Bisbibenzyls from Serbian Primula veris subsp. Columnae (Ten.) Lȕdi and P. acaulis (L.) L.

Bisbibenzyls are specialized metabolites found exclusively in liverworts, until recently; they represent chemical markers of liverworts. Their occurrence in vascular plants was noticed in 2007, when they were found in Primula veris subsp. macrocalyx from Russia. This report prompted us to chemically analyze the two most common Serbian Primula species, P. veris subsp. columnae and P. acaulis, in order to determine the presence of bisbibenzyls in them. Our study revealed nine structurally distinct bisbibenzyls (1-9), identified based on 1D and 2D NMR, IR, UV and HRESIMS data. Among them were five previously undescribed compounds (2-6). The remaining compounds found and previously described in the literature were: the bisbibenzyls riccardin C (1), isoperrottetin A (7), isoplagiochin E (8) and 11-O-demethylmarchantin I (9), as well as 4-hydroxyphenylmethylketone (10) and 4-hydroxy-3-methoxyphenylmethylketone (11). Riccardin C was the most dominant bisbibenzyl in both species studied. Previously, it was the first bisbibenzyl found in vascular plants (P. veris subsp. macrocalyx). An assessment of the cytotoxic activity of the isolated compounds against A549 lung cancer and healthy MRC5 cell lines was also the subject of our study. Compounds 6 and 9 exhibited significant cytotoxic activity expressed by IC50 values of 12 µM, but the selectivity was not satisfactory.

Novel hybrids of sclareol and 1,2,4-triazolo[1,5-a]pyrimidine show collateral sensitivity in multidrug-resistant glioblastoma cells.

The synthesis of 24 hybrid molecules, consisting of naturally occurring sclareol (SCL) and synthetic 1,2,4-triazolo[1,5-a]pyrimidines (TPs), is described. New compounds were designed with the aim of improving the cytotoxic properties, activity, and selectivity of the parent compounds. Six analogs (12a-f) contained 4-benzylpiperazine linkage, while 4-benzyldiamine linkage was present in eighteen derivatives (12g-r and 13a-f). Hybrids 13a-f consist of two TP units. After purification, all hybrids (12a-r and 13a-f), as well as their precursors (9a-e and 11a-c), were tested on human glioblastoma U87 cells. More than half of the tested synthesized molecules, 16 out of 31, caused a significant reduction of U87 cell viability (more than 75% reduction) at 30 µM. The concentration-dependent cytotoxicity of these 16 compounds was also examined on U87 cells, corresponding multidrug-resistant (MDR) U87-TxR cells with increased P-glycoprotein (P-gp) expression and activity, and normal lung fibroblasts MRC-5. Importantly, 12l and 12r were active in the nanomolar range, while seven compounds (11b, 11c, 12i, 12l, 12n, 12q, and 12r) were more selective towards glioblastoma cells than SCL. All compounds except 12r evaded MDR, showing even better cytotoxicity in U87-TxR cells. In particular, 11c, 12a, 12g, 12j, 12k, 12m, 12n, and SCL showed collateral sensitivity. Hybrid compounds 12l, 12q, and 12r decreased P-gp activity to the same extent as a well-known P-gp inhibitor - tariquidar (TQ). Hybrid compound 12l and its precursor 11c affected different cellular processes including the cell cycle, cell death, and mitochondrial membrane potential, and changed the levels of reactive oxygen and nitrogen species (ROS/RNS) in glioblastoma cells. Collateral sensitivity towards MDR glioblastoma cells was caused by the modulation of oxidative stress accompanied by inhibition of mitochondria.

Bis-bibenzyls, Bibenzyls, and Terpenoids in 33 Genera of the Marchantiophyta (Liverworts): Structures, Synthesis, and Bioactivity.

