Recent Advances in the Phytochemistry of Bryophytes: Distribution, Structures and Biological Activity of Bibenzyl and Bisbibenzyl Compounds

Research on bryophyte phytochemistry has revealed the presence of different phytochemicals like fatty acids, terpenoids, small phenolic molecules, etc. Small phenolic molecules, i.e., bibenzyls (of two aromatic rings) and bisbibenzyls (four aromatic rings), are unique signature molecules of liverworts. The first bisbibenzyls marchantin A and riccardin A were discovered in two consecutive years, i.e., 1982 and 1983, respectively, by Asakawa and coworkers. Since then, about 70 bisbibenzyls have been reported. These molecules are characterized and identified using different spectroscopic techniques and surveyed for different bioactivity and structure-activity relations. Biochemistry is determined by the season, geography, and environment. In this review, quantitative and qualitative information on bibenzyls and bisbibenzyl compounds and their distribution in different liverworts across, geographies along withtraditional to advanced extraction methods, and characterization techniques are summarized. Also, a comprehensive account of characteristic spectra of different bisbibenzyl compounds, their subtypes, and their basic skeleton patterns are compared. A comprehensive table is provided here for the first time presenting the quantity of bibenzyls, bisbenzyls, and their derivatives found in bryophytes, mentioning the spectroscopic data and mass profiles of the compounds. The significance of these compounds in different bioactivities like antibiotic, antioxidative, antitumor, antivenomous, anti-influenza, insect antifeedant, cytotoxic, and anticancerous activities are surveyed and critically enumerated.

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.

Two New Eremophilane-Type Sesquiterpenoids from Japanese Liverwort Bazzania japonica

Two new eremophilane-type sesquiterpenoids, fusumaols A (1) and B (2), were isolated from the stem-leafy liverwort, Bazzaniajaponica collected in Mori-Machi, Shizuoka, Japan. Their structures were established using extensive spectroscopic (IR, MS, and 2D NMR) data, and the absolute configuration of 1 was determined by the modified Mosher's method. This is the first time eremophilanes have been discovered in the liverwort genus Bazzania. Compounds 1 and 2 were evaluated for their repellent activity against the adult population of the rice weevil Sitophilus zeamais using the modified filter paper impregnation method. Both sesquiterpenoids showed moderate repellent activities.

Volatile Organic Compounds of Bryophytes from Peninsular Malaysia and Their Roles in Bryophytes

Volatile emissions from 22 bryophyte species from Peninsular Malaysia were collected using a dynamic headspace technique and analyzed by gas chromatography-mass spectrometry (GC-MS). Thirty organic compounds (VOCs) from eight different groups were detected in bryophytes from the montane forest in Cameron Highlands and the lowland dipterocarp forest in Lata Belatan. The headspace of bryophytes in Cameron Highlands was dominated by tetradecane, 2-ethyl-1-hexanol, decanal, pentanoic acid, 2,2,4-trimethyl-3-carboxyisopropyl, isobutyl ester, D-limonene and naphthalene. On the contrary, in the bryophyte headspace of Lata Belatan, naphthalene and tetradecane were dominant compounds. The elevational pattern detected in VOC composition of bryophytes appears to be an evolutionary feature at the family level that needs verification at other sites. The results also confirmed that the VOC composition of bryophytes is species-specific. The roles of VOCs in bryophytes are presented, including plant-plant communication and plant-insect interaction and as an additional taxonomic character in chemotaxonomy.

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.

Chemical Diversity of Liverworts From Frullania Genus

Frullania is one of the largest and taxonomically most complex genus of leafy liverworts. Current morphology-based estimates of Frullania diversity are close to 400 species; however, species level-classification of Frullania has been regarded notoriously difficult and subject to many studies. The liverworts classified in this genus have been studied using morphological evidence and molecular markers but also in terms of secondary metabolite composition. Up to now 98 Frullania species have been chemically investigated. As a result, it is known that Frullania species are characterized by a remarkable chemical diversity. The most characteristic compounds present in this liverwort genus are sesquiterpene lactones with eudesamnolides as the most diverse group, and aromatic compounds belonging to bibenzyls. In this review paper we report the distribution of secondary metabolites in all chemically investigated Frullania species and discuss some aspects concerning the division of this genus into chemotypes.

Dimeric and esterified sesquiterpenes from the liverwort Chiastocaulon caledonicum

This is the first chemical investigation of Chiastocaulon caledonicum, an endemic liverwort from New Caledonia. We herein present the isolation of thirteen compounds including seven undescribed sesquiterpenoids, namely four barbatane- and three myltaylane-type sesquiterpenes. The structures of these compounds were elucidated based on the interpretation of their chemical and spectroscopic/spectrometric data. Chiastocaulins A and B are the first examples of dimers based on two myltaylane units. The chemotaxonomic importance and the biosynthesis of the chiastocaulin structure are discussed. Terpenoid dimers formed via a Diels-Alder cyclization are thought to be specific to the Plagiochilaceae family.

