Potential Bioactive Constituents Research Articles

UPLC-ESI-Q-TOF-MS/MS analysis of anticancer fractions from Ophiocordyceps xuefengensis and Ophiocordyceps sinensis.

Ophiocordyceps xuefengensis (O. xuefengensis), a new species of caterpillar fungus, has been identified as the sister taxon of Ophiocordyceps sinensis (O. sinensis). The aims of the present study are to evaluate the anticancer activity and to qualitatively analyze the potential bioactive chemical constituents of O. xuefengensis and O. sinensis, comparatively. An MTT assay was used to evaluate the in vitro anticancer activities of different fractions from O. xuefengensis and O. sinensis. The results show that ethyl acetate fractions of O. xuefengensis and O. sinensis have significant in vitro anticancer activity. These two bioactive fractions were analyzed by ultra-performance liquid chromatography-electrospray ionization with quadrupole-time of flight tandem mass spectrometry technology. A total of 82 compounds and 101 compounds were identified or tentatively characterized in the bioactive fractions of O. xuefengensis and O. sinensis, respectively. Among these compounds, 68 existed in both O. xuefengensis and O. sinensis. A total of 67 compounds were reported in O. xuefengensis and 8 compounds were reported in caterpillar fungus for the first time. This is the first detailed comparative analysis of the in vitro anticancer activity and chemical ingredients between O. xuefengensis and O. sinensis. The application of this work will provide reliable fundamental pharmacological substances for the use of O. xuefengensis by Yao people.

Untargeted gas chromatography–mass spectrometry analysis and evaluation of antimicrobial and antioxidant activity of Zingiber nimmonii (J. Graham) Dalzell rhizome extracts

Background: Zingiber nimmonii (J. Graham) Dalzell (syn. Z. cernuum) endemic to peninsular India have been documented to be in use since ancient times in several traditional systems of medicine. Z. nimmonii with ethnomedicinal applications constitute a rich source of secondary metabolites toward identifying potential bioactive constituents with antioxidant and antimicrobial properties. Objective: Rhizomes of Z. nimmonii (J. Graham) Dalzell, endemic to the Western Ghats, were analyzed for bioactivity and phytochemical composition. Materials and Methods: Polyphenolic contents, namely total phenolics (TPs), total flavonoids (TFs) and total tannin (TT), were determined and expressed using gallic acid (GA), catechin (C) and tannic acid (TA) as standards. Antibacterial and antifungal activities were evaluated against two Gram-positive, three Gram-negative bacteria and three fungi by agar well diffusion method. Antioxidant activity was determined by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and Ferric Reducing Antioxidant Power (FRAP) assay, and volatile metabolite composition was determined by gas chromatography–mass spectrometry (GC-MS) analysis. Results: THE highest TF and TT contents were detected in ethyl acetate (557.64 ± 41.74 mg CE. 100 g-1 DW) and isopropanol (63.995 ± 2.062 mg TA equivalent. 100 g-1 DW) extract, respectively. High TP content in isopropanol extract (112.80 ± 10.99 mg GA equivalent. 100 g-1 DW) contributed to antimicrobial activity against Gram-positive Staphylococcus aureus (16.3 ± 0.6 mm) and antifungal activity against Aspergillus flavus (11.7 ± 0.6 mm). Methanol extracts showed high antioxidant activity as determined by DPPH (67.4 ± 12.5 μg/ml) and FRAP (127.8 ± 12.4 μg/ml) assays. Major bioactive phytochemical constituents in Z. nimmonii rhizome following GC-MS analysis included heptanediamide, N, N'-di-benzoyloxy (arachidonic acid inhibitor), n-hexadecanoic acid (antibacterial, cytotoxic, and antioxidant), and oleic acid (antitumor). Conclusion: The present study demonstrates potential of Z. nimmonii rhizomes as a rich source of secondary metabolites which can be exploited toward developing anti-infective formulations and free radical quenchers.

