Development of a sustainable procedure for smartphone-based colorimetric determination of benzalkonium chloride in pharmaceutical preparations.

A sustainable procedure offering green, simple, and rapid analysis was developed to determine benzalkonium chloride (BKC) in pharmaceutical preparations. The determination using smartphones was based on the ion pair colorimetric reaction with bromothymol blue (BTB), which produces a yellow color. The intensity of the product color, which is proportional to the concentration of BKC, was detected and evaluated using a smartphone camera and an image processing application. The procedure was performed in a microliter and was rapidly detected within 1 min after incubation. This offered high throughput at 28 samples per well plate in duplicate. Linear calibration, which was a plot of BKC concentrations and relative red intensities, was in the range of 2.0-24.0 µg/mL with an R2 of 0.997. The limits of detection (LOD) and quantitation (LOQ) were 1.0 and 3.2 µg/mL, respectively. This work was successful in applying it to pharmaceutical materials, disinfectant products, and pharmaceutical products containing BKC. It was discovered that the concentrations of BKC as an active ingredient in pharmaceutical materials were 82% w/v, whereas those in disinfectant products ranged from 0.4 to 2.1% w/v. In pharmaceutical products, ophthalmic drops and nasal sprays contain BKC as preservatives in the 0.01-0.02, and the 0.02% w/v, respectively. The results obtained by the proposed procedure compared with a reference titration method showed no significant differences at a 95% confidence level with 1.2-3.4% RSDs. This promotes the efficiency of pharmaceutical preparations regarding infection prevention and control by ensuring that available disinfectants contain a sufficient concentration of BKC. Additionally, this improves the efficiency of pharmaceutical preparations for quality control of pharmaceutical products by ensuring that the available preservatives maintain a sufficient concentration throughout the lifespan of the products.

The in vitro effects of black soldier fly larvae (Hermitia illucens) oil as a high-functional active ingredient for inhibiting hyaluronidase, anti-oxidation benefits, whitening, and UVB protection.

Objective: Larvae of Hermitia illucens, or black soldier fly larvae (BSFL), have been recognized for their high lipid yield with a remarkable fatty acid profile. BSFL oil (SFO) offers the added value of a low environmental footprint and a sustainable product. In this study, the characteristics and cosmetic-related activities of SFO were investigated and compared with rice bran oil, olive oil and krill oil which are commonly used in cosmetics and supplements. Methods: The physicochemical characteristics were determined including acid value, saponification value, unsaponifiable matter and water content of SFO. The fatty acid composition was determined using GC-MS equipped with TR-FAME. The in vitro antioxidant properties were determined using DPPH, FRAP and lipid peroxidation inhibition assays. Antihyaluronidase (anti-HAase) activity was measured by detecting enzyme activity and molecular docking of candidate compounds toward the HAase enzyme. The safety assessment towards normal human cells was determined using the MTT assay and the UVB protection upon UVB-irradiated fibroblasts was determined using the DCF-DA assay. The whitening effect of SFO was determined using melanin content inhibition. Results: SFO contains more than 60% polyunsaturated fatty acids followed by saturated fatty acids (up to 37%). The most abundant component found in SFO was linoleic acid (C18:2 n-6 cis). Multiple anti-oxidant mechanisms of SFO were discovered. In addition, SFO and krill oil prevented hyaluronic acid (HA) degradation via strong HAase inhibition comparable with the positive control, oleanolic acid. The molecular docking confirmed the binding interactions and molecular recognition of major free fatty acids toward HAase. Furthermore, SFO exhibited no cytotoxicity on primary human skin fibroblasts, HaCaT keratinocytes and PBMCs (IC50 values > 200 µg/mL). SFO possessed significant in-situ anti-oxidant activity in UVB-irradiated fibroblasts and the melanin inhibition activity as effective as well-known anti-pigmenting compounds (kojic acid and arbutin, p < 0.05). Conclusion: This study provides scientific support for various aspects of SFO. SFO can be considered an alternative oil ingredient in cosmetic products with potential implications for anti-skin aging, whitening and UVB protection properties, making it a potential candidate oil in the cosmetic industry.

