Antibacterial, antioxidant and enzyme inhibition activity capacities of Doronicum macrolepis (FREYN&SINT): An endemic plant from Turkey

The essential oil chemical composition of a sicilian (Italy) accession of Doronicum caucasicum M. Bieb

Doronicum is a relatively small genus belonging to the tribe Senecioneae (Fam. Asteraceae), distributed in Asia, Europe, and North Africa. Some of its species are considered toxic due to the presence of pyrrolizidine alkaloids whereas some other ones are largely utilised in the ethnopharmacology of several countries. In the present study, the essential oil composition of a Sicilian accession of Doronicum caucasicum M. Bieb (syn. D. orientale Hoffm.), not previously investigated, is particularly rich in sesquiterpene hydrocarbons (80.3%) with germacrene D (58.9%), α-humulene (8.8%), and β-caryophyllene (6.5%) as main metabolites. A comparison with all the essential oils from Doronicum taxa studied so far has been carried out.

Nascent pharmacological advancement in adamantane derivatives

The adamantane moiety has attracted significant attention since its discovery in 1933 due to its remarkable structural, chemical, and medicinal properties. This molecule has a notable impact in the therapeutic field because of its "add-on" lipophilicity to any pharmacophoric moieties. As in the case of molecular hybridization, in which one pharmacophore is attached to another one(s) with a probability of increasing the biological activity, adding an adamantane unit improves the absorption distribution, metabolism and excretion properties of the resultant hybrid molecule. This review summarizes various reports highlighting the biological activities of adamantane-based synthetic compounds and their structure-activity relationship study. The information presented in this review may open up possible dimensions for adamantane-based drug development and discovery in the pharmaceutical industry after proper structural modifications.

Determination of Antioxidant, Anti-Alzheimer, Antidiabetic, Antiglaucoma and Antimicrobial Effects of Zivzik Pomegran-ate (Punica granatum)—A Chemical Profiling by LC-MS/MS)

Zivzik pomegranate (Punica granatum) has recently sparked considerable interest due to its nutritional and antioxidant properties. To evaluate the antioxidant capacities of P. granatum juice, ethanol (EEZP), and water (WEZP) extracts from peel and seed, the antioxidant methods of 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical (ABTS•+) scavenging, 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH•) scavenging, Fe3+-2,4,6-tris(2-pyridyl)-S-triazine (TPTZ) reducing, Fe3+ reducing, and Cu2+ reducing methods were used. The antioxidant capacities of samples were compared with the most commonly used synthetic antioxidants, i.e., BHA, BHT, α-tocopherol, and Trolox. In terms of setting an example, the IC50 values of EEZP for ABTS•+ and DPPH• scavenging activities were found to be lower than standards, at 5.9 and 16.1 μg/mL, respectively. The phenolic and flavonoid contents in EEZP peel were 59.7 mg GAE/g and 88.0 mg QE/g, respectively. Inhibition of α-glycosidase, α-amylase, acetylcholinesterase, and human carbonic anhydrase II (hCA II) enzymes was also investigated. EEZP demonstrated IC50 values of 7.3 μg/mL against α-glycosidase, 317.7 μg/mL against α-amylase, 19.7 μg/mL against acetylcholinesterase (AChE), and 106.3 μg/mL against CA II enzymes. A total of 53 phenolic compounds were scanned, and 30 compounds were determined using LC-MS/MS. E. coli and S. aureus bacteria were resistant to all four antibiotics used as standards in hospitals.

A Comparative Study of Chemical Profiling and Biological Effects of Doronicum orientale Extracts

In this study, phytochemical and pharmacological screening of the aerial part and roots extracts from Doronicum orientale Hoffm. (Asteraceae) was carried out. Plant extracts were obtained using solvents of different polarity (hexane, ethyl acetate, ethanol, ethanol/water, water) for selection the most optimal solvent for the extraction of active compounds. For instance, the extracts yielded total phenolic and flavonoid contents in the range of 12.13-45.67 mg GAE/g and 0.75-12.44 mg QE/g, respectively, while the total antioxidant capacity of the extracts determined by the phosphomolybdenum assay ranged from 0.88-2.53 mmol TE/g. HPLC/MS/MS analysis revealed 5-caffeoylquinic acid (2.52-337.05 μg/g) and 3,5-dicaffeoylquinic acid (3.12-299.36 μg/g) to be the major components present in the investigated extracts. Antioxidant activity in terms of radical scavenging ability of the extracts ranged from 0.82-45.56 mg TE/g in DPPH assay and from 5.07-104.58 mg TE/g in ABTS assay. The tested extracts were found to inhibit acetylcholinesterase (aerial part: 0.50-2.33 mg GALAE/g; roots: 0.40-2.43 mg GALAE/g), while with the exception of the water extracts, the other extracts showed butyrylcholinesterase inhibition (aerial part: 2.46-5.02 mg GALAE/g; root: 2.93-4.17 mg GALAE/g). Overall, this study presented an interesting scope of this species in phytomedicine with preliminary data demonstrating some of the tested extracts to possess high bioactive contents, antioxidant potential and enzyme inhibitory activity. Thus, additional investigations are necessary to confirm their safety in herbal drug applications.

