Astonishing diversity of natural surfactants: 5. Biologically active glycosides of aromatic metabolites

Highly Efficient Verbascoside Production from Olive (Olea europea L. var. Cellina di Nardò) In Vitro Cell Cultures

Olive (Olea europea L.) is one of the oldest and most important fruit tree species cultivated in the Mediterranean region. Various plant tissues, drupes, and olive oil contain several phenolics (including verbascoside, although it is present in the plant at a low level) that are well-known for their highly beneficial effects on human health. An in vitro olive cell suspension culture (cultivar Cellina di Nardò, "CdN") was established, characterized for its growth and morphological features. Furthermore, a vital and relatively uniform population of protoplasts was generated from the olive suspension culture to investigate their cellular characteristics during growth. The polyphenolic extract of the in vitro "CdN" olive cells contained almost exclusively verbascoside, as revealed by the UPLC-ESI-MS analysis. The content of verbascoside reached up to 100 mg/g DW, with an average production rate of approximately 50 mg/g DW over one year of culture. This level of production has not been previously reported in a limited number of previous studies. This remarkable production of verbascoside was associated with an exceptionally high antioxidant capacity. The high level of verbascoside production and purity of the extract make this system a promising tool for secondary metabolite production.

Glycosylated coumarins, flavonoids, lignans and phenylpropanoids from Wikstroemia nutans and their biological activities

Wikstroemia nutans Champ. ex Benth., a traditional herbal medicine collected at the Lingnan region of China, was chemically investigated. A new biscoumarin glucoside, wikstronutin (1), along with three known bis- and tricoumarin glucosides (2–4), two flavonoid glycosides (5–6), and eleven lignan glucosides (7–17) were isolated from the stems and roots of W. nutans. The new structure including its absolute configuration was elucidated based on a combination of 1D and 2D NMR, UV, IR, HRESIMS spectroscopic data, as well as chemical transformation. Compounds 1–17 were first isolated from the plant species W. nutans, while compounds 1–3, 8, and 11 were reported from the genus Wikstroemia for the first time. All co-isolates were evaluated for their in vitro inhibitory effects on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in murine RAW264.7 macrophage cells. The antibacterial activity of the selected compounds was also tested. Our work enriches the structure diversity of the secondary metabolites from the genus Wikstroemia.

The isolation of water-soluble natural products - challenges, strategies and perspectives

Covering period: up to 2019Water-soluble natural products constitute a relevant group of secondary metabolites notably known for presenting potent biological activities. Examples are aminoglycosides, β-lactam antibiotics, saponins of both terrestrial and marine origin, and marine toxins. Although extensively investigated in the past, particularly during the golden age of antibiotics, hydrophilic fractions have been less scrutinized during the last few decades. This review addresses the possible reasons on why water-soluble metabolites are now under investigated and describes approaches and strategies for the isolation of these natural compounds. It presents examples of several classes of hydrosoluble natural products and how they have been isolated. Novel stationary phases and chromatography techniques are also reviewed, providing a perspective towards a renaissance in the investigation of water-soluble natural products.

Total Synthesis of Resvebassianol A, a Metabolite of Resveratrol by Beauveria bassiana

Resveratrol is a well-known dietary polyphenol because it has a variety of beneficial biological activities. The fungus Beauveria bassiana is one of the most frequently used microorganisms for the biotransformation of polyphenols. Recently, resvebassianol A (2), a glycosylated metabolite of resveratrol by B. bassiana, was isolated and structurally elucidated. It was demonstrated to exhibit antioxidant, regenerative, and anti-inflammatory activities with no cytotoxicity. Here, we report the first total synthesis of resvebassianol A, 4′-O-β-(4‴-O-methylglucopyranosyl)resveratrol (2), and its regiomer, 3-O-β-(4‴-O-methylglucopyranosyl)resveratrol (3). Key reactions include (i) the construction of a stilbene core via a novel Heck reaction of aryl halides and styrenes, and (ii) glycosylation with unnatural methylglucopyranosyl bromide. The glycosylation step was carefully optimized by varying the bases and solvents. Resveratrol metabolites 2 and 3 were obtained at 7.5% and 6.3% of the overall yield, respectively.

