In vitro and in vivo evaluation of the delivery of topical formulations containing glycoalkaloids of Solanum lycocarpum fruits

Gel Formulations for Topical Treatment of Skin Cancer: A Review

Skin cancer, with all its variations, is the most common type of cancer worldwide. Chemotherapy by topical application is an attractive strategy because of the ease of application and non-invasiveness. At the same time, the delivery of antineoplastic agents through the skin is difficult because of their challenging physicochemical properties (solubility, ionization, molecular weight, melting point) and the barrier function of the stratum corneum. Various approaches have been applied in order to improve drug penetration, retention, and efficacy. This systematic review aims at identifying the most commonly used techniques for topical drug delivery by means of gel-based topical formulations in skin cancer treatment. The excipients used, the preparation approaches, and the methods characterizing gels are discussed in brief. The safety aspects are also highlighted. The combinatorial formulation of nanocarrier-loaded gels is also reviewed from the perspective of improving drug delivery characteristics. Some limitations and drawbacks in the identified strategies are also outlined and considered within the future scope of topical chemotherapy.

Impact of ripening on the health-promoting components from fruta-do-lobo (Solanum lycocarpum St. Hill)

Fruta-do-lobo (Solanum lycocarpum St. Hill) is an underutilized native fruit commonly found in the Brazilian Cerrado, very known due to the presence of glycoalkaloids. In this work we evaluated the biochemical changes on carbohydrates, phenolic and alkaloids during ripening of fruta-do-lobo using chromatographic and spectrometric techniques. During ripening, we observed an increase in glucose, fructose and sucrose, while oligosaccharides levels varied. Chlorogenic acid isomers represented 80% of the identified phenolic compounds in unripe stage, but they reduced during ripening, resulting in predominance of p-coumaroylquinic acid (peel and pulp) and 1-O-sinapoyl-glucoside (seeds). Statistical analysis shows that the unripe fractions were richer in alkaloids compounds, which were the most important for antioxidant activity. Molecular network analysis summarizes the compound changes during ripening, especially regarding the alkaloid compounds, with a reduction of around 85% of solamargine abundance. These data show that fruta-do-lobo can presents different chemical compositions due their ripening stage providing support for future research aimed to the application of these compounds in glycemia control or uses of their extracts with higher content of alkaloids compounds.

Skin Penetration and Permeation Properties of Transcutol®-Neat or Diluted Mixtures

A heightened interest in (trans)dermal delivery is in part driven by the need to improve the existing skin therapies and also the demand for alternative routes of administration, notably for pharmaceutical actives with undesirable oral absorption characteristics. The premise of delivering difficult actives to the skin or via the skin however is weighed down by the barrier function properties of the stratum corneum. Short of disrupting the skin by physical means, scientists have resorted to formulation with excipients known to enhance the skin penetration and permeation of drugs. A vehicle that has emerged over the years as a safe solubilizer and enhancer for a broad range of drug actives is the highly purified NF/EP grade of diethylene glycol monoethyl ether (DEGEE) commercially known as Transcutol®. Whereas numerous studies affirm its enhancing effect on drug solubilization, percutaneous absorption rate, and/or drug retention in the skin, there are few publications that unite the body of the published literature in describing the precise role and mechanisms of action for Transcutol®. In view of the current mechanistic understanding of skin barrier properties, this paper takes on a retrospective review of the published works and critically evaluates the data for potential misses due to experimental variables such as formulation design, skin model, skin hydration levels, and drug properties. The goal of this review is to mitigate the incongruence of the published works and to construct a unified, comprehensive understanding of how Transcutol® influences skin penetration and permeation. Graphical Abstract Transcutol has affinity for the hydrophilic head groups of the stratum corneum structures.

Evaluation of critical parameters for in vitro skin permeation and penetration studies using animal skin models

In vitro skin permeation/penetration studies may be affected by many sources of variation. Herein, we aimed to investigate the major critical procedures of in vitro skin delivery studies. These experiments were performed with model drugs according to official guidelines. The influence of skin source on penetration studies was studied as well as the use of a cryopreservation agent on skin freezing evaluated by transepidermal water loss, electrical resistance, permeation/penetration profiles and histological changes of the skin. The best condition for tape stripping procedure was validated through the evaluation of the distribution of corneocytes, mass of stratum corneum (SC) removed and amount of protein removed using finger pressure, a 2kg weight and a roller. The interchangeability of the tape stripping procedures followed by the epidermis and dermis homogenate and the micrometric horizontal cryostat skin sectioning methods were also investigated, besides the effect of different formulations. Noteworthy, different skin sources were able to ensure reliable interchangeability for in vitro permeation studies. Furthermore, an increased penetration was obtained for stored frozen skin compared to fresh skin, even with the addition of a cryoprotectant agent. The best method for tape stripping was the finger pressure followed by the addition of a propylene glycol solvent leading to better SC removal. Finally, no significant difference was found in skin penetration studies performed by different methods suggesting their possible interchangeability.