The Marchantiophyta (liverworts) are rich sources of phenolic substances, especially cyclic and acyclic bis-bibenzyls, which are rare natural products in the plant kingdom, together with bibenzyls and characteristic terpenoids. At present, more than 125 bis-bibenzyls have been found in liverworts. They are biosynthesized from the dimerization of lunularic acid via dihydrocoumaric acid and prelunularin. The structurally unusual cyclic and acyclic bis-bibenzyls show various biological activities such as antimicrobial, antifungal, cytotoxic, muscle relaxation, antioxidant, tubulin polymerization inhibitory, and antitrypanosomal activities, among others. The present review article deals with the distribution and structure of bis-bibenzyls, bibenzyls, and several characteristic ent-sesqui- and diterpenoids in liverworts. Furthermore, the biosynthesis and total syntheses and biological activities of bis-bibenzyls are also surveyed.

Bis-Bibenzyls from the Liverwort Pellia endiviifolia and Their Biological Activity.

Based on previous investigations where bis-bibenzyls isolated from liverworts showed various biological activities (cytotoxic, antimicrobial, and antiviral), we investigated their cytotoxic activity in several human cancer cell lines. From the methylene-chloride/methanol extract of the liverwort Pellia endiviifolia, three bis-bibenzyls of the perrottetin type were isolated, namely perrottetin E, 10'-hydroxyperrottetin E, and 10,10'-dihydroxyperrottetin E. The last two were found for the first time in this species. Their structures were resolved using 1D and 2D NMR, as well as by comparison with data in the literature. Cytotoxic activity of the isolated compounds was tested on three human leukemia cell lines, HL-60 (acute promyelocytic leukemia cells), U-937 (acute monocytic leukemia cells), and K-562 (human chronic myelogenous leukemia cells), as well as on human embryonal teratocarcinoma cell line (NT2/D1) and human glioblastoma cell lines A-172 and U-251, and compared to the previously isolated bis-bibenzyls (perrottetins) of similar structure. The isolated compounds exhibited modest activity against leukemia cells and significant activity against NT2/D1 and A-172. Overall, the most active cytotoxic compounds in this investigation were perrottetin E (1), isolated in this work from Pellia endiviifolia, and perrottetin F phenanthrene derivative (7), previously isolated from Lunularia cruciata and added for a comparison of their cytotoxic activity.

Cytotoxic triterpenoids and triterpene sugar esters from the medicinal mushroom Fomitopsis betulina.

Thirteen undescribed 24-methylene lanostane triterpenoids, named polyporenic acids E-M and fomitosides L-O, as well as seventeen known analogues, were isolated from the fruiting bodies of the mushroom Fomitopsis betulina. Their structures were determined using 1D, 2D NMR, IR, and HRESIMS. Fomitoside L and fomitoside N exhibited cytotoxicity against HL60 leukemia cells (IC50 = 15.8 and 23.7 µM, respectively). Among the known compounds, notable cytotoxicities against HL60 leukemia cells and selectivity with respect to MRC-5 healthy cells were noticed for dehydropachymic acid (IC50 = 10.9 µM, SI 8.6), pachymic acid (IC50 = 11.0 µM, SI 9.8), 3-epi-dehydrotumulosic acid (IC50 = 19.9 µM, SI 5.8) and 12α-hydroxy-3α-(3'-hydroxy-4'-methoxycarbonyl-3'-methylbutyryloxy)-24-methyllanosta-8,24 (31)-dien-26-oic acid (IC50 = 19.2 µM, SI 2.2).

Lamiaceae in the treatment of cardiovascular diseases.

Lamiaceae (Labiatae) are an important group of medicinal plants, which have been used for treating heart disease in traditional medicine for centuries. These mainly aromatic plants are used as essential oils, extracts or isolated components (polyphenols, phenolic compounds, terpenes, iridoids etc.). Some Labiatae species (more than 30, such as cornmint, lavender, patchouli, rosemary etc.) are famous for their use in essential oil production worldwide. In this review, cardioprotective effects of Lamiaceae and their active secondary metabolites, as well as mechanism of action against cardiovascular diseases (hypertension, angina pectoris, hyperlipidemia, thromboembolism, coronary heart disease, heart failure, venous insufficiency, arrhythmia) will be discussed. Use of Labiatae as food or food additives (such as spices) may prevent risk of cardiovascular diseases, diabetes and cancer. This approach is also described as a part of the article. Studies on developing new, effective and safe natural products from Lamiaceae (rich source of flavonoids and other active compounds) are promising and may offer prevention and treatment for patients with coronary disease and other related diseases.

