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Thomas H. Nash - One of the best experts on this subject based on the ideXlab platform.
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New species of the genus Ramalina (Ascomycotina: Ramalinaceae) from the Sonoran Desert, Mexico
Mycotaxon, 2002Co-Authors: Hiroyuki Kashiwadani, Thomas H. NashAbstract:Ramalina chihuahuana and R. psoromica from the Sonoran Desert, Mexico are described as new to science.
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dose response relationships for so2 fumigations in the lichens evernia prunastri l ach and Ramalina fraxinea l ach
New Phytologist, 1992Co-Authors: María José Sanz, Corinna Gries, Thomas H. NashAbstract:SUMMARY Sulphur dioxide fumigation of the lichens Evernia prunastri (L.) Ach and Ramalina fraxinea (L.) Ach, whose thallus water content was held at 100-120%, throughout each experiment, resulted in changes in net photosynthesis, dark respiration and chlorophyll content in relation to both concentration and duration of exposure. Net photosynthesis was the most sensitive response variable. Significant reduction in chlorophyll content was found when no recovery in net photosynthesis occurred after two weeks. A reduction in dark respiration was only found at high SO2 concentrations. Evernia prunastri was affected by lower concentrations and shorter exposure times than Ramalina fraxinea and the data for both species showed dose-response relationships.
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Dose—response relationships for SO2 fumigations in the lichens Evernia prunastri (L.) Ach. and Ramalina fraxinea (L.) Ach.
New Phytologist, 1992Co-Authors: María José Sanz, Corinna Gries, Thomas H. NashAbstract:SUMMARY Sulphur dioxide fumigation of the lichens Evernia prunastri (L.) Ach and Ramalina fraxinea (L.) Ach, whose thallus water content was held at 100-120%, throughout each experiment, resulted in changes in net photosynthesis, dark respiration and chlorophyll content in relation to both concentration and duration of exposure. Net photosynthesis was the most sensitive response variable. Significant reduction in chlorophyll content was found when no recovery in net photosynthesis occurred after two weeks. A reduction in dark respiration was only found at high SO2 concentrations. Evernia prunastri was affected by lower concentrations and shorter exposure times than Ramalina fraxinea and the data for both species showed dose-response relationships.
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The Role of the Fruticose Lichen Ramalina menziesii in the Annual Turnover of Biomass and Macronutrients in a Blue Oak Woodland
Botanical Gazette, 1990Co-Authors: V. L. Boucher, Thomas H. NashAbstract:The pendulous, fruticose lichen Ramalina menziesii Tayl. is a conspicuous canopy component of the deciduous blue oak Quercus douglasii H. & A. woodland of central coastal California. With destructive sampling techniques the standing biomass of R. menziesii and other epiphtyic lichens was determined to be 515 g per tree or 706 kg/ha. Ramalina menziesii represented an average of 94% of total epiphytic lichens by weight. Monthly litterfall, collected in traps, was used to estimate canopy component biomass turnover, nutrient content of leaves and Ramalina menziesii, and canopy component nutrient turnover. In comparison with blue oak leaves, Ramalina menziesii contained 32% as much N, 29% P, 25% K, 4% Ca, 11% Mg, and 41% Na. Ramalina biomass was estimated to turn over 29% per yr and as a consequence this lichen contributed 13% N, 4% P, 7% K, 1% Ca, 3% Mg, and 8% Na of the annual canopy nutrient turnover. Although the study area is much drier than those of other similar studies, R. menziesii contributed as much...
