Enantiomeric cuparene-type sesquiterpenoids from Bazzania pompeana

Two enantiomeric cuparene-type sesquiterpenoids, (R)-(−)-cuparene (1) and (R)-(−)-δ-cuparenol (2), have been isolated from the liverwort, Bazzania pompeana. The structures and absolute configurations of the two compounds have been determined.     

Enantiomeric type sesquiterpenoids of the liverwort Marchantia polymorpha

A series of ent-sesquiterpenoids corresponding to the optical antipodes of those in higher plants have been isolated from the liverwort Marchantia polymorpha. These sesquiterpenoids provide yet another example of the peculiar stereospecificity of the biogenesis of the liverwort sesquiterpenoids and suggest a special taxonomic position of the liverworts in the plant kingdom.     

Pinguisane and dimeric pinguisane-type sesquiterpenoids from the Japanese liverwort Porella acutifolia subsp. tosana

Two new pinguisane-type, three new Diels-Alder reaction-type dimeric pinguisane sesquiterpenoids and known sesqui and diterpenoids were isolated from the ether extract of the Japanese liverwort Porella acutifolia subsp. tosano. Their absolute stereostructures were established by a combination of extensive 2D-NMR, CD spectra, X-ray crystallographic analysis, modified Mosher's method and chemical correlation.     

Fragrant Volatile Compounds in the Liverwort Drepanolejeunea madagascariensis (Steph.) Grolle: Approach by the HS‐SPME Technique

Three populations of the epiphyllous liverwort Drepanolejeunea madagascariensis collected in the cloud forests of Reunion Island (Mascarene Archipelago) were investigated for their volatile compounds, because of the pleasant, sweet, warm, woody‐spicy, and herbaceous fragrance, slightly reminiscent of dill, of this species. By applying the headspace solid‐phase microextraction (HS‐SPME) technique coupled to GC/MS analysis, 34 compounds were detected in total, with p‐menth‐1‐en‐9‐ol (28.8–43.5%), limonene (10.5–14.7%), β‐phellandrene (8.8–11.6%), and the so‐called dill ether (8.5–16.6%) as the main components. The presence of 1‐epi‐α‐pinguisene confirms the possible use of pinguisane‐type sesquiterpenoids as a characteristic chemical marker for the order Jungermanniales.     

Soluble carbohydrates of liverworts

Five soluble carbohydrates, (−)-l-bornesitol, (−)-d-mannitol, (+)-d-glucose, (+)-sucrose and (+)-trehalose, have been isolated as their acetyl derivatives from the liverwort, Mylia taylorii. The absolute configuration of these carbohydrates is the same as that of sugars found in vascular plants, although the liverwort sesquiterpenoids are usually enantiomeric relative to those of vascular plants. The soluble carbohydrates in seven other liverwort species have also been analysed by HPLC.     

Optimization of pyrethroid and repellent on fabrics against Stegomyia albopicta (=Aedes albopictus) using a microencapsulation technique

A new approach employing a combination of pyrethroid and repellent is proposed to improve the protective efficacy of conventional pyrethroid‐treated fabrics against mosquito vectors. In this context, the insecticidal and repellent efficacies of commonly used pyrethroids and repellents were evaluated by cone tests and arm‐in‐cage tests against Stegomyia albopicta (=Aedes albopictus) (Diptera: Culicidae). At concentrations of LD₅₀ (estimated for pyrethroid) or ED₅₀ (estimated for repellent), respectively, the knock‐down effects of the pyrethroids or repellents were further compared. The results obtained indicated that deltamethrin and DEET were relatively more effective and thus these were selected for further study. Synergistic interaction was observed between deltamethrin and DEET at the ratios of 5 : 1, 2 : 1, 1 : 1 and 1 : 2 (but not 1 : 5). An optimal mixing ratio of 7 : 5 was then microencapsulated and adhered to fabrics using a fixing agent. Fabrics impregnated by microencapsulated mixtures gained extended washing durability compared with those treated with a conventional dipping method. Results indicated that this approach represents a promising method for the future impregnation of bednet, curtain and combat uniform materials.     