Sulfated and Sulfur-Containing Steroids and Their Pharmacological Profile

The review focuses on sulfated steroids that have been isolated from seaweeds, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. Sulfur-containing steroids and triterpenoids are sourced from sedentary marine coelenterates, plants, marine sediments, crude oil, and other geological deposits. The review presents the pharmacological profile of sulfated steroids, sulfur-containing steroids, and triterpenoids, which is based on data obtained using the PASS program. In addition, several semi-synthetic and synthetic epithio steroids, which represent a rare group of bioactive lipids that have not yet been found in nature, but possess a high level of antitumor activity, were included in this review for the comparative pharmacological characterization of this class of compounds. About 140 steroids and triterpenoids are presented in this review, which demonstrate a wide range of biological activities. Therefore, out of 71 sulfated steroids, thirteen show strong antitumor activity with a confidence level of more than 90%, out of 50 sulfur-containing steroids, only four show strong antitumor activity with a confidence level of more than 93%, and out of eighteen epithio steroids, thirteen steroids show strong antitumor activity with a confidence level of 91% to 97.4%.

Supramolecular aggregation of colloidal natural organic matter masks priority pollutants released in water from peat soil

Natural organic matter (NOM) from Sphagnum peat soil is extracted in water and subjected to several investigations to obtain structural and conformational information. Data show that the extracted NOM is self-organized in colloidal aggregates of variable sizes (from nano to micro scales, depending on the solvent composition, i.e., ultrapure water, solutions with denaturing agents, acetone, ethanol). Aggregates are formed by highly heterogeneous classes of organic compounds. According to the results of nuclear magnetic resonance and fluorescence measurements, the three-dimensional structure of aggregates, revealed by scanning electron microscope imaging, is supposed to be stabilized by the exposition of polar functional groups to the solvent, with consequent formation of hydrogen bonds, dipole-interactions and cation bridging. In contrast, the inner part of the aggregates displays hydrophobic features and is hypothesized to be further reinforced by the establishment of π-stacking interactions. The structure is assumed to be a supramolecular aggregation of small-medium oligomeric fragments (Max 750 Da) in which priority pollutants are entrapped by dispersive forces. The structures are shown to be nanosized spheroidal particles further aggregated to form higher dimension supra-structures. Carbohydrates play primary role, stabilizing the structure and giving marked hydrophilic properties to the aggregates.

Antiprotozoal and Antitumor Activity of Natural Polycyclic Endoperoxides: Origin, Structures and Biological Activity

Polycyclic endoperoxides are rare natural metabolites found and isolated in plants, fungi, and marine invertebrates. The purpose of this review is a comparative analysis of the pharmacological potential of these natural products. According to PASS (Prediction of Activity Spectra for Substances) estimates, they are more likely to exhibit antiprotozoal and antitumor properties. Some of them are now widely used in clinical medicine. All polycyclic endoperoxides presented in this article demonstrate antiprotozoal activity and can be divided into three groups. The third group includes endoperoxides, which show weak antiprotozoal activity with a reliability of up to 70%, and this group includes only 1.1% of metabolites. The second group includes the largest number of endoperoxides, which are 65% and show average antiprotozoal activity with a confidence level of 70 to 90%. Lastly, the third group includes endoperoxides, which are 33.9% and show strong antiprotozoal activity with a confidence level of 90 to 99.6%. Interestingly, artemisinin and its analogs show strong antiprotozoal activity with 79 to 99.6% confidence against obligate intracellular parasites which belong to the genera Plasmodium, Toxoplasma, Leishmania, and Coccidia. In addition to antiprotozoal activities, polycyclic endoperoxides show antitumor activity in the proportion: 4.6% show weak activity with a reliability of up to 70%, 65.6% show an average activity with a reliability of 70 to 90%, and 29.8% show strong activity with a reliability of 90 to 98.3%. It should also be noted that some polycyclic endoperoxides, in addition to antiprotozoal and antitumor properties, show other strong activities with a confidence level of 90 to 97%. These include antifungal activity against the genera Aspergillus, Candida, and Cryptococcus, as well as anti-inflammatory activity. This review provides insights on further utilization of polycyclic endoperoxides by medicinal chemists, pharmacologists, and the pharmaceutical industry.