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Growth patterns in Ramalina menziesii in California : coastal vs. Inland populations
The Bryologist, 1990Co-Authors: V. L. Boucher, Thomas H. NashAbstract:The fruticose lichen Ramalina menziesii varies morphologically across its range in central, coastal California: The thallus is thin and filamentous near the ocean, net-like and coarser inland. We used a nondestructive sampling technique to estimate seasonal and annual linear growth of the inland form transplanted within an inland site and to a coastal site. Growth at the inland site was concentrated in thefall and winter months when precipitation occurred; growth at the coastal site was nearly constant through the first year of the study. Ramalina menziesiifrom the inland site grew significantly faster at the coast (38.7%/yr.) than inland (20.1%/yr.). Lichen from both sites was transplanted both within and between sites and biomass increase was measured destructively after 1 yr. Both morphs grew equally within the same site, and more rapidly at the coastal site. Annual growth rates were lower when estimated as biomass: Approximately 14%/yr. inland and 24%/yr. at the coast. Some genetic differences appeared to exist between morphological types, but their growth responses to the environment were plastic. Ramalina menziesii Tayl. is a fruticose lichen, characterized by a reticulate thallus, that dominates the epiphytic community of central coastal Califor- nia, often forming a dense, pendulous canopy. Its thallus morphology ranges from relatively coarse nets in sunny, inland areas to thin filaments in foggy,
Thuchuy Duong - One of the best experts on this subject based on the ideXlab platform.
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three new phenolic compounds from the lichen Ramalina peruviana ach Ramalinaceae
Natural Product Research, 2020Co-Authors: Builinhchi Huynh, Thithuylinh Nguyen, Vankieu Nguyen, Warinthorn Chavasiri, Kimphiphung Nguyen, Thuchuy DuongAbstract:Three new phenolic compounds, peruvinides A-C were isolated from the lichen Ramalina peruviana Ach. (Ramalinaceae). Their structures were unambiguously determined by extensive spectroscopic analyse...
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Three new phenolic compounds from the lichen Ramalina peruviana Ach. (Ramalinaceae).
Natural product research, 2020Co-Authors: Builinhchi Huynh, Thithuylinh Nguyen, Vankieu Nguyen, Warinthorn Chavasiri, Kimphiphung Nguyen, Thuchuy DuongAbstract:Three new phenolic compounds, peruvinides A-C were isolated from the lichen Ramalina peruviana Ach. (Ramalinaceae). Their structures were unambiguously determined by extensive spectroscopic analyses and comparison with literature data. Peruvinides A and B bearing unusual moieties were found for the first time among lichen metabolites.
Builinhchi Huynh - One of the best experts on this subject based on the ideXlab platform.
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three new phenolic compounds from the lichen Ramalina peruviana ach Ramalinaceae
Natural Product Research, 2020Co-Authors: Builinhchi Huynh, Thithuylinh Nguyen, Vankieu Nguyen, Warinthorn Chavasiri, Kimphiphung Nguyen, Thuchuy DuongAbstract:Three new phenolic compounds, peruvinides A-C were isolated from the lichen Ramalina peruviana Ach. (Ramalinaceae). Their structures were unambiguously determined by extensive spectroscopic analyse...
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Three new phenolic compounds from the lichen Ramalina peruviana Ach. (Ramalinaceae).
Natural product research, 2020Co-Authors: Builinhchi Huynh, Thithuylinh Nguyen, Vankieu Nguyen, Warinthorn Chavasiri, Kimphiphung Nguyen, Thuchuy DuongAbstract:Three new phenolic compounds, peruvinides A-C were isolated from the lichen Ramalina peruviana Ach. (Ramalinaceae). Their structures were unambiguously determined by extensive spectroscopic analyses and comparison with literature data. Peruvinides A and B bearing unusual moieties were found for the first time among lichen metabolites.
María José Sanz - One of the best experts on this subject based on the ideXlab platform.
