Plant Products in the Prevention of Diabetes Mellitus.

The beneficial effect of plants in treating diabetes is not only well-known in traditional medicine but also confirmed in numerous scientific studies. The basic platform for testing the potential antidiabetic activity of traditionally known plants and their bioactive compounds is a set of in vitro, in vivo experiments, clinical trials, and molecular docking studies. Basic assays usually measure enzyme inhibitory activity (α-amylase and α-glucosidase) and other aspects related to diabetes mellitus disease. Recently, the use of plant-derived compounds has proven useful in treating diabetes and reducing complications resulting from high blood sugar levels. The main goal is to establish an action mechanism of plant extracts or active compounds to find new antidiabetic drugs with less toxicological properties. This work aims to collect data and discuss the newest results in the area of plant extracts, compounds, and antidiabetic effects using in vitro, in vivo, and in silico models. The data covered in this review include plant extracts, polyphenols, terpenoids, saponins, phytosterols, and other bioactive compounds, with some of the investigated plants being less known. Isolation of new compounds might be a plentiful source for treatment and prevention of diabetes mellitus. Clinical trials with adequate monitoring give the best results of plants' product efficacy and safety. Many studies have confirmed the importance of patent and use of medicinal herbs in the treatment of diabetes.

Traditional uses of autochthonous medicinal and ritual plants and other remedies for health in Eastern and South-Eastern Serbia.

ETHNOPHARMACOLOGICAL RELEVANCE: River and mountain regions in Eastern and South-Eastern Serbia are geographically interesting and, historically they represent an important resource of plants used as food, spices and as remedies for treating many diseases. Different cultures have lived in these regions for ages. They have used wild plants and the methods of their preparation and application, which has remained throughout the history and now is passed on from generation to generation. The aim of the study is a survey of herbal drug uses for the specific ailment categories and their comparison between the two research regions. METHODS: Semi-structured anonymous ethnobotanical interviews were conducted. The interviews took place in the River Timok region and Mountain Svrljig region as they make two of the most interesting centers of plant biodiversity. Volunteers in the Timok region were 64 median age and in the Svrljig region - 73 median age. People were interviewed about the local names of plants, the preparation process and about which disease the plants were used for. RESULTS AND DISCUSSION: 161 Respondents from 10 Timok and 10 Svrljig municipality villages were interviewed and 2199 use-reports were recorded. The results of the ethnobotanical research showed 195 plant taxa from the Timok and Svrljig regions. In the Timok region, the recorded species were classified into 47 families and in the Svrljig region they were classified into 64 families. Out of 195 taxa used for medicinal purposes, only 52 species are also included in the European Pharmacopoeia 9.0. The most commonly used plants in Timok region were Hypericum spp., Matricaria chamomilla, Mentha x piperita, Urtica dioica, Juglans regia, while the residents of Svrljig region most frequently used Satureja montana, Sambucus nigra, Polygonum aviculare, Marrubium vulgare and Teucrium chamaedrys. Different statistical analyzes showed that Vlachs used more medical specimens per person than Serbs in the Timok region. The study demonstrated that female informants treated more body organs with medical species per person than male informants. There was a significant difference between the male and female respondents of the Svrljig region in terms of organ systems for which they used certain plant species. CONCLUSION: The ethnopharmacological study showed a great importance of medicinal plants in the daily life of local communities. According to the analysis, it can be concluded that the village population of the Timok and Svrljig regions use medicinal plants to treat digestive tract problems rather than seeking professional medical attention in health facilities. The aerial part and rhizome of Elymus repens are used for digestive problems in both the Timok and Svrljig regions, and the use of this plant in for the treatment of digestive tract problems is not mentioned in the similar studies conducted in the Balkan region. Also, it can be observed that the population of the two different regions mainly use different herbal drugs to treat the same systems. The reason for that is the availability of certain plants that grow in the two different areas - river and mountain area.

Chemical characterization, in vitro biological activity of essential oils and extracts of three Eryngium L. species and molecular docking of selected major compounds.

