Browsing by Author "Lauberte, Līga"

Now showing 1 - 7 of 7
  • No Thumbnail Available
    Item
    Anti-Inflammatory, Anti-Bacterial, and Anti-Fungal Activity of Oligomeric Proanthocyanidins and Extracts Obtained from Lignocellulosic Agricultural Waste
    (2023-01-15) Andersone, Anna; Janceva, Sarmite; Lauberte, Līga; Ramata-Stunda, Anna; Nikolajeva, Vizma; Zaharova, Natalija; Rieksts, Gints; Telesheva, Galina; Laboratory of Finished Dosage Forms
    It has now been proven that many pathogens that cause infections and inflammation gradually mutate and become resistant to antibiotics. Chemically synthesized drugs treating inflammation most often only affect symptoms, but side effects could lead to the failure of human organs’ functionality. On the other hand, plant-derived natural compounds have a long-term healing effect. It was shown that sea buckthorn (SBT) twigs are a rich source of biologically active compounds, including oligomeric proanthocyanidins (PACs). This study aimed to assess the anti-pathogenic and anti-inflammatory activity of water/ethanol extracts and PACs obtained from the lignocellulosic biomass of eight SBT cultivars. The anti-pathogenic activity of extracts and PACs was studied against pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus cereus and fungus Candida albicans in 96-well plates by the two-fold serial broth microdilution method. The anti-bacterial activity of purified PACs was 4 and 10 times higher than for water and water/ethanol extracts, respectively, but the extracts had higher anti-fungal activity. Purified PACs showed the ability to reduce IL-8 and IL-6 secretion from poly-I:C-stimulated peripheral blood mononuclear cells. For the extracts and PACs of SBT cultivar ‘Maria Bruvele’ in the concentration range 0.0313–4.0 mg/mL, no toxic effect was observed.
  • No Thumbnail Available
    Item
    Antibacterial Activity of Tanacetum vulgare L. Extracts against Clinical Isolates of Bovine Mastitis
    (2023-03) Šukele, Renāte; Bārzdiņa, Ance; Koka, Rudīte; Skadins, Ingus; Lauberte, Līga; Brangule, Agnese; Kovalcuka, Liga; Bandere, Dace; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Department of Biology and Microbiology; Laboratory of Finished Dosage Forms
    A bovine mastitis is an infectious disease, which is usually treated with antibiotics. Alternatively, herbal medicine has been proposed due to bacterial resistance. The aim of this study was to determine the antibacterial activity of the acetonic and ethanolic extracts of dried flowers and leaves of Tanacetum vulgare L. against bovine mastitis-inducing clinical isolates such as Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus, and reference cultures of S. aureus and E. coli. The extracts of T. vulgare showed partial antibacterial activity against tested strains of S. aureus. The MIC and MBC values of a 70% ethanol extract of flowers (MIC = 3.4 mg/mL, MBC = 3.4–6.8 mg/mL) were lower than for the 70% ethanol extract of leaves (MIC = 15.7–31.4 mg/mL, MBC = 62.9–125.9 mg/mL). The flower extracts showed low activity against E. coli (MIC = 53.9 mg/mL, MBC = 53.9–107.8 mg/mL) and S. agalactiae (MIC, MBC = 53.9 mg/mL). T. vulgare leaf extracts had minimal antibacterial effects against Streptococcus strains (MIC = 31.4–62.9 mg/mL, MBC = 53.9–125.9 mg/mL) and Serratia liquefaciens (MIC, MBC = 125.9 mg/mL). However, flower extracts had a higher phenolic content that did not correlate with antibacterial effects. T. vulgare flower and leaf extracts could be combined to obtain broader antibacterial effects.