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dose response relationships for so2 fumigations in the lichens evernia prunastri l ach and Ramalina fraxinea l ach
New Phytologist, 1992Co-Authors: María José Sanz, Corinna Gries, Thomas H. NashAbstract:SUMMARY Sulphur dioxide fumigation of the lichens Evernia prunastri (L.) Ach and Ramalina fraxinea (L.) Ach, whose thallus water content was held at 100-120%, throughout each experiment, resulted in changes in net photosynthesis, dark respiration and chlorophyll content in relation to both concentration and duration of exposure. Net photosynthesis was the most sensitive response variable. Significant reduction in chlorophyll content was found when no recovery in net photosynthesis occurred after two weeks. A reduction in dark respiration was only found at high SO2 concentrations. Evernia prunastri was affected by lower concentrations and shorter exposure times than Ramalina fraxinea and the data for both species showed dose-response relationships.
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Dose—response relationships for SO2 fumigations in the lichens Evernia prunastri (L.) Ach. and Ramalina fraxinea (L.) Ach.
New Phytologist, 1992Co-Authors: María José Sanz, Corinna Gries, Thomas H. NashAbstract:SUMMARY Sulphur dioxide fumigation of the lichens Evernia prunastri (L.) Ach and Ramalina fraxinea (L.) Ach, whose thallus water content was held at 100-120%, throughout each experiment, resulted in changes in net photosynthesis, dark respiration and chlorophyll content in relation to both concentration and duration of exposure. Net photosynthesis was the most sensitive response variable. Significant reduction in chlorophyll content was found when no recovery in net photosynthesis occurred after two weeks. A reduction in dark respiration was only found at high SO2 concentrations. Evernia prunastri was affected by lower concentrations and shorter exposure times than Ramalina fraxinea and the data for both species showed dose-response relationships.
Jounghan Yim - One of the best experts on this subject based on the ideXlab platform.
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anticancer activity of ramalin a secondary metabolite from the antarctic lichen Ramalina terebrata against colorectal cancer cells
Molecules, 2017Co-Authors: Sungsuk Suh, Jounghan Yim, Se Jong Han, Tai Kyoung Kim, Jung Eun Kim, Jumi Hong, Trang Thu Thi Nguyen, Ui Joung Youn, Ilchan KimAbstract:Colorectal cancer is a leading cause of death worldwide and occurs through the highly complex coordination of multiple cellular pathways, resulting in carcinogenesis. Recent studies have increasingly revealed that constituents of lichen extracts exhibit potent pharmaceutical activities, including anticancer activity against various cancer cells, making them promising candidates for new anticancer therapeutic drugs. The main objective of this study was to evaluate the anticancer capacities of ramalin, a secondary metabolite from the Antarctic lichen Ramalina terebrata, in the human colorectal cancer cell line HCT116. In this study, ramalin displayed concentration-dependent anticancer activity against HCT116 cells, significantly suppressing proliferation and inducing apoptosis. Furthermore, ramalin induced cell cycle arrest in the gap 2/mitosis (G2/M) phase through the modulation of hallmark genes involved in the G2/M phase transition, such as tumour protein p53 (TP53), cyclin-dependent kinase inhibitor 1A (CDKN1A), cyclin-dependent kinase 1 (CDK1) and cyclin B1 (CCNB1). At both the transcriptional and translational level, ramalin caused a gradual increase in the expression of TP53 and its downstream gene CDKN1A, while decreasing the expression of CDK1 and CCNB1 in a concentration-dependent manner. In addition, ramalin significantly inhibited the migration and invasion of colorectal cancer cells in a concentration-dependent manner. Taken together, these data suggest that ramalin may be a therapeutic candidate for the targeted therapy of colorectal cancer.