Chemical Diversity of Soft Coral Steroids and Their Pharmacological Activities

The review is devoted to the chemical diversity of steroids produced by soft corals and their determined and potential activities. There are about 200 steroids that belong to different types of steroids such as secosteroids, spirosteroids, epoxy- and peroxy-steroids, steroid glycosides, halogenated steroids, polyoxygenated steroids and steroids containing sulfur or nitrogen heteroatoms. Of greatest interest is the pharmacological activity of these steroids. More than 40 steroids exhibit antitumor and related activity with a confidence level of over 90 percent. A group of 32 steroids shows anti-hypercholesterolemic activity with over 90 percent confidence. Ten steroids exhibit anti-inflammatory activity and 20 steroids can be classified as respiratory analeptic drugs. Several steroids exhibit rather rare and very specific activities. Steroids exhibit anti-osteoporotic properties and can be used to treat osteoporosis, as well as have strong anti-eczemic and anti-psoriatic properties and antispasmodic properties. Thus, this review is probably the first and exclusive to present the known as well as the potential pharmacological activities of 200 marine steroids.

Therapeutic potential of phenylethanoid glycosides: A systematic review

Phenylethanoid glycosides (PhGs) are generally water-soluble phenolic compounds that occur in many medicinal plants. Until June 2020, more than 572 PhGs have been isolated and identified. PhGs possess antibacterial, anticancer, antidiabetic, anti-inflammatory, antiobesity, antioxidant, antiviral, and neuroprotective properties. Despite these promising benefits, PhGs have failed to fulfill their therapeutic applications due to their poor bioavailability. The attempts to understand their metabolic pathways to improve their bioavailability are investigated. In this review article, we will first summarize the number of PhGs compounds which is not accurate in the literature. The latest information on the biological activities, structure-activity relationships, mechanisms, and especially the clinical applications of PhGs will be reviewed. The bioavailability of PhGs will be summarized and factors leading to the low bioavailability will be analyzed. Recent advances in methods such as bioenhancers and nanotechnology to improve the bioavailability of PhGs are also summarized. The existing scientific gaps of PhGs in knowledge are also discussed, highlighting research directions in the future.

Dietary Biotechnological Ajuga reptans Extract in Post Weaning Piglets: Effects on Growth Performance, Oxidative Status and Immune Parameters

The effect of dietary supplementation with a biotechnological extract of Ajuga reptans on growth performance, oxidative status and immune parameters was evaluated in post weaning piglets. At weaning, 120 piglets with an average live weight of 8.1±1.3 kg, were assigned to one of three experimental groups. The first group was fed a control diet (C). The second and third groups were fed the same diet supplemented with 5 mg (T1) and 10 mg (T2) of teupolioside/kg feed from a biotechnological plant extract. Growth performances were recorded and blood samples were collected at the beginning, at 14 days, and at the end of the trial (56 days). Serum biochemical parameters, oxidative status and immunoglobulin titres were determined. Average daily gain tended to be higher (P=0.057) and live weight was higher in piglets (P<0.05) fed with different amounts of plant extract (T1 and T2) than the controls. The production of reactive oxygen metabolites (ROMs) was higher (P<0.05) in the control group than in the groups receiving teupolioside (T1 and T2). Concentration of serum immunoglobulin of class G improved (P<0.001) in piglets fed the T1 and T2 diets than the controls. Overall, the results suggested that the biotechnological extract of Ajuga reptans containing teupolioside has an antioxidant and immunomodulant effect.

Plant-derived Glycosides with α-Glucosidase Inhibitory Activity: Current Standing and Future Prospects

Background:

The α-glucosidase (EC 3.2.1.20), a calcium-containing intestinal enzyme which is positioned in the cells which cover the intestinal microvilli brush border. The carbohydrates require metabolism by α-glucosidase before being absorbed into the small intestine, and as a result, this enzyme represents a significant drug target for the effective management of diabetes. There are few α- glucosidase inhibitors in the clinical practice that is challenged by several limitations. Thus, new effective and safe therapeutic agents in this class are required. In this regard, plant secondary metabolites are a very promising source to be investigated. Herein in this review, we have focused on the preclinical studies on various glycosides with in vitro α-glucosidase inhibitory activity.

Methods:

The literature available on various websites such as GoogleScholar, PubMed, Scopus. All the peer-reviewed articles were included without considering the impact factor.

Results:

The surveyed literature revealed marked inhibitory profile of various glycosides derived from plants, and some of them were extremely potent relatively to the standard, acarbose in preclinical trials and exhibited multiple targeted effects.

