No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Seasonal variation in the content of a febrifugine and isofebrifugine alkaloid mixture in aerial parts of Hydrangea macrophylla var. Otaksa, with special reference to its antimalarial activity
Abstract
Febrifugine and isofebrifugine alkaloid mixtures extracted from the leaves and buds of Hydrangea macrophylla var. Otaksa, collected during different months, in Japan, were quantified using high-performance liquid chromatography. Leaves collected
during the flowering season, namely from June to August, contained 0.16–0.31mg/g of the alkaloid mixture, whereas those collected
from September to December had less than 0.03mg/g of the mixture. However, extracts of buds harvested from October to February
contained a consistently larger amount (more than 0.49mg/g) of the alkaloids. Hot-water extracts from the leaves and buds
collected during different seasons were evaluated for antimalarial activity against Plasmodium yoelii 17XL in mice. The extract of leaves collected in August demonstrated high antimalarial activity, and all mice that received
the extract survived the infection. In contrast, the extract of leaves collected in December showed little activity. The extract
of buds collected in December cleared parasites, but with subsequent mortality to mouse. The present results show that the
amount of antimalarial agent—febrifugine and isofebrifugine mixture—in H. macrophylla var. Otaksa is both part- and season-dependent, suggesting that the choice of plant parts and their harvesting season are important factors
worth considering in the pharmacological use of medicinal plants.
... Febrifugine is also found in the common garden plants of the genus Hydrange a (Ishih et al. 2006), which do serve as a nectar source for honey bees (Suppl Figure 4). Animals are known to employ self-medication or zoopharmacognosy (de Roode et al. 2013) and many invertebrates (Schmid-Hempel 2017), including honey bees (Erler and Moritz 2016), and participate in this behavior. ...
... Bumble bees ingest more nectar containing the antiparasitic compound anabasine when parasitized by a specific trypanosome (Anthony et al. 2015). While Febrifugine levels in nectar are unknown (Ishih et al. 2006), it is tempting to speculate that honey bees may preferentially consume Hydrangea nectar when parasitized by microsporidia. ...
Nosema ceranae is a microsporidian parasite that is pathogenic to honey bees, causing disease at the individual and colony level. N. ceranae infection can be controlled by treatment with Fumagillin, but as this the future of this drug is uncertain, alternative treatment strategies are critical. Genomic examination of proteostasis pathways in N. ceranae and its host, Apis mellifera, has revealed key differences in component conservation. One example is the amino acid response (AAR), which responds to amino acid limitation through the sensing of uncharged tRNA molecules. The AAR is conserved in the honey bee, but not in N. ceranae. Pharmacological inhibition of prolyl-tRNA synthetase activity resulted in a substantial reduction in N. ceranae infection intensity. Evident toxicity to bees suggests further work is required to make this approach safe and feasible. However, these results provide proof of principle that tRNA synthetase inhibition could be an effective future treatment strategy.
... All of these are known to influence sterol levels in plant species 2,4,7,11,13 . Seasonal variation of metabolite content in plants has been reported 10,12,14,18,19,23 . Temperature and UV-B radiation could have been the key to variation of metabolites in plants 1 . ...
Rauvolfia serpentina (L). Benth. ex Kurz. (Apocynaceae) occupies a prominent position in the ethno-therapeutics practiced in the Indian subcontinent. The plant is known to contain a number of bioactive secondary metabolites including indole alkaloids. The objective of our present study is to estimate the seasonal variation of stigmasterol content in the roots of the plant. Seasonal modulation in stigmasterol content in R. serpentina roots was analyzed by High Performance Thin Layer Chromatography (HPTLC) performed on Silica gel 60 F254 TLC plates with benzene-acetone 86:14 (v/v) as mobile phase. Densitometric analysis was carried out at λ=366 nm after derivatization with vanillin-10 % (v/v) sulphuric acid alcohol. In the root samples stigmasterol was present at Rf value of 0.44. Stigmasterol content was found to be the highest in roots harvested during summer and the lowest in winter and there was a gradual decrease from summer to winter through monsoon and autumn and from spring the hike was again found. Modulation in stigmasterol content during different seasons was noted which can be implicated to the popular notion of variation in secondary metabolites depending on temperature, ultraviolet radiation and other factors related to seasonal changes. Popular use of the plant in Indian ethnomedicine may be attributed to the presence of stigmasterol as one of the important constituents of the plant.
