The influence of the chlorine atom on the biological activity of 2'-hydroxychalcone in relation to the lipid phase of biological membranes - Anticancer and antimicrobial activity.

The study investigates the effect of the presence of a chlorine atom in the 2'-hydroxychalcone molecule on its interaction with model lipid membranes, in order to discern its potential pharmacological activity. Five chlorine derivatives of 2'-hydroxychalcone were synthesized and evaluated against liposomes composed of POPC and enriched with cationic (DOTAP) or anionic (POPG) lipids. The physicochemical properties of the compounds were initially simulated using SwissAdame software, revealing high lipophilicity (ilogP values: 2.79-2.90). The dynamic light scattering analysis of liposomes showed that chloro chalcones induce minor changes in the diameter of liposomes of different surface charges. Fluorescence quenching assays with a TMA-DPH probe demonstrated the strong ability of the compounds to interact with the lipid bilayer, with varying quenching capacities based on chlorine atom position. FTIR studies indicated alterations in carbonyl, phosphate, and choline groups, suggesting a transition area localization rather than deep penetration into the hydrocarbon chains. Additionally, dipole potential reduction was observed in POPC and POPC-POPG membranes, particularly pronounced by derivatives with a chlorine atom in the B ring. Antibacterial and antibiofilm assays revealed enhanced activity of derivatives with a chlorine atom compared to 2'-hydroxychalcone, especially against Gram-positive bacteria. The MIC and MBIC50 values showed increased efficacy in the presence of chlorine with 3'-5'-dichloro-2'-hydroxychalcone demonstrating optimal antimicrobial and antibiofilm activity. Furthermore, antiproliferative assays against breast cancer cell lines indicated higher activity of B-ring chlorine derivatives, particularly against MDA-MB-231 cells. In general, the presence of a chlorine atom in 2'-hydroxychalcone improves its pharmacological potential, with derivatives showing improved antimicrobial, antibiofilm, and antiproliferative activities, especially against aggressive breast cancer cell lines. These findings underscore the importance of molecular structure in modulating biological activity and highlight chalcones with a chlorine as promising candidates for further drug development studies.

The Effect of Methyl-Derivatives of Flavanone on MCP-1, MIP-1ß, RANTES, and Eotaxin Release by Activated RAW264.7 Macrophages.

Chemokines, also known as chemotactic cytokines, stimulate the migration of immune cells. These molecules play a key role in the pathogenesis of inflammation leading to atherosclerosis, neurodegenerative disorders, rheumatoid arthritis, insulin-resistant diabetes, and cancer. Moreover, they take part in inflammatory bowel disease (IBD). The main objective of our research was to determine the activity of methyl-derivatives of flavanone, namely, 2'-methylflavanone (5B), 3'-methylflavanone (6B), 4'-methylflavanone (7B), and 6-methylflavanone (8B), on the releasing of selected cytokines by RAW264.7 macrophages activated by LPS. We determined the concentration of chemokines belonging to the CC chemokine family, namely, MCP-1, MIP-1ß, RANTES, and eotaxin, using the Bio-Plex Magnetic Luminex Assay and the Bio-PlexTM 200 System. Among the tested compounds, only 5B and 6B had the strongest effect on inhibiting the examined chemokines' release by macrophages. Therefore, 5B and 6B appear to be potentially useful in the prevention of diseases associated with the inflammatory process.

Structural investigation of interactions between halogenated flavonoids and the lipid membrane along with their role as cytotoxic agents.

This study focuses on understanding the structural and molecular changes in lipid membranes under the influence of six halogenated flavonoid derivatives differing in the number and position of substitution of chlorine and bromine atoms (D1-D6). Utilizing various analytical techniques, including fluorometric methods, dynamic light scattering (DLS), attenuated Fourier transform infrared spectroscopy (ATR- FTIR), and FT-Raman spectroscopy, the research aims to elucidate the mechanisms underlying the interaction of flavonoids with cell membranes. Additionally, the study includes in silico analyses to explore the physicochemical properties of these compounds and their potential pharmaceutical applications, along with toxicity studies to assess their effects on cancer, normal, and red blood cells. Our study showed the ability of halogenated derivatives to interact mostly with the outer part of the membrane, especially in the lipid heads region however, some of them were able to penetrate deeper into the membrane and affect the fluidity of hydrocarbon chains. The potential to reduce cancer cell viability, the lack of toxicity towards erythrocytes, and the favourable physicochemical and pharmacokinetic properties suggest these halogenated flavonoids potential candidates for exploring their potential for medical use.