Chemical Composition, Total Phenols and Flavonoids Contents and Antioxidant Activity as Nutritive Potential of Roasted Hazelnut Skins (Corylus avellana L.).

The present study evaluates natural composition of Serbian roasted hazelnut skins (HS) with potential role in application as functional nutrient of various food products. Total phenols (TPC) and flavonoids contents (TFC) in HS extracts obtained with different ethanol concentrations (10%-I, 50%-II and 96%-III) and their antioxidant activities were investigated. The highest total phenols content (706.0 ± 9.7 mgGAE/gextract) was observed in 96% ethanol HS extract. Ethanol HS extracts showed very high antioxidant activity with effective concentrations (EC50) ranged between 0.052 and 0.066 mg/mL. The phenol and flavonoid content of roasted HS extracts I-III was determined by HPLC-ESI-MS/MS analyses. Contents of lipids, proteins, carbohydrates, metals, and C, H, N, S elements in roasted HS were also determined. Relatively high C/N, C/P and C/N/P ratios, rich metal contents and fatty acids composition indicated that hazelnut skin might be a good candidate for use as either human or fungal functional nutrient. In addition, possible application of phenolic HS extracts as UV booster was studied by recording UV spectra (220-440 nm) of 10 mg/L of HS extracts I-III combined with 10 mg/L of chemical sunscreen agent benzophenone-3 and in vitro sun protection factor (SPF) was calculated.

Chemo- and biocatalytic esterification of marchantin A and cytotoxic activity of ester derivatives.

Chemical and biocatalytic synthesis of seven previously undescribed marchantin A ester derivatives has been presented. Chemical synthesis afforded three peresterified bisbibenzyl products (TE1-TE3), while enzymatic method, using lipase, produced regioselective monoester derivatives (ME1-ME4). The antiproliferative activities of all prepared derivatives of marchantin A were tested on MRC-5 healthy human lung fibroblast, A549 human lung cancer, and MDA-MB-231 human breast cancer cell lines. All tested esters were less cytotoxic in comparison to marchantin A, but they also exhibited lower cytotoxicity against healthy cells. Monoesters displayed higher cytotoxic activities than the corresponding peresterified products, presumably due to the presence of free catechol group. Monohexanoyl ester ME3 displayed the same IC50 like marchantin A against MDA-MB-231 cells, but the selectivity was higher. In this way, regioselective enzymatic monoesterification enhanced selectivity of marchantin A. ME3 was also the most active among all derivatives against lung cancer cells A549 with the slightly lower activity and selectivity in comparison to marchantin A.

The Healing Effects of Spices in Chronic Diseases.

Spices are not only just herbs used in culinary for improving the taste of dishes, they are also sources of a numerous bioactive compounds significantly beneficial for health. They have been used since ancient times because of their antimicrobial, anti-inflammatory and carminative properties. Several scientific studies have suggested their protective role against chronic diseases. In fact, their active compounds may help in arthritis, neurodegenerative disorders (Alzheimer's, Parkinson, Huntington's disease, amyotrophic lateral sclerosis, etc.), diabetes, sore muscles, gastrointestinal problems and many more. In the present study, possible roles of spices and their active components, in chronic diseases (cancer, arthritis, cardiovascular diseases, etc.) along with their mechanism of action have been reviewed.

Antibacterial and Antibiofilm Activity of Flavonoid and Saponin Derivatives from Atriplex tatarica against Pseudomonas aeruginosa.

