Polyphenol-Rich Larix decidua Bark Extract with Antimicrobial Activity against Respiratory-Tract Pathogens: A Novel Bioactive Ingredient with Potential Pharmaceutical and Nutraceutical Applications

Larch (Larix decidua) bark is a sawmill waste, traditionally used for antiseptic, expectorant and dermatological (wound healing, eczema, psoriasis) purposes. In this work, we developed a food-grade dry larch bark extract (LBE) from sawmill by-products using hydro-alcoholic extraction. The antibacterial activity of LBE was evaluated against respiratory-tract pathogens, i.e. Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Haemophilus influenza, and it was compared to that of grapefruit seed extract (GSE), a commercially available raw material commonly proposed as antibacterial ingredient for over-the-counter products. Procyanidins (PACs) and other polyphenols contents in LBE were determined by HPLC-FLD-MS and HPLC-DAD-MSn, respectively. The antimicrobial activity of LBE and GSE was assessed using the micro-plate dilution technique in concentration range of 2–200 µg/mL, and the safety of these dosages was assessed in cellular and animal models. LBE showed considerable contents of PACs (15% w/w; especially B-type) and other polyphenols (3.8% w/w), among which the characteristic spiropolyphenols larixinol and epilarixinol were identified, together with the flavonoids isoquercitrin and rutin, already reported as growth inhibitors of different respiratory-tract pathogens. LBE showed higher antimicrobial activity compared to GSE, demonstrated by a growth inhibition range of 10–40% towards five of six strains tested, compared to 10–15% of GSE. These results suggest that LBE may represent a natural and sustainable source of active compounds with antibacterial activity for pharmaceutical and nutraceutical applications.

Callus cultures of Thymus vulgaris and Trifolium pratense as a source of geroprotectors

Introduction. Geroprotectors are biologically active substances that inhibit the aging process. Many plant species are natural geroprotectors. For instance, Thymus vulgaris and Trifolium pratense are callus cultures with strong geroprotective properties. Study objects and methods. The present research featured T. vulgaris and T. pratense grown in vitro on various nutrient media. Their extracts were obtained by aqueous-alcoholic extraction using the following parameters: water-ethanol solvent Se = 30, 50, and 70 %; temperature Te = 30, 50, and 70°C; time τe = 2, 4, and 6 h. The quantitative and qualitative analysis was based on high-performance liquid mass spectrometry, gas mass spectrometry, and thin-layer chromatography. Results and discussion. The optimal extraction parameters for T. vulgaris were τe = 4 h, Te = 50°C, Se = 70 %, for T. pratense – τe = 6 h, Te = 70°C, Se = 70 %. The chromatography detected flavonoids, phenylpropanoids, simple phenols, higher fatty acids, mono- and sesquiterpenes, and aliphatic hydrocarbons. T. vulgaris appeared to have the highest content of thymol (23.580 ± 1.170 mg/mL); its thymol, apigenin, gallic, chlorogenic, and caffeic components demonstrated geroprotective properties. The extract of T. pratense possessed the highest rutin content (10.05 ± 0.35 mg/mL), and it owed its geroprotective characteristics to rutin, chlorogenic and p-coumaric acids. Conclusion. The callus cultures of T. vulgaris and T. pratense proved to be promising sources of geroprotective biologically active substances.

Optimization of Aqueous and Alcoholic Extraction of Phenolic and Antioxidant Compounds From Caper (Capparis spinosa L.) Roots Assisted by Ultrasound Waves

Background: Herbals are rich in effective compounds such as phenolic and antioxidant. Various methods are developed to extract these compounds, including Soxhlet, maceration, microwave, and ultrasound. The extraction method affects the quantity and quality of materials. Objectives: The current study aimed to investigate the effect of ultrasound in phenolic and antioxidants compounds extraction from Caper roots. Methods: Response surface methodology (RSM) and Box-Behnken design were used to optimize the two extraction parameters, including extraction time (10, 25, and 40 min) and ultrasound power (40%, 70%, 100 %) by aqueous and alcoholic solvents. Results: Based on the results, ultrasound power was more effective than the extraction time. A direct association was observed between ultrasound power and the extraction time with the total extraction. The optimum aqueous and alcoholic extraction condition for phenolic and antioxidant compounds extraction were as follow: extraction time 36 min and ultrasound power 91 percent. Total phenolic content was obtained 14.96 mg/g with aqueous solvent and 17.24 mg/g with alcoholic solvent, and IC50 was 52.17 µg/mg with aqueous solvent and 40.20 µg/mg with alcoholic solvent. Conclusions: Overall, alcoholic extracts had more phenolic and antioxidant compounds than aqueous extracts.