Characteristic Odor of the Japanese Liverwort (Leptolejeunea elliptica)

The volatile components produced by Leptolejeunea elliptica (Lejeuneaceae), which is a liverwort grown on the leaves of tea (Camellia sinensis), were collected and analyzed using headspace solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS). 1-Ethyl-4-methoxybenzene (1), 1-ethyl-4-hydroxybenzene (2), and 1-acetoxy-4-ethylbenzene (3) were identified as the major components together with several other phenolic compounds, including 1,2-dimethoxy-4-ethylbenzene, and 4-ethylguaiacol in addition to sesquiterpene hydrocarbons, such as α-selinene, β-selinene, β-elemene, and β-caryophyllene. GC/Olfactometry showed the presence of linalool, acetic acid, isovaleric acid, trans-methyl cinnamate, and trans-4,5-epoxy-(2E)-decenal, as the volatile components produced by L. elliptica.

The characteristic smell emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens

The volatile components emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens, were identified using GC-MS analysis. The major volatile components of the solvent extract from C. japonicus were α-humulene (35.8%) and δ-cadinene (17.0%), while those of C. rubens were β-selinene (10.3%) and β-elemene (5.1%). In GC/olfactometry, linalool, butyric acid, 3-methylbutyric acid, 2-methylbutyric acid, and vanillin were identified as the odor-active components of the extract from C. japonicus, in addition to trace amounts of trans-4,5-epoxy-(2E)-decenal, 4-methyl-(3E)-hexenoic acid, and phenylacetic acid. With regard to C. rubens, trans-4,5-epoxy-(2E)-decenal, 3-methylbutyric acid, and phenylacetic acid were identified as the odor-active components. Besides, decan-1,4-olide (γ-decalactone) with milky cherry-like note and 3-hydroxy-4,5-dimethylfuran-2(5H)-one (sotolone) with brown sugar-like note were also detected as the characteristic cherry-like sweet-and-sour note of these two scale insects.

ABBREVIATIONS

GC: Gas chromatography; GC/O: gas chromatography/olfactometry.

Distribution of Bibenzyls, Prenyl Bibenzyls, Bis-bibenzyls, and Terpenoids in the Liverwort Genus Radula

Plants of the Radula genus are chemically very distinct from the other liverworts since they mainly elaborate bibenzyls including bibenzyl cannabinoids and prenyl bibenzyl derivatives, as well as bis-bibenzyls. Several of these components show biological activities such as psychoactivity, vasopressin antagonist, antimicrobial, antifungal, and NO production inhibitory activity, and cytotoxic activity against human cancer cell lines. While distribution of terpenoids in Radula species is in general very limited, some Portuguese species are rich sources of sesquiterpenoids. Among 679 liverwort species so far examined chemically, 264 species contained α-tocopherol, which may play an important antioxidative role for the constituents of oil bodies of liverworts.

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.

Diterpenoids From the Argentine and Malaysian Liverworts Anastrophyllum and Jungermannia Species

We are engaged in the ongoing investigation into the chemical constituents of liverworts in our search for novel compounds and biologically active substances. In the present study, two new rosane diterpenoids were isolated from the Argentine liverwort Anastrophyllum species, together with known aromadendrane sesqui- and rosane diterpenoids. Two new ent-kaurene and 4 ent-kaurene diterpenoids were isolated from the Malaysian liverwort Jungermannia species. Their structures were determined using nuclear magnetic resonance spectroscopy techniques, circular dichroism spectroscopy, and chemical transformation.

Chemotaxonomy and cytotoxicity of the liverwort Porella Viridissima

The first chemotaxonomic study based on volatile components of Porella viridissima (Mitt.) Grolle is reported. The GC-MS analysis of ether extract was performed; ten santalane and five pinguisane-type sesquiterpenes were identified together with perrottetianal A as major diterpene. Most of detected santalane-type sesquiterpenes are reported for the first time in liverwort. P. viridissima was found to belong to the chemotype III (pinguisane/sacculatane) and shared chemical similarities with P. navicularis. Perrotettianal A was isolated and has shown strong cytotoxicity against ovarian cancer.