Hydrangea [Hydrangea macrophylla (Thunb.) Ser.] is a high aluminum-tolerant ornamental plant species, which has a specific characteristic of color change, ie. some cultivars' floral color will change from red to blue or blue-violet planted in acidic soil containing aluminum. This study aims to understand the complex molecular mechanisms of floral color change under Al stress, through comparative biochemistry and transcriptome analyses between an Al³⁺-sensitive cultivar ‘Bailer’ and insensitive cultivar ‘Ruby’ under Al-stress. The results of biochemistry analysis showed that ‘Bailer’ displayed higher contents of Al³⁺ and delphinium-3-O-glucoside than that of ‘Ruby’ after Al2(SO4)3 treating. Meanwhile, the transcriptome analysis of different tissues identified 12,321 differentially expressed genes (DEGs) in ‘Bailer’ and 6703 in ‘Ruby’. Transcriptome analysis showed that changes in genes' expression pattern in several genes and pathways [such as including metal transporters, reactive oxygen species (ROS) scavenging enzyme, plant hormone signal transduction and favonoid biosynthesis pathway] were the key contributors to the Al³⁺-sensitive cultivar ‘Bailer’. Besides, gene co-expression network analysis (WGCNA) demonstrated that five hub genes, including ABC transporters (TRINITY_DN1053_c0_g1, TRINITY_DN3377_c0_g2), cationic amino acid transporter (TRINITY_DN9684_c0_g2), oligopeptide transporter (TRINITY_DN1147_c0_g2) and flavonol synthase (TRINITY_DN15902_c0_g1), played vital roles in the networks regulating Al tolerance in hydrangea. Furthermore, HmABCI17′s (TRINITY_DN1053_c0_g1) expression enhanced Al tolerance in yeast. The conclusions of this study are helpful to elucidate the differences and molecular mechanisms of different hydrangea cultivars on Al tolerance, and provide new insights into molecular assisted-screening for breeding blue flowers in hydrangea and other ornamental plants.
A diastereoselective approach to access cis‐pyrido and pyrrolo[1,2‐c][1,3]oxazin‐1‐ones has been developed through a one‐pot BF3.Et2O‐catalyzed [4+2] process starting with N,O‐acetals and terminal alkynes. In addition, the utility of this transformation is demonstrated by the scalable synthesis of (+)‐Febrifugine in 7 steps from the N,O‐acetal (15% overall yield).
OBJECTIVE: To develop an effective HPLC method for determining the content of febrifugine and isofebrifugine mixture in Dichroa febrifuga root and its Yinpian. METHODS: The column used was Kromasil C18 (4.6 mm x 250 mm, 5 μm). The mobile phase consisted of acetonitrile, water, glacial acetic acid and triethylamine (9:91:0. 3:0.745), and pH was adjusted with glacial acetic acid to 5.2-6.2. The flow rate was 1 mL · min-1 and the column temperature was 30 °C. The detection wavelength was at 225 nm. The content was quantified by an external standard method. RESULTS: Good linearity of the febrifugine and isofebrifugine mixture was obtained in the range of 0.021-2.18 μg. The method recovery was between 95.16% and 103.97%, and the RSD was 3.28%. CONCLUSION: The method is simple, fast and accurate, and is suitable for the determination of content of febrifugine and isofebrifugine mixture in the Dichroa febrifuga root and its Yinpian.