A new flavonoid glucoside derivative, patuletin 3 -O-(2- O-feruloyl)-ß-d-glucuronopyranosyl-(1→2)-ß-d-glucopyranoside, named atriplexin IV (1), and three new triterpenoid saponin derivatives, two sulfonylated, ß-d-glucopyranosyl-3 -O-(2- O-sulfo-ß-d-galactopyranosyl)-(1→2)-α-l-arabinopyranoside-30-alolean-12-en-28-oate (2), named atriplexogenin I, ß-d-glucopyranosyl-3- O-(2- O-sulfo-ß-d-galactopyranosyl)-(1→2)-α-l-arabinopyranoside)-30-hydroxyolean-12-en-28-oate (3), named atriplexogenin II, and ß-d-glucopyranosyl-3 -O-(ß-d-glucopyranosyl-(1→2)-ß-d-galactopyranosyl-(1→2)-α-l-arabinopyranoside)-30-alolean-12-en-28-oate (4), named atriplexogenin III, were isolated by silica gel column and semipreparative HPLC chromatography from the n-butanol extract of the salt marsh plant Atriplex tatarica. In addition, two known secondary metabolites, patuletin3 -O-ß-d-apiofuranosyl-(1‴→2″)-ß-d-glucopyranoside (5) and patuletin 3 -O-5‴- O-feruloyl-ß-d-apiofuranosyl-(1‴→2″)-ß-d-glucopyranoside (6), were isolated for the first time from A. tatarica. The structures of the isolated compounds were elucidated by 1D and 2D NMR, HRESIMS, IR, and UV data. Antibacterial activity by the microdilution method and antibiofilm activity against P. aeruginosa were assessed. Compound 5 possesses significant antibacterial activity, while the most potent antibiofilm agent is compound 2.

Cytotoxic Activity of Riccardin and Perrottetin Derivatives from the Liverwort Lunularia cruciata.

Seven new bisbibenzyls (1-7) were isolated from the methanol extract of the liverwort Lunularia cruciata along with one previously known bibenzyl and five known bisbibenzyls. The structures of compounds 1-7 were elucidated on the basis of the spectroscopic data. These newly isolated bisbibenzyls may be divided into two groups, the acyclic bisbibenzyls, perrottetins (1-3), and the cyclic analogues, riccardins (4-7). Besides standard perrottetin and riccardin structures (1 and 4, respectively), they contain phenanthrene (3 and 5), dihydrophenanthrene (2), and quinone moieties (6 and 7), rarely found in natural products. The new compounds 3 and 5, as well as the known riccardin G, exhibited cytotoxic activity against the A549 lung cancer cell line with IC50 values of 5.0, 5.0, and 2.5 µM, respectively.

New aurone epoxide and auronolignan from the heartwood of Cotinus coggygria Scop.

New aurone epoxide, 2,10-oxy-10-methoxysulfuretin (14), and new auronolignan (15), named cotinignan A, were isolated by silica gel column and semipreparative HPLC chromatography from the methylene chloride/methanol extract of Cotinus coggygria Scop. heartwood. In addition, thirteen known secondary metabolites namely sulfuretin, 2,3-trans-fustin, fisetin, butin, butein, taxifolin, eriodictyol, 3',5,5',7-tetrahydroxyflavanone, 3',4',7-trihydroxyflavone, 3-O-methyl-2,3-trans-fustin, 3-O-galloyl-2,3-trans-fustin, ß-resorcylic acid and 3-O-ß-sitosterol glucoside were isolated as well. Their structures were elucidated by 1D and 2D NMR, HR-ESI-MS, IR and UV. Ten out of eleven isolated flavonoids possess 7, 3' and 4' hydroxy groups. These structural features could be considered as chemotaxonomic characteristic of flavonoids from C. coggygria. Cotinignan A (15) represents new subclass of secondary metabolites - auronolignans.

Multielement analysis and antioxidant capacity of Merlot wine clones developed in Montenegro.

The overall aim of this paper was to compare the multielement composition and antioxidant capacity of two Montenegrin Merlot wines obtained from specific vine clones (VCR1 and VCR 101) along with commercial Merlot wine throughout the consecutive vintages in 2010 and 2011. Elemental composition was analysed using inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Additionally, antioxidant capacity was assessed by cyclic voltammetry. VCR 1 wine from 2011 stood out for its elemental composition. On the other hand, antioxidant capacity of VCR 101 wines was the highest one for the both vintages. According to the experimental data obtained, all three wines are good source of essential elements and products with a significant antioxidant activity and specific geographical origin.

Secondary metabolites from endemic species Iris adriatica Trinajstic ex Mitic (Iridaceae).