Rapid discovery of chemical constituents and absorbed components in rat serum after oral administration of Fuzi-Lizhong pill based on high-throughput HPLC-Q-TOF/MS analysis

BackgroundFuzi-Lizhong pill (FZLZP), which was first recorded in the Classic–“Taiping Huimin Heji Ju Fang” of the Song Dynasty, has been widely used to treat gastrointestinal disease in clinic for thousands of years in China. However, an in-depth understanding of the chemical constituents of FZLZP and its potential bioactive constituents is lacking.MethodsA simple, sensitive and selective method of high-performance liquid chromatography coupled with quadrupole-time-of-flight high-definition mass spectrometry (HPLC-Q-TOF/MS) and automated data analysis (Agilent MassHunter Qualitative Analysis B.06.00 Workstation Software) was developed to simultaneously identify the chemical constituents of FZLZP and the absorbed prototypes as well as the metabolites in rat serum after the oral administration of FZLZP.ResultsSixty-seven compounds, including alkaloids, flavonoids, triterpenes, gingerols, phenylpropanoids and volatile oil, in the FZLZP extract were tentatively characterized by comparing the retention time and mass spectrometry data and retrieving the reference literatures. Additionally, 23 prototype compounds and 3 metabolites in the rat serum samples were identified after oral administration of FZLZP, which might be the potential active components in vivo. In addition, the absorption of alkaloids decreased when Aconitum carmichaeli Debx. was in the form of combined application as a prescription compared to when it was in the form of herb powder.ConclusionsHerein, the chemical constituent in vitro and the absorbed compounds in the serum of a traditional Chinese formula, Fuzi-Lizhong pill, were fully characterized using a rapid and comprehensive analysis approach based on high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry coupled to MassHunter Qualitative Analysis software data processing approach. The results provide helpful chemical information on FZLZP for further pharmacology and active mechanism research. In view of the bioactive constitutes that basically were derived from these absorbed compounds in vivo, this work could provide a useful strategy to explore the bioactive substances of traditional Chinese medicine.

Antidiabetic and antihyperlipidemic effects of the flower extract of Eriobotrya japonica in streptozotocin-induced diabetic mice and the potential bioactive constituents in vitro

This study was designed to evaluate the effects of flower extracts of Eriobotrya japonica (EJ) on diabetes and hyperlipidemia for 4 weeks in streptozotocin (STZ)-induced diabetic mice. EJ treatment significantly lowered levels of blood glucose, HbA1C, plasma triglyceride (TG), and total cholesterol (TC) but increased the size of the islets of Langerhans within the pancreas. Membrane expression levels of glucose transporter 4 (GLUT4) and phospho-Akt in the skeletal muscles from EJ-treated STZ mice were increased, but G6Pase mRNA levels were decreased, contributing to EJ’s antidiabetic activity. EJ caused an increase in hepatic expression of peroxisome proliferator-activated receptor α (PPARα) but a decrease in lipogenic FAS and mRNA levels of SREBP2, which decreased plasma TG and TC levels. One explanation for EJ’s antidiabetic and hypolipidemic activity is that tormentic acid represents the major component of EJ. These findings support the amelioration of the diabetic and dyslipidemic state by EJ in STZ-induced diabetic mice.

Multi-component identification and target cell-based screening of potential bioactive compounds in toad venom by UPLC coupled with high-resolution LTQ-Orbitrap MS and high-sensitivity Qtrap MS.