Chemical Constituents of the Aerial Parts ofDaucus carotasubsp.hispidusGrowing in Tunisia

Three known polyol menthane monoterpenoids, namely, (4 R)-1- p-menthen-6,8-diol (1), (4 R)-1- p-menthen-4,7-diol (2), and (1 R,2 R,4 R)- p-menthane-1,2,4-triol (3), and 6 known phenolics (4-9), in addition to β-sitosterol 3- O-glucoside (10), were isolated from the aerial parts of Daucus carota subsp. hispidus (Ball) Heywood (Family: Apiaceae) growing in Tunisia. The structures of the isolated compounds were established depending upon the spectroscopic techniques including one and two-dimensional nuclear magnetic resonance (1D, and 2D NMR) and high resolution mass spectroscopy (HRMS). The absolute configuration of the compounds 1 to 3 was determined using experimental circular dichroism (CD) for the first time. Compounds 1 to 3 were reported for the first time from this plant. Compounds 1 to 3 exhibited no antimicrobial and antioxidant activity using superoxide dismutase-like activities. Compounds 2 and 3 exhibited weak activity, while 1 showed negative cytotoxic activity against human mouth squamous carcinoma (HSC-2) and human cervical cells (HeLa) cancer cells.

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.

Malagasy Liverworts, Source of New and Biologically Active Compounds

The phytochemical investigation of eight Jungermaniales liverwort species: Bazzania decrescens, B. madagassa (Lepidoziaceae), Plagiochila barteri, P. terebrans (Plagiochilaceae), Isotachis aubertii (Isotachidaceae), Mastigophora diclados (Lepicoleaceae), Radula appressa (Radulaceae), and Thysananthus spathulistipus (Lejeuneaceae), collected from Madagascar, has been carried out to afford new and structurally interesting terpenoids and aromatic compounds. The biological activities of the isolated secondary metabolites were determined and the herbertene-type sesquiterpenoids were shown to have antibacterial activity. A new ent-clerodane diterpene from Thysananthus spathulistipus and bis-bibenzyls-type aromatic compounds exhibited strong inhibition of NO production in RAW 264.7 cells, while marchantin C produced moderate α-glucosidase inhibition. The chemosystematics of the studied species are discussed.

Dinorcassane Diterpenoid from Boesenbergia rotunda Rhizomes Collected in Lower Myanmar

A new dinorcassane diterpenoid, seikphoochinal A (1), and four known compounds, pinostrobin (2), 4',7-dimethylkaempferol (3), and galanals A (4) and B (5), were isolated from the chloroform-soluble crude extract of wild type Boesenbergia rotunda rhizomes collected in Lower Myanmar. The chemical structures of these compounds were identified, using a combination of spectroscopic methods. The presence of the diterpenoids 1, 4, and 5 demonstrated the structural diversity of wild type B. rotunda. Among the isolates, compounds 4 and 5 exhibited significant antiproliferative activities against a small panel of human cancer cell lines, including lung (LK-2, A549), stomach (ECC4), breast (MCF7), cervix (HeLa), and prostate (DU145).

Characteristic Scent from the Tahitian Liverwort, Cyathodium foetidissimum

The volatile components of the Tahitian liverwort Cyathodium foetidissimum was analyzed using headspace solid phase micro-extraction (SPME) and GC-MS. Three volatile components, 4-methoxystyrene (24.4%), 3,4-dimethoxystyrene (28.7%), and skatole (15.9%) were identified as the major components from the fresh C. foetidissimum, along with several aliphatic aldehydes, n-octanal, n-nonanal, and n-decanal. However, (E)-2-nonenal recognized as aged malodor was not identified. In GC-O analysis, 2-aminoacetophenone was detected as one of the minor components with a strong aging note. In fact, C. foetidissimum showed the characteristic aging odor reminiscent the damp smell from old chest of drawers, or the civet like note with very strong feces and urine odor. The mixture consisted of 4-methoxystyrene, 3,4-dimethoxystyrene, and skatole in the detected ratio showed the sedative effect on CNV (contingent negative variation) measurement.

An Aromatic Farnesyltransferase Functions in Biosynthesis of the Anti-HIV Meroterpenoid Daurichromenic Acid