KLVFF Conjugated Curcumin Microemulsion-Based Hydrogel for Transnasal Route: Formulation Development, Optimization, Physicochemical Characterization, and Ex Vivo Evaluation.

Curcumin is a potent natural compound used to treat Alzheimer's disease (AD). However, the clinical usefulness of curcumin to treat AD is restricted by its low oral bioavailability and difficulty permeating the blood-brain barrier. To overcome such drawbacks, various alternative strategies have been explored, including the transnasal route. However, rapid mucociliary clearance in the nasal cavity is a major hindrance to drug delivery. Thus, designing a delivery system for curcumin to lengthen the contact period between the drug and nasal mucosa must be employed. This study describes the optimization of KLVFF conjugated curcumin microemulsion-base hydrogel (KCMEG) to formulate a prototype transnasal preparation using the response surface method to improve a mucoadhesive property. A central composite design was employed to optimize and evaluate two influencing factors: the concentration of carbopol 940 and the percentage of KLVFF conjugated curcumin microemulsion (KCME). The physicochemical properties, anti-cholinesterase activity, and anti-aggregation activities of KCME were investigated in this study. The studied factors, in terms of main and interaction effects, significantly (p < 0.05) influenced hardness and adhesiveness. The optimized KCMEG was evaluated for pH, spreadability, and mucoadhesive properties. Ex vivo nasal ciliotoxicity to optimize KCMEG was performed through the porcine nasal mucosa. KCME was transparent, with a mean globule size of 70.8 ± 3.4 nm and a pH of 5.80 ± 0.02. The optimized KCMEG containing 2% carbopol 940 showed higher in vitro mucoadhesive potential (9.67 ± 0.13 min) compared with microemulsion and was also found to be free from nasal ciliotoxicity during histopathologic evaluation of the porcine nasal mucosa. The result revealed that both the concentration of carbopol 940 and the percentage of KCME play a crucial role in mucoadhesive properties. In conclusion, incorporating a mucoadhesive agent in a microemulsion can increase the retention time of the formulation, leading to enhanced brain delivery of the drug. Findings from the investigation revealed that KCMEG has the potential to constitute a promising approach to treating AD via transnasal administration.

Discovery of Natural Lead Compound from Dendrobium sp. against SARS-CoV-2 Infection.

Since the pandemic of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in December 2019, the infection cases have quickly increased by more than 511 million people. The long epidemic outbreak over 28 months has affected health and economies worldwide. An alternative medicine appears to be one choice to alleviate symptoms and reduce mortality during drug shortages. Dendrobium extract is one of the traditional medicines used for COVID-19 infection. Several compounds in Dendrobium sp. had been reported to exert pharmacological activities to treat common COVID-19-related symptoms. Herein, in silico screening of 83 compounds from Dendrobium sp. by using the SARS-CoV-2 spike protein receptor-binding domain (RBD) as a drug target was performed in searching for a new lead compound against SARS-CoV-2 infection. Four hit compounds showing good binding affinity were evaluated for antiviral infection activity. The new lead compound DB36, 5-methoxy-7-hydroxy-9,10-dihydro-1,4-phenanthrenequinone, was identified with the IC50 value of 6.87 ± 3.07 µM. The binding mode revealed that DB36 bound with the spike protein at the host receptor, angiotensin-converting enzyme 2 (ACE2) binding motif, resulted in antiviral activity. This study substantiated the use of Dendrobium extract for the treatment of SARS-CoV-2 infection and has identified new potential chemical scaffolds for further drug development of SARS-CoV-2 entry inhibitors.

Potential Anti-Alzheimer Agents from Guanidinyl Tryptophan Derivatives with Activities of Membrane Adhesion and Conformational Transition Inhibitions.

