Lead is one of the major environmental pollutions worldwide, particularly in developing countries. Though, various occupational and public health measures have been undertaken to control lead exposure. The present study is designed to investigate the role of zinc oxide nanoparticles (ZnO-NPs) to reduce the bioaggregation of lead in the brain, liver, and kidneys and prevent these organ oxidative damage and apoptosis. Twenty male Wistar rats were grouped into 4 gatherings and exposed to the following materials daily on the skin for 2 weeks: 1—normal saline, 2—ZnO-NPs, 3—PbO, and 4—ZnO-NPs+ PbO. Topical application of PbO to rats increased lead contents in blood and different organs causing remarkable oxidative stress damage, apoptosis, and histopathological alterations in these organs. Moreover, PbO-receiving group showed strong positive caspase-3 protein expression with up-regulation of mRNA levels of BAX and COX-2. Co-treatment of ZnO-NPs with PbO could diminish the toxicologic parameters and the above-mentioned immune marker and gene expression levels. Our data suggest the role of ZnO-NPs cream to reduce the risk of lead dermal exposure via preventing absorption and accumulation of it in the internal organs so that it protects these organs from further damage.

This study aimed to investigate the concentrations of heavy metals, including lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), cobalt (Co), and arsenic metalloid (As), to assess their health risks in the popular depilatory products of the Iranian markets. Twenty-one samples of 7 popular brands of depilatory products, inclusive of cream and powder, were examined. Selected elements were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) using the appropriate procedure for acid digestion and the measurement of heavy metal contents. The differences in heavy metal concentrations were investigated according to the type of product, brand, country of production, and product price using t test and one-way analysis of variance and post hoc Tukey test. Finally, carcinogenic and non-carcinogenic risk assessments were calculated for the studied elements. The results showed that Pb (5.46±2.30 mg/kg) and Co (0.16±0.69 mg/kg) had the highest and lowest concentrations in these products, respectively. In general, the concentration of heavy metals in depilatory creams was less than the concentration of elements in depilatory powders and less than the maximum allowable limits as defined by the Institute of Standards and Industrial Research of Iran (ISIRI). There was a direct and significant relationship between the concentration of heavy metals in depilatory powders and the product’s price. Moreover, the amount of As in one of the brands of depilatory powder was determined to exceed the standard value (2 mg/kg). Also, hazard index (HI) and lifetime cancer risk (LCR) were below 1 and 10⁻⁶, respectively, which indicated that this mentioned heavy metal had no probable non-carcinogenic and carcinogenic risks for consumers. According to this study, it was evident that the chances of cancer and non-cancer risk using depilatory products were unlikely, but continuous use can be harmful due to the excessive accumulation of these heavy metals.

Nowadays, the sunscreen creams are composed of mostly synthetic chemicals and other organic compounds which were found to enter into the blood stream on topical application raising concerns in the scientific community. The scientific community has now shifted their attention to herbal formulations due to toxicity of these synthetic molecules. Aloe vera is a xerophitic plant having excellent anti-oxidant properties. The permeation effect and drug stability of the drug candidate can be significantly enhanced by formulating it into solid lipid nanoparticles (SLN). The main objectives of the study were to formulate and evaluate Aloe vera-loaded SLN sunscreen cream and to determine its photoprotective potential. The Aloe vera-loaded SLNs were formulated by microemulsification technique. The developed SLNs were studied for its entrapment efficiency, poly dispersity index (PDI), zeta potential, particle size, and other characterization techniques. Finally, the optimized SLNs were incorporated into the sunscreen cream and evaluated for its spreadability, viscosity, extrudability, drug content, in vitro drug release, ex vivo permeation, determination of sun protection factor (SPF), skin irritation test, and accelerated stability studies. The in vitro SPF was found out to be 16.9 ± 2.44 and the in vivo SPF observed to be approximately 14.81 ± 3.81, respectively. Stability studies were performed under accelerated conditions and no appreciable changes in the parameters were noticed. The solid lipid nanoparticles of Aloe vera were incorporated into a cream and the SPF of the resultant sunscreen cream was found to be on par with the sunscreens that were currently available in the market.

The Aedes albopictus mosquito is a vector of several deadly diseases of humans and domesticated animals. Usually, synthetic insecticides are used for mosquito control. The excessive use of synthetic insecticides is hazardous for humans and the environment. Therefore, there is a need to develop environment-friendly and novel mosquito larvicides. In the current study, we evaluated larvicidal and bite protection properties of Seriphidium brevifolium essential oil (SBEO) and its active constituents against this mosquito. SBEO and its active constituents, α, β-thujone, and limonene, were toxic to A. albopictus, with LC₅₀ values of 21.43, 45.99, 47.38, and 49.46 μg/mL. The cream formulation of EO at 5 % (w/v) provided complete protection against mosquito bites until 70 min after application. Among the EO constituents tested, α and β-thujone showed considerable protections against mosquito bites but lower as compared with the whole oil. Furthermore, 1:1 combinations of active constituent α-thujone and β-thujone and 1:1:1 combinations of α-thujone, β-thujone, and limonene displayed a synergistic effect against the larvae. Particularly, the EO and its active constituents were safer to Poecilia reticulata a mosquito predator, with LC₅₀ ranging from 3934.33 to 14,432.11 μg/mL. Our current study indicated that SBEO and some of its constituents can be used for the control of A. albopictus mosquito, as a novel alternative to hazardous synthetic insecticides and to overcome the problem of increasing insecticides resistance.