Peculiarities of Aluminum Anodization in AHAs-Based Electrolytes: Case Study of the Anodization in Glycolic Acid Solution

The anodization of aluminum (Al) in three alpha-hydroxy acids (AHAs): glycolic (GC), malic (MC), and citric (CC), was analyzed. Highly ordered pores in GC were obtained for the first time. However, the hexagonal cells were characterized by a non-uniform size distribution. Although common features of current density behavior are visible, the anodization in AHAs demonstrates some peculiarities. The electric conductivity (σ) of 0.5 M GC, MC, and CC electrolytes was in the following order: σ(CC) > σ(MC) > σ(GC), in accordance with the acid strength pKa(CC) < pKa(MC) < pKa(GC). However, the anodization voltage, under which a self-organized pore formation in anodic alumina (AAO) was observed (Umax), decreased with increasing pKa: Umax(CC) > Umax(MC) ≥ Umax(GC). This unusual behavior is most probably linked with the facility of acid ions to complex Al and the active participation of the Al complexes in the AAO formation. Depending on the AHA, its tendency and different modes to coordinate Al ions, the contribution of stable Al complexes to the AAO growth is different. It can be concluded that the structure of Al complexes, their molecular mass, and the ability to lose electrons play more important roles in the AAO formation than pKa values of AHAs.

Formulation and physical evaluation of facial cream preparations from Ceremai fruit juice (Phyllanthus acidus (l.) Skeels)

Introduction: Ceremai (Phyllanthus acidus (L.) Skeels) fruit contains AHA (Alpha Hydroxy Acids) compounds which are widely used as a moisturizer or as an exfoliating process in cosmetics production. It also contains vitamin C and flavonoids, both of which acts as whitening agents. Aim: This study aims to utilise a source of natural AHA active substances found in P.acidus in face cream preparations. Methods: The juice from P.acidus was dried by freeze-drying method and formulated into a cream with the preparation process evaluated for one month. Results: The observation results showed that after one month, there was no change in colour during storage, with the pH, viscosity and spreadability of the cream in the range 4.5-6.2, 2700-3996 cps, and 4.8-5.7 cm, respectively. Conclusion: P.acidus fruit juice containing AHA can be formulated into a face cream with good physical stability.

Oxidation or dehydrogenation of alpha-hydroxy acids in bioenergetic metabolism: A murburn perspective

Glycolate, lactate, malate, hydroxyglutarate and isocitrate are key alpha-hydroxyacyl metabolic intermediates found in the tissues/cells/organelles of diverse life forms. They are respectively oxidized to glyoxylate, pyruvate, oxaloacetate, ketoglutarate and oxalosuccinate in cell bioenergetic metabolism. These molecules form key junction points for divergent pathways of two to six carbon-backboned molecules (of various classes of biomolecules like carbohydrates, amino acids, etc.). The oxido-reduction of the alpha-hydroxyacyl species is traditionally believed to be carried out by reversible (de)hydrogenases, employing nicotinamide cofactors. Herein, I propose that while the reductive pathway can be mediated in a facile manner by the (de)hydrogenases, the oxidative reaction could more efficiently be coupled with murzyme activities, which employ diffusible reactive (oxygen) species (DRS/DROS/ROS). Such a murburn strategy would enable the system to tide over the highly unfavorable energy barriers of the sequential dehydrogenase reaction (~450 kJ/mol, or more!), to give kinetically viable bimolecular reactions catering to cellular needs. Further, such a scheme does not necessitate any ‘intelligent governance’ or ‘smart decision-making’ of/by the pertinent redox enzymes.

