Christina Zalaru

Yellow onion (Allium cepa L.) outer skins are a high-volume agricultural waste that can be converted into commercially valuable bioproducts using various extraction techniques. This research focused on optimizing a green ultrasound-assisted extraction (UAE) method which allows for the isolation of several phytochemicals valued for their health benefits, such as polyphenols and flavonoids. HPLC/UV analysis of the extracts showed that the main component was quercetin. A one-factor-at-a-time (OFAT) design was used to identify the extraction parameters needed in order to maximize the amount of extracted target phytochemicals. The polyphenols, flavonoids and quercetin contents, along with the antioxidant activity of the extracts, were optimized by response surface methodology using a Box–Behnken design. Ultrasound amplitude, ethanol concentration, and time were selected as the most appropriate variables. The final results showed that TPC ranged from 78.16 to 97.16 mg GAE/g DM, TFC ranged from 22.77 to 26.46 mg QE/g DM, while CUPRAC values varied between 145.24 and 163.75 mg TE/g DM. The optimal extraction conditions were determined using a Box–Behnken model as 30% ultrasound amplitude, 53% ethanol concentration, and an extraction time of 13 min. The use of these conditions allowed the TPC, TFC and CUPRAC to show predicted values of 97.8 mg GAE/g DM, 27.2 mg QE/g DM, and 159.8 mg TE/g DM, respectively. These findings indicate that onion skin extracts could represent a green and promising source of antioxidant phytochemicals.

Objective: Based on our previous findings, we designed new molecules by extending functionalized pyrazole derivatives containing iodine atoms, which are linked via an amino bond to halogen-substituted phenyl groups. In addition, these newly developed pyrazole compounds exhibit anti-tumor, antibacterial, and anti-biofilm activities. Methods: Three new series of pyrazole compounds were designed. Fifteen novel pyrazole derivatives, distributed across three series (4a–d, 5a–d, and 6a–g), were synthesized and structurally characterized by ¹H-NMR, ¹³C-NMR, FTIR, UV-Vis spectroscopy, and elemental analysis. Results: Among them, compound 4c, which exhibited notable anti-tumor activity, crystallized in a monoclinic system and was further analyzed via single-crystal X-ray diffraction. All synthesized compounds were evaluated in vitro on NCTC normal fibroblast cells and HEp-2 tumor epithelial cells. Compound 4c demonstrated significant anti-tumor activity while displaying no cytotoxic effects on normal cells. The antibacterial and anti-biofilm activities of the compounds were also assessed against four bacterial strains. Compounds 5a and 5c exhibited the highest antibacterial activity against Staphylococcus aureus ATCC 25923, both with a minimum inhibitory concentration (MIC) of 0.023 μg/mL. Additionally, compounds 4a, 5a, 6a, 6e, and 6f showed the strongest anti-biofilm effects, each presenting a minimum biofilm inhibition concentration (MBIC) of 0.023 μg/mL. ADME and ADMET in silico predictions indicated that all compounds exhibit generally favorable, drug-like physicochemical properties. Conclusions: The study reinforces the applicability of these compounds as promising anticancer, antibacterial, and anti-biofilm drugs.

Background: Heterocyclic compounds represent a key class of compounds in medicinal chemistry. Both benzimidazoles and pyrimidines are essential heterocycles in medicinal chemistry, with various therapeutic properties. Recent literature presents a series of hybrid heterocyclic compounds, as their medicinal properties are generally improved compared to those of single heterocyclic rings. Methods: A literature search was conducted across relevant scientific literature from peer-reviewed sources, using keywords, including “benzimidazole”, “pyrimidine”, “Biginelli”, “benzimidazole-pyrimidine hybrids”, “anticancer”, “antiviral”, “antimicrobial”, and “anti-inflammatory”. Results: In this review, benzimidazole–pyrimidine hybrids are reported as anticancer, antimicrobial, antiviral, anti-inflammatory, analgesic, antiulcer, antidepressant, anti-Alzheimer’s, or antioxidant agents, with activities even better than those of existing drugs. The IC₅₀ values for these anticancer hybrids are in the nanomolar range, which signifies potent anticancer agents. It can be mentioned here that the anticancer hybrid Abemaciclib, as a CDK4/6 inhibitor for the treatment of certain types of breast cancer, was approved in 2017. The antimicrobial activity of these hybrids proved especially potent against a broad variety of infections, with MIC values in the range of µM or even nM. Moreover, these hybrids exhibited good antiviral properties against SARS-CoV-2, HIV-1, and the hepatitis C virus. The hybrids also functioned as JAK3 inhibitors, COX-1 inhibitors, and MAO-A inhibitors. Conclusions: This review presents synthesis methods of benzimidazole–pyrimidine hybrids, their medicinal properties, and SAR studies reported in the last 20 years. For almost every therapeutic activity, SAR studies have revealed the essential presence of a substituent on the aromatic rings or between the two benzimidazole and pyrimidine nuclei.