STRUCTURE-ACTIVITY-RELATIONSHIP OF THE POLYPHENOLS INHIBITION OF α-AMYLASE AND α-GLUCOSIDASE

Background: Diabetes mellitus (DM) is a serious public health challenge, projected by WHO to be one of the 7 leading cause of death by 2030. Medicinal plants have been demonstrated to be useful in DM local management because of polyphenols present in these plants. For an alternative treatment approach especially with polyphenols-rich herbs, knowledge of comparative efficacy of the polyphenols will lead to enhanced therapy especially in postprandial hyperglyceamic control. Materials and Methods: Vegetative parts of Anacardium occidentale, Abelmoschus ecsulentus and Ceiba pentandra, prominent in the local management of DM were identified, collected and subjected to alcoholic extraction. From the crude extracts were isolated agathisflavone, quercetin 3-O-glucoside, quercetin 3-O-diglycoside, mangiferin, isomangiferin and pentagalloyl glucose, belonging to flavonoid, xanthones and tannins structural classes. These polyphenols were evaluated for their potentials to inhibit both α-glucosidase and α-amylase. Physicochemical parameters of the polyphenols were evaluated and molecular docking experiments were carried out to gain insight into the observed inhibitory activity. Results: quercetin 3-O-glucosidewas the most potent of the polyphenols against the two enzymes. Increase in the number of phenolic hydroxyl group did not increase the inhibitory activity and neither computation of the binding energies with the enzymes nor physicochemical parameters of the polyphenols could explain the observed inhibitory activity against the enzymes, across the structural classes. Thus, only the bioassay against the enzymes α-glucosidase and α-amylase correlated well with the use of the plants in treating diabetic mellitus Conclusion: Medicinal plants rich in quercetin 3-O-glycoside may have better treatment outcomes in postprandial hyperglycaemia control.

Toxicity of the hydroalcoholic extracts of fruit leaves from the Peruvian Amazon in Artemia salina

Background: Medicinal plants have been used since ancient times, receiving interest in their healing potential because of their active components. The Amazon rainforest in the east of Peru has great diversity of flora, especially monocotyledons (Cocos nucifera, Mauritia flexuosa and Coffea spp.) and dicotyledons (Theobroma cacao L. and Musa spp. The toxicity of the hydroalcoholic extract of plant leaves from the Peruvian Amazon in Artemia salina was evaluated in this study. Methods: The leaves of the plants Cocos nucifera, Mauritia flexuosa, Theobroma cacao L., Coffea sp, and Musa sp were collected in the district of Cacatachi, San Martín. Phytochemical analysis of the leaves was carried out to identify their active components. The eggs of Artemia salina were provided by the Department of Animal Physiology of Universidad Nacional de Trujillo. The hydro-alcoholic extraction was carried out via the maceration method using 300 g of leaves and 500 mL of 96% ethanol for 15 days in agitation. The solutions were taken to a vertical rotavapor to obtain dry extracts and concentrations of 10, 100 and 1000 μL/ml were prepared. To test toxicity, 10 larvae were given the extract for each plant species and concentration in triplicate. The CL50 toxicity of Artemia salina samples was classified as: ˃ 1000 μL/ml (non-toxic), 500˂CL50 ≤ 1000 (low toxicity), 100˂CL50 ≤ 500 (moderate toxicity), CL50˂100 (high toxicity). Results: It was observed that Mauritia flexuosa and Musa sp. at concentrations of 10, 100 and 1000 μL/ml have high, medium and low toxicity, respectively. However, only low toxicity was observed in Cocos nucifera, Theobroma cacao L. and Coffea sp. Conclusions: It can be concluded that the obtained results are in accordance with other studies that examined different extracts, indicating that if a sample is non-toxic to Artemia salina, then its effects will also be similar in humans.

The Inhibitory Effect of some Plant Extracts on some Pathogenic Bacteria

The purpose of the present study is to assay the inhibitory effect of five concentrations 10, 20, 30, 40 and 50 % of the aqueous and alcoholic extracts for leaves of the Sidr (Zizyphusspin-csit) and Eucalyptus leaves (Eucalyptus camaldulensis) in vitro, against the three types of the experimental bacteria, which Escherichia coli, Staphylococcus aureus and Salmonella typhimurium for their clinical importance as common, pathogenic in urinary tract infection by using the well diffusion assay method .The results showed that antimicrobial activity depends on kind of extract and tested microorganism. and the most bioactivity was done by methanol extract than the aqueous extract, the methanolic extract of Sidr leaves presented the inhibitory effectiveness of all the species used in this study ,the highest inhibition was 36 mm at 50%concentration against E. coli and methanolic extract of eucalyptus leaves showed an inhibitory effect on the growth of all bacteria except E. coli, showed resistance to the extract, As for the aquatic extracts, all the bacteria species illustrated resistance to the aquatic extracts of the leaves of the Sidr except Staph .aureus Inhibition rates were recorded at 17 and 15 mm at the concentration (30 and 20%), respectively, and the aquatic extracts of Eucalyptus leaves had no inhibitory effect on the growth of all the species used in this study, except S. typhimurium bacteria and all concentrations used. The result of the qualitative chemical detection of the active compounds found in the extract indicated that it s contains, mainly like flavonids, alkaloids, Tannins and phenols, Saponins, Glycosides. in aquatic and alcoholic extraction. http://dx.doi.org/10.25130/tjps.24.2019.010