Traditional Chinese medicines (TCMs) are undoubtedly treasured natural resources for discovering effective medicines in treating and preventing various diseases. However, it is still extremely difficult for screening the bioactive compounds due to the tremendous constituents in TCMs. In this work, the chemical composition of toad venom was comprehensively analyzed using ultra-high performance liquid chromatography (UPLC) coupled with high-resolution LTQ-Orbitrap mass spectrometry and 93 compounds were detected. Among them, 17 constituents were confirmed by standard substances and 8 constituents were detected in toad venom for the first time. Further, a compound database of toad venom containing the fullest compounds was further constructed using UPLC coupled with high-sensitivity Qtrap MS. Then a target cell-based approach for screening potential bioactive compounds from toad venom was developed by analyzing the target cell extracts. The reliability of this method was validated by negative controls and positive controls. In total, 17 components in toad venom were discovered to interact with the target cancer cells. Further, in vitro pharmacological trials were performed to confirm the anti-cancer activity of four of them. The results showed that the six bufogenins and seven bufotoxins detected in our research represented a promising resource to explore bufogenins/bufotoxins-based anticancer agents with low cardiotoxic effect. The target cell-based screening method coupled with the compound database of toad venom constructed by UPLC-Qtrap-MS with high sensitivity provide us a new strategy to rapidly screen and identify the potential bioactive constituents with low content in natural products, which was beneficial for drug discovery from other TCMs. ᅟ Graphical abstract.

Antioxidative Potential of a Streptomyces sp. MUM292 Isolated from Mangrove Soil.

Mangrove derived microorganisms constitute a rich bioresource for bioprospecting of bioactive natural products. This study explored the antioxidant potentials of Streptomyces bacteria derived from mangrove soil. Based on 16S rRNA phylogenetic analysis, strain MUM292 was identified as the genus Streptomyces. Strain MUM292 showed the highest 16S rRNA gene sequence similarity of 99.54% with S. griseoruber NBRC12873T. Furthermore, strain MUM292 was also characterized and showed phenotypic characteristics consistent with Streptomyces bacteria. Fermentation and extraction were performed to obtain the MUM292 extract containing the secondary metabolites of strain MUM292. The extract displayed promising antioxidant activities, including DPPH, ABTS, and superoxide radical scavenging and also metal-chelating activities. The process of lipid peroxidation in lipid-rich product was also retarded by MUM292 extract and resulted in reduced MDA production. The potential bioactive constituents of MUM292 extract were investigated using GC-MS and preliminary detection showed the presence of pyrazine, pyrrole, cyclic dipeptides, and phenolic compound in MUM292 extract. This work demonstrates that Streptomyces MUM292 can be a potential antioxidant resource for food and pharmaceutical industries.

A strategy for screening of α-glucosidase inhibitors from Morus alba root bark based on the ligand fishing combined with high-performance liquid chromatography mass spectrometer and molecular docking

A new method based on ligand fishing combined with high-performance liquid chromatography quadrupole-time-of-flight mass spectrometer and molecular docking was established to screen α-glucosidase inhibitors from a traditional Chinese medicine Morus alba root bark. α-Glucosidase was immobilized on magnetic nanoparticles, used as a solid support to incubate with crude extract. After ligand fishing, the eluates were analyzed by high-performance liquid chromatography quadrupole-time-of-flight mass spectrometer, obtaining eleven ligands (1–4, 6–12) eventually. In order to discriminate the non-specific binders and discover powerful enzyme inhibitors, molecular docking was further performed and three of the eleven ligands were optimized to be excellent α-glucosidase inhibitors by the confirmation of isolation and bioassay of individual compounds. These three ligands, sanggenons G (6), O (7) and sanggenol G (12) exhibited striking inhibitory activities with extremely low IC50 values. The results suggest that established method will be applied to a wide range of target protein to screen potential bioactive constituents from herbal medicines.

Spasmolytic Mechanism of Aqueous Licorice Extract on Oxytocin-Induced Uterine Contraction through Inhibiting the Phosphorylation of Heat Shock Protein 27.

