Primaquine-NSAID twin drugs: Synthesis, radical scavenging, antioxidant and Fe2+ chelating activity

Comparison of Cytotoxic, Genotoxic, and DNA-Protective Effects of Skyrin on Cancerous vs. Non-Cancerous Human Cells

Secondary metabolites as a potential source of anticancer therapeutics have been the subject of many studies. Since hypericin, a metabolite isolated from Hypericum perforatum L., shows several biomedical properties applicable in oncology, the aim of our study was to investigate its potential precursor skyrin in terms of genotoxic and DNA-protective effects. These skyrin effects were analyzed by cell-free methods, and cytotoxicity was estimated by an MTT assay and by a trypan blue exclusion test, while the genotoxic/antigenotoxic potential was examined by comet assay using non-cancerous human lymphocytes and the HepG2 cancer cell line. Skyrin did not show DNA-damaging effects but rather exhibited DNA-protectivity using a DNA-topology assay. However, we observed only weak antioxidant and chelating skyrin properties in other cell-free methods. Regarding the cytotoxic activity of skyrin, HepG2 cells were more prone to skyrin-induced death in comparison to human lymphocytes. Skyrin in non-cytotoxic concentrations did not exhibit elevated genotoxicity in both cell types. On the other hand, skyrin displayed moderate DNA-protective effects that were more noticeable in the case of non-cancerous human lymphocytes. The potential genotoxic effects of skyrin were not observed, and its DNA-protective capacity was more prominent in non-cancerous cells. Therefore, skyrin might be a promising agent used in anticancer therapy.

Optimization of Bioactive Phenolics Extraction and Cosmeceutical Activity of Eco-Friendly Polypropylene-Glycol-Lactic-Acid-Based Extracts of Olive Leaf

Olive leaf is a rich source of phenolic compounds with numerous activities related to skin health and appearance. In this study, a green extraction method was developed using eco-friendly solvents: polypropylene glycol (PPG), lactic acid (LA), and water. The optimal extraction conditions were established, including solvent, extraction time, technique (magnetic stirrer vs. ultrasound-assisted extraction), and herbal material/solvent ratio. The composition of the solvent mixture was optimized using a mixture design. The content of phenolic compounds, including oleuropein and verbascoside, was determined using high-performance liquid chromatography (HPLC) and spectrophotometric methods. Using different extraction conditions, three extracts were prepared and their phytochemical compositions and antioxidant and skin-related bioactivities were investigated. The extracts were excellent inhibitors of elastase, collagenase, tyrosinase, and lipoxygenase. The best activity was shown by the extract richest in phenolics and prepared using magnetic-stirrer-assisted extraction for 20 min, with 0.8 g of herbal material extracted in 10 mL of PPG/LA/water mixture (28.6/63.6/7.8, w/w/w), closely followed by the extract prepared using the same extraction conditions but with 0.42 g of herbal material. The investigated PPG/LA/water mixtures contributed to the overall enzyme-inhibitory activity of the extracts. The prepared extracts were appropriate for direct use in cosmetic products, thus saving the time and energy consumption necessary for the evaporation of conventional solvents.

Optimization of Two Eco-Friendly Extractions of Black Medick (Medicago lupulina L.) Phenols and Their Antioxidant, Cosmeceutical, α-Glucosidase and α-Amylase Inhibitory Properties

Medicago lupulina is an ancient edible plant from the Fabaceae family. In this work, two eco-friendly methods for extraction of bioactive phenolics from M. lupulina were developed using mixtures of water with two non-toxic, skin- and environmentally-friendly polyol solvents: glycerol and polypropylene glycol. Ultrasound-assisted extractions were optimized using a Box–Behnken design. The independent variables were the concentration of organic solvent in water (X₁), extraction temperature (X₂) and time (X₃), while the response was phenolic content. The optimum conditions for extraction of polyphenols were (X₁, X₂, X₃): (45%, 70 °C, 60 min) and (10%, 80 °C, 60 min) for glycerol and polypropylene glycol extraction, respectively. The extracts prepared at optimum conditions were rich in phenolic compounds, mainly derivatives of apigenin, kaempferol, luteolin, quercetin, caffeic and ferulic acid, as well as coumestrol. Their cosmeceutical and antidiabetic activity was tested. Both extracts demonstrated notable antioxidant, anti-lipoxygenase and anti-α-amylase activity. In addition to those activities, the glycerol extract efficiently inhibited protein coagulation, elastase and α-glucosidase activity. Glycerol present in the extract displayed enzyme-inhibiting activity in several assays and supported the action of the bioactive constituents. Thus, the optimized glycerol extract is a desirable candidate for direct incorporation in antidiabetic food supplements and cosmeceutical products.