Rhododendron dauricum produces daurichromenic acid, an anti-HIV meroterpenoid, via oxidative cyclization of the farnesyl group of grifolic acid. The prenyltransferase (PT) that synthesizes grifolic acid is a farnesyltransferase in plant specialized metabolism. In this study, we demonstrated that the isoprenoid moiety of grifolic acid is derived from the 2-C-methyl-d-erythritol-4-phosphate pathway that takes place in plastids. We explored candidate sequences of plastid-localized PT homologs and identified a cDNA for this PT, RdPT1, which shares moderate sequence similarity with known aromatic PTs. RdPT1 is expressed exclusively in the glandular scales, where daurichromenic acid accumulates. In addition, the gene product was targeted to plastids in plant cells. The recombinant RdPT1 regiospecifically synthesized grifolic acid from orsellinic acid and farnesyl diphosphate, demonstrating that RdPT1 is the farnesyltransferase involved in daurichromenic acid biosynthesis. This enzyme strictly preferred orsellinic acid as a prenyl acceptor, whereas it had a relaxed specificity for prenyl donor structures, also accepting geranyl and geranylgeranyl diphosphates with modest efficiency to synthesize prenyl chain analogs of grifolic acid. Such a broad specificity is a unique catalytic feature of RdPT1 that is not shared among secondary metabolic aromatic PTs in plants. We discuss the unusual substrate preference of RdPT1 using a molecular modeling approach. The biochemical properties as well as the localization of RdPT1 suggest that this enzyme produces meroterpenoids in glandular scales cooperatively with previously identified daurichromenic acid synthase, probably for chemical defense on the surface of R. dauricum plants.

Diversity of Secondary Metabolites in the Liverwort Syzygiella rubricaulis (Nees) Stephani (Jamesoniellaceae, Marchantiophyta) from Neotropical High Mountains

In order to evaluate the chemical diversity of Syzygiella rubricaulis (Nees) Stephani, a species with a disjunct distribution in the neotropical high mountains, a phytochemical study was carried out with samples from 12 different populations of different altitudes from four South American countries. The chemical profiles of lipophilic extracts were analyzed by GC/MS for each population and 50 different compounds were found with the predominance and richness of sesquiterpenes. The majority of the compounds were found only in one population and the total number of substances ranged from 1 to 15 among the populations, but these numbers were not correlated with altitude, and characterize each population as distinct, based on similarity analysis. The qualitative and quantitative variations of metabolites found are a response to different conditions, under which they live, mostly likely altitudinal conditions. Further studies on the quantification of these chemicals may provide information on their ecological roles and importance for the distribution of S. rubricaulis at different altitudes. Despite the known richness of secondary metabolites produced by bryophytes, they are still poorly explored in the context of the ecological expressions.

Biotransformation of Bicyclic Sesqui- and Diterpene 1,2-dials and Their Derivatives by the Fungus, Aspergillus niger

Microbial biotransformation of naturally occurring pungent sesquiterpene 1,2-dials, polygodial and cinnamodial, and a diterpene 1,2-dial, sacculatal as well as their tetrahydro derivatives was carried out by using Aspergillus niger. The pungent polygodial and sacculatal are toxic against A. niger not to produce any metabolites while A. niger biotransformed cinnamodial to the lactonized products in small amount. On the other hands, the dihydroxy derivatives of the former two dialdehydes were bioconverted by the same fungus to give hydroxy-, oxo-, carboxylic- and epoxy-products. The stereostructures of each metabolite and their metabolic pathways were described.

Volatile Components of Some Selected Turkish Liverworts

The distribution of liverworts and hornworts in Turkey has been described. The volatile components of the ether extracts of some selected Turkish, Spanish and French liverwort species, Corsinia coriandrina, Lejeunea lamacerina, Lunularia cruciata, Marchantia polymorpha, Metzgeria furcata, Pellia neesiana, Porella cordaeana, Porella platyphylla and Scapania undulata were analysed by GC-MS. C. coriandrina produces isothiocyanates and S,S-dimethyliminodithiocarbonates similar to those isolated from the marine hydroid, Tridentata marginata. The species also produces the characteristic 2-arylbenzofurans. L. lamacerina is closely related chemically to the Japanese Lejeunea aquatica, L. flava and L. japonica since it elaborates the same cuparene sesquiterpenoids as those found in the latter three species.

Chemotypes and Biomarkers of Seven Species of New Caledonian Liverworts from the Bazzanioideae Subfamily

Volatile components of seven species of the Bazzanioideae sub-family (Lepidoziaceae) native to New Caledonia, including three endemic species (Bazzania marginata, Acromastigum caledonicum and A. tenax), were analyzed by GC-FID-MS in order to index these plants to known or new chemotypes. Detected volatile constituents in studied species were constituted mainly by sesquiterpene, as well as diterpene compounds. All so-established compositions cannot successfully index some of them to known chemotypes but afforded the discovery of new chemotypes such as cuparane/fusicoccane. The major component of B. francana was isolated and characterized as a new zierane-type sesquiterpene called ziera-12(13),10(14)-dien-5-ol (23). In addition, qualitative intraspecies variations of chemical composition were very important particularly for B. francana which possessed three clearly defined different compositions. We report here also the first phytochemical investigation of Acromastigum species. Moreover, crude diethyl ether extract of B. vitatta afforded a new bis(bibenzyl) called vittatin (51), for which a putative biosynthesis was suggested.