Chemical Constituents and Biological Properties of Genus Doronicum (Asteraceae)

The genus Doronicum, belonging to tribe Senecioneae (Fam. Asteraceae), is found mainly in the Asia, Europe and North Africa. This genus of plant has always been used in traditional medicinal treatments due to the many biological properties shown such as killing parasitic worms and for relieving constipation, as well as to improve heart health, to alleviate pain and inflammation, to treat insect bites, etc. According to the World Flora the genus Doronicum contains 39 subordinate taxa.^[1-3] The purpose of this article, which covers data published from 1970 to 2021 with more than 110 articles, aims to carry out a complete and critical review of the Doronicum genus, examining traditional uses and reporting the antioxidant, antimicrobial, anti-inflammatory and antitumor activity shown from crude extracts or essential oils, and from single isolated compounds. Furthermore, critical considerations of the published data have been highlighted by comparing them with the results obtained from species of other genus belonging to the Asteraceae family.

Natural Compounds With Antimicrobial and Antiviral Effect and Nanocarriers Used for Their Transportation

Due to the increasing prevalence of life-threatening bacterial, fungal and viral infections and the ability of these human pathogens to develop resistance to current treatment strategies, there is a great need to find and develop new compunds to combat them. These molecules must have low toxicity, specific activity and high bioavailability. The most suitable compounds for this task are usually derived from natural sources (animal, plant or even microbial). In this review article, the latest and most promising natural compounds used to combat bacteria, filamentous fungi and viruses are presented and evaluated. These include plant extracts, essential oils, small antimicrobial peptides of animal origin, bacteriocins and various groups of plant compounds (triterpenoids; alkaloids; phenols; flavonoids) with antimicrobial and antiviral activity. Data are presented on the inhibitory activity of each natural antimicrobial substance and on the putative mechanism of action against bacterial and fungal strains. The results show that among the bioactive compounds studied, triterpenoids have significant inhibitory activity against coronaviruses, but flavonoids have also been shown to inhibit SARS-COV-2. The last chapter is devoted to nanocarriers used to improve stability, bioavailability, cellular uptake/internalization, pharmacokinetic profile and reduce toxicity of natural compunds. There are a number of nanocarriers such as liposomes, drug delivery microemulsion systems, nanocapsules, solid lipid nanoparticles, polymeric micelles, dendrimers, etc. However, some of the recent studies have focused on the incorporation of natural substances with antimicrobial/antiviral activity into polymeric nanoparticles, niosomes and silver nanoparticles (which have been shown to have intrinsic antimicrobial activity). The natural antimicrobials isolated from animals and microorganisms have been shown to have good inhibitory effect on a range of pathogens, however the plants remain the most prolific source. Even if the majority of the studies for the biological activity evaluation are in silico or in vitro, their internalization in the optimum nanocarriers represents the future of “green therapeutics” as shown by some of the recent work in the field.

Polyacrylamide-Metilcellulose Hydrogels Containing Aloe barbadensis Extract as Dressing for Treatment of Chronic Cutaneous Skin Lesions

Chronic wounds are severe breaks in the skin barrier that fail to heal in an acceptable time-frame, thus preventing the complete restoration of the tissue’s anatomical and functional integrity, increasing the likelihood of infections and apoptosis. Hydrogels are known as a drug delivery system and have the potential to cover wounds and burns on the skin. Aloe barbadensis contains over 75 different bioactive compounds which are responsible for its anti-inflammatory and antimicrobial properties. In this study, the polyacrylamide-co-methylcellulose hydrogel containing Aloe barbadensis were developed. The extract was prepared from lyophilized Aloe barbadensis, using methanolic extraction, characterized by high performance liquid chromatography and incorporated into the hydrogels. These Aloe barbadensis hydrogels were characterized by degree of swelling, Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermal profiling using thermogravimetric analysis. The minimum inhibitory concentration test was done on the Aloe barbadensis extract to evaluate its antibacterial and antifungal activity in vitro. The Aloe barbadensis hydrogels and were shown to swell to almost 2000% of their original sizes. The Fourier-transform infrared spectroscopy indicated the presence of bands characteristic of Aloe barbadensis and hydrogel polymers. The basic hydrogel showed greater thermal stability than the hydrogels with Aloe barbadensis. The minimum inhibitory concentration showed inhibition of the growth of S. aureus and Salmonella spp. at specific concentrations. The hydrogel therefore presents itself as an excellent potential curative cover of cutaneous lesions.