Many Eryngium species have been traditionally used as ornamental, edible or medicinal plants. The gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) analyses have shown that the major compounds in the aerial parts were spathulenol (in E. campestre and E. palmatum oils) and germacrene D (in E. amethystinum oil). The main compounds in the root oil were nonanoic acid, 2,3,4-trimethylbenzaldehyde and octanoic acid for E. campestre, E. amethystinum and E. palmatum, respectively. All the oils expressed the highest potential against Gram-positive bacteria Staphylococcus aureus as well as Gram-negative Klebsiella pneumoniae and Proteus mirabilis. Molecular docking analysis was used for determining a potential antibacterial activity mechanism of compounds present in the essential oils. Molecular docking confirmed that the binding affinity of spathulenol to the active site of tyrosyl-tRNA synthetase was the highest among the tested dominant compounds. Regarding the total phenolic content (determined by the Folin-Ciocalteu assay) and flavonoid content (evaluated using aluminum nitrate nonahydrate), the highest amount was found in the ethyl acetate extract of E. palmatum. The results of DPPH and ABTS assay indicated that the highest antioxidant activity was present in the water extract of E. amethystinum. Extracts of the aerial parts presented as minimum inhibitory concentration (MIC) expressed the activity in the range 0.004-20.00 mg/mL, with the highest activity exhibited by the acetone and ethyl acetate extracts against Proteus mirabilis. The obtained results suggest that Eryngium species may be considered a beneficial native source of the compounds with antioxidant and antimicrobial properties.

Research on Chemical Composition and Biological Properties Including Antiquorum Sensing Activity of Angelica pancicii Vandas Aerial Parts and Roots.

The essential oil, different extracts, and isolated compounds of Angelica pancicii Vandas (Apiaceae) were investigated for the first time. The GC-FID and GC-MS analyses revealed sesquiterpenoids as the main constituents of A. pancicii essential oil of aerial parts with bornyl acetate (8.08%), n-octanol (5.82%), kessane (4.26%), and ß-selinene (4.26%) as the main constituents. Analysis of methanol extracts, using an HPLC-DAD/ESI-ToF-MS system, showed a total of 52 compounds in the aerial parts and 53 in the roots, indicating coumarins as the main constituents. In addition, new chromone (1) and six known furanocoumarins (2-7) were isolated from the roots and structurally elucidated by combined spectroscopic methods. The aerial part extracts exhibited higher polyphenolic contents and antioxidant activity evaluated by three radical scavenging assays. Using a microwell dilution method, the strongest antibacterial activity profiles were determined for ethanol and methanol root extracts (minimum bactericidal concentrations (MBCs) = 0.25-3.00 mg/mL), which were comparable to the activity of streptomycin (MBCs = 0.34-1.24 mg/mL), while the strongest antibacterial compound of A. pancicii was oxypeucedanin hydrate (MBCs = 0.50-8.00 mg/mL). Antifungal potential was in moderate extent, and the highest activity was obtained for root methanol extract (minimum fungicidal concentrations (MFCs) = 4.00-14.00 mg/mL). Tested sub-minimum inhibitory concentrations (subMICs) of the extracts and isolated compounds inhibited selected Pseudomonas aeruginosa PAO1 virulence determinants. The most reduced growth of P. aeruginosa colony was in the presence of isolated oxypeucedanin. Ethanol (17.36-46.98%) and methanol (34.54-52.43%) root extracts showed higher anti-biofilm activity compared to streptomycin (49.40-88.36%) and ampicillin (56.46-92.16%).

Heracleum orphanidis: chemical characterisation, and comparative evaluation of antioxidant and antimicrobial activities with specific interest in the influence on Pseudomonas aeruginosa PAO1.