Licorice derived from the roots and rhizomes of Glycyrrhiza uralensis Fisch. (Fabaceae), is one of the most widely-used traditional herbal medicines in China. It has been reported to possess significant analgesic activity for treating spastic pain. The aim of this study is to investigate the spasmolytic molecular mechanism of licorice on oxytocin-induced uterine contractions and predict the relevant bioactive constituents in the aqueous extract. The aqueous extraction from licorice inhibited the amplitude and frequency of uterine contraction in a concentration-dependent manner. A morphological examination showed that myometrial smooth muscle cells of oxytocin-stimulated group were oval-shaped and arranged irregularly, while those with a single centrally located nucleus of control and licorice-treated groups were fusiform and arranged orderly. The percentage of phosphorylation of HSP27 at Ser-15 residue increased up to 50.33% at 60 min after oxytocin stimulation. Furthermore, this increase was significantly suppressed by licorice treatment at the concentration of 0.2 and 0.4 mg/mL. Colocalization between HSP27 and α-SMA was observed in the myometrial tissues, especially along the actin bundles in the oxytocin-stimulated group. On the contrary, the colocalization was no longer shown after treatment with licorice. Additionally, employing ChemGPS-NP provided support for a preliminary assignment of liquiritigenin and isoliquiritigenin as protein kinase C (PKC) inhibitors in addition to liquiritigenin, isoliquiritigenin, liquiritin and isoliquiritin as MAPK-activated protein kinase 2 (MK2) inhibitors. These assigned compounds were docked with corresponding crystal structures of respective proteins with negative and low binding energy, which indicated a high affinity and tight binding capacity for the active site of the kinases. These results suggest that licorice exerts its spasmolytic effect through inhibiting the phosphorylation of HSP27 to alter the interaction between HSP27 and actin. Furthermore, our results provide support for the prediction that potential bioactive constituents from aqueous licorice extract inhibit the relevant up-stream kinases that phosphorylate HSP27.

A characterization of the antimalarial activity of the bark of Cylicodiscus gabunensis Harms

Ethnopharmacological relevance and aimA decoction of the bark of Cylicodiscus gabunensis Harms is used as a traditional medicine in the treatment of malaria in Nigeria. This study aims to validate the antimalarial potency of this decoction in vitro against Plasmodium falciparum and define potential bioactive constituents within the C. gabunensis bark. Materials and methodsA bioassay-guided separation and fractionation protocol was applied to C. gabunensis extracts, exploiting the use of a Malaria Sybr Green I Fluorescence assay method to monitor antiproliferative effects on parasites as well as define 50% inhibition concentrations. Spectroscopic techniques, including GC-MS, TOF LC-MS and 1H NMR were used to identify phytochemicals present in bioactive fractions. Analogues of gallic acid were synthesized de novo to support the demonstration of the antimalarial action of phenolic acids identified in C. gabunensis bark. In vitro cytotoxicity of plant extracts, fractions and gallate analogues was evaluated against the HepG2 cell line. ResultsThe antimalarial activity of ethanolic extracts of C. gabunensis bark was confirmed in vitro, with evidence for phenolic acids, primarily gallic acid and close analogues such as ethyl gallate, likely providing this effect. Further fractionation produced the most potent fraction with a 50% inhibitory concentration of 4.7µg/ml. Spectroscopic analysis, including 1H NMR, LC-MS and GC-MS analysis of this fraction and its acid hydrolyzed products, indicated the presence of conjugates of gallic acid with oligosaccharides. The extracts/fractions and synthetic alkyl and alkenyl gallates showed moderate selectivity against P. falciparum. ConclusionsThese results support the use of the bark of C. gabunensis as a traditional medicine in the treatment of human malaria, with phenolic acid oligosaccharide complexes evident in the most bioactive fractions.