Antimicrobial Properties of Flavonoid Derivatives with Bromine, Chlorine, and Nitro Group Obtained by Chemical Synthesis and Biotransformation Studies.

The search for new substances of natural origin, such as flavonoids, is necessary in the fight against the growing number of diseases and bacterial resistance to antibiotics. In our research, we wanted to check the influence of flavonoids with chlorine or bromine atoms and a nitro group on pathogenic and probiotic bacteria. We synthesized flavonoids using Claisen-Schmidt condensation and its modifications, and through biotransformation via entomopathogenic filamentous fungi, we obtained their glycoside derivatives. Biotransformation yielded two new flavonoid glycosides: 8-amino-6-chloroflavone 4'-O-ß-D-(4″-O-methyl)-glucopyranoside and 6-bromo-8-nitroflavone 4'-O-ß-D-(4″-O-methyl)-glucopyranoside. Subsequently, we checked the antimicrobial properties of the aforementioned aglycon flavonoid compounds against pathogenic and probiotic bacteria and yeast. Our studies revealed that flavones have superior inhibitory effects compared to chalcones and flavanones. Notably, 6-chloro-8-nitroflavone showed potent inhibitory activity against pathogenic bacteria. Conversely, flavanones 6-chloro-8-nitroflavanone and 6-bromo-8-nitroflavanone stimulated the growth of probiotic bacteria (Lactobacillus acidophilus and Pediococcus pentosaceus). Our research has shown that the presence of chlorine, bromine, and nitro groups has a significant effect on their antimicrobial properties.

Methoxychalcones as potential anticancer agents for colon cancer: Is membrane perturbing potency relevant?

Chalcones are naturally produced by many plants, and constitute precursors for the synthesis of flavons and flavanons. They were shown to possess antibacterial, antifungal, anti-cancer, and anti- inflammatory properties. The goal of the study was to assess the suitability of three synthetic methoxychalcones as potential anticancer agents. In a panel of colon cancer cell lines they were demonstrated to be cytotoxic, proapoptotic, causing cell cycle arrest, and increasing intracellular level of reactive oxygen species. Anticancer activity of the compounds was not diminished in the presence of stool extract containing microbial enzymes that could change the structure of chalcones. Moreover, methoxychalcones interacted strongly with model phosphatidylcholine membranes as detected by differential scanning calorimetry. Metohoxychalcones particularly affected the properties of lipid domains in giant unilamellar liposomes formed from raft-mimicking lipid composition. This may be of importance since many molecular targets for therapy of metastatic colon cancer are raft-associated receptors (e.g., receptor tyrosine kinases). The importance of membrane perturbing potency of methoxychalcones for their biological activity was additionally corroborated by the results obtained by molecular modelling.

Multienzymatic biotransformation of flavokawain B by entomopathogenic filamentous fungi: structural modifications and pharmacological predictions.