GC-FID and GC-MS were used to determine the chemical composition of the essential oil of the aerial parts of Heracleum orphanidis Boiss. Also, the HPLC-DAD/ESI-ToF-MS profile of the methanol extracts of aerial parts and roots was determined. The main components of the essential oil were n-octanol, octyl hexanoate and n-octyl acetate, while coumarins were the most prevalent compounds in methanol extracts. An evaluation of antioxidant activity showed that the methanol and aqueous extracts of the aerial parts had the highest potential. In terms of antimicrobial activity determined by microdilution assays, the essential oil and methanol extract of the roots showed the greatest effectiveness. The colonies of Pseudomonas aeruginosa PAO1 treated with H. orphanidis samples produced less toxic pyocyanin, showed lower twitching and flagella mobility and biofilm formatting was reduced. The analyses in this study showed the considerable biological potential of H. orphanidis considering free radicals and various pathogenic strains, including the wild type of P. aeruginosa.

Biological activity of Pinus nigra terpenes--evaluation of FtsZ inhibition by selected compounds as contribution to their antimicrobial activity.

In the current work, in vitro antioxidant, antibacterial, and antifungal activites of the needle terpenes of three taxa of Pinus nigra from Serbia (ssp. nigra, ssp. pallasiana, and var. banatica) were analyzed. The black pine essential oils showed generally weak antioxidative properties tested by two methods (DPPH and ABTS scavenging assays), where the highest activity was identified in P. nigra var. banatica (IC50=25.08 mg/mL and VitC=0.67 mg (vitamin C)/g when tested with the DPPH and ABTS reagents, respectively). In the antimicrobial assays, one fungal (Aspergilus niger) and two bacterial strains (Staphylococcus aureus and Bacillus cereus) showed sensitivity against essential oils of all three P. nigra taxa. The tested oils have been shown to possess inhibitory action in the range from 20.00 to 0.62 mg/mL, where var. banatica exhibited the highest and ssp. nigra the lowest antimicrobial action. In order to determine potential compounds that are responsible for alternative mode of action, molecular docking simulations inside FtsZ (a prokaryotic homolog of tubulin) were performed. Tested compounds were the most abundant terpenoid (germacrene D-4-ol) and its structurally similar terpene (germacrene D), both present in all three essential oils. It was determined that the oxygenated form of the molecule creates stable bonds with investigated enzyme FtsZ, and that this compound, through this mechanism of action participates in the antimicrobial activity.

Antimicrobial and antioxidant activities of essential oils of Satureja thymbra growing wild in Libya.

The composition of essential oil isolated from Satureja thymbra, growing wild in Libya, was analyzed by GC and GC-MS. The essential oil was characterized by γ-terpinene (39.23%), thymol (25.16%), p-cymene (7.17%) and carvacrol (4.18%) as the major constituents. Antioxidant activity was analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. It possessed strong antioxidant activity (IC50 = 0.0967 mg/mL). The essential oil was also screened for its antimicrobial activity against eight bacterial and eight fungal species, showing excellent antimicrobial activity against the microorganisms used, in particular against the fungi. The oil of S. thymbra showed bacteriostatic activity at 0.001-0.1 mg/mL and was bactericidal at 0.002-0.2 mg/mL; fungistatic effects at 0.001-0.025 mg/mL and fungicidal effects at 0.001-0.1 mg/mL. The main constituents thymol, carvacrol and γ-terpinene also showed strong antimicrobial activity. The commercial fungicide bifonazole showed much lower antifungal activity than the tested oil.

Essential oil composition of Cachrys cristata--a rare and endangered species in the flora of Serbia.

Cachrys cristata DC. (Apiaceace) is a rare and critically endangered species in the flora of Serbia. Essential oil isolated by hydrodistillation from the aerial parts and fruits of this species was analyzed using combined GC and GC/MS. The oil from the aerial parts was rich in sesquiterpenes (45.7%) and oxygenated sesquiterpenes (32.9%), while the fruit oil consisted of a higher percentage of sesquiterpenes (48.3%) and oxygenated sesquiterpenes (36.7%). The dominant constituents in the oil from aerial parts were phytol (13.1%) and germacrene D (12.9%), while in the fruit oil suberosin (19.7%) and germacrene D (12.3%) were the most abundant.