Multi-constituent identification in Australian cane toad skin extracts using high-performance liquid chromatography high-resolution tandem mass spectrometry

Toad skins and venom glandular secretions have been widely used for centuries in traditional Chinese and Japanese medicine for the treatment of various ailments such as cancer, sores, toothache, local inflammation and pain. The active chemical constituents from traditional oriental medicines have demonstrated potential in the development of effective therapeutic pharmaceuticals. Our primary focus in this research was to identify and characterise ‘active’ compounds or groups of compounds for their potential as neuropsychiatric disorder therapeutics. For this aim, we utilised a variety of solvents, i.e., the aqueous, 60% ethanol (aqueous) and acetic acid (aq) (at two different pHs) for extractions of Australian cane toad skins to identify chemical constituents. The identification of compounds was carried out using HPLC-ESI-Q-TOF-MS/MS based on the accurate mass measurement for molecular ions and MS/MS analysis, whereby accurate mass pseudo-molecular ions and characteristic fragment ions were compared to published reference data, including mass bank and NIST. As a result, we have to date identified 42 major constituents including alkaloids, amino acids, bufadienolides, fatty acids, nucleobases, nucleosides and vitamins mostly from the aqueous and 60% ethanol extracts. Of the 42 constituents identified, 29 were found in the aqueous extract, 35 were found in the ethanol (aq) extract and only 10 in the pH 1.78 acetic acid extract and 11 in the pH 2.17 acetic acid extract of the cane toad skins. Therefore, the aqueous and 60% ethanolic extracts present the greatest potential for ongoing development in our assays. There have been no previous reports on the identification of many of the constituents we have here identified in Australian cane toad skins. These findings, while somewhat consistent with findings in toad skins in other countries, identifies the presence of potential bioactive constituents. Our results showed that HPLC-ESI-Q-TOF-MS/MS is an effective method to characterise and identify components in Australian cane toad skin extracts. Chemical profiling is an essential initial step in the identification and therapeutic exploitation of bioactive agents present in Australian cane toad skin extracts.

Rapid Analysis and Identification of Absorbed Components and Their Metabolites of Yuanhu Zhitong Dropping Pill in Rat Plasma and Brain Tissue Using UPLC-Q-TOF/MS with Multivariate Statistical Analysis

ObjectiveTo establish an effective approach for rapid and comprehensive analysis on the absorbed and metabolic components in rats after ig administration of Yuanhu Zhitong Dropping Pill (YHZT). MethodsBased on the combination of UPLC-Q-TOF/MS and multivariate statistical analysis, the absorbed prototype constituents and their metabolites in rat plasma were rapidly analyzed and identified, and the components absorbed into brain were further identified by comparing the extracted ion chromatograms (EICs) of control and brain tissue samples of dosed rats. ResultsA total of 38 YHZT-related xenobiotic compounds were detected and identified as the potential bioactive constituents in rat plasma, including 24 absorbed prototype constituents and 14 metabolites. In particular, of all prototype constituents, 14 were also detected in rat brain tissue, indicating that they could penetrate the blood-brain barrier and enter into brain. ConclusionAn effective method is established and applied to analyze the potential bioactive constituents in YHZT, which provides a pathway to further investigate the pharmacological pattern and mechanism of YHZT.

Screening and identification of potential bioactive constituents in a new herbal prescription seaweed complex preparation

Background: Seaweed Complex Preparation (SCP) is a clinical traditional Chinese medicine preparation composed of seven traditional Chinese herbs, and has been used for treatment of lung cancer, liver cancer and digestive cancer.Materials and Methods: In this study, the potential bioactive constituents of SCP were isolated and identified by chromatographic and spectroscopic methods. The immunomodulatory and DPPH radical scavenging activities of the constituents were also evaluated in vitro.Results: Forty-three compounds were isolated from the EtOAc and n BuOH fractions of the decocted extracts. More than 10 structural types of chemical constituents were found, including flavonoid glycosides, flavonoids, phenolic acid compounds, lignans, iridoid glycosides, and polysaccharides mainly composed of galactose and glucose. Flavonoid glycosides exhibited potential immunomodulatory by promoting splenic lymphocyte proliferation and stimulating the secretion of cytokines IL 2 and IFN-γ, as well as free radical (DPPH) scavenging activities. Caffeic acid derivatives showed remarkable free radical (DPPH) scavenging activity, while polysaccharides also displayed immunological enhancement effects.Conclusion: Four molecular communities, flavonoid glycosides, flavonoids, phenolic compounds and polysaccharides, might be the potential bioactive components of SCP. Synergism of these four molecular communities in SCP may endue the anticancer properties and reflect the feature of multi-components and multi targets of traditional Chinese medicine formula.Keywords: Traditional Chinese Medicine Preparation, Seaweed Complex Preparation, Bioactive constituents, Free radical scavenging; Immunomodulatory

