Phenolic Profile and Antioxidant Potential of Leaves from Selected Cotoneaster Medik. Species

The antioxidant efficiency of 70% aqueous methanolic extracts from the leaves of twelve selected Cotoneaster Medik. species was evaluated using four complementary in vitro tests based on SET- (single electron transfer) and HAT-type (hydrogen atom transfer) mechanisms (DPPH, FRAP, O2•− and H2O2 scavenging assays). The samples exhibited the dose-dependent responses in all assays with activity parameters of EC50 = 18.5–34.5 µg/mL for DPPH; 0.9–3.8 mmol Fe2+/g for FRAP; SC50 = 27.7–74.8 µg/mL for O2•−; and SC50 = 29.0–91.3 µg/mL for H2O2. Significant linear correlations (|r| = 0.76–0.97, p < 0.01) between activity parameters and total contents of phenolics (5.2%–15.4% GAE) and proanthocyanidins (2.1%–15.0% CYE), with weak or no effects for chlorogenic acid isomers (0.69%–2.93%) and total flavonoids (0.28%–1.40%) suggested that among the listed polyphenols, proanthocyanidins are the most important determinants of the tested activity. UHPLC-PDA-ESI-QTOF-MS analyses led to detection of 34 polyphenols, of which 10 B-type procyanidins, 5 caffeoylquinic acids and 14 flavonoids were identified. After cluster analysis of the data matrix, the leaves of Cotoneaster zabelii, C. splendens, C. bullatus, C. divaricatus, C. hjelmqvistii and C. lucidus were selected as the most promising sources of natural antioxidants, exhibiting the highest phenolic levels and antioxidant capacities, and therefore the greatest potential for pharmaceutical applications

An Overview of the Genus Cotoneaster (Rosaceae): Phytochemistry, Biological Activity, and Toxicology

Traditional herbal medicines have become a subject of global importance with both medical and economic implications. The regular consumption of herbal drugs has led to serious concerns regarding their quality, effectiveness, and safety. Thus, relevant scientific evidence has become an important criterion for the acceptance of traditional health claims. The genus Cotoneaster Medikus provides numerous species traditionally used in Asian medicine for the treatment of haemorrhoids, diabetes, and cardiovascular diseases. This review summarises the achievements of modern research on the Cotoneaster taxa, including ethnobotany, phytochemistry, pharmacology, and toxicology. To date, more than 90 compounds have been isolated or analytically identified in Cotoneaster leaves, fruits, flowers or twigs. These phytochemicals are categorised into flavonoids, procyanidins, phenolic acids, cotonefurans, cyanogenic glycosides, triterpenes, sterols, fatty acids, volatile compounds, and carbohydrates, and many of them are responsible for Cotoneaster pharmacological properties including antioxidant, anti-inflammatory, antimicrobial, antiparasitic, hepatoprotective, anti-diabetic or anti-dyslipidaemic activity. In order to ensure the safety of pharmaceutical applications, the potential toxicity of Cotoneaster extracts has also been investigated. In conclusion, this systematic review provides an important reference base for further study into the various medical applications of both the dry extracts and pure isolates of Cotoneaster species

Effect of Sucrose Concentration on Rhaponticum carthamoides (Willd.) Iljin Transformed Root Biomass, Caffeoylquinic Acid Derivative, and Flavonoid Production

Rhaponticum carthamoides (Willd.) Iljin is a rare, pharmacopoeial, and medicinal plant, endemic to Siberia and endangered due to the massive collection of raw material from the natural habitat. The aim of the current study was to estimate the effect of sucrose concentration (0–7%) on R. carthamoides transformed root growth and on caffeoylquinic acid derivative (CQA) and flavonoid production. Sucrose in higher concentrations may induce osmotic stress and thus may affect secondary metabolism in plants. It was revealed that sucrose concentration influenced R. carthamoides transformed root biomass and modified the phenolic compound metabolic pathway. However, the dynamics of both processes varied significantly. The optimal sucrose level was different for biomass accumulation and the biosynthesis of specialized metabolite. The highest dry weight of roots was achieved for 7% sucrose (31.17 g L−1 of dry weight), while 1% sucrose was found to be optimal for phenolic acid and flavonoid production. Considering the dry weight increase and metabolite accumulation, 3% sucrose was revealed to give optimal yields of CQAs (511.1 mg L−1) and flavonoids (38.9 mg L−1). Chlorogenic acid, 3,5-, 4,5-di-O-caffeoylquinic acids, 1,4,5-O-tricaffeoylquinic acid, and a tentatively-identified tricaffeoylquinic acid derivative 1 were found to be the most abundant specialized metabolites among the identified CQAs. Our findings indicate that R. carthamoides transformed roots may be an efficient source of CQA derivatives, with valuable health-promoting activities

