Extracts of six selected Malaysian plants with a reputation of usefulness in treating diabetes were examined for α-amylase inhibition using an in vitro model. Inhibitory activity studied by two ...different protocols (with and without pre-incubation) showed that
Phyllanthus amarus hexane extract had α-amylase inhibitory properties. Hexane and dichloromethane extracts of
Anacardium occidentale,
Lagerstroemia speciosa,
Averrhoa bilimbi
Pithecellobium jiringa and
Parkia speciosa were not active when tested without pre-incubation. Extraction and fractionation of
Phyllanthus amarus hexane extract led to the isolation of dotriacontanyl docosanoate, triacontanol and a mixture of oleanolic acid and ursolic acid. Dotriacontanyl docosanoate and the mixture of oleanolic acid and ursolic acid are reported from this plant species for the first time. All compounds were tested in the α-amylase inhibition assay and the results revealed that the oleanolic acid and ursolic acid (2:1) mixture was a potent α-amylase inhibitor with IC
50
=
2.01
μg/ml (4.41
μM) and that it contributes significantly to the α-amylase inhibition activity of the extract. Three pure pentacyclic triterpenoids, oleanolic acid, ursolic acid and lupeol were shown to inhibit α-amylase.
30 healers in South-west Nigeria were interviewed for plants used to treat cancer. 45 species were identified and their extracts tested for cytotoxicity against various cell lines. Five species ...displayed considerable activity, including
Cajanus cajan leaves, and two stilbenes longistylin A and longistylin C were isolated from this as major active compounds.
There is only scant literature on the anticancer components of medicinal plants from Nigeria, yet traditional healers in the area under study claim to have been managing the disease in their patients with some success using the species studied.
To document plants commonly used to treat cancer in South-western Nigeria and to test the scientific basis of the claims using
in vitro cytotoxicity tests.
Structured questionnaires were used to explore the ethnobotanical practices amongst the traditional healers. Methanol extracts of the most common species cited were screened for cytotoxicity using the sulforhodamine B (SRB) assay in both exposure and recovery experiments. Three cancer cell lines (human breast adenocarcinoma cell line MCF-7, human large cell lung carcinoma cell line COR-L23 and human amelanotic melanoma C32) and one normal cell line (normal human keratinocytes SVK-14) were used for the screening of the extracts and the fractions obtained. The extract of
Cajanus cajan showed considerable activity and was further partitioned and the dichloromethane fraction was subjected to preparative chomatography to yield six compounds: hexadecanoic acid methyl ester, α-amyrin, β-sitosterol, pinostrobin, longistylin A and longistylin C. Pinostrobin and longistylins A and C were tested for cytotoxicity on the cancer cell lines. In addition, an adriamycin-sensitive acute T-lymphoblastic leukaemia cell line (CCRF-CEM) and its multidrug-resistant sub-line (CEM/ADR5000) were used in an XTT assay to evaluate the activity of the pure compounds obtained.
A total of 30 healers from S W Nigeria were involved in the study. 45 species were recorded with their local names with parts used in the traditional therapeutic preparations. Cytotoxicity (IC
50 values less than 50
μg/mL) was observed in 5 species (
Acanthospermum hispidum,
Cajanus cajan,
Morinda lucida,
Nymphaea lotus and
Pycnanthus angolensis).
Acanthospermum hispidum and
Cajanus cajan were the most active. The dichloromethane fraction of
Cajanus cajan had IC
50 value 5–10
μg/mL, with the two constituent stilbenes, longistylins A and C, being primarily responsible, with IC
50 values of 0.7–14.7
μM against the range of cancer cell lines.
Most of the species tested had some cytotoxic effect on the cancer cell lines, which to some extent supports their traditional inclusion in herbal preparations for treatment of cancer. However, little selectivity for cancer cells was observed, which raises concerns over their safety and efficacy in traditional treatment. The longistylins A and C appear to be responsible for much of the activity of
Cajanus cajan extract.