MAO-A Inhibitory Potential of Terpene Constituents from Ginger Rhizomes-A Bioactivity Guided Fractionation

BACKGROUND

In the search for novel antidepressive drug candidates, bioguided fractionation of nonpolar constituents present in the oleoresin from ginger rhizomes (Zingiber officinale Roscoe, Zingiberaceae) was performed. This particular direction of the research was chosen due to the existing reports on the antidepressive properties of ginger total extract. The search for individual metabolites acting as MAO-A inhibitors, which correspond to the apparent effect of the total extract, is the subject of this work.

METHODS

Hexane extracts from ginger rhizomes were fractionated by using column chromatography (including silica gel impregnated with silver nitrate) and semi-preparative high-performance chromatography. For the activity assessment, an in vitro monoamine oxidase A (MAO-A) inhibition luminescence assay was performed on 10 purified terpenes: 1,8-cineole, α-citronellal, geraniol, β-sesquiphellandrene, γ-terpinen, geranyl acetate, isobornyl acetate, terpinen-4-ol, (E,E)-α-farnesene, and α-zingiberene.

RESULTS

Geraniol and (-)-terpinen-4-ol were found to be the strongest enzyme inhibitors with inhibition of 44.1% and 42.5%, respectively, at a concentration of 125 µg/mL. No differences in the inhibition potential were observed for the different groups of terpenes: sesquiterpenes, monoterpenes, or sesquiterpene alcohols; however, the two most active compounds contained a hydroxyl moiety.

CONCLUSIONS

Terpene constituents from ginger's extract were found to exhibit moderate inhibitory properties against the MAO-A enzyme in in vitro tests.

Microbial Transformation of Calamintha glandulosa Essential Oil by Aspergillus niger

A number of potentially useful compounds with various biological activities can be obtained from plant metabolites by microorganisms. In present research, essential oil of Calamintha glandulosa was subjected to the biotransformation process by mycromicete Aspergillus niger. GC/MS analyses of the original and biotransformed essential oil have revealed six (1–6) biotransformed compounds from one of the main component-limonene and one biotransformed product (7) originating from the less abundant component-thymol. Piperitone epoxide and piperitenone epoxide, the most abundant components of the original oil, were not biotransformed but gave three artefacts (A1, A2, B1) due to the acidic conditions formed in A. niger medium. Compounds 5, 6 as well as 7 have not been previously found as a biotransformation products of limonene (5 and 6) and thymol (7 rebpectively. New uct (5, 6, and 7) together with the artefacts, were isolated by silica gel column chromatography followed by preparative silica gel thin layer chromatography, and their structures were established by a combination of 1D and 2D NMR spectra and GC/MS data. Biotransformation has one more confirmed as useful method, complementary to synthesis, for obtaining different type of molecules.

Chemical Constituents of Bryophytes: Structures and Biological Activity

Comparatively little attention has been paid to the bryophytes for use in the human diet or medicine in spite of the presence of 23 000 species globally. Several hundred new compounds have been isolated from the liverworts (Marchantiophyta), and more than 40 new carbon skeletons of terpenoids and aromatic compounds were found. Most of the liverworts studied elaborate characteristic odiferous, pungent, and bitter-tasting compounds, of which many show antimicrobial, antifungal, antiviral, allergic contact dermatitis, cytotoxic, insecticidal, anti-HIV, plant growth regulatory, neurotrophic, NO production and superoxide anion radical release inhibitory, muscle relaxing, antiobesity, piscicidal, and nematocidal activities. The biological effects ascribed to the liverworts are mainly due to lipophilic sesqui- and diterpenoids, phenolic compounds, and polyketides, which are the principal constituents of their oil bodies. Some mosses and liverworts produce significant levels of vitamin B₂ and tocopherols, as well as prostaglandin-like highly unsaturated fatty acids. The most characteristic chemical phenomenon of the liverworts is that most of the sesqui- and diterpenoids are enantiomers of those found in higher plants. In this review, the chemical constituents and potential medicinal uses of bryophytes are discussed.

Volatile Chemical Constituents of the Chilean Bryophytes

The aim of this study is to increase the phytochemical knowledge of South American bryophytes, particularly from those of the southern tip of the continent, due to the uniqueness of its poorly known bryoflora. Thirty-two specimens were analyzed using GC-MS technique. Most of the molecules found in the present bryophyte species belong to sesquiterpenes. In general, liverworts resulted to be richer in terpenoid compounds, while mosses in n-alkanes. Oplopanone, trans- chrysanthenyl acetate and 6,7-secoeudesm-7(11)-en-6-al are compounds here newly reported to the bryophytes. α-Ylangene and α-herbertenol are new to hornworts, while α-herbertenol and n-heneicosane are new to mosses.