Guanidinyl tryptophan derivatives TGN1, TGN2, TGN3, and TGN4 were synthesized, and these compounds were shown to possess in vitro inhibitory activity for amyloid aggregation in a previous study. Nevertheless, the influence of the TGN series of compounds on the binding and permeation behaviors of an Aß monomer to the cell membranes was not elucidated. In this study, we investigated the effect of compounds in the TGN series on the behavior of an Aß monomer regarding its toxicity toward the bilayer lipid membrane using molecular dynamics (MD) simulation. MD simulations suggest that TGN4 is a potential agent that can interfere with the movement of the Aß monomer into the membrane. The MM-GBSA result demonstrated that TGN4 exhibits the highest affinity to the Aß1-42 monomer but has the lowest affinity to the bilayer. Moreover, TGN4 also contributes to a decrease in the binding affinity between the Aß1-42 monomer and the POPC membrane. Regarding the results of the binding mode and conformational analyses, a high number of amino-acid residues were shown to provide the binding interactions between TGN4 and the Aß1-42 monomer. TGN4 also reduces the conformational transition of the Aß1-42 monomer by means of interacting with the monomer. The present study presents molecular-level insights into how the TGN series of compounds affect the membrane adsorption and the conformational transition of the Aß1-42 monomer, which could be valuable for the further development of new anti-Alzheimer agents.

Validated HPTLC and antioxidant activities for quality control of catechin in a fermented tea (Camellia sinensis var. assamica).

Miang, a Thai traditional fermented tea (Camellia sinensis var. assamica), is exploited as nutraceutical and cosmeceutical ingredients despite limited standardization studies. Thus, this research aimed to develop a simple and rapid method for miang quality control using catechin and high-performance thin-layer chromatography (HPTLC) validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) and the Association of Official Analytical Collaboration (AOAC). The developing solvent consisting of toluene: ethyl acetate: acetone: formic acid (6:6:6:1 v/v/v/v) showed acceptable specificity with R f value of 0.54 ± 0.02 and linearity with correlation coefficient of 0.9951. The recovery was 98.84%-103.53%, and the RSD of intra- and inter-day precision was 0.70%-3.00% and 1.93%-4.94%, respectively. Miang ethyl acetate fraction is suggested to be attractive ingredient due to rich catechin (25.78 ± 0.53%), prolonged stability at 40 ◦C, and strong antioxidants determined by the assays of ABTS (IC50 = 3.32 ± 0.74 mg/ml), FRAP (89.05 ± 15.49 mg equivalent of FeSO4/g), and inhibition of lipid peroxidation (IC50 = 4.36 ± 0.67 mg/ml).

Novel Multifunctional Ascorbic Triazole Derivatives for Amyloidogenic Pathway Inhibition, Anti-Inflammation, and Neuroprotection.

Alzheimer's disease (AD) is a common neurodegenerative disorder. The number of patients with AD is projected to reach 152 million by 2050. Donepezil, rivastigmine, galantamine, and memantine are the only four drugs currently approved by the United States Food and Drug Administration for AD treatment. However, these drugs can only alleviate AD symptoms. Thus, this research focuses on the discovery of novel lead compounds that possess multitarget regulation of AD etiopathology relating to amyloid cascade. The ascorbic acid structure has been designated as a core functional domain due to several characteristics, including antioxidant activities, amyloid aggregation inhibition, and the ability to be transported to the brain and neurons. Multifunctional ascorbic derivatives were synthesized by copper (I)-catalyzed azide-alkyne cycloaddition reaction (click chemistry). The in vitro and cell-based assays showed that compounds 2c and 5c exhibited prominent multifunctional activities as beta-secretase 1 inhibitors, amyloid aggregation inhibitors, and antioxidant, neuroprotectant, and anti-inflammatory agents. Significant changes in activities promoting neuroprotection and anti-inflammation were observed at a considerably low concentration at a nanomolar level. Moreover, an in silico study showed that compounds 2c and 5c were capable of being permeated across the blood-brain barrier by sodium-dependent vitamin C transporter-2.

Semisynthesis and biological evaluation of prenylated resveratrol derivatives as multi-targeted agents for Alzheimer's disease.