Global Carbon Budget 2020 Friedlingstein, Pierre; O'Sullivan, Michael; Jones, Matthew W ...
Earth system science data,
12/2020, Letnik:
12, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and
their redistribution among the atmosphere, ocean, and terrestrial biosphere
in a changing climate – the “global carbon budget” ...– is important to
better understand the global carbon cycle, support the development of
climate policies, and project future climate change. Here we describe and
synthesize data sets and methodology to quantify the five major components
of the global carbon budget and their uncertainties. Fossil CO2
emissions (EFOS) are based on energy statistics and cement production
data, while emissions from land-use change (ELUC), mainly
deforestation, are based on land use and land-use change data and
bookkeeping models. Atmospheric CO2 concentration is measured directly
and its growth rate (GATM) is computed from the annual changes in
concentration. The ocean CO2 sink (SOCEAN) and terrestrial
CO2 sink (SLAND) are estimated with global process models
constrained by observations. The resulting carbon budget imbalance
(BIM), the difference between the estimated total emissions and the
estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a
measure of imperfect data and understanding of the contemporary carbon
cycle. All uncertainties are reported as ±1σ. For the last
decade available (2010–2019), EFOS was 9.6 ± 0.5 GtC yr−1 excluding the cement carbonation sink (9.4 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and
ELUC was 1.6 ± 0.7 GtC yr−1. For the same decade, GATM was 5.1 ± 0.02 GtC yr−1 (2.4 ± 0.01 ppm yr−1), SOCEAN 2.5 ± 0.6 GtC yr−1, and SLAND 3.4 ± 0.9 GtC yr−1, with a budget
imbalance BIM of −0.1 GtC yr−1 indicating a near balance between
estimated sources and sinks over the last decade. For the year 2019 alone, the
growth in EFOS was only about 0.1 % with fossil emissions increasing
to 9.9 ± 0.5 GtC yr−1 excluding the cement carbonation sink (9.7 ± 0.5 GtC yr−1 when cement carbonation sink is included), and ELUC was 1.8 ± 0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.5 ± 0.9 GtC yr−1 (42.2 ± 3.3 GtCO2). Also for 2019, GATM was
5.4 ± 0.2 GtC yr−1 (2.5 ± 0.1 ppm yr−1), SOCEAN
was 2.6 ± 0.6 GtC yr−1, and SLAND was 3.1 ± 1.2 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2
concentration reached 409.85 ± 0.1 ppm averaged over 2019. Preliminary
data for 2020, accounting for the COVID-19-induced changes in emissions,
suggest a decrease in EFOS relative to 2019 of about −7 % (median
estimate) based on individual estimates from four studies of −6 %, −7 %,
−7 % (−3 % to −11 %), and −13 %. Overall, the mean and trend in the
components of the global carbon budget are consistently estimated over the
period 1959–2019, but discrepancies of up to 1 GtC yr−1 persist for the
representation of semi-decadal variability in CO2 fluxes. Comparison of
estimates from diverse approaches and observations shows (1) no consensus
in the mean and trend in land-use change emissions over the last decade, (2)
a persistent low agreement between the different methods on the magnitude of
the land CO2 flux in the northern extra-tropics, and (3) an apparent
discrepancy between the different methods for the ocean sink outside the
tropics, particularly in the Southern Ocean. This living data update
documents changes in the methods and data sets used in this new global
carbon budget and the progress in understanding of the global carbon cycle
compared with previous publications of this data set (Friedlingstein et al.,
2019; Le Quéré et al., 2018b, a, 2016, 2015b, a, 2014,
2013). The data presented in this work are available at https://doi.org/10.18160/gcp-2020 (Friedlingstein et al., 2020).
In preparation for the fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), the international community is developing new advanced Earth System Models (ESMs) to ...assess the combined effects of human activities (e.g. land use and fossil fuel emissions) on the carbon-climate system. In addition, four Representative Concentration Pathway (RCP) scenarios of the future (2005–2100) are being provided by four Integrated Assessment Model (IAM) teams to be used as input to the ESMs for future carbon-climate projections (Moss et al.