Secondary metabolites from endemic species Iris adriatica Trinajstić ex Mitić (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-β-D-glucopyranoside) and nigricin-4'-(1-O-β-D-glucopyranosyl (1-6)-β-D-glucopyranoside) with 2.5, 10 and 1% of the total extract, respectively. Irisxanthone - xanthone C-glucoside, β-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-β-D-glucopyranoside) and benzophenone have been isolated from Iris species for the first time.

Sesqui- and Diterpenoids from Tahitian and Japanese Liverworts Jungermannia species

A new cembrane diterpenoid was isolated from the Tahitian liverwort Jungermannia species, together with several known sesquiterpenoids, and labdane and verticillane diterpenoids. Two new labdane diterpenoids, and known labdane and clerodane diterpenoids were isolated from the Japanese Jungermannia infusca collected in the three different locations. Their structures were determined by use of NMR techniques.

Two New Cyclobutane Dimers from Diospyros macrocarpa

A biochemical and phytochemical study of Diospyros macrocarpa Hiern, an endemic plant of New Caledonia, was realized. Indeed, bark and leaf extracts were tested for their cytotoxic and antibiotic activities as well as for their radical scavenging properties. Methanol extracts showed promising radical scavenging activity with an IC50 value of 5.6 ± 0.9 μg/mL for the leaves and 8.1 ± 1.4 μg/mL for the barks. The ethyl acetate extract from the barks showed strong and selective activity against NCI-H727 cancer cell line with an IC50 value of 9.5 ± 0.6 μg/mL.. Two new cyclobutane dimers: macrocarpasin A (1) and B (2) (figure 1) together with six known compounds: yangonin (3), betulinic acid (4), α-amyrin (5), β–amyrin (6), loliolide (7) and oleanderolide (8) were isolated from leaf extracts. Their structures were established by 1D and 2D NMR along with HRMS analyses. Cytotoxic activities of isolated compounds were also evaluated. None of them showed interesting cytotoxicity against the seven tested cancer cell lines.

A New Diphenyl Ether Glycoside from Xylosma longifolium Collected from North-East India

A new diphenyl ether glycoside, xylosmaloside (1), was isolated from the MeOH extract of Xylosma longifolium Clos. The structure of xylosmaloside (1) was elucidated using MS analyses, extensive 2D-homo and heteronuclear NMR data interpretation and the chemical conversions. Xylosmaloside (1) showed stronger antioxidant activity than ascorbic acid.

GC/MS Fingerprinting of Solvent Extracts and Essential Oils Obtained from Liverwort Species

Studies concerning chemical profiling of the volatiles present in the solvent extracts from liverworts help to determine inter- and intraspecific relationships in this plant group. Due to the fact that the liverworts are morphologically very small and it is difficult to collect their sufficient amounts, there are still a few data concerning the chemistry of essential oils. The available data indicate however, that the components present in the essential oils can be used in chemosystematic studies of these spore-forming plants. Compounds occurring in the essential oils constitute a powerful tool for studying chemical differences between or within liverwort species for which the characteristic components are mono- and sesquiterpenoids. Good results were obtained for the liverworts species from the genera Asterella, Conocephalum, Diplophyllum, Jungermannia, Lepidozia, Radula, Reboulia or Scapania.

Transcriptome Analysis of Marchantin Biosynthesis from the Liverwort Marchantia polymorpha

Marchantin A, the first characterized macrocyclic bis(bibenzyls) found in the liverwort Marchantia polymorpha shows interesting biological activities such as antifungal, antimicrobial, cytotoxic, antioxidant and muscle relaxing activity. Previously, Zenk et al. reported the phenylpropane/polymalonate pathway in the biosynthesis of the marchantins in M. polymorpha. To clear this pathway, transcriptome sequencing and digital gene expression analyses of M. polymorpha were carried out by using Illumina RNA-seq system.