Primaquine derivatives: Modifications of the terminal amino group

Numerous modifications of the well-known antimalarial drug primaquine, both at the quinoline ring and at the primary amino group, have been reported, mostly to obtain antimalarial agents with improved bioavailability, reduced toxicity and/or prolonged activity. Modifications of the terminal amino group were made with the main idea to prevent the metabolic pathway leading to inactive and toxic carboxyprimaquine (follow-on strategy), but also to get compounds with different activity (repurposing strategy). The modifications undertaken until 2009 were included in a review published in the same year. The present review covers various classes of primaquine N-derivatives with diverse biological profiles, prepared in the last decade by our research group as well as the others. We have summarized the synthetic procedures applied for their preparation and discussed the main biological results. Several hits for the development of novel antiplasmodial, anticancer, antimycobacterial and antibiofilm agents were identified.

Antidiabetic and Cosmeceutical Potential of Common Barbery (Berberis vulgaris L.) Root Bark Extracts Obtained by Optimization of 'Green' Ultrasound-Assisted Extraction

Berberis vulgaris is rich in berberine, an isoquinoline alkaloid, with antidiabetic activity, often used topically for skin-related problems. The aim of this work was to develop a “green” method for berberine extraction using mixtures of water with glycerol, a non-toxic, environmentally-friendly solvent. Response surface methodology based on Box–Behnken design was used to optimize the experimental conditions for ultrasound-assisted extraction of berberine and anti-radical components from B. vulgaris root bark. The independent variables were temperature (X₁), glycerol concentration (X₂), and ultrasound power (X₃), while the responses were berberine concentration and DPPH radical scavenging activity of the extracts (RSA IC₅₀). The response values of the extracts prepared at optimum conditions were (response, X₁, X₂, X₃): berberine yield (145.5 μg/mL; 80 °C, 50%, 144 W) and RSA IC₅₀ (58.88 μL/mL; 80 °C, 30%, 720 W). The observed values deviated from the predicted values by −3.45% and 6.42% for berberine and RSA IC₅₀, respectively, thus indicating the validity of the selected models. The prepared extracts demonstrated antioxidant, anti-melanogenic, and anti-inflammatory activity, as well excellent α-glucosidase and α-amylase inhibitory activity. The displayed biological properties and lack of glycerol toxicity makes the prepared extracts suitable for direct inclusion into antidiabetic and dermatologic food supplements and topical products.

Glycerolic Licorice Extracts as Active Cosmeceutical Ingredients: Extraction Optimization, Chemical Characterization, and Biological Activity

A green ultrasound-assisted extraction (UAE) method using glycerol/water mixtures for extraction of licorice (Glycyrrhiza glabra) bioactive constituents was developed in this study. The response surface method, according to the Box-Behnken design, was employed to optimize the extraction parameters: glycerol concentration (X₁), temperature (X₂), and the amount of herbal drug used in the production (X₃). The responses were content of total phenols (TP), TP extraction efficiency (TPy) and the content of licorice characteristic constituents, glabridin (Gla) and isoliquiritigenin (Iso). Response surface analysis predicted the optimal extraction conditions for maximized amounts of TP, Tpy, Gla, and Iso. The extracts were prepared using the calculated conditions. The analysis of the selected constituents confirmed the validity of the model. Furthermore, biological activity of the extracts was tested. The results demonstrate that UAE using glycerol is a fast and efficient method for preparation of extracts with excellent radical scavenging, Fe²⁺ chelating and antioxidant activity. Furthermore, the observed notable tyrosinase and elastase inhibitory activity of the extracts, as well as their anti-inflammatory activity, indicate the anti-aging properties of the investigated extracts. The fact that the extracts were prepared using the safe, cosmetically active solvent, glycerol, makes them suitable for direct use in specialized cosmeceutical formulations.

Total Phenolic Content and In vitro Antioxidant Activity of Endophytic Fungi Isolated from Calotropis procera L

Background:

Endophytic fungi are microorganisms that colonize inside the plant tissues without causing any disease symptoms. Endophytic fungi isolated from medicinal plants have emerged as an interesting source for the isolation of bioactive compounds. In this study, we selected Calotropis procera, a member of the Asclepiadaceae family commonly called ‘Aak’ to evaluate the antioxidant potential of isolated endophytic fungi. </P><P> Objective: The aim of this study was to assess the total phenolic content (TPC), antioxidant capacity by using different assay and phytochemical screening of endophytic fungi isolated from Calotropis procera (leaves, stem and root). </P><P> Method: Crude ethyl acetate extracts of 20 different endophytic fungi isolated from Calotropis procera were tested for their preliminary phytoconstituents presence, TPC estimation (by Folin–Ciocalteu colorimetric assay) and antioxidant potential [1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, hydrogen peroxide (H2O2) free radical scavenging assay, β-carotene-linoleic free radical scavenging assay, metal chelating assay and xanthine oxidase inhibitory assay].