BACKGROUND: Flavokawain B is one of the naturally occurring chalcones in the kava plant (Piper methysticum). It exhibits anticancer, anti-inflammatory and antimalarial properties. Due to its therapeutic potential, flavokawain B holds promise for the treatment of many diseases. However, due to its poor bioavailability and low aqueous solubility, its application remains limited. The attachment of a sugar unit impacts the stability and solubility of flavonoids and often determines their bioavailability and bioactivity. Biotransformation is an environmentally friendly way to improve the properties of compounds, for example, to increase their hydrophilicity and thus affect their bioavailability. Recent studies proved that entomopathogenic filamentous fungi from the genera Isaria and Beauveria can perform O-methylglycosylation of hydroxyflavonoids or O-demethylation and hydroxylation of selected chalcones and flavones. RESULTS: In the present study, we examined the ability of entomopathogenic filamentous fungal strains of Beauveria bassiana, Beauveria caledonica, Isaria farinosa, Isaria fumosorosea, and Isaria tenuipes to transform flavokawain B into its glycosylated derivatives. The main process occurring during the reaction is O-demethylation and/or hydroxylation followed by 4-O-methylglycosylation. The substrate used was characterized by low susceptibility to transformations compared to our previously described transformations of flavones and chalcones in the cultures of the tested strains. However, in the culture of the B. bassiana KCh J1.5 and BBT, Metarhizium robertsii MU4, and I. tenuipes MU35, the expected methylglycosides were obtained with high yields. Cheminformatic analyses indicated altered physicochemical and pharmacokinetic properties in the derivatives compared to flavokawain B. Pharmacological predictions suggested potential anticarcinogenic activity, caspase 3 stimulation, and antileishmanial effects. CONCLUSIONS: In summary, the study provided valuable insights into the enzymatic transformations of flavokawain B by entomopathogenic filamentous fungi, elucidating the structural modifications and predicting potential pharmacological activities of the obtained derivatives. The findings contribute to the understanding of the biocatalytic capabilities of these microbial cultures and the potential therapeutic applications of the modified flavokawain B derivatives.

In Vitro Anti-Inflammatory Activity of Methyl Derivatives of Flavanone.

Inflammation plays an important role in the immune defense against injury and infection agents. However, the inflammatory chronic process may lead to neurodegenerative diseases, atherosclerosis, inflammatory bowel diseases, or cancer. Flavanones present in citrus fruits exhibit biological activities, including anti-oxidative and anti-inflammatory properties. The beneficial effects of flavanones have been found based on in vitro cell cultures and animal studies. A suitable in vitro model for studying the inflammatory process are macrophages (RAW264.7 cell line) because, after stimulation using lipopolysaccharide (LPS), they release inflammatory cytokines involved in the immune response. We determined the nitrite concentration in the macrophage cell culture and detected ROS using chemiluminescence. Additionally, we measured the production of selected cytokines using the Bio-Plex Magnetic Luminex Assay and the Bio-PlexTM 200 System. For the first time, we have shown that methyl derivatives of flavanone inhibit NO and chemiluminescence generated via LPS-stimulated macrophages. Moreover, the tested compounds at 1-20 µM dose-dependently modulate proinflammatory cytokine production (IL-1ß, IL-6, IL-12p40, IL-12p70, and TNF-α) in stimulated RAW264.7 cells. The 2'-methylflavanone (5B) and the 3'-methylflavanone (6B) possess the strongest anti-inflammatory activity among all the tested flavanone derivatives. These compounds reduce the concentration of IL-6, IL-12p40, and IL12p70 compared to the core flavanone structure. Moreover, 2'-methylflavanone reduces TNF-α, and 3'-methylflavanone reduces IL-1ß secreted by RAW264.7 cells.

Biotransformation of Flavonoids with -NO2, -CH3 Groups and -Br, -Cl Atoms by Entomopathogenic Filamentous Fungi.