Microbial Transformation of Some Natural and Synthetic Aromatic Compounds by Fungi: Aspergillus and Neurospora Strains

Microbial transformation of chalcone (1), 4-hydroxychalcone (2) and 4′-hydroxychalcone (3), 1,1-diphenylmethane (4), 1,3-diphenylacetone (5), 1,3-diphenylpropane (6), bibenzyl (7), ( E)-stilbene (8a)- and ( Z)-stilbenes (8b), and phenylcyclohexane (9), (1 R,2 S)-1-phenyl-2-hydroxycyclohexane (9a) and (1 S,2 R)-1-phenyl-2-hydroxycyclohexane (9b), and a naturally occurring bis-bibenzyl, marchantin A (10) were performed by using Aspergillus niger TBUYN-2 and the other Aspergillus strains, and Neurospora crassa which were capable to hydrogenation and epoxidation of a conjugated double bond, and direct hydroxylation and hydroperoxidation on benzene ring, and hydroxylation and carbonization on cyclohexane ring. Aspergillus species converted chalcone (1) to dihydrochalcone (1a) almost quantitatively.

The Isolation, Structure Elucidation, and Bio- and Total Synthesis of Bis-bibenzyls, from Liverworts and Their Biological Activity

Little attention has been paid to the bryophytes for use in the human diet in spite of the presence of 23,000 species in the world. Some liverworts produce lipophilic terpenoids and phenolic bis-bibenzyls, possessing antimicrobial, antifungal, antiviral, cytotoxic, anti-oxidant, muscle relaxing, and antiobesity activities. In this review, the isolation, structures elucidation, bio- and total syntheses of bis-bibenzyls from several liverworts are discussed.

Comparative Study on Volatile Compounds of Alpinia japonica and Elettaria cardamomum

The volatile compounds obtained from the ether extracts, headspace gases and steam distillates of Alpinia japonica and Elettaria cardamomum were analyzed by GC/MS. Both species were rich sources of naturally rare fenchane-type monoterpenoids, fenchene, fenchone, fenchyl alcohol and its acetate, together with 1,8-cineole. The distributions of volatile sesquiterpenoids were very poor in both species. Chiralities of fenchone in A. japonica and E. cardamomum were 99% of (1S,4R)-(+)-form. Camphor in A. japonica is composed of a mixture of (1R,4R)-(+)-form (94.3%) and (1S,4S)-(-)-form (5.7%). On the other hand, E. cardamomum produced only (1R,4R)-(+)-camphor (99%).

Identification and Characterization of Daurichromenic Acid Synthase Active in Anti-HIV Biosynthesis

Daurichromenic acid (DCA) synthase catalyzes the oxidative cyclization of grifolic acid to produce DCA, an anti-HIV meroterpenoid isolated from Rhododendron dauricum We identified a novel cDNA encoding DCA synthase by transcriptome-based screening from young leaves of R. dauricum The gene coded for a 533-amino acid polypeptide with moderate homologies to flavin adenine dinucleotide oxidases from other plants. The primary structure contained an amino-terminal signal peptide and conserved amino acid residues to form bicovalent linkage to the flavin adenine dinucleotide isoalloxazine ring at histidine-112 and cysteine-175. In addition, the recombinant DCA synthase, purified from the culture supernatant of transgenic Pichia pastoris, exhibited structural and functional properties as a flavoprotein. The reaction mechanism of DCA synthase characterized herein partly shares a similarity with those of cannabinoid synthases from Cannabis sativa, whereas DCA synthase catalyzes a novel cyclization reaction of the farnesyl moiety of a meroterpenoid natural product of plant origin. Moreover, in this study, we present evidence that DCA is biosynthesized and accumulated specifically in the glandular scales, on the surface of R. dauricum plants, based on various analytical studies at the chemical, biochemical, and molecular levels. The extracellular localization of DCA also was confirmed by a confocal microscopic analysis of its autofluorescence. These data highlight the unique feature of DCA: the final step of biosynthesis is completed in apoplastic space, and it is highly accumulated outside the scale cells.

Volatile Compounds from the Different Organs of Houttuynia cordata and Litsea cubeba (L. citriodora)

The volatile compounds obtained from the different organs of Houttuynia cordata (Saururaceae) and Litsea cubeba (Lauraceae) were analyzed by Gas Chromatography/Mass Spectrometry (GC/MS), Headspace Solid Phase Micro Extraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS), and GC/olfactometry (GC/O). The major component of all parts of H. cordata is assigned as 4-tridecanone. Each organ produces myrcene as the major monoterpenoid. The major monoterpene in the rhizomes and roots was β-pinene instead of myrcene. 1-Decanal which was responsible for the unpleasant odor of this plant, was the predominant polyketide in both leaves and stems. The presence of 1-decanal was very poor in flowers, stem collected in summer, rhizomes, and roots. GC/MS analyses were very simple in case of the crude extracts of flowers. The content of sesquiterpenoids was extremely poor. (8Z)-Heptadecene, geranial, and neral were detected as the major components in Litsea cubeba. Odor-contributing components by GC/O analysis of the ether extract of the fresh flowers of L. cubeba were neral and geranial which played an important role in sweet-lemon fragrance of the flowers. The role of a high content of (8Z)-heptadecene was still unknown but it might play a significant role in the dispersion of the volatile monoterpene hydrocarbons and aldehydes. The flower volatiles of the Japanese L. cubeba were chemically quite different from those of the Chinese same species.