New haloaminopyrazole derivatives differing in the number of pyrazole nuclei 4a–f and 5a–e, respectively, were synthesized and characterized by ¹H-NMR, ¹³C-NMR, IR, UV-Vis, and elemental analysis. The single-crystal X-ray diffraction method was used to describe compounds 4a and 5d. When tested on normal NCTC fibroblasts in vitro, the newly synthesized derivatives were shown to be non-cytotoxic at a dosage of 25 μg/mL. Two compounds 4a and 5d showed a high degree of biocompatibility. From the two series of compounds tested on HEp-2 human cervical carcinoma cells, compound 5d showed a more pronounced antiproliferative effect. Gram-positive strains of Staphylococcus aureus ATCC25923, Enterococcus faecalis ATCC29212, Gram-negative strains of Pseudomonas aeruginosa ATCC27853, and strains of Escherichia coli ATCC25922 were used to test the newly synthesized compounds antibacterial and antibiofilm properties. Among the studied pyrazole compounds, 2 compounds 4a and 5a with fluorine content on the phenyl ring and 4 compounds 4b, 4e, 4f, and 5b with chlorine content on the phenyl ring were noted, which proved to be the most active compared with the two reference drugs, metronidazole and nitrofurantoin. The six compounds showed a broad spectrum of action against all four tested bacterial strains, the most active being compound 4b, with a chlorine atom in the “4” position of the phenyl nucleus and a MIC of 460 μg/mL. Compounds 4a and 5a showed the best antibiofilm activity against the bacterial strain Staphylococcus aureus ATCC25923, with an MBIC of 230 μg/mL.

Hedera helix L. contains phytochemicals with good biological properties which are beneficial to human health and can be used to protect plants against different diseases. The aim of this research was to find the most suitable extraction method and the most favorable parameters for the extraction of different bioactive compounds from ivy leaves. Different extraction methods, namely microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and conventional heating extraction (CHE), were used. The most suitable method for the extraction of saponins is MAE with an extraction efficiency of 58%, while for carbohydrates and polyphenols, the best results were achieved via UAE with an extraction efficiency of 61.7% and 63.5%, respectively. The antioxidant activity (AA) of the extracts was also determined. The highest AA was obtained via UAE (368.98 ± 9.01 µmol TR/gDM). Better results were achieved at 50 °C for 10 min of extraction, using 80% ethanol in water as solvent. In order to evaluate their in vitro cytotoxicity, the extracts richest in bioactive compounds were tested on NCTC fibroblasts. Their influence on the DNA content of RAW 264.7 murine macrophages was also tested. Until 200 µg/mL, the extracts obtained via UAE and MAE were cytocompatible with NCTC fibroblasts at 48 h of treatment. Summarizing the above, both MAE and UAE can be employed as green and efficient methods for producing extracts rich in bioactive compounds, exhibiting strong antioxidant properties and good noncytotoxic activity.

Phytochemicals from Hedera helix L. lead to extracts with good biological properties which are beneficial to human health and can be used to protect plants against different diseases. The aim of this research was to find the most suitable extraction method and the most favorable parameters for different bioactive compounds extraction from ivy leaves. Different extraction methods, namely microwave assisted extraction (MAE), ultrasound assisted extraction (UAE), and conventional heating extraction (CHE), were used. The most suitable method for saponins extraction is MAE with an extraction efficiency of 58%, while for carbohydrates and polyphenols the best results were achieved by UAE with an extraction efficiency of 61.7% and 63.5%, respectively. The antioxidant activity (AA) of the extracts was also determined. The highest AA was obtained by UAE (368.98±9.01 µmol TR/gDM). Better results were achieved at 50 °C for 10 min of extraction, using 80% ethanol in water as solvent. In order to evaluate their in vitro cytotoxicity, the extracts richest in bioactive compounds were tested on NCTC fibroblasts. Their influence on the DNA content of RAW 264.7 murine macrophages was also tested. Until 200 µg/mL, the extracts obtained by UAE and MAE were cytocompatible with NCTC fibroblasts at 48 h of treatment.