Genus Hydrangea: diversity of pigments and phenolic compounds
Natural products remain a rich source of novel molecular scaffolds for novel antimalarial agents in the fight against malaria. This has been well demonstrated in the case of quinine and artemisinin both of which have served as templates for the development of structurally simpler analogues that either served or continue to serve as effective antimalarials. This review will expound on these two natural products as well as other selected natural products that have served either as antimalarial agents or as potential lead compounds in the development of antimalarial drugs.
The in vitro activities of furo[2,3b]quinoline and acridone alkaloids against Plasmodium falciparum were evaluated by an isotopic
semimicrotest. A pyran ring in the furoquinoline nucleus and 2-O-pyranoglycoside and 2-nitro substituents in the acridone
nucleus improved the antimalarial activities of the compounds. These findings provide a clue for further chemical modifications.
Artemisinin and its derivatives are endoperoxide-containing compounds which represent a promising new class of antimalarial drugs. In the presence of intraparasitic iron, these drugs are converted into free radicals and other electrophilic intermediates which then alkylate specific malaria target proteins. Combinations of available derivatives and other antimalarial agents show promise both as first-line agents and in the treatment of severe disease.
Hot-water extracts of 7 plants of the family Saxifragaceae; Hydrangea macrophylla var. Otaksa, H. macrophylla, H. macrophylla serrata var. acuminata, H. involucrata, H. hirta, H. paniculata, and Cardiandra alternifolia, were screened for antimalarial activity in ICR mice infected with Plasmodium yoelii 17XL. The leaf extract of H. macrophylla var. Otaksa or H. macrophylla had an antimalarial activity against rodent malaria, showing low parasitemia levels during administration. Following a transient recrudescence of malaria parasites in the bloodstream of treated mice, no parasites could be detected by a microscopic examination. Mice treated with the leaf extract of H. macrophylla var. Otaksa or H. macrophylla survived during the experiment, though mice in the non-treated control and other treated groups died with a gradual body weight loss from day 6 to day 10 post infection. Furthermore, the antimalarial activity of the hot-water extract of H. macrophylla leaf extract seemed higher than that of H. macrophylla var. Otaksa leaf extract in respect of the degree of suppression of parasite multiplication and of mouse body weight loss.
The antimalarial activity of the hot-water extract of leaves and roots of Dichroa febrifuga was evaluated against Plasmodium yoelii 17XL in ICR mice. Untreated control mice died with a gradual body weight loss and increase of parasitemia by day 9 after infection. The hot-water extract of leaves collected in June showed an antimalarial activity, and furthermore the possible adverse side effect was also observed. All mice given orally the extract of leaves (0.1 g/ml) collected in June died by day 9 without parasite multiplication. The mice given the lower concentration (0.025 g/ml) of the same leaf extract showed low parasitemia levels during administration. Following a transient increase of malaria parasites in the bloodstream, no parasites could be detected by a microscopic examination, and all mice survived during the experiment. On the other hand, the extract of leaves (0.1 g/ml) collected in December showed no activity. The extract of roots (0.1 g/ml) of D. febrifuga collected in December, however, had an antimalarial activity, and three mice out of four survived during the experiment. The leaves collected in June contained about 30 times as much febrifugine and isofebrifugine mixture as those in December.
The herb Artemisia annua has been used for many centuries in Chinese traditional medicine as a treatment for fever and malaria. In 1971, Chinese chemists isolated from the leafy portions of the plant the substance responsible for its reputed medicinal action. This compound, called qinghaosu (QHS, artemisinin), is a sesquiterpene lactone that bears a peroxide grouping and, unlike most other antimalarials, lacks a nitrogen-containing heterocyclic ring system. The compound has been used successfully in several thousand malaria patients in China, including those with both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. Derivatives of QHS, such as dihydroqinghaosu, artemether, and the water-soluble sodium artesunate, appear to be more potent than QHS itself. Sodium artesunate acts rapidly in restoring to consciousness comatose patients with cerebral malaria. Thus QHS and its derivatives offer promise as a totally new class of antimalarials.