Chemical profile and antibacterial activity of essential oils from leaves and fruits of Gaultheria procumbens L. cultivated in Poland

Essential oils (EOs) of Gaultheria procumbens were obtained by hydrodistillation with the yield of 1.30% ± 0.05 (v/dw) for leaves and 2.68% ± 0.08 (v/dw) for fruits. The GC-FID/MS analysis led to the identification of 64 volatile components, among which 27 were found in leaf EO, 49 in fruit EO, and 59 analytes were detected for the first time in G. procumbens. Methyl salicylate, which is known as a potent anti-inflammatory agent, was the dominant component making up to 97.5% and 99.8% of the total fruit and leaf EOs, respectively. The remaining volatiles of the leaves included mainly monoterpenes (α-pinene, β-pinene, limonene), methyl-o-anisate, massoilactone, spiro[4,5]decane-1-one, and aliphatic alcohols (heptan-2-ol, octan-1-ol), while the fruit EO contained apart from the dominant aliphatic and aromatic alcohols (benzyl alcohol, heptan-2-ol, p-cymen-7-ol) also carboxylic acids (3-hydroxyphenylacetic acid, heptanoic acid, octanoic acid) and aldehydes (hexanal, furfural, pent-4-enal). The antibacterial activity of the EOs was evaluated using a microdilution broth method against twelve reference strains, as well as clinical and environmental isolates. Differences between activity parameters of both EOs were not statistically significant (p > 0.05) for most tested bacteria. On the other hand, both EOs were significantly more effective against Gram-negative (MIC, 8.2-10.0 mg/mL) than Gram-positive bacteria (MIC, 13.5-16.7 mg/mL). Leaves and especially fruits of G. procumbens cultivated in Poland were proved valuable sources of methyl salicylate-rich EOs of moderate antibacterial activity, which, therefore, could partly explain the traditional use of the plant materials and the EOs in the treatment of bacterial infections-related inflammatory disorders

The Inhibition of α-Glucosidase, α-Amylase and Protein Glycation by Phenolic Extracts of Cotoneaster bullatus, Cotoneaster zabelii, and Cotoneaster integerrimus Leaves and Fruits: Focus on Anti-Hyperglycemic Activity and Kinetic Parameters

Cotoneaster species have gained significant importance in traditional Asian medicine for their ability to prevent and treat hyperglycemia and diabetes. Therefore, in this study, some aspects of the beneficial health effects of hydromethanolic extracts of C. bullatus, C. zabelii, and C. integerrimus leaves and fruits were evaluated, including their influence on α-glucosidase, α-amylase, and nonenzymatic protein glycation. The activity was investigated in relation to the polyphenolic profile of the extracts determined by UV-spectrophotometric and HPLC-PDA-fingerprint methods. It was revealed that all leaf and fruit extracts are a promising source of biological components (caffeic acid pseudodepsides, proanthocyanidins, and flavonols), and the leaf extracts of C. bullatus and C. zabelii contain the highest levels of polyphenols (316.3 and 337.6 mg/g in total, respectively). The leaf extracts were also the most effective inhibitors of digestive enzymes and nonenzymatic protein glycation. IC50 values of 8.6, 41.8, and 32.6 µg/mL were obtained for the most active leaf extract of C. bullatus (MBL) in the α-glucosidase, α-amylase, and glycation inhibition tests, respectively. In the kinetic study, MBL was displayed as a mixed-type inhibitor of both enzymes. The correlations between the polyphenol profiles and activity parameters (|r| > 0.72, p < 0.05) indicate a significant contribution of proanthocyanidins to the tested activity. These results support the traditional use of Cotoneaster leaves and fruits in diabetes and suggest their hydrophilic extracts be promising in functional applications