This manuscript describes the first detailed chemical investigation of endemic species Iris adriatica, including isolation and structure elucidation. Chemical analyses of the rhizome CH2Cl2/MeOH (2:1) extract revealed fourteen secondary metabolites, mainly isoflavonoids. Among isoflavonoids, two groups have been found: nigricin-type and tectorigenin-type. Dominant group of the isolated compounds has been nigricin-type isoflavones: nigricin, nigricin-4'-(1-O-ß-D-glucopyranoside) and nigricin-4'-(1-O-ß-D-glucopyranosyl (1-6)-ß-D-glucopyranoside) with 2.5, 10 and 1% of the total extract, respectively. Irisxanthone - xanthone C-glucoside, ß-sitosterol, benzophenone and one of its derivatives have also been found. Nigricin-type isoflavonoids and irisxanthone can be considered as possible chemotaxonomic markers for I. adriatica. 5,3',5'-Trimethoxy-6,7-methylenedioxyisoflavone-4'-(1-O-ß-D-glucopyranoside) and benzophenone have been isolated from Iris species for the first time.

Bioactive Pentacyclic Triterpene Ester Derivatives from Alnus viridis ssp. viridis Bark.

Seven derivatives of pentacyclic triterpene acids (1-7) were isolated from the bark of Alnus viridis ssp. viridis using a combination of column chromatography and semipreparative HPLC. Compounds 1-3, 6, and 7 were determined to be new after spectroscopic data interpretation and were assigned as 27-hydroxyalphitolic acid derivatives (1-3), a 27-hydroxybetulinic acid derivative (6), and a 3-epi-maslinic acid derivative (7), respectively. Pentacyclic triterpenoids with a C-27 hydroxymethyl group have been found in species of the genus Alnus for the first time. These compounds were subjected to cytotoxicity testing against a number of cancer cell lines. Also, selected pentacyclic triterpenoids were selected as potential inhibitors of topoisomerases I and IIα for an in silico investigation.

Comparative analytical study of the selected wine varieties grown in Montenegro.

Samples of the selected red wine varieties grown in Montenegro (Merlot, Cabernet Sauvignon and Vranac; vintages 2010-2012) were compared according to total phenolic content, anti-DPPH radical activity, phenolic profile and elemental composition. All the samples showed profound anti-DPPH radical activity, due to high content of total phenolic compounds (R = 0.92). The most abundant phenolics were catechin and gallic acid with the highest values recorded for Merlot 2012 (43.22 and 28.65 mg/L, respectively). In addition to this, the content of essential elements including the potentially toxic ones was within healthy (safe) level for all the samples analysed. This study has actually pointed out Merlot wine variety as the best quality one, though all three varieties may be used as safe and health-promoting nutritional products.

Diarylheptanoids from Alnus viridis ssp. viridis and Alnus glutinosa: Modulation of Quorum Sensing Activity in Pseudomonas aeruginosa.

Diarylheptanoids from the barks of Alnus viridis ssp. viridis (green alder) and Alnus glutinosa (black alder) were explored for anti-quorum sensing activity. Chemicals with anti-quorum sensing activity have recently been examined for antimicrobial applications. The anti-quorum sensing activity of the selected diarylheptanoids was determined using two biosensors, namely Pseudomonas aeruginosa PAO1 and Chromobacterium violaceum CV026. Although all of the investigated compounds negatively influenced the motility of P. aeruginosa PAO1, four were able to inhibit biofilm formation of this human opportunistic pathogen for 40-70 %. Three of the diarylheptanoids (3, 4, and 5) negatively influenced the biosynthesis of pyocyanin, which is under the control of quorum sensing. Platyphyllenone (7) and hirsutenone (5) were able to inhibit the biosynthesis of violacein in C. violaceum CV026, with 5 being able to inhibit the synthesis of both biopigments. Only one of the tested diarylheptanoids (1) was shown to significantly decrease the production of acyl homoserine lactones (AHL) in P. aeruginosa PAO1, more specifically, production of the long chain N-(3-oxododecanoyl)-l-HSL. On the other side, four diarylheptanoids (2-5) significantly reduced the synthesis of 2-alkyl-4-quinolones, part of the P. aeruginosa quinolone-mediated signaling system. To properly assess therapeutic potential of these compounds, their in vitro antiproliferative effect on normal human lung fibroblasts was determined, with doses affecting cell proliferation between 10 and 100 µg/mL. This study confirms that the barks of green and black alders are rich source of phytochemicals with a wide range of biological activities that could further be exploited as natural agents against bacterial contaminations and infections.