The functional heterogeneity of the CD4+ T cell response to Plasmodium chabaudi has been evaluated. Using a limiting dilution assay system and a variety of assays to detect γ-interferon (IFN-γ), interleukln-2
(IL-2), IL-3, and T helper (Th) cells for malaria-specific antibody production, the precursor frequencies of P. chabaudl-reactive T cells have been calculated. The patterns of lymphokines produced by individual microcultures of the limiting dilution
assay generally supported the Idea of two functionally distinct CD4+ subsets: one which produces IFN-γ and IL-2 (Th1) and one which Is an effective helper cell for antibody production (Th2) However, it could not be determined whether the overiapping functions observed in some cultures represented T cells which
could produce all factors or separate clones which were developing In the same wells. During the first 14 days of an erythrocytic
Infection of P. chabaudi the predominant T cell response was of the Th1-tupe. The frequency of these cells decreased after 14 days. By 3 weeks after Infection the CD4+ T cell response was characterized by Th2 cells, as defined by their ability to act as helper cells in the production of malaria-specific antibody. These data support
the hypothesis that early clearance of P. chabaudi may be antibody-Independent but that the final clearance mechanism coincides with the appearance of helper cells and antibody.
The herb Artemisia annua has been used for many centuries in Chinese traditional medicine as a treatment for fever and malaria.
In 1971, Chinese chemists isolated from the leafy portions of the plant the substance responsible for its reputed medicinal
action. This compound, called qinghaosu (QHS, artemisinin), is a sesquiterpene lactone that bears a peroxide grouping and,
unlike most other antimalarials, lacks a nitrogen-containing heterocyclic ring system. The compound has been used successfully
in several thousand malaria patients in China, including those with both chloroquine-sensitive and chloroquine-resistant strains
of Plasmodium falciparum. Derivatives of QHS, such as dihydroqinghaosu, artemether, and the water-soluble sodium artesunate,
appear to be more potent than QHS itself. Sodium artesunate acts rapidly in restoring to consciousness comatose patients with
cerebral malaria. Thus QHS and its derivatives offer promise as a totally new class of antimalarials.
The induction of T helper cell subsets during the course of non-lethal or lethal blood-stage Plasmodium chabaudi AS infection was investigated using inbred strains of mice which differ in the level of resistance to this intraerythrocytic parasite. Resistant C57Bl/6 mice experience a non-lethal course of infection characterized by moderate levels of both parasitaemia and anaemia and resolution of primary acute infection by 4 weeks, while susceptible A/J mice experience lethal infection with fulminant parasitaemia and severe anaemia. T helper subset function was assessed during infection by determining the kinetics of spleen cell production in vitro of the Th1-derived cytokine, interferon-gamma (IFN-gamma), and of the Th2-derived cytokine, IL-5, using sandwich ELISAs. Spleen cells from resistant C57Bl/6 mice were found to produce high levels of IFN-gamma within 1 week of infection in response to both the mitogen concanavalin A (Con A) and malaria antigen. Furthermore, CD4+ T cells were found to be the source of IFN-gamma while both CD4+ and CD8+ T cells were found to produce IL-5. Decreased IFN-gamma production after day 10 was concomitant with significant production of IL-5 between 2 and 3 weeks post infection. In contrast, spleen cells from susceptible A/J mice produced high levels of IL-5 within the first week of infection. In addition, these animals were found to have high serum levels of IL-5. These results, thus, confirm previous observations that resolution of primary blood-stage P. chabaudi infection occurs by sequential activation of Th1 CD4+ T cells followed by activation of the Th2 subset, and in addition, suggest that induction of a strong Th2 response early in infection may lead to a severe and lethal course of malaria.