  • No Thumbnail Available
    Item
    Antidiabetic Properties of the Root Extracts of Dandelion (Taraxacum officinale) and Burdock (Arctium lappa)
    (2024-04-03) Zolotova, Daria; Teterovska, Renāte; Bandere, Dace; Lauberte, Līga; Niedra, Santa; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Laboratory of Finished Dosage Forms
    Several preclinical studies suggest the potential of edible plants in controlling blood sugar levels and stabilizing diet. The goals of the study were to examine, analyze, and describe whether there are chemical compounds in dandelion and burdock roots that could have antidiabetic properties. The 70% ethyl alcohol and lyophilizate extracts (AE and LE, respectively), were used, and analyses were carried out on their total polysaccharide (TP), total phenolic content (TPC), tannin, and inulin. The antioxidant activity of extracts was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, and hypoglycemic properties were based on α-amylase activity. Liquid chromatography–mass spectrometry was used for the tentative identification of the chemical components. Qualitative techniques confirmed the presence of inulin in both roots. Analysis of TPC, tannin content, DPPH assay, and α-amylase activity revealed higher values for burdock compared to dandelion. However, dandelion exhibited higher TP content. Burdock contained a small amount of tannin, whereas the tannin content in dandelion was insignificant. All LE consistently exhibited higher values in all analyses and assays for all roots compared to AE. Despite burdock root showing overall better results, it is uncertain whether these plants can be recommended as antidiabetic agents without in vivo studies.
  • No Thumbnail Available
    Item
    A Comparative Assessment of Sea Buckthorn (Hippophae rhamnoides L.) Pruning Waste as a Potential Source of Serotonin
    (2024-02) Janceva, Sarmīte; Andersone, Anna; Lauberte, Līga; Zaharova, Natalija; Krasiļņikova, Jeļena; Rieksts, Gints; Laboratory of Finished Dosage Forms; Department of Human Physiology and Biochemistry
    Sea buckthorn (Hippophae rhamnoides L.) twigs, remaining after harvesting and pruning, are an underutilized and little-explored biomass resource. This study investigated the content of serotonin in 10 sea buckthorn cultivars (‘Maria Bruvele’, ‘Botanicheskaya Lubitelskaya’, ‘Tatiana’, ‘Otto’, ‘Leikora’, ‘Duet’, ‘Clara’, ‘Lord’, ‘Eva’, ‘Tarmo’) for the first time, and for further adjustment of the extraction conditions, cultivar ‘Maria Bruvele’ was extracted by water and water/ethanol solution with 20-25, 50, 70, and 96% ethanol at different temperatures. The results showed that 50% water/ethanol solutions are the most suitable for extraction, which makes it possible to increase the yield of serotonin by 1.3-fold. The 2-year-old twigs and bark from ‘Maria Bruvele’ collected in autumn contained higher serotonin content compared to spring-collected biomass. Serotonin sequential purification allowed the serotonin content in the fraction to increase to 26%/DM. The serotonin-rich fraction showed antimicrobial activity against gram-positive and gram-negative bacteria. In tests with salivary amylase, a serotonin-rich fraction at the amount of 0.1-0.4 mg/mL of saliva, under normal physiological conditions, tended to increase amylase activity, resulting in acceleration of starch degradation to glucose. Thus, the results support further study of the serotonin fraction for the treatment of people having underweight, malnutrition, and malabsorption conditions.