Structural differences in diarylheptanoids analogues from Alnus viridis and Alnus glutinosa influence their activity and selectivity towards cancer cells.

Diarylheptanoids represent a group of plant secondary metabolites that possess multiple biological properties and are increasingly recognized for their therapeutic potential. A comparative study was performed on structurally analogous diarylheptanoids isolated from the bark of green (Alnus viridis) and black alder (Alnus glutinosa) to address their biological effects and determine structure-activity relationship. The structures and configurations of all compounds were elucidated by NMR, HR-ESI-MS, UV and IR. Diarylheptanoids actions were studied in human non-small cell lung carcinoma cells (NCI-H460) and normal keratinocytes (HaCaT). A. viridis compounds 3v, 5v, 8v and 9v that possess a carbonyl group at C-3 were considerably more potent than compounds without this group. A. viridis/A. glutinosa analogue pairs, 5v/5g and 9v/9g, which differ in the presence of 3' and 3″-OH groups, were evaluated for anticancer activity and selectivity. 5v and 9v that do not possess 3' and 3″-OH groups showed significantly higher cytotoxicity compared to analogues 5g and 9g. In addition, these two A. viridis compounds induced a more prominent apoptosis in both cell lines and an increase in subG0 cell cycle phase, compared to their A. glutinosa analogues. 5v and 9v treatment triggered intracellular superoxide anion accumulation and notably decreased mitochondrial transmembrane potential. In HaCaT cells, 9v and 9g with a 4,5 double bond caused a more prominent loss of mitochondrial transmembrane potential compared to 5v and 5g which possess a 5-methoxy group instead. Although green alder diarylheptanoids 5v and 9v displayed higher cytotoxicity, their analogues from black alder 5g and 9g could be more favorable for therapeutic use since they were more active in cancer cells than in normal keratinocytes. These results indicate that minor differences in the chemical structure can greatly influence the effect of diarylheptanoids on apoptosis and redox status and determine their selectivity towards cancer cells.

Micromeria thymifolia Essential Oil Suppresses Quorum-sensing Signaling in Pseudomonas aeruginosa.

The chemical composition, antimicrobial and antiquorum sensing activity of the essential oil of Micromeria thymifolia (Scop.) Fritsch were investigated. Limonene, piperitone epoxide and piperitenone epoxide were found as the main constituents using a gas chromatography-mass spectrometry technique. In vitro antimicrobial activity of the oil was tested against six bacterial and seven fungal strains and high antimicrobial potential was noticed. Minimum inhibitory concentration varied from 0.031 mg/mL to 0.5 mg/mL for bacterial and 0.062 mg/mL to 0.5 mg/mL for fungal strains. The antiquorum properties of the essentidl oil were evaluated on Pseudomonas aeruginosa PAO 1. The oil was tested at subMIC concentrations for anti-quorum sensing activity. The analyses on quorum-sensing functions have been carried out by evaluating twitching and swarming of bacterial cultures and the total amount of pyocyanin production produced by P. aeruginosa. This study showed that M thymifolia essential oil exhibited antiquorum sensing activity and may be used as an antipathogenic drug.

Bis-bibenzyls from the Cameroon Liverwort Marchantia debilis.

Liverworts are rich sources of terpenoids and aromatic compounds among which bis-bibenzyls are well known for their wide spectrum of biological activities. This is the first report of chemical analysis of the African liverwort Marchantia debilis Goebel. From the methanol extract marchantinquinone-l'-methyl ether was newly isolated together with three known bis-bibenzyls, marchantin C, marchantinquinone and perrottetin E. The presence of bis-bibenzyls with a quinone moiety is noted for the first time in the Marchantia genus.