SCREENING AND IDENTIFICATION OF POTENTIAL BIOACTIVE CONSTITUENTS IN A NEW HERBAL PRESCRIPTION SEAWEED COMPLEX PREPARATION

Background: Seaweed Complex Preparation (SCP) is a clinical traditional Chinese medicine preparation composed of seven
 traditional Chinese herbs, and has been used for treatment of lung cancer, liver cancer and digestive cancer.
 Materials and Methods: In this study, the potential bioactive constituents of SCP were isolated and identified by chromatographic
 and spectroscopic methods. The immunomodulatory and DPPH radical scavenging activities of the constituents were also evaluated
 in vitro.
 Results: Forty-three compounds were isolated from the EtOAc and n-BuOH fractions of the decocted extracts. More than 10
 structural types of chemical constituents were found, including flavonoid glycosides, flavonoids, phenolic acid compounds, lignans,
 iridoid glycosides, and polysaccharides mainly composed of galactose and glucose. Flavonoid glycosides exhibited potential
 immunomodulatory by promoting splenic lymphocyte proliferation and stimulating the secretion of cytokines IL-2 and IFN-γ, as
 well as free radical (DPPH) scavenging activities. Caffeic acid derivatives showed remarkable free radical (DPPH) scavenging
 activity, while polysaccharides also displayed immunological enhancement effects.
 Conclusion: Four molecular communities, flavonoid glycosides, flavonoids, phenolic compounds and polysaccharides, might be the
 potential bioactive components of SCP. Synergism of these four molecular communities in SCP may endue the anticancer properties
 and reflect the feature of multi-components and multi-targets of traditional Chinese medicine formula.

Identification and pharmacokinetics of multiple potential bioactive constituents after oral administration of radix astragali on cyclophosphamide-induced immunosuppression in Balb/c mice.

Radix Astragali (RA) is one of the commonly-used traditional Chinese medicines (TCMs) with an immunomodulatory effect confirmed in the clinic. In order to better understand the material basis for the therapeutic effects, this study was to investigate the absorbed components and their pharmacokinetic profile after oral administration of RA on cyclophosphamide-induced immunosuppression in Balb/c mice. As a result, 51 compounds in RA extract and 31 prototype compounds with nine metabolites were detected in mice plasma by the ultra-fast liquid chromatography (UFLC)-DAD-Q-TOF-MS/MS method. The pharmacokinetic parameters of five main constituents, including calycosin-7-O-glucoside, ononin, calycosin, formononetin and astragaloside IV, were obtained using HPLC-MS/MS. These results offered useful information for research on the pharmacological mechanism of RA and for its further development.

Antinociceptive, anti-gastric ulcerogenic and anti-inflammatory activities of standardized egyptian pomegranate peel extract

The utilization of the peels of the widely popular pomegranate fruit is the subject of this study. This biowaste product, which has been under study for some time as a source of potential bioactive constituents is investigated for its biological activity. A method for the extract standardization was developed using HPLC and ellagic acid as a reference standard. Results revealed that the pomegranate methanolic extract exhibited potent analgesic and anti-inflammatory activity comparable to indomethacin, used as a reference, and furthermore, caused no gastric ulcer formation.