Combining chemical and microbiological methods using entomopathogenic filamentous fungi makes obtaining flavonoid glycosides possible. In the presented study, biotransformations were carried out in cultures of Beauveria bassiana KCH J1.5, Isaria fumosorosea KCH J2, and Isaria farinosa KCH J2.6 strains on six flavonoid compounds obtained in chemical synthesis. As a result of the biotransformation of 6-methyl-8-nitroflavanone using the strain I. fumosorosea KCH J2, two products were obtained: 6-methyl-8-nitro-2-phenylchromane 4-O-ß-D-(4″-O-methyl)-glucopyranoside and 8-nitroflavan-4-ol 6-methylene-O-ß-D-(4″-O-methyl)-glucopyranoside. 8-Bromo-6-chloroflavanone was transformed by this strain to 8-bromo-6-chloroflavan-4-ol 4'-O-ß-D-(4″-O-methyl)-glucopyranoside. As a result of microbial transformation by I. farinosa KCH J2.6 effectively biotransformed only 8-bromo-6-chloroflavone into 8-bromo-6-chloroflavone 4'-O-ß-D-(4″-O-methyl)-glucopyranoside. B. bassiana KCH J1.5 was able to transform 6-methyl-8-nitroflavone to 6-methyl-8-nitroflavone 4'-O-ß-D-(4″-O-methyl)-glucopyranoside, and 3'-bromo-5'-chloro-2'-hydroxychalcone to 8-bromo-6-chloroflavanone 3'-O-ß-D-(4″-O-methyl)-glucopyranoside. None of the filamentous fungi used transformed 2'-hydroxy-5'-methyl-3'-nitrochalcone effectively. Obtained flavonoid derivatives could be used to fight against antibiotic-resistant bacteria. To the best of our knowledge, all the substrates and products presented in this work are new compounds and are described for the first time.

Novel O-Methylglucoside Derivatives of Flavanone in Interaction with Model Membrane and Transferrin.

Flavonoids were biotransformed using various microorganisms, in order to obtain new compounds with potentially high biological activity. The aim of this work was to determine and compare the biological activity of four novel 6-methylflavanone O-methylglucosides. The tested compounds have the same flavonoid core structure and an attached O-methylglucose and hydroxyl group at different positions of ring A or B. The studies on their biological activity were conducted in relation to phosphatidylcholine membrane, erythrocytes and their membrane, and with human transferrin. These studies determined the compounds' toxicity and their impact on the physical properties of the membranes. Furthermore, the binding ability of the compounds to holo-transferrin was investigated. The obtained results indicate that used compounds bind to erythrocytes, change their shape and decrease osmotic fragility but do not disrupt the membrane structure. Furthermore, the used compounds ordered the area of the polar heads of lipids and increased membrane fluidity. However, the results indicate the binding of these compounds in the hydrophilic region of the membranes, like other flavonoid glycosides. The used flavanones formed complexes with transferrin without inducing conformational changes in the protein's structure. The relationship between their molecular structure and biological activity was discussed.

Regiospecific Hydrogenation of Bromochalcone by Unconventional Yeast Strains.

This research aimed to select yeast strains capable of the biotransformation of selected 2'-hydroxybromochalcones. Small-scale biotransformations were carried out using four substrates obtained by chemical synthesis (2'-hydroxy-2″-bromochalcone, 2'-hydroxy-3″-bromochalcone, 2'-hydroxy-4″-bromochalcone and 2'-hydroxy-5'-bromochalcone) and eight strains of non-conventional yeasts. Screening allowed for the determination of the substrate specificity of selected microorganisms and the selection of biocatalysts that carried out the hydrogenation of tested compounds in the most effective way. It was found that the position of the bromine atom has a crucial influence on the degree of substrate conversion by the tested yeast strains. As a result of the biotransformation of the 2'-hydroxybromochalcones, the corresponding 2'-hydroxybromodihydrochalcones were obtained. The products obtained belong to the group of compounds with high potential as precursors of sweet substances.

Glycosylation of Methylflavonoids in the Cultures of Entomopathogenic Filamentous Fungi as a Tool for Obtaining New Biologically Active Compounds.