Results:

Phenols, carbohydrates, saponins, tannins, alkaloids and flavanoids were the main phytoconstituents present in the endophytic fungi. Among the endophytes, Aspergillus nomius showed the highest TPC [72.71±1.67 µg GAE (gallic acid equivalent) /mg dry weight of fungi] and antioxidant activity for DPPH free radical scavenging assay (68.86±0.19%). A high positive linear correlation was found between TPC and xanthine oxidase inhibitory assay (R2-0.890) and between TPC and DPPH free radical scavenging assay (R2-0.839). Aspergillus and Fusarium genus species showed significant antioxidant activity by the different assay.

Conclusion:

The present study revealed some endophytic fungi from Calotropis procera could be a potential source of novel natural antioxidant compounds.

Phytochemical Analysis, Antibacterial and Antioxidant Activity of Calotropis procera and Calotropis gigantea

Background:

Medicinal plants are having immense potential to cure various health ailments and used as drugs and remedies for the treatment of various diseases since civilization. Medicinal property of these plants lies in their secondary metabolites which covered various classes like phenols, alkaloids, flavonoids, tannins, etc. Besides this, these secondary metabolites serve as a prototype to synthesize the new synthetic drugs. </P><P> Objective: The present study was carried out to evaluate the antioxidant and antibacterial activity of leaves extracts of Calotropis procera and Calotropis gigantea and characterization of their bioactive metabolites by Fourier Transform Infrared (FTIR) spectroscopy and Gas Chromatography-Mass Spectroscopy (GC-MS).

Methods:

Methanol, petroleum ether and water were used for the extract preparation using cold percolation method. Antibacterial activity was assessed by agar well diffusion assay. The antioxidant activity of both the plants of Calotropis species was carried out by using different assay. Phytochemical analysis was carried out by using FTIR spectroscopy and GC-MS analysis.

Results:

Methanol extract of both the plants was found to possess highest antioxidant potential in comparison to other extracts. Methanol extract of C. gigantea and aqueous extract of C. procera showed the maximum antibacterial activity against the tested bacterial strains. FTIR analysis of plants extracts indicates the presence of phenolic compounds, alkanes, carboxylic acids, aldehydes, aliphatic and aromatic amines, allene, sulfoxides, phenyl ester nitrocompounds and imines. GC-MS analysis of C. procera aqueous extract showed the presence of R-limonene, mannosamine, tridecane, 1-bromo-, 2-propenoic acid, tridecyl ester, pentatriacontane and 1-hexacosene as major phytochemicals. C. gigantea methanol extract indicated the presence of hentriacontane, eicosane, 3,3- dimethylnonadecane, pentacosane, 1-hexacosene, pentatriacontane and clocortolone as major phytochemicals.

Conclusion:

This study provides a systematic base for isolation of the novel bioactive phytochemicals from the Calotropis plant species and to evaluate their efficacy especially for antioxidant and antibacterial activities.

Oleuropein-Rich Olive Leaf Extracts May Ameliorate Consequences of Glucose-Induced Oxidative Stress in Hep G2 Cells

Olive leaf is reputed to have many beneficial health-related properties, often attributed to the iridoid glycoside oleuropein. In this work, the composition and antioxidant activity of oleuropein-rich olive leaf extracts prepared by ultrasonication were investigated. In addition, the influence of the extracts on Hep G2 cells subjected to glucose-induced oxidative stress was examined. The prepared extracts acted as antioxidants rich in oleuropein and other polyphenols. Among them, the extract prepared at 20°C using 100% ethanol was the most effective radical scavenger, antioxidant and metal chelator. It also contained the largest amount of oleuropein and other phenolic constituents. The extract prepared at 20°C using 70% ethanol, on the other hand, showed the best yield among the investigated extracts. Furthermore, it was able to preserve the cell-membrane integrity of Hep G2 cells subjected to glucose-induced oxidative stress, as well as to maintain intracellular concentration of glutathione and the activity of glutathione S-transferase on the levels comparable to those observed in non-stressed cells. The presented results demonstrate that oleuropein-rich olive leaf extracts can effectively ameliorate the consequences of glucose-induced oxidative stress in liver cells.

