.73 ± 0.75% and 42.29 ± 5.2%, respectively, and for CAP-1.5SE, the melanin inhibition was found to be 55.84%±1.47 and 46.44%±1.05, respectively, for the non-toxic concentrations of 50 and 25µg/mL. The CAP-50CR extract showed 43.78% and 39.37% tyrosinase inhibition at the tested concentrations of 7 and 3 µg/mL, respectively. Similarly, CAP-1.5SE showed tyrosinase inhibitions at 34.6% and 22.9% for the concentrations of 50 and 25 µg/mL, respectively. The test substances CAP-50CR and CAP-1.5SE exhibited a CTC50 value of 76.59±3.25 μg/mL and 664.95 ± 2.88 µg/mL on the HaCaT cells. In the gene expression study, both the test substances showed an increase in the levels of AQP-3 mRNAs at lower and higher concentrations as compared to the control in the semi-quantitative RT-PCR procedure.

CAP-50CR and CAP-1.5SE exhibited skin protection from UV radiation and hyperpigmentation. They also exhibited anti-fungal, skin brightening, anti-wrinkle, and moisturizing properties. These results suggest that capsanthin from red bell pepper fruits can be employed as a cosmetically active ingredient in skin guard formulations and as a potential therapeutic agent for a variety of dermatological disorders. This study provides a new ground for investigating the potential of capsanthin in the management of skin protection.