Flavonoid compounds are secondary plant metabolites with numerous biological activities; they naturally occur mainly in the form of glycosides. The glucosyl moiety attached to the flavonoid core makes them more stable and water-soluble. The methyl derivatives of flavonoids also show increased stability and intestinal absorption. Our study showed that such flavonoids can be obtained by combined chemical and biotechnological methods with entomopathogenic filamentous fungi as glycosylation biocatalysts. In the current paper, two flavonoids, i.e., 2'-hydroxy-4-methylchalcone and 4'-methylflavone, have been synthesized and biotransformed in the cultures of two strains of entomopathogenic filamentous fungi Isaria fumosorosea KCH J2 and Beauveria bassiana KCH J1.5. Biotransformation of 2'-hydroxy-4-methylchalcone resulted in the formation of two dihydrochalcone glucopyranoside derivatives in the culture of I. fumosorosea KCH J2 and chalcone glucopyranoside derivative in the case of B. bassiana KCH J1.5. 4'-Methylflavone was transformed in the culture of I. fumosorosea KCH J2 into four products, i.e., 4'-hydroxymethylflavone, flavone 4'-methylene-O-ß-d-(4″-O-methyl)-glucopyranoside, flavone 4'-carboxylic acid, and 4'-methylflavone 3-O-ß-d-(4″-O-methyl)-glucopyranoside. 4'-Methylflavone was not efficiently biotransformed in the culture of B. bassiana KCH J1.5. The computer-aided simulations based on the chemical structures of the obtained compounds showed their improved physicochemical properties and antimicrobial, anticarcinogenic, hepatoprotective, and cardioprotective potential.

4'-Methylflavanone Glycosides Obtained Using Biotransformation in the Entomopathogenic Filamentous Fungi Cultures as Potential Anticarcinogenic, Antimicrobial, and Hepatoprotective Agents.

Flavonoid compounds exhibit numerous biological activities and significantly impact human health. The presence of methyl or glucosyl moieties attached to the flavonoid core remarkably modifies their physicochemical properties and improves intestinal absorption. Combined chemical and biotechnological methods can be applied to obtain such derivatives. In the presented study, 4'-methylflavanone was synthesized and biotransformed in the cultures of three strains of entomopathogenic filamentous fungi, i.e., Isaria fumosorosea KCH J2, Beauveria bassiana KCH J1.5, and Isaria farinosa KCH J2.1. The microbial transformation products in the culture of I. fumosorosea KCH J2, flavanone 4'-methylene-O-ß-D-(4″-O-methyl)-glucopyranoside, 2-phenyl-(4'-hydroxymethyl)-4-hydroxychromane, and flavanone 4'-carboxylic acid were obtained. Biotransformation of 4'-methylflavanone in the culture of B. bassiana KCH J1.5 resulted in the formation of one main product, i.e., flavanone 4'-methylene-O-ß-D-(4″-O-methyl)-glucopyranoside. In the case of I. farinosa KCH J2.6 as a biocatalyst, three products, i.e., flavanone 4'-methylene-O-ß-D-(4″-O-methyl)-glucopyranoside, flavanone 4'-carboxylic acid, and 4'-hydroxymethylflavanone 4-O-ß-D-(4″-O-methyl)-glucopyranoside were obtained. The Swiss-ADME online simulations confirmed the increase in water solubility of 4'-methylflavanone glycosides and analyses performed using the Way2Drug Pass Online prediction tool indicated that flavanone 4'-methylene-O-ß-D-(4″-O-methyl)-glucopyranoside and 4'-hydroxymethylflavanone 4-O-ß-D-(4″-O-methyl)-glucopyranoside, which had not been previously reported in the literature, are promising anticarcinogenic, antimicrobial, and hepatoprotective agents.

The modulating effect of methoxy-derivatives of 2'-hydroxychalcones on the release of IL-8, MIF, VCAM-1 and ICAM-1 by colon cancer cells.

Colon cancer is one of the leading causes of death in the world. The search for effective and minimally invasive methods of treating colon cancer is the aim of modern medicine. Chalcones and their derivatives have shown an anticancer activity. The aim of the study was to evaluate the effect of methoxy-derivatives of 2'-hydroxychalcones: 2'-hydroxy-3"-methoxychalcone (TJ3), 2'-hydroxy-2"-methoxychalcone (TJ6) and 2'-hydroxy-4"-metoxychalcone (TJ7) at the concentrations of 10 µM and 25 µM on the release of IL-8, MIF, VCAM-1, ICAM-1 by colon cancer SW480 and SW620 cell lines. The cytokines and adhesion molecules were detected using the Bio-Plex Magnetic Luminex Assay and the Bio-Plex Suspension Array System. Our results showed that all tested methoxy-derivatives of 2'-hydroxychalcone compounds significantly reduced ICAM-1 released by SW480 cancer cells. The tested compounds at both concentrations did not significantly affect VCAM-1 released by SW480 and SW620 cancer cell lines. All methoxy-derivatives significantly reduced the concentration of MIF in dose dependent manner on SW480 cells. The TJ3 at the concentration of 25 µM significantly decreased IL-8 secreted by SW480 and SW620 cancer cells. Our results demonstrated that tested methoxy-derivatives of 2'-hydroxychalcones showed modulating effect on colon cancer cells.