The aim of this study was to establish the best ultrasound assisted extraction (UAE) conditions of saponins from Hedera helix L. leaves and to evaluate the in vitro biocompatibility of the extracts richest in saponins. Different parameters, such as extraction time, temperature, ultrasound power, solvent to plant material ratio, and solvent concentration, were investigated. The most efficient extraction conditions were a temperature of 50 °C, an ultrasound amplitude of 40%, an extraction time of 60 min, a plant material to solvent ratio of 1:20 (w:v), and 80% ethanol as solvent. In vitro cytotoxicity of the extracts richest in saponins and their influence on the DNA content of L929 (NCTC) fibroblasts were tested. Until 200 µg/mL, the studied extracts were cytocompatible with L929 fibroblast cell lines at 48 h of treatment. These in vitro cell culture results provide useful information for further applications of Hedera helix extracts in a pharmaceutical field.

A new series of pyrazolo-benzimidazole hybrid Mannich bases were synthesized, characterized by ¹H-NMR, ¹³C-NMR, IR, UV-Vis, MS, and elemental analysis. In vitro cytotoxicity of the new compounds studied on fibroblast cells showed that the newly synthesized pyrazolo-benzimidazole hybrid derivatives were noncytotoxic until the concentration of 1 μM and two compounds presented a high degree of biocompatibility. The antibacterial and antibiofilm activity of the newly synthesized compounds was assayed on Gram-positive Staphylococcus aureus ATCC25923, Enterococcus faecalis ATCC29212, and Gram-negative Pseudomonas aeruginosa ATCC27853, Escherichia coli ATCC25922 strains. All synthesized compounds 5a–g are more active against all three tested bacterial strains Staphylococcus aureus ATCC25923, Enterococcus faecalis ATCC29212, and Escherichia coli ATCC25922 than reference drugs (Metronidazole, Nitrofurantoin), with the exception of compounds 5d and 5g, which are less active compared to Nitrofurantoin, and all synthesized compounds 5a–g are more active against Pseudomonas aeruginosa ATCC27853 compared to reference drugs (Metronidazole, Nitrofurantoin). Compound 5f showed the best activity against Staphylococcus aureus ATCC 25923, with a MIC of 150 μg/mL and has also inhibited the biofilm formed by all the bacterial strains, having an MBIC of 310 µg/mL compared to the reference drugs (Metronidazole, Nitrofurantoin).

Hedera helix L. is known for its therapeutic properties, such as analgesic, anti-inflammatory, expectorant activity. It is currently known that the characteristic therapeutic effects of ivy extracts are induced by phytocompunds, such as: saponins (hederagenin, α and β-hederin, hederacoside B and C), phytosterols (sitosterol, stigmasterol, campesterol), flavonoids, falcarinol, falcarinone, scopoline, chlorogenic acid, caffeic acid, phytoestrogens [¹]. The purpose of our study was to evaluate the total saponin content of Hedera helix L. leaves extracts obtained by both conventional, and unconventional methods. The commercial fresh leaves of Hedera helix L. were purchased from Hofigal SA, Romania. The following reagents used for testing were α-hederin, hederagenin, and hederacoside C at purity ≥98% (HPLC), DMSO were purchased from Sigma Aldrich. The chemical composition of the obtained extracts was analyzed by HPLC-MS/MS, and the total saponin content was evaluated [²,³]. Our study indicated an optimal method for obtaining Hedera helix L. leaves extract with an enriched saponin content.

We present a series of pyrazolato-bridged copper complexes with interesting structures that can be considered prototypic patterns for tri-, hexa- and hepta- nuclear systems. The trinuclear shows an almost regular triangle with a μ₃-OH central group. The hexanuclear has identical monomer units, the Cu₆ system forming a regular hexagon. The heptanuclear can be described as two trinuclear moieties sandwiching a central copper ion via carboxylate bridges. In the heptanuclear system, the pyrazolate bridges are consolidating the triangular faces, which are sketching an elongated trigonal antiprism. The magnetic properties of these systems, dominated by the strong antiferromagnetism along the pyrazolate bridges, were described transparently, outlining the energy levels formulas in terms of Heisenberg exchange parameters J, within the specific topologies. We succeeded in finding a simple Kambe-type resolution of the Heisenberg spin Hamiltonian for the rather complex case of the heptanuclear. In a similar manner, the weak intermolecular coupling of two trimer units (aside from the strong exchange inside triangles) was resolved by closed energy formulas. The hexanuclear can be legitimately proposed as a case of coordination-based aromaticity, since the phenomenology of the six-spins problem resembles the bonding in benzene. The Broken-Symmetry Density Functional Theory (BS-DFT) calculations are non-trivial results, being intrinsically difficult at high nuclearities.