Bioavailability and pharmacokinetics of caffeoylquinic acids and flavonoids after oral administration of Artichoke leaf extracts in humans

Extracts from artichoke leaves are traditionally used in the treatment of dyspeptic and hepatic disorders. Various potential pharmacodynamic effects have been observed in vitro for mono- and dicaffeoylquinic acids (e.g. chlorogenic acid, cynarin), caffeic acid and flavonoids (e.g. luteolin-7-O-glucoside) which are the main phenolic constituents of artichoke leaf extract (ALE). However, in vivo not only the genuine extract constituents but also their metabolites may contribute to efficacy. Therefore, the evaluation of systemic availability of potential bioactive plant constituents is a major prerequisite for the interpretation of in vitro pharmacological testing. In order to get more detailed information about absorption, metabolism and disposition of ALE, two different extracts were administered to 14 healthy volunteers in a crossover study. Each subject received doses of both extracts. Extract A administered dose: caffeoylquinic acids equivalent to 107.0 mg caffeic acid and luteolin glycosides equivalent to 14.4 mg luteolin. Extract B administered dose: caffeoylquinic acids equivalent to 153.8 mg caffeic acid and luteolin glycosides equivalent to 35.2 mg luteolin. Urine and plasma analysis were performed by a validated HPLC method using 12-channel coulometric array detection. In human plasma or urine none of the genuine target extract constituents could be detected. However, caffeic acid (CA), its methylated derivates ferulic acid (FA) and isoferulic acid (IFA) and the hydrogenation products dihydrocaffeic acid (DHCA) and dihydroferulic acid (DHFA) were identified as metabolites derived from caffeoylquinic acids. Except of DHFA all of these compounds were present as sulfates or glucuronides. Peak plasma concentrations of total CA, FA and IFA were reached within 1 h and declined over 24 h showing almost biphasic profiles. In contrast maximum concentrations for total DHCA and DHFA were observed only after 6-7 h, indicating two different metabolic pathways for caffeoylquinic acids. Luteolin administered as glucoside was recovered from plasma and urine only as sulfate or glucuronide but neither in form of genuine glucosides nor as free luteolin. Peak plasma concentrations were reached rapidly within 0.5 h. The elimination showed a biphasic profile.

Membrane stabilising effects of natural polyphenols and flavonoids from Sempervivum tectorum on hepatic microsomal mixed-function oxidase system in hyperlipidemic rats

The extensive role of the microsomal mixed-function oxidase (MFO) system in the oxidation of endo-and xenobiotics, in the detoxication, in the generation of reactive free radicals and in the decomposition of the end products of lipid peroxides is well documented in the literature. Steatotic liver is a very frequent damage with different etiology. Drug metabolising reactions are suppressed in fatty liver, in which pathologically increased production of reactive oxygen intermediates may lead to the peroxidation of microsomal membrane lipids and to the change of membrane bound enzyme activities because of overwhelmed protective mechanisms. The subnormal activity of the MFO system may diminish the non specific resistance of the organism. Therefore we have studied the effects of natural flavonoids and polyphenolic compounds on the mixed-function oxidases. Antioxidant, O 2 − and OH scavenger properties of Sempervivum tectorum extract (STF1) were proved by EPR spectroscopic and chemiluminometric techniques. Potential bioactive constituents were determined by chromatography (HPLC, TLC) and spectrometric (UV, UV–VIS) methods. In the present study we reflect on the membrane stabilising, antioxidant and lipid metabolism modifying effects of this extract. It was established that activities of NAD(P)H reductase and content of cytochrome P450 were normalised in liver microsomes of hyperlipidemic rats, if the animals were treated with STF1 (2 g/bwkg for 9 days in drinking water parallel with fat-rich diet feeding). Fatty acid composition, examined by HRGLC analysis, was changed beneficially. NADPH induced lipid peroxidation was also decreased in microsomes in in vivo and in vitro experiments. At the same time the STF1 had no significant influence on MFO system in normolipidemic animals and on cytochrome b5 concentration of microsome fractions of hyperlipidemic rats.