Fungal Biotransformation of 2'-Methylflavanone and 2'-Methylflavone as a Method to Obtain Glycosylated Derivatives.

Methylated flavonoids are promising pharmaceutical agents due to their improved metabolic stability and increased activity compared to unmethylated forms. The biotransformation in cultures of entomopathogenic filamentous fungi is a valuable method to obtain glycosylated flavones and flavanones with increased aqueous solubility and bioavailability. In the present study, we combined chemical synthesis and biotransformation to obtain methylated and glycosylated flavonoid derivatives. In the first step, we synthesized 2'-methylflavanone and 2'-methylflavone. Afterwards, both compounds were biotransformed in the cultures of two strains of entomopathogenic filamentous fungi Beauveria bassiana KCH J1.5 and Isaria fumosorosea KCH J2. We determined the structures of biotransformation products based on NMR spectroscopy. Biotransformations of 2'-methyflavanone in the culture of B. bassiana KCH J1.5 resulted in three glycosylated flavanones: 2'-methylflavanone 6-O-ß-d-(4″-O-methyl)-glucopyranoside, 3'-hydroxy-2'-methylflavanone 6-O-ß-d-(4″-O-methyl)-glucopyranoside, and 2-(2'-methylphenyl)-chromane 4-O-ß-d-(4″-O-methyl)-glucopyranoside, whereas in the culture of I. fumosorosea KCH J2, two other products were obtained: 2'-methylflavanone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside and 2-methylbenzoic acid 4-O-ß-d-(4'-O-methyl)-glucopyranoside. 2'-Methylflavone was effectively biotransformed only by I. fumosorosea KCH J2 into three derivatives: 2'-methylflavone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside, 2'-methylflavone 4'-O-ß-d-(4″-O-methyl)-glucopyranoside, and 2'-methylflavone 5'-O-ß-d-(4″-O-methyl)-glucopyranoside. All obtained glycosylated flavonoids have not been described in the literature until now and need further research on their biological activity and pharmacological efficacy as potential drugs.

New Glycosylated Dihydrochalcones Obtained by Biotransformation of 2'-Hydroxy-2-methylchalcone in Cultures of Entomopathogenic Filamentous Fungi.

Flavonoids, including chalcones, are more stable and bioavailable in the form of glycosylated and methylated derivatives. The combined chemical and biotechnological methods can be applied to obtain such compounds. In the present study, 2'-hydroxy-2-methylchalcone was synthesized and biotransformed in the cultures of entomopathogenic filamentous fungi Beauveria bassiana KCH J1.5, Isaria fumosorosea KCH J2 and Isaria farinosa KCH J2.6, which have been known for their extensive enzymatic system and ability to perform glycosylation of flavonoids. As a result, five new glycosylated dihydrochalcones were obtained. Biotransformation of 2'-hydroxy-2-methylchalcone by B. bassiana KCH J1.5 resulted in four glycosylated dihydrochalcones: 2'-hydroxy-2-methyldihydrochalcone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside, 2',3-dihydroxy-2-methyldihydrochalcone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside, 2'-hydroxy-2-hydroxymethyldihydrochalcone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside, and 2',4-dihydroxy-2-methyldihydrochalcone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside. In the culture of I. fumosorosea KCH J2 only one product was formed-3-hydroxy-2-methyldihydrochalcone 2'-O-ß-d-(4″-O-methyl)-glucopyranoside. Biotransformation performed by I. farinosa KCH J2.6 resulted in the formation of two products: 2'-hydroxy-2-methyldihydrochalcone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside and 2',3-dihydroxy-2-methyldihydrochalcone 3'-O-ß-d-(4″-O-methyl)-glucopyranoside. The structures of all obtained products were established based on the NMR spectroscopy. All products mentioned above may be used in further studies as potentially bioactive compounds with improved stability and bioavailability. These compounds can be considered as flavor enhancers and potential sweeteners.