Growth and sesquiterpenoid production by Calypogeia granulata inoue cells in suspension culture

Growth and the production of volatile sesquiterpenoids by a chlorophyllous cell suspension culture from gametophytes of C. granulata, a leafy liverwort, were examined. Glucose was more effective than 2,4-dichlorophenoxyacetic acid for callus induction, and elimination of glucose from the medium resulted in prompt redifferentiation of plantlets. The cells grew photoheterotrophically, but not in the dark. 1,4-Dimethylazulene, a trinorsesquiterpenoid, was produced as the major volatile sesquiterpenoid in the cultured cells; bicyclogermacrene, compound II, an indene-type aldehyde (a trinorsesquiterpenoid aldehyde), compound I and tetrahydro-1,4-dimethylazulene (a trinorsesquiterpenoid) followed in decreasing order. The azulene was produced both in light and the dark, and its yield was proportional to the growth in light. The yield in light was four times higher than that in the dark. The content of 1,4-dimethylazulene was 0.9–10.% and that of total essential oils was 2.0–3.3% of the dry werght of the cultured cells. The quantity, quality, and proportions of the volatile sesquiterpenoids of the cell culture were almost equal to those of intact (original) plants and redifferentiated plantlets. Previous name: Institute of Food Chemistry     

Repellent efficacy of essential oils and plant extracts against Tribolium castaneum and Plodia interpunctella

This study was conducted to investigate the repellent efficacy of essential oils (Origanum vulgare, Pimpinella anisum, and Tanacetum cinerariifolium) and four plant extracts (Agastache rugosa, Capsicum annuum, Citrus reticulata, and Ginkgo biloba) against Tribolium castaneum (adults and larvae) and Plodia interpunctella (larvae). Gas chromatography/mass spectrometry analysis revealed the presence of carvacrol, anethole, and jasmolin I as the predominant constituent in O. vulgare, P. anisum, and T. cinerariifolium, respectively. Furthermore, ethyl hexopyranoside, 9,12‐octadecadienoic acid, cyclopentanol, and 2‐cresol were identified in A. rugosa, C. annuum, C. reticulata, and G. biloba, respectively. The repellent efficacy of each essential oil, plant extract, and the combination of oils was evaluated using a specially designed cylinder trap for 120 h. Among the three oils, O. vulgare and T. cinerariifolium had greatest repellent efficacy against P. interpunctella larvae. T. cinerariifolium exhibited effective repellence against the adults and larvae of T. castaneum. Therefore, O. vulgare (O) and T. cinerariifolium (T) were selected for further investigation of combined effects. Two essential oils were mixed in three different ratios of OT1 (1:3), OT2 (1:1), and OT3 (3:1). The repellent efficacies of OT1 and OT2 against the adults of T. castaneum were significantly greater than that of OT3. OT1 was effective against the larvae of T. castaneum, whereas OT2 was effective against the larvae of P. interpunctella. OT1 enhanced the repellent efficacy by approximately five times against larvae of T. castaneum, compared with that of T. cinerariifolium. Overall, OT1 was selected as the best repellent substance against all the tested insects.     

First report of the repellency of 2-tridecanone against ticks

2‐Tridecanone and 2‐undecanone are both found naturally in the trichomes of wild tomato plants and are important in plant resistance to herbivory. 2‐Undecanone is the U.S. Environmental Protection Agency (EPA)‐registered active ingredient in the commercially available arthropod repellent, BioUD^®. The goal of this study was to examine the tick repellency of 2‐tridecanone. Two‐choice bioassays were conducted using 8% 2‐tridecanone vs. the repellent carrier (absolute ethanol) and compared with two‐choice studies using 8% 2‐undecanone vs. absolute ethanol. Unfed, host‐seeking adult (mixed sex) Amblyomma americanum (L.) (Acari: Ixodidae) and Dermacentor variabilis Say (Acari: Ixodidae) were used to evaluate repellency and time to repellent failure at room temperature. The present study shows in filter paper assays (0.63 mg test compound/cm²) that 2‐tridecanone was 87% repellent to A. americanum at 12 h after application, but had no statistically significant repellency at 15 h and 24 h, and was 72% repellent to D. variabilis at 15 h, but had no statistically significant repellency at 24 h. By contrast, 2‐undecanone was 74% and 75% repellent to A. americanum and D. variabilis, respectively, at 2 h after application, but no statistically significant repellency was noted at 2.5 h and 3 h. In two‐choice assays on cheesecloth, 2‐tridecanone at 0.25 mg/cm² was 85% repellent to A. americanum 6 h after application, demonstrating its potential use as an arthropod repellent that can be used on clothing without the need for formulation. No statistically significant repellency was found at 9 h or 12 h. The potential use of 2‐tridecanone as a tick repellent is discussed.     

Isotachin c and balantiolide two aromatic compounds from the new zealand liverwort balantiopsis rosea

Isotachin C and balantiolide, two new aromatic compounds, were isolated from the New Zealand liverwort Balantiopsis rosea. Their structures were established to be 2-methoxybenzyl trans-β-methylthioacrylate and 3-[3′,4′-dimethoxybenzyl]-7-hydroxy-5-methoxyphthalide, respectively, by spectral methods. The previously known isotachin A, isotachin B, benzoates, cinnamates and sesquiterpenoids were also found. B. rosea is chemically quite close to Isotachis japonica.     