  • No Thumbnail Available
    Item
    The Effect of Microcrystalline Cellulose–CaHPO4 Mixtures in Different Volume Ratios on the Compaction and Structural–Mechanical Properties of Tablets
    (2024-03-05) Mohylyuk, Valentyn; Paulausks, Artūrs; Radzins, Oskars; Lauberte, Līga; Laboratory of Finished Dosage Forms; Department of Orthodontics
    Using microcrystalline cellulose (MCC) with plastic behaviour and calcium phosphate anhydrous (CaHPO4) with brittle behaviour under compaction is very popular in the pharmaceutical industry for achieving desirable structural–mechanical properties of tablet formulations. Thus, mixtures of specific grades of MCC and CaHPO4 were tested in volume proportions of 100-0, 75-25, 50-50, 25-75, and 0-100 at a constant weight-by-weight concentration of sodium stearyl fumarate lubricant, utilizing a state-of-the-art benchtop compaction simulator (STYL’One Nano). Tablet formulations were prepared at 100, 150, 250, 350, 450, and 500 MPa, and characterized by tabletability profile, ejection force profile, proportion–tensile strength relationship, proportion–porosity relationship, pressure–displacement, and elastic recovery profiles, as well as by in-/out-of-die Heckel plots and yield pressures. Interestingly, the 25-75 formulation demonstrated a two-stage out-of-die Heckel plot and was additionally investigated with X-ray micro-computed tomography (µCT). By post-processing the µCT data, the degree of brittle CaHPO4 particles falling apart, along with the increasing compression pressure, was quantified by means of the surface area to volume (S/V) ratio. For the 25-75 formulation, the first stage (up to 150 MPa) and second stage (above the 150 MPa) of the out-of-die Heckel plot could be attributed to predominant MCC and CaHPO4 deformation, respectively.
  • No Thumbnail Available
    Item
    Flavonoids in the Spotlight : Bridging the Gap between Physicochemical Properties and Formulation Strategies
    (2023-10-03) Berga, Marta; Logviss, Konstantīns; Lauberte, Līga; Paulausks, Artūrs; Mohylyuk, Valentyn; Laboratory of Finished Dosage Forms
    Flavonoids are hydroxylated polyphenols that are widely distributed in plants with diverse health benefits. Despite their popularity, the bioavailability of flavonoids is often overlooked, impacting their efficacy and the comparison of products. The study discusses the bioavailability-related physicochemical properties of flavonoids, with a focus on the poorly soluble compounds commonly found in dietary supplements and herbal products. This review sums up the values of pKa, log P, solubility, permeability, and melting temperature of flavonoids. Experimental and calculated data were compiled for various flavonoid subclasses, revealing variations in their physicochemical properties. The investigation highlights the challenges posed by poorly soluble flavonoids and underscores the need for enabling formulation approaches to enhance their bioavailability and therapeutic potential. Compared to aglycones, flavonoid glycosides (with sugar moieties) tend to be more hydrophilic. Most of the reviewed aglycones and glycosides exhibit relatively low log P and high melting points, making them “brick dust” candidates. To improve solubility and absorption, strategies like size reduction, the potential use of solid dispersions and carriers, as well as lipid-based formulations have been discussed.
  • No Thumbnail Available
    Item
    Lignocellulosic Waste Compounds for Pancreatic Lipase Inhibition : Preliminary Extraction by Freon, Obtaining of Proanthocyanidins and Testing on Lipase Activity
    (2023-08) Andersone, Anna; Janceva, Sarmite; Lauberte, Līga; Krasiļņikova, Jeļena; Zaharova, Natalija; Nikolajeva, Vizma; Rieksts, Gints; Telysheva, Galina; Department of Human Physiology and Biochemistry
    The twigs of sea buckthorn, blackcurrant, gooseberries, quince, and grapes were evaluated as a promising source of biologically active compounds—proanthocyanidins (PACs). Sea buckthorn twigs had the highest content of PACs (9.2% on dry biomass). Preliminary pretreatment of biomass with freon R134a did not allow an increase in PACs content in the composition of hydrophilic extract but confirmed the value of freon extract as an antibacterial agent against P. aeruginosa and B. cereus. The content of PACs was used as an indicator for assessment of the influence of hydrophilic extracts on pancreatic lipase activity. Under normal physiological conditions, in the presence of bile, the extract, which contained 42.4% of PACs was more effective compared to the extract which contained 17.5% of PACs. At all concentrations (0.2–40 mg of sample/g of pancreatic lipase), it inhibited lipase activity by 33%. Purified PACs were the most effective in inhibiting lipase activity (by 36%). However, in pathological physiological conditions (without bile), the opposite effect on lipase activity was observed. Thus, PACs and extracts can be used as inhibitors of pancreatic lipase only under normal physiological conditions.