Interaction of 4'-methylflavonoids with biological membranes, liposomes, and human albumin.

The aim of the study was to compare the impact of three synthesized chemical compounds from a group of methylated flavonoids, i.e. 2'-hydroxy-4-methylchalcone (3), 4'-methylflavanone (4), and 4'-methylflavone (5), on a red blood cell membranes (RBCMs), phosphatidylcholine model membranes (PC), and human serum albumin (HSA) in order to investigate their structure-activity relationships. In the first stage of the study, it was proved that all of the compounds tested do not cause hemolysis of red blood cells and, therefore, do not have a toxic effect. In biophysical studies, it was shown that flavonoids have an impact on the hydrophilic and hydrophobic regions of membranes (both RBCMs and PC) causing an increase in packing order of lipid heads and a decrease in fluidity, respectively. Whereas, on the one hand, the magnitude of these changes depends on the type of the compound tested, on the other hand, it also depends on the type of membrane. 4'-Methylflavanone and 4'-methylflavone are located mainly in the hydrophilic part of lipid membranes, while 2'-hydroxy-4-methylchalcone has a greater impact on the hydrophobic area. A fluorescence quenching study proved that compounds (3), (4) and (5) bind with HSA in a process of static quenching. The binding process is spontaneous whereas hydrogen bonding interactions and van der Waals forces play a major role in the interaction between the compounds and HSA.

Biotransformation of 5,7-Methoxyflavones by Selected Entomopathogenic Filamentous Fungi.

5,7-Dimethoxyflavone, a chrysin derivative, occurs in many plants and shows very low toxicity, even at high doses. On the basis of this phenomenon, we biotransformed a series of methoxy-derivatives of chrysin, apigenin, and tricetin obtained by chemical synthesis. We used entomopathogenic fungal strains with the confirmed ability of simultaneous hydroxylation/demethylation and glycosylation of flavonoid compounds. Both the amount and the place of attachment of the methoxy group influenced the biotransformation rate and the product's amount nascent. Based on product and semi-product structures, it can be concluded that they are the result of cascading transformations. Only in the case of 5,7,3',4',5'-pentamethoxyflavone, the strains were able to attach a sugar molecule in place of the methoxy substituent to give 3'-O-ß-d-(4″-O-methylglucopyranosyl)-5,7,4',5'-tetramethoxyflavone. However, we observed the tested strains' ability to selectively demethylate/hydroxylate the carbon C-3' and C-4' of ring B of the substrates used. The structures of four hydroxyl-derivatives were determined: 4'-hydroxy-5,7-dimethoxyflavone, 3'-hydroxy-5,7-dimethoxyflavone, 3'-hydroxy-5,7,4',5'-tetramethoxyflavone, and 5,7-dimethoxy-3',4'-dihydroxyflavone (5,7-dimethoxy-luteolin).

The Callus of Phaseolus coccineus and Glycine max Biotransform Flavanones into the Corresponding Flavones.

In vitro plant cultures are gaining in industrial importance, especially as biocatalysts and as sources of secondary metabolites used in pharmacy. The idea that guided us in our research was to evaluate the biocatalytic potential of newly obtained callus tissue towards flavonoid compounds. In this publication, we describe new ways of using callus cultures in the biotransformations. In the first method, the callus cultures grown on a solid medium are transferred to the water, the reaction medium into which the substrate is introduced. In the second method, biotransformation is carried out on a solid medium by growing callus cultures. In the course of the research, we have shown that the callus obtained from Phaseolus coccineus and Glycine max is capable of converting flavanone, 5-methoxyflavanone and 6-methoxyflavanone into the corresponding flavones.