Conclusion:

Keeping in view the results, these glycosides are strong candidates for further, more detailed studies to ascertain their clinical potential and for effective contribution in effective management of diabetes, where multiple targets are required to address

In Vitro Human Metabolism and Inhibition Potency of Verbascoside for CYP Enzymes

Verbascoside is found in many medicinal plant families such as Verbenaceae. Important biological activities have been ascribed to verbascoside. Investigated in this study is the potential of verbascoside as an adjuvant during tuberculosis treatment. The present study reports on the in vitro metabolism in human hepatic microsomes and cytosol incubations as well as the presence and quantity of verbascoside within Lippia scaberrima. Additionally, studied are the inhibitory properties on human hepatic CYP enzymes together with antioxidant and cytotoxic properties. The results yielded no metabolites in the hydrolysis or cytochrome P450 (CYP) oxidation incubations. However, five different methylated conjugates of verbascoside could be found in S-adenosylmethionine incubation, three different sulphate conjugates with 3'-phosphoadenosine 5'-phosphosulfate (PAPS) incubation with human liver samples, and very low levels of glucuronide metabolites after incubation with recombinant human uridine 5'-diphospho-glucuronosyltransferase (UGT) 1A7, UGT1A8, and UGT1A10. Additionally, verbascoside showed weak inhibitory potency against CYP1A2 and CYP1B1 with IC50 values of 83 µM and 86 µM, respectively. Potent antioxidant and low cytotoxic potential were observed. Based on these data, verbascoside does not possess any clinically relevant CYP-mediated interaction potential, but it has effective biological activity. Therefore, verbascoside could be considered as a lead compound for further drug development and as an adjuvant during tuberculosis treatment.

ES2 as a Novel Verbascoside-Derived Compound in the Treatment of Cutaneous Wound Healing

Several pathologies are characterized by chronic wounds and often resistant to many of the common therapies, leading to chronic infections that can become even life-threatening for patients. For this reason, the identification of new products able to ameliorate the healing process is still an on-going research. Natural compounds have been used to improve skin conditions due to their dermo-cosmetic and therapeutic activities including anti-inflammatory, antioxidant and cell-migratory properties. Among these compounds, it has been recently demonstrated that Verbascoside, a phenyl propanoid glycoside widely used in the cosmetic field, can improve keratinocytes proliferation. Because of its high hydrophilic character, Verbascoside has a limited range of possible topical applications and the synthesis of ES2, a semi-synthetic derivative of Verbascoside was performed to bypass some of the drawback aspects of this molecule. In the present study, the wound healing properties of Verbascoside and ES2 were compared in both keratinocytes “in vitro” wound scratch and in wounded SKH1 mice. The results showed that both compounds were not cytotoxic and ES2 showed an efficient ability to promote the proliferation of human keratinocytes compared to Verbascoside. The findings were also confirmed in vivo but only at early time points (2/3 days). Taken together, these data suggest that the Verbascoside-derivative ES2 could be considered a novel and promising candidate for the topical treatment of wounds.

Phytochemical study of the trunk bark of Citharexylum spinosum L. growing in Tunisia: Isolation and structure elucidation of iridoid glycosides

A phytochemical investigation of the trunk bark ethyl acetate extract of Citharexylum spinosum L. has led to the isolation of four previously undescribed iridoid glycosides, tunispinosides A-D, and five known phenylethanoid glycosides, verbascoside, leucosceptoside A, martynoside, isoverbascoside and plantainoside C, together with 4-hydroxy-2,6-dimethoxyphenyl 6'-O-vanilloyl-β-D-glucopyranoside, two 8,3'-neolignan glycosides, plucheosides D₁-D₂, coniferyl aldehyde, vanillic acid, syringic acid, ferulic acid and tyrosol. All compounds were isolated for the first time from C. spinosum. Their isolation was carried out using silica gel column and high performance liquid chromatography (HPLC). Structures were established by spectroscopic means including 1D and 2D NMR experiments, and spectrometric ESI-HRMS analysis.