Eudesmane-type sesquiterpenes from the liverwort Apomarsupella revolute

Phytochemical investigation of the Et₂O extract of liverwort Apomarsupella revolute led to isolation and identification of five new eudesmane-type sesquiterpenoids, 6β-hydroxy-9β-acetoxy-eudesma-4,11-dien (1), 6β-hydroxy-9β-acetoxy-eudesma-4,11-dien-3-one (2), 5α,6β-dihydroxy-9β-acetoxy-eudesma-4(15),11-dien (3) 4β-hydroxy-9β-acetoxy-11,12,13-trinor-5-eudesmen-7-one (4) and 4β-methox-9β-acetoxy-11,12,13-trinor-5-eudesmen-7-one (5), two of which were trinorsesquiterpenoids. Their structures were established unequivocally on the basis of spectroscopic data analysis. All compounds were preliminary bioscreened for their cytotoxicities and antifungal activities.     

VOLATILE CONSTITUENTS OF CHAROPHYTES AS OVIPOSITION DETERRENTS OF CULEX PIPIENS PALLENS (DIPTERA: CULICIDAE)1

Four populations of charophytes (including three species), Chara inconnexa T. F. Allen (populations 1 and 2), C. vulgaris L., and Nitellopsis obtusa (Desv.) J. Groves, were studied for effective chemicals as oviposition deterrents of Culex pipiens pallens. The charophyte volatile organic compounds (VOCs) were retained in Tenax GR, subsequently desorbed using a thermal desorption cold trap injector (TCT), and analyzed by gas chromatography/mass spectrometry (GC/MS) to elucidate that charophytes have repellent properties. C. inconnexa (1) and C. inconnexa (2) exhibited strong repellent activities, and C. vulgaris showed some repellent activity against C. pipiens pallens with terpenes and benzothiazole playing major roles, while N. obtusa lacked those compounds and did not have an effect. These results suggest that charophytes have potential application as pesticides, but there are interspecific differences. In addition, benzene hydrocarbons were among the volatiles in Chara but not in N. obtusa, implying that some charophytes could be used to absorb these compounds.     

Terpenoids isolated from Chinese liverworts Lepidozia reptans and their anti-inflammatory activity

Five new terpenoids (1–5) including two dollabellane-type, one ent-kaurane-type diterpenoids and two sesquiterpenoids were isolated from the Chinese liverwort Lepidozia reptans (L.) Dumort., together with nine known terpenoids (6–14). Their structures were determined on the basis of analysis of MS and NMR spectroscopic data, single-crystal X-ray diffraction and electronic circular dichroism calculations. The selected compounds 1, 2, 6, 7, 9 and 14 were screened for anti-inflammatory activities by the model of LPS-induced nitric oxide (NO) production with macrophage cells, and the mechanism of the active compounds 1 and 2 were further explored.     

Cotranscriptional expression of mitochondrial genes for subunits of NADH dehydrogenase, nad5, nad4, nad2, in Marchantia polymorpha

Three genes for the subunits of the NADH dehydrogenase (nad5, nad4, and nad2) are tandemly clustered on the liverwort mitochondrial genome. Their gene products showed high levels of amino acid sequence identity with the corresponding subunits from higher plant mitochondria (82.8–84.4%), and significant levels of identity with those from liverwort chloroplast (32.0–33.5%), Podospora anserina mitochondria (21.4–45.9%), and human mitochondria (18.4–27.9%). In addition, these three subunits from liverwort mitochondria have conserved amino acid residues in their central regions. The gene nad5 is interrupted by a 672 by group I intron, while genes nad4 and nad2 are interrupted by group II introns of 899 by and 1418 bp, respectively. Northern blot analysis using exon-intron specific probes indicated that these three genes are transcribed as a single precursor mRNA of 9.6 kb in length and are processed into mature mRNA molecules in liverwort mitochondria. Several regions of this nad gene cluster are repeated in the liverwort mitochondrial genome.Communicated by R.G. Herrmann     

中华光萼苔的化学成分研究

首次对中华光萼苔(Porella chinensis(Steph.)Hat.)的化学成分进行了研究,从中分离得到四种倍半萜类化合物.通过波谱学数据并与已知化合物的数据比较,它们分别鉴定为环色烯酮(cycloeolorenone,1)、辛辣木醇(drimenol,2)、辛辣木素(drimenin,3)及α-古巴烯(α-copacne,4).通过NOESY确定了化合物1的相对构型.化合物2和4首次从该植物的配子体中分离得到.     