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ramalin isolated from Ramalina terebrata attenuates atopic dermatitis like skin lesions in balb c mice and cutaneous immune responses in keratinocytes and mast cells
Phytotherapy Research, 2016Co-Authors: Hyejin Park, Jounghan Yim, Hong Kum Lee, Yeon Jeong Jang, Suhkneung PyoAbstract:Atopic dermatitis (AD) is a chronic inflammatory skin disease that involves eczematous skin lesions with pruritic erythematous papules. In this study, we investigated the mitigating effects of ramalin, a component of the Antarctic lichen Ramalina terebrata against AD in vivo and in vitro. Oral administration of ramalin lessened scratching behaviors and significantly reduced both serum immunoglobulin E and IL-4 levels, and mRNA levels of IL-4 and IL-10 in AD-induced Balb/c mice. In vitro, treatment with ramalin produced significantly less inflammatory chemokines and cytokines, including TARC, MCP-1, RANTES, and IL-8 in TNF-α-stimulated HaCaT cells. In addition, ramalin inhibited the activation of nuclear factor-kappa B as well as the phosphorylation of mitogen-activated protein kinases (MAPK). Furthermore, ramalin treatment resulted in decreased production of β-hexosaminidase and proinflammatory cytokines IL-4, IL-6, and TNF-α in 2,4 dinitrophenyl-human serum albumin-stimulated RBL-2H3 cells through blocking MAPK signaling pathways. The results suggest that ramalin modulates the production of immune mediators by inhibiting the nuclear factor-kappa B and MAPK signaling pathways. Taken together, ramalin effectively attenuated the development of AD and promoted the mitigating effects on Th2 cell-mediated immune responses and the production of inflammatory mediators in mast cells and keratinocytes. Thus, ramalin may be a potential therapeutic agent for AD. Copyright © 2016 John Wiley & Sons, Ltd.
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inhibition of melanogenesis by ramalin from the antarctic lichen Ramalina terebrata
Journal of the Society of Cosmetic Scientists of Korea, 2012Co-Authors: Yunhee Chang, Jongseong Ryu, Sanghwa Lee, Sungyoo Park, Hari Datta Bhattarai, Jounghan Yim, Moohyun JinAbstract:남극 지의류인 Ramalina terebrata에서 분리 정제된 라말린( ${\gamma}$ -glutamyl-N'-(2-hydroxyphenyl)hydrazide)은 이전 연구에서 강력한 항산화능을 확인하였다. 본 연구에서는 라말린의 추가적인 효능을 확인하기 위하여, 비암세포 세포주인 멜란에이 세포를 이용하여 라말린의 멜라닌 합성에 대한 효과를 확인하였다. 라말린은 세포 독성이 없는 농도에서, 멜란에이 세포에서 멜라닌 합성을 농도 의존적으로 감소시켰으며, 이러한 효과는 널리 사용되고 있는 미백제인 알부틴보다 우수하였다. 라말린은 무세포 타이로시네이즈의 활성을 직접 저해했을 뿐만 아니라, 세포 내의 타이로시네이즈의 활성도 저해하는 효과를 보였다. 라말린의 이러한 멜라닌 합성 저해의 기전 연구를 위하여, 멜라닌 합성에 중요한 단백질인 타이로시네이즈, TRP-1, TRP-2의 mRNA와 단백질 발현을 조사한 결과, mRNA양에는 영향을 주지 않고, 단백질의 발현은 감소되는 것으로 나타났다. 또한, 0.2 % 라말린을 포함한 제형을 사람피부에 도포하였을 때, 3주 후에 피부 밝기가 개선됨을 확인하였다. 이상의 결과를 통해서, 라말린은 타이로시네이즈의 직접적인 저해뿐만 아니라 멜라닌 합성과 관련된 단백질의 발현을 저해함으로써 미백효과를 나타낸다고 할 수 있으며, 이러한 효과를 인체시험을 통해 확인하였다. 따라서, 라말린은 멜라닌 합성을 저해하는 미백 소재로 활용될 수 있을 것으로 판단된다. 【Ramalin ( ${\gamma}$ -glutamyl-N'-(2-hydroxyphenyl)hydrazide) isolated from the Antarctic lichen Ramalina terebrata has been shown to have strong antioxidant activities in the previous study. To investigate additional activities of ramalin, we studied the effects of ramalin on melanogenesis in melan-a cells, a non-tumorigenic melanocyte cell line. At a non-cytotoxic concentration, ramalin dramatically decreased melanin synthesis in melan-a cells in a dose-dependent manner, which was more potent than arbutin, a well-known tyrosinase inhibitor. Ramalin inhibited cell-free tyrosinase activity directly and intracellular tyrosinase activity as well. Its inhibitory mechanisms on melanin production were further assessed, and we found that ramalin significantly decreased the protein levels of melanogenic enzymes such as tyrosinase, tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2). However, the mRNA levels of these enzymes were not altered. In a clinical study, application of 0.2 % ramalin on human skin significantly improved the degree of skin brightness after 3 weeks. In conclusion, ramalin has strong anti-melanogenic activity that is exerted both by the direct inhibition of tyrosinase activity and by down-regulation of melanogenic proteins. Furthermore, ramalin showed skin brightening effect in a clinical study. Collectively, these results suggest that ramalin may be a useful inhibitor for melanogenesis in skin.】