Natural Substances for Prevention of Skin Photoaging: Screening Systems in the Development of Sunscreen and Rejuvenation Cosmetics

Solar broadband UV irradiation is commonly regarded as a major causative reason for cutaneous photoaging. The pro-aging molecular pathways and cellular targets affected by UVA+UVB light in human skin have been extensively investigated. Notwithstanding growing knowledge in mechanisms of photoaging, research and development of clinically efficient, nontoxic, and sustainable topical preparations providing full physical, chemical, and biological photoprotection still remain a great challenge for pharmaceutical and cosmetic industries. In this study, we are proposing a panel of the in vitro methods for preselection of natural photoprotective substances with high photostability and low phototoxicity able of absorbing a broadband UVA+UVB irradiation (physical sunscreen), reducing UV-related overproduction of free radicals and loss of endogenous antioxidants (chemical protection), and attenuating UV-induced cytotoxicity and immune and metabolic responses (biological protection) in primary human epidermal keratinocytes and immortalized human keratinocyte cultures. Our data showed that secondary metabolites biosynthesized in plant cells in response to UV irradiation, such as phenylpropanoids and their glycosylated metabolites, aglycons and glycosylated flavonoids, and leontopodic acids, hold the best promise for complete natural topical prevention of photoaging and rejuvenation of photoaged skin. Meristem plant cell cultures elicited by solar simulating UV could be the most environmentally sustainable biotechnological source of polyphenols with combined photoprotective and antiaging properties.

Meristem Plant Cells as a Sustainable Source of Redox Actives for Skin Rejuvenation

Recently, aggressive advertisement claimed a “magic role” for plant stem cells in human skin rejuvenation. This review aims to shed light on the scientific background suggesting feasibility of using plant cells as a basis of anti-age cosmetics. When meristem cell cultures obtained from medicinal plants are exposed to appropriate elicitors/stressors (ultraviolet, ultrasound ultraviolet (UV), ultrasonic waves, microbial/insect metabolites, heavy metals, organic toxins, nutrient deprivation, etc.), a protective/adaptive response initiates the biosynthesis of secondary metabolites. Highly bioavailable and biocompatible to human cells, low-molecular weight plant secondary metabolites share structural/functional similarities with human non-protein regulatory hormones, neurotransmitters, pigments, polyamines, amino-/fatty acids. Their redox-regulated biosynthesis triggers in turn plant cell antioxidant and detoxification molecular mechanisms resembling human cell pathways. Easily isolated in relatively large quantities from contaminant-free cell cultures, plant metabolites target skin ageing mechanisms, above all redox imbalance. Perfect modulators of cutaneous oxidative state via direct/indirect antioxidant action, free radical scavenging, UV protection, and transition-metal chelation, they are ideal candidates to restore photochemical/redox/immune/metabolic barriers, gradually deteriorating in the ageing skin. The industrial production of plant meristem cell metabolites is toxicologically and ecologically sustainable for fully “biological” anti-age cosmetics.

Anticancer Activity of Stilbene-Based Derivatives

Stilbene is an abundant structural scaffold in nature, and stilbene-based compounds have been widely reported for their biological activity. Notably, (E)-resveratrol and its natural stilbene-containing derivatives have been extensively investigated as cardioprotective, potent antioxidant, anti-inflammatory, and anticancer agents. Starting from its potent chemotherapeutic activity against a wide variety of cancers, the stilbene scaffold has been subject to synthetic manipulations with the aim of obtaining new analogues with improved anticancer activity and better bioavailability. Within the last decade, the majority of new synthetic stilbene derivatives have demonstrated significant anticancer activity against a large number of cancer cell lines, depending on the type and position of substituents on the stilbene skeleton. This review focuses on the structure-activity relationship of the key compounds containing a stilbene scaffold and describes how the structural modifications affect their anticancer activity.

Resveratrol-Related Polymethoxystilbene Glycosides: Synthesis, Antiproliferative Activity, and Glycosidase Inhibition