2010
). The diversity of approaches and requirements among IAMs and ESMs for tracking land-use change, along with the dependence of model projections on land-use history, presents a challenge for effectively passing data between these communities and for smoothly transitioning from the historical estimates to future projections. Here, a harmonized set of land-use scenarios are presented that smoothly connects historical reconstructions of land use with future projections, in the format required by ESMs. The land-use harmonization strategy estimates fractional land-use patterns and underlying land-use transitions annually for the time period 1500–2100 at 0.5° × 0.5° resolution. Inputs include new gridded historical maps of crop and pasture data from HYDE 3.1 for 1500–2005, updated estimates of historical national wood harvest and of shifting cultivation, and future information on crop, pasture, and wood harvest from the IAM implementations of the RCPs for the period 2005–2100. The computational method integrates these multiple data sources, while minimizing differences at the transition between the historical reconstruction ending conditions and IAM initial conditions, and working to preserve the future changes depicted by the IAMs at the grid cell level. This study for the first time harmonizes land-use history data together with future scenario information from multiple IAMs into a single consistent, spatially gridded, set of land-use change scenarios for studies of human impacts on the past, present, and future Earth system.
In vitro tests are now widely employed in ethnopharmacological research because of ethical reasons and their usefulness in bioactive-guided fractionation and determination of active compounds. For ...many disease conditions, a variety of in vitro tests can now be employed as the biochemical mechanisms underlying disease and healing processes are understood. Approaches to the in vitro investigations of wound healing processes are exemplified by studies on extracts of
Buddleja species and three Ghanaian species
Spathodea campanulata,
Commelina diffusa and
Secamone afzelii. Most studies have been carried out on
Buddleja officinalis or
Buddleja globosa. The extracts have been shown to have anti-inflammatory and antioxidant properties due to flavonoids, triterpenoids, diterpenoids and caffeic acid derivatives. There appears to a slight effect on proliferation of fibroblasts at lower concentrations, but this was not significant, and higher concentrations appeared to be cytotoxic. Novel findings are the ability of
Buddleja globosa leaf extracts to induce differentiation in keratinocytes and to alter the profile of proteins produced by cultured fibroblasts. Extracts also had some effect on lattice contraction. The three Ghanaian species examined show a mixture of antimicrobial and antioxidant activities. The evolution over recent years of tests for wound healing, from in vivo tests to cell-based systems and chemical reactions and on to investigations into effects on secondary messengers and protein expression, is described.
This review describes 183 compounds obtained from plants and fungi which have been shown to inhibit acetylcholinesterase. The mechanism of action of cholinesterase, together with the binding sites, ...and, where this is known, the mode of action of inhibitors is described. The relative activities of the different compounds are recorded. The strongest inhibitors are generally alkaloids although some meroterpenoids from fungi have also been found to be active and display better selectivity.
mTOR and cancer therapy Easton, J B; Houghton, P J
Oncogene,
10/2006, Letnik:
25, Številka:
48
Journal Article
Recenzirano
Odprti dostop
Proteins regulating the mammalian target of rapamycin (mTOR), as well as some of the targets of the mTOR kinase, are overexpressed or mutated in cancer. Rapamycin, the naturally occurring inhibitor ...of mTOR, along with a number of recently developed rapamycin analogs (rapalogs) consisting of synthetically derived compounds containing minor chemical modifications to the parent structure, inhibit the growth of cell lines derived from multiple tumor types in vitro, and tumor models in vivo. Results from clinical trials indicate that the rapalogs may be useful for the treatment of subsets of certain types of cancer. The sporadic responses from the initial clinical trials, based on the hypothesis of general translation inhibition of cancer cells are now beginning to be understood owing to a more complete understanding of the dynamics of mTOR regulation and the function of mTOR in the tumor microenvironment. This review will summarize the preclinical and clinical data and recent discoveries of the function of mTOR in cancer and growth regulation.