Application of Chromatographic and Spectroscopic Methods towards the Quality Assessment of Ginger (Zingiber officinale) Rhizomes from Ecological Plantations

The usefulness of ginger in the food industry and pharmacotherapy is strictly related to its content of various components. The study elucidates the chemical composition of Zingiber officinale rhizomes cultivated on ecological plantations on Shikoku Island (Japan). GC-MS analysis of terpene content, LC-MS determination of phenolic content, and the determination of 12 elements using AAS spectrometry were performed to give more detailed insight into the samples. Ninety-five percent of terpene composition was elucidated, with zingiberene as the most abundant sesquiterpene (37.9%); the quantification of gingerols and shogaols was performed, showing the highest contribution of 6-gingerol (268.3 mg/kg); a significant K (43,963 mg/kg of dry mass) and Mn (758.4 mg/kg of dry mass) content was determined in the elemental analysis of the rhizomes and low concentration of toxic elements (Cd, Ni and Pb) remaining below the safe level values recommended by European Commission Directives. The main phenolic compound was (6)-gingerol, which is characteristic of fresh rhizomes and is responsible for their taste and aroma. Surprisingly, high amounts of (6)-shogaol were determined, even though this phenolic compound usually occurs in old or processed material and not in fresh rhizomes. Sesquiterpenes were the major fraction of volatiles. The highest concentrations were determined for α-zingiberene, β-sesquiphellandrene, (E,E)-α-farnesene, geranial, and ar-curcumene. The volatiles composition of ginger cultivated on Shikoku Island is specific and strongly differs from plants cultivated in China, Nigeria, or Australia. The elemental composition of ginger rhizomes grown in ecological plantations is more beneficial for human health compared to products grown in normal cultivars, as the products contain high amounts of potassium and manganese and are characterized by low sodium content and lower levels of toxic heavy metals.

Mechanisms of action and structure-activity relationships of cytotoxic flavokawain derivatives

22 Flavokawain derivatives (FKd) were obtained by one step syntheses in order to conduct a SAR study to understand the structural requirements for optimum and selective cytotoxicity. FKd and natural flavokawains A and B found into kava, a South Pacific traditional beverage, were evaluated against nine cancer and one healthy cell lines. The targeted cell cycle phases as well as the effects on the induction of apoptosis and cell cycle protein levels were investigated. Therapeutic improvements (more activity and selectivity) were achieved with FKd compared to natural flavokawains and notably with the 2',3,4',6'-tetramethoxychalcone (FKd 19). FKd induced a G1/S arrest on p53 wild-type cells and an M arrest on p53 mutant-type, via the up-regulation of p21 and cyclin B1 proteins, followed by apoptosis. Moreover, FKd exhibited a 24h-effect on Akt/mTor normal cells versus a 48h-effect on Akt/mTor up-regulated cells. The SAR study resulted in the conclusion that trimethoxy A-ring allowed the best compromise between cytotoxicity and selectivity, as well as the substitution of the meta position on the B-ring and the use of halogens substituents.

Constituents of Fermented Male Flowers of Alnus sieboldiana (Betulaceae)

Fractionation of the ethyl acetate crude extract of the fermented male flowers of Alnus sieboldiana resulted in the isolation of two diarylheptanoids and six flavonoids. Yashabushidiol A, yashabushidiol B and naringenin were known constituents of the male flowers of A. sieboldiana while kaempferol, quercetin, pinocembrin dimethyl ether, 5,7-dimethoxy-3-hydroxyflavanone and 5,7-dimethoxy-3-hydroxyflavone were isolated for first time from the fermented male flowers of A. sieboldiana. The isolated compounds were characterized using NMR and HRMS and compared with available literature.

Constituents of Fermented Male Flowers of Alnus sieboldiana (Betulaceae)

Fractionation of the ethyl acetate crude extract of the fermented male flowers of Alnus sieboldiana resulted in the isolation of two diaryiheptanoids and six flavonoids. Yashabushidiol A, yashabushidiol B and naringenin were known constituents of the male flowers of A. sieboldiana while kaenipferol, quercetin, pinocembrin dimethyl ether, 5,7-dimethoxy-3-hydroxyflavanone and 5,7-dimethoxy-3-hydroxyflavone were isolated for first time from the fermented mile flowers of A. sieboldiana. The isolated compounds were characterized using NMR and HRMS and compared with available literature. -.