Erimopyrone,a Lignan Derivative from the Liverwort Moerckia erimona

The new lignan derivative, erimopyrone, was isolated from the liverwort, Moerckia erimona. Its structure was established as [1R, 2S]-1(6-carboxy-2-oxo-2H-4-pyranyl)- 6,7-dihydroxy-1,2-dihydro-2,3-naphthalenedicarboxylic acid by spectroscopic methods.     

In vitro neuroprotective activity of sesquiterpenoids from the flower buds of Tussilago farfara

Abstract

We have isolated four sesquiterpenoids from Tussilago farfara, a traditional herbal medicine in Korea and China, and investigated the protective effects on LPS-induced neuronal cell death. Four sesquiterpenoids inhibited the production of nitric oxide, prostaglandin E₂ and tumor necrosis factor-α in LPS-treated BV-2 cells through the inhibition of NF-κB pathway. These sesquiterpenoids also inhibited reactive oxygen species (ROS) generation in LPS-treated BV-2 cells. Furthermore, they inhibited LPS-induced neuronal cell death in co-culture system through the inhibition of NF-κB pathway and scavenging of ROS. These results indicated that sesquiterpenoids from Tussilago farfara may have beneficial therapeutic potential for the treatment of neurodegenerative diseases through inhibition of microglial activation.     

荔枝草中一个新的倍半萜

为了研究荔枝草全草中的倍半萜类化学成分,该文运用大孔吸附树脂D101、MCI、硅胶和反相HPLC等色谱技术对其进行分离纯化,根据HR-ESI-MS、NMR波谱数据鉴定了化合物的结构。结果表明:从荔枝草全草95%乙醇提取物的乙酸乙酯部位中分离得到3个桉叶烷型倍半萜类化合物,分别鉴定为8-ethoxy-eudebeiolide B(1)、salplebeone D(2)、salplebeone A(3)。其中,化合物1为新化合物。     

Postfledging parental care and unexpected foraging behaviour of juvenile Sooty Terns Onychoprion fuscata in the southern Mozambique Channel

The Berlese funnel method, and its variations, is commonly used for the extraction of arthropods from various substrates such as nest material. However, little is known about its effectivity in extracting ectoparasites from penguin nests. This study aimed to assess the efficacy of a modified Berlese funnel method in extracting ectoparasites from African Penguin Spheniscus demersus nests and to determine differences in extraction capacity across parasite taxa and life stages. African Penguin nests (n = 278) were sampled at five penguin colonies along the south-west coast of South Africa in 2017. Nest samples were subjected to a modified Berlese funnel method with naphthalene as a repellent. Thereafter, all remaining ectoparasites were removed by hand sorting. Ectoparasite abundance was positively correlated between the two extraction methods (Spearman’s r = 0.73–0.89). Compared to total counts, flea (combined life stages and larvae) and total ectoparasite abundance and prevalence were significantly lower with the modified Berlese funnel method. In addition, adult flea and tick prevalence (but not abundance) was significantly lower with the modified Berlese funnel method compared with total counts. The modified Berlese funnel method fails as a quantitative method and can only provide a crude indication of the incidence of ectoparasites in penguin nests.     

High‐throughput screening method for evaluating spatial repellency and vapour toxicity to mosquitoes

Spatial repellents are an essential tool for personal protection against mosquitoes that bite and transmit disease pathogens to humans. Current repellent screening methods, such as olfactometers and alternative choice tests, are complex systems that require a relatively large quantity of compound (mg). The present study validates a high‐throughput spatial repellent screening method using a glass tube that has the ends covered with netting, in addition to treated filters and plastic end caps. The apparatus occupies relatively little space, is easy to decontaminate, and requires small amounts of compound (μg). In a horizontal tube orientation, DEET (N,N‐diethyl‐meta‐toluamide), citronella oil and IR3535 had 1 h half repellent concentration (EC₅₀) values of 32, 32 and 298 μg/cm², respectively, against the Orlando strain of Aedes aegypti (L.) (Diptera: Culicidae). Vertical tube orientation increased EC₅₀ values by approximately two‐fold, except IR3535, which remained essentially unchanged. Transfluthrin showed concentration‐dependent spatial repellency (1 h EC₅₀ = 0.5 μg/cm²) without any knockdown, although only in vertical tubes. Transfluthrin showed 50% knockdown in 1 h at 0.5 μg/cm² and 50% mortality at 0.15 μg/cm² in horizontal tubes. In conclusion, this high‐throughput screening method is useful for assessing vapour toxicity and the spatial repellency of candidate molecules prior to semi‐field and field studies.