Biotransformation of Methoxyflavones by Selected Entomopathogenic Filamentous Fungi.

The synthesis and biotransformation of five flavones containing methoxy substituents in the B ring: 2'-, 3'-, 4'-methoxyflavones, 2',5'-dimethoxyflavone and 3',4',5'-trimethoxyflavone are described. Strains of entomopathogenic filamentous fungi were used as biocatalysts. Five strains of the species Beauveria bassiana (KCh J1.5, J2.1, J3.2, J1, BBT), two of the species Beauveria caledonica (KCh J3.3, J3.4), one of Isaria fumosorosea (KCh J2) and one of Isaria farinosa (KCh KW 1.1) were investigated. Both the number and the place of attachment of the methoxy groups in the flavonoid structure influenced the biotransformation rate and the amount of nascent products. Based on the structures of products and semi-products, it can be concluded that their formation is the result of a cascading process. As a result of enzymes produced in the cells of the tested strains, the test compounds undergo progressive demethylation and/or hydroxylation and 4-O-methylglucosylation. Thirteen novel flavonoid 4-O-methylglucosides and five hydroxy flavones were isolated and identified.

New 6,19-oxidoandrostan derivatives obtained by biotransformation in environmental filamentous fungi cultures.

BACKGROUND: Steroid compounds with a 6,19-oxirane bridge possess interesting biological activities including anticonvulsant and analgesic properties, bacteriostatic activity against Gram-positive bacteria and selective anti-glucocorticoid action, while lacking mineralocorticoid and progestagen activity. RESULTS: The study aimed to obtain new derivatives of 3ß-acetyloxy-5α-chloro-6,19-oxidoandrostan-17-one by microbial transformation. Twelve filamentous fungal strains were used as catalysts, including entomopathogenic strains with specific activity in the transformation of steroid compounds. All selected strains were characterised by high biotransformation capacity for steroid compounds. However, high substrate conversions were obtained in the cultures of 8 strains: Beauveria bassiana KCh BBT, Beauveria caledonica KCh J3.4, Penicillium commune KCh W7, Penicillium chrysogenum KCh S4, Mucor hiemalis KCh W2, Fusarium acuminatum KCh S1, Trichoderma atroviride KCh TRW and Isaria farinosa KCh KW1.1. Based on gas chromatography (GC) and nuclear magnetic resonance (NMR) analyses, it was found that almost all strains hydrolysed the ester bond of the acetyl group. The strain M. hiemalis KCh W2 reduced the carbonyl group additionally. From the P. commune KCh W7 and P. chrysogenum KCh S4 strain cultures a product of D-ring Baeyer-Villiger oxidation was isolated, whereas from the culture of B. bassiana KCh BBT a product of hydroxylation at the 11α position and oxidation of the D ring was obtained. Three 11α-hydroxy derivatives were obtained in the culture of I. farinosa KCh KW1.1: 3ß,11α-dihydroxy-5α-chloro-6,19-oxidoandrostan-17-one, 3ß,11α,19-trihydroxy-5α-chloro-6,19-oxidoandrostan-17-one and 3ß,11α-dihydroxy-5α-chloro-6,19-oxidoandrostan-17,19-dione. They are a result of consecutive reactions of hydrolysis of the acetyl group at C-3, 11α- hydroxylation, then hydroxylation at C-19 and its further oxidation to lactone. CONCLUSIONS: As a result of the biotransformations, seven steroid derivatives, not previously described in the literature, were obtained: 3ß-hydroxy-5α-chloro-6,19-oxidoandrostan-17-one, 3ß,17α-dihydroxy-5α-chloro-6,19-oxidoandrostane, 3ß-hydroxy-5α-chloro-17α-oxa-D-homo-6,19-oxidoandrostan-17-one, 3ß,11α-dihydroxy-5α-chloro-17α-oxa-D-homo-6,19-oxidoandrostan-17-one and the three above-mentioned 11α-hydroxy derivatives. This study will allow a better understanding and characterisation of the catalytic abilities of individual microorganisms, which is crucial for more accurate planning of experiments and achieving more predictable results.