Combination of essential oil from Zanthoxylum bungeanum Maxim. and a microemulsion system: Permeation enhancement effect on drugs with different lipophilicity and its mechanism

Development, validation and application of a gas chromatography method for the determination of dillapiole from Piper aduncum essential oil in skin permeation samples

The essential oil extracted from the leaves of Piper aduncum has antifungal, insecticidal and antibacterial activity. Studies with its main compound, dillapiole (DIL) revealed antibacterial and anti-inflammatory potential. Despite all this bioactivity, there is no updated report on the development and validation of analytical and bioanalytical methodology to quantify DIL in skin samples. A selective, precise, accurate and adequate method for the determination of DIL in solutions, porcine ear skin samples and receptor fluid was developed and validated by headspace extraction-gas chromatography with flame ionization detection (HS-GC-FID). HS-GC-FID was applied to determine DIL in Franz cell permeation and retention studies using porcine ear skin samples. In the HS-GC-FID method, matrix-related interferences were not observed at the peak of the DIL retention time. The results showed a high recovery (>97%) after the extraction procedure, allowing the quantification of DIL in complex matrices. In vitro permeation/retention for DIL showed cumulative amounts permeated in the order: receptor fluid (21.98 ± 1.19 μg/cm² ) > epidermis (15.40 ± 1.20 μg/cm² ) > dermis (9.52 ± 1.13 μg/cm² ). HS-GC-FID was successfully validated and the results point to DIL transdermal permeation and to the potential to develop pharmaceutical formulations for skin delivery to treat inflammation or infections.

Combined morphological and multi-omics analyses to reveal the developmental mechanism of Zanthoxylum bungeanum prickles

Zanthoxylum bungeanum Maxim. as an important economic forest, its epidermis bears prickles which complicate the harvesting process and increase the labor costs. To explore the developmental mechanism of prickles, three varieties of Zanthoxylum bungeanum (PZB, SZB, GSZB) were selected for morphological and multi-omics analyses. The absorption spectra of prickles and stems were detected using Fourier-transform infrared spectroscopy (FTIR), and they were found different at 1617, 1110, 3319, and 1999 cm^-1. The morphology of prickles and stems were observed using light microscopy and transmission electron microscopy (TEM). The growth direction of cells on the prickle side and stem side were perpendicular to each other, and there was a resembling abscission zone (RAZ) between them. The vacuolar deposits of prickle cells were much more than stem cells, indicating that the lignification degree of prickles was higher than stems. In addition, 9 candidate genes (ZbYABBY2, ZbYABBY1, ZbYABBY5, ZbWRKY, ZbLOG5, ZbAZG2, ZbGh16, ZbIAA33, and ZbGh16X1) were screened out and validated base on transcriptome and qRT-PCA. As well as, 30 key metabolites were found related to prickle development base on metabolome analysis. Among them, 4-hydroxy-2-oxopentanoate, trans-2-hydroxy-cinnamate, trans-cinnamate, polyhydroxy-fatty acid, 10,16-dihydroxypalmitate, cinnamic acid were related to the biosynthesis of cutin, suberine and wax. Indole-3-acetate, tryptamine, anthranilate, fromylanthranilate, N6-(delta2-isopentenyl)-adenine were related to plant hormone signal transduction. Generally, this is the first study to reveal the developmental mechanism of prickles. The results of this study lay the foundation for the breeding of non-prickle Zanthoxylum bungeanum.

Chemotaxonomic variation in volatile component contents and their correlation between climate factors in Chinese prickly ash peels (Zanthoxylum bungeanum Maxim.)

In this study, we analyzed the characteristics of volatile compounds of Chinese prickly ash peels with different climate conditions and their correlation. The data revealed that the contents of limonene and linalool in peels from southwest and northwest regions were higher, and the aroma was stronger, while the contents of β-myrcene and (E)-ocimene in them from north, east and central China were higher, and the spicy flavor was heavier. Hierarchical cluster analysis demonstrated that the classification had geographical continuity. Through the correlation analysis and path analysis, it was found that the contents of volatile compounds were closely related to the climatic factors. The influence of wind speed and annual average temperature on volatile substances was greater than that of annual average precipitation and annual sunshine duration. This enriched the effect of climatic factors on the accumulation of volatile substances, and promoted the agriculture practices in area having similar climate conditions.

Skin penetration/permeation success determinants of nanocarriers: Pursuit of a perfect formulation

The advent of nanocarriers in the field of pharmaceutical drug delivery, while exhibiting considerable advantages, has created challenges for researchers. Among the applications of nanocarriers, drug delivery to the skin has attracted increasing attention in recent decades due to its advantages over oral and parenteral administration. Accordingly, this work attempts to discuss the major obstacles surrounding topically applied formulations and different nanocarriers' potential to overcome these barriers to investigate whether their passive penetration through the skin is likely. Therefore, skin anatomical views and transcutaneous pathways are briefly reviewed. Factors commonly thought to influence skin penetration are discussed from the perspective of particularly penetrating nanocarriers. The formulation of these nanocarriers is outlined, and promising constituents are highlighted to help investigators optimize nanocarrier formulations.

The Evaluation of the Effects of Nanoemulsion Formulations Containing Boron and/or Zinc on the Wound Healing in Diabetic Rats

Wound healing remains a challenging clinical problem, especially in the presence of diabetes. Diabetic patients have the impaired ability to fight infection and insufficient inflammatory response. The aim of this study was to evaluate the effects of boronophenylalanine (BFA) and/or Zn-containing nanoemulsion (NE) formulations on wound healing in diabetic rats. MTT and scratch assays were performed to evaluate the proliferative effects of BFA and/or Zn on human dermal fibroblast (HDF) cells and the migration of these cells, respectively. The BFA and/or Zn-NE were prepared, and the effects of NEs on wound healing in diabetic rats were evaluated by applying once a day for 14 days. MTT assay showed that 10 to 25 µM BFA and/or 50 µM Zn had very significant positive effects on cell proliferation. In the scratch assay, 10 µM BFA significantly increased the migration of HDF cell compared with control. The droplet sizes of all the NEs were <115 nm and their zeta potential values were in range of (-) 23.9 ± 2.356 to (-) 33.1 ± 1.438 mV. There was a significant reduction in the wound contraction values (%) of the groups treated with the BFA and/or Zn-NE on the 14th day compared with the untreated diabetic rats group. According to histopathological findings, wound healing was nearly complete in BFA and/or Zn-NE compared with untreated diabetic rats. Especially, the group treated with the NE containing the low concentration of BFA showed highly promising results in wound healing of diabetic rats within 14 days with complete epithelialization and the completely closed wound area.