Assessment of the Content of Phenolics and Antioxidant Action of Inflorescences and Leaves of Selected Species from the Genus Sorbus Sensu Stricto

In order to find new sources of natural antioxidants, the antioxidant potential of 70% methanolic extracts from the inflorescences and leaves of 16 species from the genus Sorbus s.s. was evaluated using two complementary in vitro test systems: the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging assay and the AAPH [2,2¢-azobis-(2-amidinopropane)dihydrochloride]-induced linoleic acid (LA) peroxidation test. The radical-scavenging capacities of the extracts towards the DPPH radical were in the range of 0.25-0.86 millimolar Trolox® equivalents/g dry weight. They were significantly correlated (r = -0.8089, p < 0.001) with the results of the LA-peroxidation test, indicating the Sorbus extracts to be universal antioxidants. Significant linear correlations were also found between the different antioxidant potentials and total phenolic contents as estimated by the Folin-Ciocalteu method and further verified by serial determinations of proanthocyanidins, chlorogenic acid isomers and flavonoids (çrêin the range of 0.71-0.95, p < 0.001). Cluster analysis of the data matrix identified the ten samples (inflorescences of S. aucuparia, S. pohuashanensis, S. decora, S. koehneana, S. commixta, S. gracilis, and S. sitchensis, and the leaves of S. wilfordii, S. pogonopetala, and S. gracilis) exhibiting the highest antioxidant activity and total phenolic levels and therefore the greatest potential as effective sources for natural health products

Assessment of the Content of Phenolics and Antioxidant Action of Inflorescences and Leaves of Selected Species from the Genus Sorbus Sensu Stricto

In order to find new sources of natural antioxidants, the antioxidant potential of 70% methanolic extracts from the inflorescences and leaves of 16 species from the genus Sorbus s.s. was evaluated using two complementary in vitro test systems: the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging assay and the AAPH [2,2¢-azobis-(2-amidinopropane)dihydrochloride]-induced linoleic acid (LA) peroxidation test. The radical-scavenging capacities of the extracts towards the DPPH radical were in the range of 0.25-0.86 millimolar Trolox® equivalents/g dry weight. They were significantly correlated (r = -0.8089, p &lt; 0.001) with the results of the LA-peroxidation test, indicating the Sorbus extracts to be universal antioxidants. Significant linear correlations were also found between the different antioxidant potentials and total phenolic contents as estimated by the Folin-Ciocalteu method and further verified by serial determinations of proanthocyanidins, chlorogenic acid isomers and flavonoids (çrêin the range of 0.71-0.95, p &lt; 0.001). Cluster analysis of the data matrix identified the ten samples (inflorescences of S. aucuparia, S. pohuashanensis, S. decora, S. koehneana, S. commixta, S. gracilis, and S. sitchensis, and the leaves of S. wilfordii, S. pogonopetala, and S. gracilis) exhibiting the highest antioxidant activity and total phenolic levels and therefore the greatest potential as effective sources for natural health products

Polyphenolic Profile, Antioxidant and Anti-Inflammatory Activity of Eastern Teaberry (Gaultheria procumbens L.) Leaf Extracts