A small library of polymethoxystilbene glycosides (20-25) related to the natural polyphenol resveratrol have been synthesized and subjected, together with their aglycones 17-19, to an antiproliferative activity bioassay toward Caco-2 and SH-SY5Y cancer cells. Six of the compounds exhibit antiproliferative activity against at least one cell line. In particular, compounds 17 and 18 proved highly active on at least one of the two cell cultures. Compound 18 showed a GI50 value of 3 μM against Caco-2 cells, a value comparable to that of the anticancer drug 5-fluorouracil. The closely related compound 19 proved inactive, and its conjugates 22 and 25 showed weak cell growth inhibition. The results indicate that minimal differences in the structure of both polymethoxystilbenes and their glycosides can substantially affect the antiproliferative activity. The possible hydrolytic release of the aglycones 17-19 by β-glucosidase or β-galactosidase was also evaluated. Compounds 20-25 were also tested as potential β-glucosidase, β-galactosidase, and α-glucosidase inhibitors. A promising inhibitory activity toward α-glucosidase was observed for 21 (IC50 = 78 μM) and 25 (IC50 = 70 μM), which might be indicative of their potential as lead compounds for development of antidiabetic or antiobesity agents.

Phytochemical analysis, antioxidant activity, fatty acids composition, and functional group analysis of Heliotropium bacciferum

Heliotropium bacciferum is paramount in medicinal perspective and belongs to Boraginaceae family. The crude and numerous fractions of leaves, stem, and roots of the plant were investigated for phytochemical analysis and DPPH radical scavenging activity. Phytochemical analysis of crude and fractions of the plant revealed the presence of alkaloids, saponins, tannins, steroids, terpenoids, flavonoids, glycosides, and phenols. The antioxidant (free radical scavenging) activity of various extracts of the Heliotropium bacciferum was resolute against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical with the avail of UV spectrophotometer at 517 nm. The stock solution (1000 mg/mL) and then several dilutions (50, 100, 150, 200, and 250 mg/mL) of the crude and fractions were prepared. Ascorbic acid was used as a standard. The plant leaves (52.59 ± 0.84 to 90.74 ± 1.00), stem (50.19 ± 0.92 to 89.42 ± 1.10), and roots extracts (49.19 ± 0.52 to 90.01 ± 1.02) divulged magnificent antioxidant activities. For the ascertainment of the fatty acid constituents a gas chromatograph hyphenated to mass spectrometer was used. The essential fatty acids for growth maintenance such as linoleic acid (65.70%), eicosadienoic acid (15.12%), oleic acid (8.72%), and palmitic acid (8.14%) were found in high percentage. The infrared spectra of all extracts of the plant were recorded by IR Prestige-21 FTIR model.

Verbascoside--a review of its occurrence, (bio)synthesis and pharmacological significance

Phenylethanoid glycosides are naturally occurring water-soluble compounds with remarkable biological properties that are widely distributed in the plant kingdom. Verbascoside is a phenylethanoid glycoside that was first isolated from mullein but is also found in several other plant species. It has also been produced by in vitro plant culture systems, including genetically transformed roots (so-called 'hairy roots'). Verbascoside is hydrophilic in nature and possesses pharmacologically beneficial activities for human health, including antioxidant, anti-inflammatory and antineoplastic properties in addition to numerous wound-healing and neuroprotective properties. Recent advances with regard to the distribution, (bio)synthesis and bioproduction of verbascoside are summarised in this review. We also discuss its prominent pharmacological properties and outline future perspectives for its potential application.

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents.

Polar constituents of Marrubium thessalum Boiss. & Heldr. (Lamiaceae) and their cytotoxic/cytostatic activity

The methanol extract of the aerial parts of Marrubium thessalum Boiss. & Heldr. (Lamiaceae) afforded 30 phenolic metabolites, belonging to the classes of phenylethanoid glycosides, flavonoids and simple phenolic compounds. The crude methanol extract as well as the secondary metabolites were screened for their cytotoxic/cytostatic effects against four human cancer cell lines, specifically HeLa, MCF-7, FM3 and HCT-116 and demonstrated considerable cell growth-inhibitory activity. The differential cytotoxicity of the compounds implied possible structure-activity relationships. Selected compounds were evaluated for their toxicity against human peripheral blood mononuclear cells, where some of them showed marginal toxic effects. The results suggest that M. thessalum produces secondary metabolites that demonstrate selective anticancer activity concomitantly with reduced toxicity on lymphocytes. The structure of such compounds can eventually lead to the development of novel pharmaceutical agents.