A New Antileishmanial Preparation of Combined Solamargine and Solasonine Heals Cutaneous Leishmaniasis through Different Immunochemical Pathways

Little has been done during the past 100 years to develop new antileishmanial drugs. Most infected individuals live in poor countries and have a low cash income to be attractive targets to pharmaceutical corporations. Two heterosidic steroids, solamargine and solasonine, initially identified as major components of the Brazilian plant Solanum lycocarpum, were tested for leishmanicidal activity. Both alkaloids killed intracellular and extracellular Leishmania mexicana parasites more efficiently than the reference drug sodium stibogluconate. A total of 10 μM each individual alkaloid significantly reduced parasite counts in infected macrophages and dendritic cells. In vivo treatment of C57BL/6 mice with a standardized topical preparation containing solamargine (45.1%) and solasonine (44.4%) gave significant reductions in lesion sizes and parasite counts recovered from lesions. Alkaloids present different immunochemical pathways in macrophages and dendritic cells. We conclude that this topical preparation is effective and a potential new and inexpensive treatment for cutaneous leishmaniasis.

Bioactive Compounds Found in Brazilian Cerrado Fruits

Functional foods include any natural product that presents health-promoting effects, thereby reducing the risk of chronic diseases. Cerrado fruits are considered a source of bioactive substances, mainly phenolic compounds, making them important functional foods. Despite this, the losses of natural vegetation in the Cerrado are progressive. Hence, the knowledge propagation about the importance of the species found in Cerrado could contribute to the preservation of this biome. This review provides information about Cerrado fruits and highlights the structures and pharmacologic potential of functional compounds found in these fruits. Compounds detected in Caryocar brasiliense Camb. (pequi), Dipteryx alata Vog. (baru), Eugenia dysenterica DC. (cagaita), Eugenia uniflora L. (pitanga), Genipa americana L. (jenipapo), Hancornia speciosa Gomes (mangaba), Mauritia flexuosa L.f. (buriti), Myrciaria cauliflora (DC) Berg (jabuticaba), Psidiumguajava L. (goiaba), Psidium spp. (araçá), Solanum lycocarpum St. Hill (lobeira), Spondias mombin L. (cajá), Annona crassiflora Mart. (araticum), among others are reported here.

Chemistry and anticarcinogenic mechanisms of glycoalkaloids produced by eggplants, potatoes, and tomatoes

Inhibition of cancer can occur via apoptosis, a genetically directed process of cell self-destruction that involves numerous biomarkers and signaling pathways. Glycoalkaloids are nitrogen-containing secondary plant metabolites found in numerous Solanaceous plants including eggplants, potatoes, and tomatoes. Exposure of cancer cells to glycoalkaloids produced by eggplants (α-solamargine and α-solasonine), potatoes (α-chaconine and α-solanine), and tomatoes (α-tomatine) or their hydrolysis products (mono-, di-, and trisaccharide derivatives and the aglycones solasodine, solanidine, and tomatidine) inhibits the growth of the cells in culture (in vitro) as well as tumor growth in vivo. This overview comprehensively surveys and consolidates worldwide efforts to define the following aspects of these natural compounds: (a) their prevalence in the three foods; (b) their chemistry and structure-activity relationships; (c) the reported factors (biomarkers, signaling pathways) associated with apoptosis of bone, breast, cervical, colon, gastric, glioblastoma, leukemia, liver, lung, lymphoma, melanoma, pancreas, prostate, and squamous cell carcinoma cell lines in vitro and the in vivo inhibition of tumor formation and growth in fish and mice and in human skin cancers; and (d) future research needs. The described results may make it possible to better relate the structures of the active compounds to their health-promoting function, individually, in combination, and in food, and allow the consumer to select glycoalkaloid-containing food with the optimal content of nontoxic beneficial compounds. The described findings are expected to be a valuable record and resource for further investigation of the health benefits of food-related natural compounds.