Salidroside, a Chemopreventive Glycoside, Diminishes Cytotoxic Effect of Cisplatin in Vitro

Natural products represent the source or the inspiration for the majority of the active ingredients of medicines because of their structural diversity and a wide range of biological effects. Our aims in this study were (i) to synthesize enzymatically salidroside (SAL), the most effective phenylethanoid glycoside in Rhodiola species; (ii) to examine its antioxidant capacity using cell-free assays (reducing power, DPPH radicals scavenging and Fe²⁺ -chelating assays); (iii) to assess its DNA-protective potential on plasmid DNA (DNA topology assay) and in HepG2 cells (comet assay) damaged by Fe²⁺ ions and hydrogen peroxide, respectively; and (iv) to investigate the effects of SAL, cisplatin (CDDP) and combined treatments of SAL + CDDP on cell viability (MTT test), level of DNA damage (comet assay), proliferation, cell cycle (flow cytometry) and the expression of signalling molecules associated with cell growth and apoptotic pathways (Western immunoblotting). We found out that SAL manifested low antioxidant and DNA-protective capacity in all assays used. In both parental A2780 and CDDP-resistant A2780/CP human ovarian carcinoma cells, SAL itself exerted in fact no impact on the viability, while in combination with CDDP it showed antagonistic effect supporting the chemopreventive activity on the CDDP-induced cell damage. These results were confirmed by the partial reversal of the cell cycle alterations and the DNA damage level, as well as with partial restoration of cell survival/signalling pathways, when the expression of these molecules partially returned to their proper levels.

Quinine conjugates and quinine analogues as potential antimalarial agents

Malaria is a tropical disease, prevalent in Southeast Asia and Africa, resulting in over half a million deaths annually; efforts to develop new antimalarial agents are therefore particularly important. Quinine continues to play a role in the fight against malaria, but quinoline derivatives are more widely used. Drugs based on the quinoline scaffold include chloroquine and primaquine, which are able to act against the blood and liver stages of the parasite's life cycle. The purpose of this review is to discuss reported biologically active compounds based on either the quinine or quinoline scaffold that may have enhanced antimalarial activity. The review emphasises hybrid molecules, and covers advances made in the last five years. The review is divided into three sections: modifications to the quinine scaffold, modifications to aminoquinolines and finally metal-containing antimalarial compounds.

Assessment of antioxidative, chelating, and DNA-protective effects of selected essential oil components (eugenol, carvacrol, thymol, borneol, eucalyptol) of plants and intact Rosmarinus officinalis oil

Selected components of plant essential oils and intact Rosmarinus officinalis oil (RO) were investigated for their antioxidant, iron-chelating, and DNA-protective effects. Antioxidant activities were assessed using four different techniques. DNA-protective effects on human hepatoma HepG2 cells and plasmid DNA were evaluated with the help of the comet assay and the DNA topology test, respectively. It was observed that whereas eugenol, carvacrol, and thymol showed high antioxidative effectiveness in all assays used, RO manifested only antiradical effect and borneol and eucalyptol did not express antioxidant activity at all. DNA-protective ability against hydrogen peroxide (H2O2)-induced DNA lesions was manifested by two antioxidants (carvacrol and thymol) and two compounds that do not show antioxidant effects (RO and borneol). Borneol was able to preserve not only DNA of HepG2 cells but also plasmid DNA against Fe(2+)-induced damage. This paper evaluates the results in the light of experiences of other scientists.

Anti-Inflammatory Drug Design Using a Molecular Hybridization Approach

The design of new drugs with better physiochemical properties, adequate absorption, distribution, metabolism, and excretion, effective pharmacologic potency and lacking toxicity remains is a challenge. Inflammation is the initial trigger of several different diseases, such as Alzheimer's disease, asthma, atherosclerosis, colitis, rheumatoid arthritis, depression, cancer; and disorders such as obesity and sexual dysfunction. Although inflammation is not the direct cause of these disorders, inflammatory processes often increase related pain and suffering. New anti-inflammatory drugs developed using molecular hybridization techniques to obtain multiple-ligand drugs can act at one or multiple targets, allowing for synergic action and minimizing toxicity. This work is a review of new anti-inflammatory drugs developed using the molecular modification approach.

Antiradical, chelating and antioxidant activities of hydroxamic acids and hydroxyureas

Reactive oxygen species, along with reactive nitrogen species, may play an important role in the pathogenesis and progress of many diseases, including cancer, diabetes and sickle cell disease. It has been postulated that hydroxyurea, one of the main treatments in sickle cell disease, achieves its activity partly also through its antioxidant properties. A series of hydroxyurea derivatives of L- and D-amino acid amides and cycloalkyl-N-aryl-hydroxamic acids was synthesized and investigated for their radical scavenging activity, chelating properties and antioxidant activity. All the compounds showed exceptional antiradical activities. For example, free radical scavenging activities of investigated hydroxyureas were higher than the activity of standard antioxidant, butylated hydroxyanisole (BHA). Moreover, most of the investigated hydroxamic acids were stronger Fe²⁺ ion chelators than quercetin. In addition, the investigated compounds, especially hydroxamic acids, were proven to be excellent antioxidants. They were as effective as BHA in inhibiting β-carotene-linoleic acid coupled oxidation. It is reasonable to assume that the antioxidant activity of the investigated compounds could contribute to their previously proven biological properties as cytostatic and antiviral agents.