Metabolic differentiations and classification of Verbascum species by NMR-based metabolomics

The genus Verbascum L. (mulleins) comprises of about 360 species of flowering plants in the Scrophulariaceae family. Mulleins have been used in the traditional folk medicine for centuries, for treatment of a wide range of human ailments, inter alia bronchitis, tuberculosis, asthma, and different inflammations. Despite all applications the knowledge of the metabolites, accumulated in different mullein species, is still limited and based mainly on determination of the major compounds. Here we report the application of 1H NMR metabolic fingerprinting in combination with principal component analyses (PCA) in five different Verbascum species. Based on the obtained results mulleins were divided in two groups: group A (Verbascum phlomoides and Verbascum densiflorum) and group B (Verbascum xanthophoeniceum, Verbascum nigrum and Verbascum phoeniceum). Further it was found that the plants in group B accumulate higher amounts of bioactive iridoid and phenylethanoid glycosides. V. xanthophoeniceum and V. nigrum accumulate higher amounts of the pharmaceutically-important harpagoside (∼0.5% on dry weight basis) and verbascoside, forsythoside B and leucosceptoside B (in total 5.6-5.8% on dry weight basis), which underlines the possibility for their application in pharmaceutical industry. To the best of our knowledge this is the first report on the analyses of Verbascum sp. leaf metabolome.

Sonication-assisted Agrobacterium rhizogenes-mediated transformation of Verbascum xanthophoeniceum Griseb. for bioactive metabolite accumulation

An efficient protocol for the establishment of transformed root culture of Verbascum xanthophoeniceum using sonication-assisted Agrobacterium rhizogenes-mediated transformation is reported. Only 10 days after the inoculation with A. rhizogenes ATCC 15834 and 45 s ultrasound exposure, hairy roots appeared on 75% of the Verbascum leaves. Ten hairy root lines were isolated, although only half of them were free of bacterial contamination and started growing when excised from mother explants. The transgenic nature of the most vigorously growing hairy root clones (VX1 and VX6) was confirmed by polymerase chain reaction. Under submerged cultivation both hairy root clones accumulated high biomass amounts (12.8 and 14.3 g L(-1), respectively) and significant amounts of bioactive phenylethanoid glycoside verbascoside (over 6-times more than in mother plant leaves). LC-APCI-MS analyses confirmed verbascoside accumulation in hairy root clones along with three other phenylethanoid glycosides (forsythoside B, leucosceptoside B and martynoside) and an iridoid glycoside aucubin. This is the first report on the induction of hairy roots of Verbascum plants.

Xanthine oxidase inhibitory properties of Czech medicinal plants

AIM OF THE STUDY

To investigate in vitro xanthine oxidase inhibitory properties of plants traditionally used in Czech Republic and Central-East Europe region for gout, arthritis or rheumatism treatment.

MATERIALS AND METHODS

Methylene chloride-methanolic and two ethanolic extracts of 27 plant species were screened for in vitro xanthine oxidase inhibitory activity using a spectrophotometric method.

RESULTS

Around 50% of the species exhibited some degree of xanthine oxidase inhibitory properties at 200 μg/mL, showing a moderate correlation (r=0.59) with total phenol content. The most active were methylene chloride-methanolic extracts of Populus nigra and Betula pendula, with IC(50) of 8.3 and 25.9 μg/mL, respectively, followed by 80% ethanolic extract of Caryophyllus aromaticus and Hypericum perforatum, both under 50 μg/mL.

CONCLUSIONS

Populus nigra and Betula pendula were identified as species with the highest xanthine oxidase inhibitory potential in our study. This correlates with the ethnobotanical data on their use in Central European folklore and provides the basis for further investigation on these plants.

Astonishing diversity of natural surfactants: 6. Biologically active marine and terrestrial alkaloid glycosides

This review article presents 209 alkaloid glycosides isolated and identified from plants, microorganisms, and marine invertebrates that demonstrate different biological activities. They are of great interest, especially for the medicinal and/or pharmaceutical industries. These biologically active glycosides have good potential for future chemical preparation of compounds useful as antioxidants, anticancer, antimicrobial, and antibacterial agents. These glycosidic compounds have been subdivided into several groups, including: acridone; aporphine; benzoxazinoid; ergot; indole; enediyne alkaloidal antibiotics; glycosidic lupine alkaloids; piperidine, pyridine, pyrrolidine, and pyrrolizidine alkaloid glycosides; glycosidic quinoline and isoquinoline alkaloids; steroidal glycoalkaloids; and miscellaneous alkaloid glycosides.