Dry leaf extracts of eastern teaberry (Gaultheria procumbens L.) were evaluated as a source of bioactive phytocompounds through systematic activity testing and phytochemical profiling. The antioxidant efficiency was tested using five complementary in vitro models (DPPH; FRAP; linoleic acid (LA) peroxidation assay; O2•− and H2O2 scavenging tests) in parallel with standard antioxidants. The 75% methanol extract and its diethyl ether, ethyl acetate (EAF), n-butanol and water fractions exhibited the dose-dependent responses in all assays, with the highest capacities found for EAF (DPPH EC50 = 2.9 μg/mL; FRAP = 12.8 mmol Fe2+/g; IC50 for LA-peroxidation = 123.9 μg/mL; O2•− SC50 = 3.9 μg/mL; H2O2 SC50 = 7.2 μg/mL). The EAF had also the highest anti-inflammatory activity in the inhibition tests of lipoxygenase and hyaluronidase (60.14% and 21.83% effects, respectively, at the concentration of 100 μg/mL). Activity parameters of the extracts correlated strongly with the levels of total phenolics (72.4–270.7 mg GAE/g), procyanidins, and phenolic acids, whereas for flavonoids only moderate effects were observed. Comprehensive UHPLC-PDA-ESI-MS3 and HPLC-PDA studies led to the identification of 35 polyphenols with a procyanidin A-type trimer, quercetin 3-O-glucuronide, isomers of caffeoylquinic acids, and (‒)-epicatechin being the dominant components. Significant activity levels, high phenolic contents and high extraction yields (39.4%–42.5% DW for defatted and crude methanol extracts, respectively) indicate the value of eastern teaberry leaves as bioactive products

Establishment of Hairy Root Cultures of Rhaponticum carthamoides (Willd.) Iljin for the Production of Biomass and Caffeic Acid Derivatives

The aim of the study was to obtain transformed roots of Rhaponticum carthamoides and evaluate their phytochemical profile. Hairy roots were induced from leaf explants by the transformation of Agrobacterium rhizogenes strains A4 and ATCC 15834. The best response (43%) was achieved by infection with A4 strain. The effects of different liquid media (WPM, B5, SH) with full and half-strength concentrations of macro- and micronutrients on biomass accumulation of the best grown hairy root line (RC3) at two different lighting conditions (light or dark) were investigated. The highest biomass (93 g L−1 of the fresh weight after 35 days) was obtained in WPM medium under periodic light. UPLC-PDA-ESI-MS3 and HPLC-PDA analyses of 80% aqueous methanol extracts from the obtained hairy roots revealed the presence of eleven caffeoylquinic acids and their derivatives and five flavonoid glycosides. The production of caffeoylquinic acids and their derivatives was elevated in hairy roots grown in the light. Only light-grown hairy roots demonstrated the capability for the biosynthesis of such flavonoid glycosides as quercetagetin, quercetin, luteolin, and patuletin hexosides. Chlorogenic acid, 3,5-di-O-caffeoylquinic acid and a tentatively identified tricaffeoylquinic acid derivative were detected as the major compounds present in the transformed roots

Valorization of the Photo-Protective Potential of the Phytochemically Standardized Olive (Olea europaea L.) Leaf Extract in UVA-Irradiated Human Skin Fibroblasts

Leaves of Olea europaea are a by-product of the olive oil industry and a dietary supplement with acknowledged antioxidant and anti-inflammatory activity but underestimated photoprotective potential. We investigated the protective effects of the LC-PDA-MS/MS standardized ethanol-water extract of olive leaves (OLE), containing 26.2% total phenols and 22.2% oleuropein, with underlying mechanisms against the UVA-induced oxidative damage in human dermal fibroblasts. Hs68 cells were pre-treated (24 h) with OLE (2.5&ndash;25 &mu;g/mL) or the reference antioxidants, quercetin and ascorbic acid (25 &mu;g/mL), followed by irradiation (8 J/cm2). OLE significantly reduced the UVA-induced DNA damage and reactive oxygen species (ROS) overproduction and increased the thioredoxin reductase (TrxR) expression and post-radiation viability of fibroblasts by inhibiting their apoptosis. Both intrinsic and extrinsic apoptotic signaling pathways appeared to be inhibited by OLE, but the activity of caspase 9 was the most reduced. We hypothesized that the TrxR up-regulation by OLE could have prevented the UVA-induced apoptosis of Hs68 cells. In addition, a significant decrease in UVA-induced secretion levels of tumor necrosis factor (TNF-&alpha;) and interleukin-2 (IL-2) was shown in human lymphocyte culture in response to OLE treatment. In summary, our results support the beneficial effect of OLE in an in vitro model and indicate its great potential for use in the cosmetic and pharmaceutical industry as a topical photoprotective, antioxidant, and anti-inflammatory agent