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ramalin a novel nontoxic antioxidant compound from the antarctic lichen Ramalina terebrata
Phytomedicine, 2011Co-Authors: Babita Paudel, Hari Datta Bhattarai, Hye Yeon Koh, Sung Gu Lee, Se Jong Han, Hong Kum Lee, Hyun Woung Shin, Jounghan YimAbstract:Abstract Ramalin (γ-glutamyl-N′-(2-hydroxyphenyl)hydrazide), a novel compound, was isolated from the methanol–water extract of the Antarctic lichen Ramalina terebrata by several chromatographic methods. The molecular structure of ramalin was determined by spectroscopic analysis. The experimental data showed that ramalin was five times more potent than commercial butylated hydroxyanisole (BHA) in scavenging 1-diphenyl-2-picryl-hydazil (DPPH) free radicals, 27 times more potent in scavenging 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid free radicals (ABTS +) than the vitamin E analogue, trolox, and 2.5 times more potent than BHT in reducing Fe3+ to Fe2+ ions. Similarly, ramalin was 1.2 times more potent than ascorbic acid in scavenging superoxide radicals and 1.25 times more potent than commercial kojic acid in inhibiting tyrosinase enzyme activity, which ultimately leads to whitening of skin cells. Ramalin showed no or very little cytotoxicity in human keratinocyte and fibroblast cells at its antioxidant concentration. Furthermore, ramalin was assessed to determine its antioxidant activity in vivo. One microgram per milliliter ramalin significantly reduced the released nitric oxide (NO) and 0.125 μg/ml ramalin reduced the produced hydrogen peroxide (H2O2) in LPS (lipopolysaccharide)-stimulated murine macrophage Raw264.7 cells. Considering all the data together, ramalin can be a strong therapeutic candidate for controlling oxidative stress in cells.
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antibacterial activities of ramalin usnic acid and its three derivatives isolated from the antarctic lichen Ramalina terebrata
Zeitschrift für Naturforschung C, 2010Co-Authors: Babita Paudel, Hari Datta Bhattarai, Hong Kum Lee, Hyun Woung Shin, Jounghan YimAbstract:The development of new antibacterial compounds is an urgent issue to meet the evolution of resistivity of pathogenic bacteria against the available drugs. The objective of this study was to investigate the antibacterial compounds from the Antarctic lichen species Ramalina terebrata. A total of five compounds, usnic acid, usimine A, usimine B, usimine C, and ramalin, were isolated by bioactivity guided-fractionation of the methanol extract of R. terebrata after several chromatographic procedures. The qualitative antibacterial activities of the crude extract and isolated compounds were determined by the disk diffusion method while the minimum inhibitory concentration (MIC) determination assay gave the quantitative strength of the test samples. All the test samples showed antibacterial activity against Bacillus subtilis. The crude extract and usnic acid showed antibacterial activity against Staphylococcus aureus. The MIC values of the isolated compounds against B. subtilis were in the range of 1 to 26 microg/mL. These observed experimental data showed the strong antibacterial potential of these compounds against B. subtilis.