Antimicrobial Properties of Mandelic Acid, Gallic Acid and their Derivatives

Purpose: Alpha-hydroxy acids (AHAs) are one of the classes of hydroxy acids being beneficial for human health. The manuscript summarizes the biological properties of two popular members of AHAs i.e. mandelic acid (MA) and gallic acid (GA) with particular emphasis on antimicrobial properties. Moreover, attempts to design of new derivatives improving the natural properties of AHAs by using the chemical and physical approach, are discussed. Methods: Antimicrobial properties of MA, an arylalkyl AHA containing phenyl group attached to α-carbon, and GA, an aromatic trihydroxybenzoic acid containing the phenolic ring and carboxylic acid functional group, and their derivatives against common human and plant pathogenic fungi have been reviewed. Results: The antimicrobial activity of MA and GA is a complex phenomenon strictly correlated with other properties exhibited by these acids e.g. pro-oxidative activity, hydrophobicity. In most cases, the acids derivatives exhibited higher antimicrobial activity than acids itself. This is probably because of the higher lipophilicity of moiety that allows better penetration through the cell membrane. Conclusion: MA and GA present an excellent health-promoting tool and are valuable starting materials for the design of new compounds such as metal complexes with alkali, or alkali earth metals. The lipophilic, antimicrobial, and pro-oxidative properties act synergistically supporting the pharmacological and therapeutic effect of acids and their derivatives.

Grapefruit-Derived Micro and Nanovesicles Show Distinct Metabolome Profiles and Anticancer Activities in the A375 Human Melanoma Cell Line

Fruit juice is one of the most easily accessible resources for the isolation of plant-derived vesicles. Here we found that micro- and nano-sized vesicles (MVs and NVs) from four Citrus species, C. sinensis, C. limon, C. paradisi and C. aurantium, specifically inhibit the proliferation of lung, skin and breast cancer cells, with no substantial effect on the growth of non-cancer cells. Cellular and molecular analyses demonstrate that grapefruit-derived vesicles cause cell cycle arrest at G2/M checkpoint associated with a reduced cyclins B1 and B2 expression levels and the upregulation of cell cycle inhibitor p21. Further data suggest the inhibition of Akt and ERK signalling, reduced intercellular cell adhesion molecule-1 and cathepsins expressions, and the presence of cleaved PARP-1, all associated with the observed changes at the cellular level. Gas chromatography-mass spectrometry-based metabolomics reveals distinct metabolite profiles for the juice and vesicle fractions. NVs exhibit a high relative amount of amino acids and organic acids whereas MVs and fruit juice are characterized by a high percentage of sugars and sugar derivatives. Grapefruit-derived NVs are in particular rich in alpha–hydroxy acids and leucine/isoleucine, myo-inositol and doconexent, while quininic acid was detected in MVs. Our findings reveal the metabolite signatures of grapefruit-derived vesicles and substantiate their potential use in new anticancer strategies.

Glycolic Acid, Lactic Acid, Mandelic Acid, Salicylic Acid, Citric Acid, Gluconolactone: Skin Exfoliators in Combination Therapy of Acne Vulgaris

Facial acne are a recurring issue in most of the population and can cause disturbing skin issues. A combination of Alpha-hydroxy acids, Beta-hydroxy-acids and Poly-hydroxy acids has become popular for treating acne vulgaris in last few years. The main objective of this research study is to evaluate the efficacy & safety of combination of these acids in the treatment of acne vulgaris. The study was conducted on 12 volunteers having mild to moderate to severe acne. They were divided into 3 groups according to the severity of their facial acne. Members of each group were treated with a series of 30% AHA, 2% BHA and 7% PHA. The improvement in their acne condition as well as skin texture was assessed over a period of 6 weeks.

Prophylaxis of Post-Inflammatory Hyperpigmentation From Energy-Based Device Treatments: A Review

Post-inflammatory hyperpigmentation (PIH) is an acquired hypermelanosis that can result from inflammatory dermatologic disease, trauma, or iatrogenesis from procedures. This condition disproportionately affects individuals with skin of color, and it can place a significant psychosocial burden on affected patients. The management of PIH is, therefore, of great interest to clinicians, especially dermatologists. The treatment of established PIH has long been a principal focus within the literature, with publications on the topic outnumbering publications on prophylaxis of PIH. Prophylaxis strategies to prevent PIH vary greatly in clinical practice, likely due to the absence of an evidence-based consensus. Published approaches to PIH prophylaxis include pretreatment (topical alpha hydroxy acids, retinoids, hydroquinone, and brimonidine) and post-treatment strategies (photoprotection, corticosteroids, and tranexamic acid). This review will examine the current literature on prophylaxis of PIH from energy-based device treatments.