Summary
Background A sensation of abdominal swelling (bloating) and actual increase in girth (distension) are troublesome features of irritable bowel syndrome (IBS), which is more common in patients ...with constipation, especially those with delayed transit.
Aim To establish whether a fermented dairy product containing Bifidobacterium lactis DN‐173 010 reduces distension in association with acceleration of gastrointestinal transit and improvement of symptoms in IBS with constipation.
Methods A single centre, randomized, double‐blind, controlled, parallel group study in which patients consumed the test product or control product for 4 weeks. Distension, orocaecal and colonic transit and IBS symptoms were assessed on an intention‐to‐treat population of 34 patients.
Results Compared with control product, the test product resulted in a significant reduction in the percentage change in maximal distension median difference – 39%, 95% CI (−78, −5); P = 0.02 and a trend towards reduced mean distension during the day −1.52 cm (−3.33, 0.39); P = 0.096. An acceleration of orocaecal −1.2 h (−2.3,0); P = 0.049 as well as colonic −12.2 h (−22.8, −1.6); P = 0.026 transit was observed and overall symptom severity −0.5 (−1.0, −0.05); P = 0.032 also improved.
Conclusions This probiotic resulted in improvements in objectively measured abdominal girth and gastrointestinal transit, as well as reduced symptomatology. These data support the concept that accelerating transit is a useful strategy for treating distension.
Although in vivo models give a more accurate reflection of the activity of substances used in traditional medicine, their use in many countries is severely restricted due to economic and ethical ...concerns, and this has resulted in the widespread use of in vitro tests in ethnopharmacological studies. Such tests are very useful where the identity of compounds responsible for the biological activity of an extract is being investigated and where limited supplies of material are available, but it is important to consider a variety of factors before making over-predictive claims of that activity in one particular system explains the traditional use. The use of only one bioassay gives a very incomplete picture of the effect of the extract on the whole system involved. A symptom may be due to a number of disease states and, consequently, a variety of mechanisms may serve as targets for bioassays. In a similar way, it is very unusual for there to be only one target for a particular disease so a variety of test systems must be employed. Examples are given of batteries of test systems used to test plants and other materials with a reputation of being useful in wound-healing, diabetes, cancer and to treat cognitive decline associated with old age. In addition, consideration must be given to factors such as absorption into the body and metabolism of any substances present, either to decrease or increase the effect of the ‘actives’.
We summarise the contemporary carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric ...environment and climate. Component flux estimate methods we consider sufficiently reliable for this purpose encompass fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and agricultural export data. Alternative methods for the estimation of the continental-scale net land to atmosphere CO2 flux, such as atmospheric transport inverse modelling and terrestrial biosphere model predictions, are, we find, hampered by the data paucity, and improved parameterisation and validation exercises are required before reliable estimates can be obtained. From our analysis of available data, we suggest that South America was a net source to the atmosphere during the 1980s (~ 0.3–0.4 Pg C a−1) and close to neutral (~ 0.1 Pg C a−1) in the 1990s. During the latter period, carbon uptake in old-growth forests nearly compensated for the carbon release associated with fossil fuel burning and deforestation. Annual mean precipitation over tropical South America as inferred from Amazon River discharge shows a long-term upward trend. Although, over the last decade dry seasons have tended to be drier, with the years 2005 and 2010 in particular experiencing strong droughts. On the other hand, precipitation during the wet seasons also shows an increasing trend. Air temperatures have also increased slightly. Also with increases in atmospheric CO2 concentrations, it is currently unclear what effect these climate changes are having on the forest carbon balance of the region. Current indications are that the forests of the Amazon Basin have acted as a substantial long-term carbon sink, but with the most recent measurements suggesting that this sink may be weakening. Economic development of the tropical regions of the continent is advancing steadily, with exports of agricultural products being an important driver and witnessing a strong upturn over the last decade.
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