A series of prenylated resveratrol derivatives were designed, semisynthesized and biologically evaluated for inhibition of ß-secretase (BACE1) and amyloid-ß (Aß) aggregation as well as free radical scavenging and neuroprotective and neuritogenic activities, as potential novel multifunctional agents against Alzheimer's disease (AD). The results showed that compound 4b exhibited good anti-Aß aggregation (IC50 = 4.78 µM) and antioxidant activity (IC50 = 41.22 µM) and moderate anti-BACE1 inhibitory activity (23.70% at 50 µM), and could be a lead compound. Moreover, this compound showed no neurotoxicity along with a greater ability to inhibit oxidative stress on P19-derived neuronal cells (50.59% cell viability at 1 nM). The neuritogenic activity presented more branching numbers (9.33) and longer neurites (109.74 µm) than the control, and was comparable to the quercetin positive control. Taken together, these results suggest compound 4b had the greatest multifunctional activities and might be a very promising lead compound for the further development of drugs for AD.

Neuritogenic activity of bi-functional bis-tryptoline triazole.

Alzheimer's disease (AD) is a common neurodegenerative disorder, one of the hallmarks of which is the deposition of aggregated ß-amyloid peptides (Aß40,42) as plaques in the brain. Oligomers of these peptides have been reported to be toxic and to inhibit neurite outgrowth, as evidenced by neurite dystrophy and significant loss of synaptic connectivity of neurons in the AD brain resulting in cognitive decline. These peptides also react with biological metal in the brain to generate free radicals, thereby aggravating neuronal cell injury and death. Herein, multifunctional triazole-based compounds acting on multiple targets, namely ß-secretase (BACE1), ß-amyloid peptides (Aß) as well as those possessing metal chelation and antioxidant properties, were developed and evaluated for neuritogenic activity in P19-derived neurons. At the non-cytotoxic concentration (1nM), all multifunctional compounds significantly enhanced neurite outgrowth. New bis-tryptoline triazole (BTT) increased the neurite length and neurite number, by 93.25% and 136.09% over the control, respectively. This finding demonstrates the ability of multifunctional compounds targeting Aß to enhance neurite outgrowth in addition to their neuroprotective action.

From BACE1 inhibitor to multifunctionality of tryptoline and tryptamine triazole derivatives for Alzheimer's disease.

Efforts to discover new drugs for Alzheimer's disease emphasizing multiple targets was conducted seeking to inhibit amyloid oligomer formation and to prevent radical formation. The tryptoline and tryptamine cores of BACE1 inhibitors previously identified by virtual screening were modified in silico for additional modes of action. These core structures were readily linked to different side chains using 1,2,3-triazole rings as bridges by copper catalyzed azide-alkyne cycloaddition reactions. Three compounds among the sixteen designed compounds exerted multifunctional activities including ß-secretase inhibitory action, anti-amyloid aggregation, metal chelating and antioxidant effects at micromolar levels. The neuroprotective effects of the multifunctional compounds 6h, 12c and 12h on Aß1₋42 induced neuronal cell death at 1 µM were significantly greater than those of the potent single target compound, BACE1 inhibitor IV and were comparable to curcumin. The observed synergistic effect resulting from the reduction of the Aß1₋42 neurotoxicity cascade substantiates the validity of our multifunctional strategy in drug discovery for Alzheimer's disease.

Triazolyl tryptoline derivatives as ß-secretase inhibitors.

Tryptoline, a core structure of ochrolifuanine E, which is a hit compound from virtual screening of the Thai herbal database against BACE1 was used as a scaffold for the design of BACE1 inhibitors. The tryptoline was linked with different side chains by 1,2,3-triazole ring readily synthesized by catalytic azide-alkyne cycloaddition reactions. Twenty two triazolyl tryptoline derivatives were synthesized and screened for the inhibitory action against BACE1. JJCA-140 was the most potent inhibitor (IC(50)=1.49 µM) and was 100 times more selective for BACE1 than for Cat-D.