Artemisinin and its derivatives are endoperoxide-containing compounds which represent a promising new class of antimalarial drugs. In the presence of intraparasitic iron, these drugs are converted into free radicals and other electrophilic intermediates which then alkylate specific malaria target proteins. Combinations of available derivatives and other antimalarial agents show promise both as first-line agents and in the treatment of severe disease.
The effect of febrifugine, the main alkaloidal constituent of an antimalarial crude drug, Dichroa febrifuga Lour., on protective immunity in mice infected with erythrocytic stage Plasmodium berghei NK65 was investigated. Febrifugine was administered orally, at a dose of 1 mg/kg/day, to mice before and/or after they were infected intraperitoneally with 2 x 10(6) parasitized red blood cells. Then, mortality and the levels of parasitemia and plasma NO3- [a degradation product of nitric oxide (NO)] were monitored. Febrifugine significantly reduced the mortality and the level of parasitemia. The plasma NO3- concentration began to rise within 2 days after treatment with febrifugine and declined to normal in 2 days when the mice were treated orally with febrifugine once a day for 3 consecutive days before parasite infection. This antimalarial activity of febrifugine was reduced by both N(G)-monomethyl-L-arginine and aminoguanidine. These results indicate that the increased production of NO by febrifugine plays an important role in host defense against malaria infection in mice.
By using a murine transplantation model, we studied the relationship between CD34 expression and expression of CD4 and Mac-1 by hematopoietic stem cells of normal adult mice.
Cells from Ly-5.1 C57BL/6 mice were used as test cells and lethally irradiated Ly-5.2 mice were used as recipient mice. Peripheral blood was obtained 6 months posttransplantation to analyze engraftment of donor-derived cells.
First, we determined that CD34- long-term reconstituting cells are CD4-, while some CD34+ stem cells express CD4. We then studied Mac-1 expression. Mac-1(-) and Mac-1(low) populations of both CD34- and CD34+ cells were capable of long-term reconstitution. Mac-1(high) population of CD34+ cells but not of CD34- cells also engrafted.
These results strongly indicate that depletion of Mac-1(+) and CD4(+) cells in stem cell purification may inadvertently discard significant populations of CD34+ stem cells. Since positive selection based on CD34 expression is the current practice for purification of human stem cells, our studies may possess implications in the purification of human hematopoietic stem cells.
Although febrifugine (1) and isofebrifugine (2), alkaloids isolated from roots of the Dichroa febrifuga plant, show powerful antimalarial activity against Plasmodium falciparum, strong side effects such as the emetic effect have precluded their clinical use against malaria. However, their antimalarial potency makes them attractive substances as leads for developing new types of chemotherapeutic antimalarial drugs. Thus, we have evaluated the in vitro antimalarial activity of the analogues of febrifugine (1) and isofebrifugine (2). The activities of the analogues derived from Df-1 (3) and Df-2 (4), condensation products of 1 and 2 with acetone, respectively, were also obtained. The 3' '-keto derivative (7, EC(50) = 2.0 x 10(-8) M) of 1 was found to exhibit potential antimalarial activity with high selectivity against P. falciparum in vitro. The in vitro activities of the reduction product (8, EC(50) = 2.0 x 10(-8) M) of 1 at C-2' and its cyclic derivatives 9 and 10 (EC(50) = 3.7 x 10(-9) and 8.6 x 10(-9) M, respectively) were found to be strongly active and selective. Additionally, the Dess-Martin oxidation product of 3 was found to be strongly active with high selectivity against P. falciparum. A structure-activity relationship study (SAR) demonstrates that the essential role played by the 4-quinazolinone ring in the appearance of activity and the presence of a 1' '-amino group and C-2', C-3' ' O-functionalities are crucial in the activity of 1. For 7, 8, and 9, prepared as racemic forms, an in vivo study has also been conducted.
The antimalarial activity of the fractions isolated from the leaves of Hydrangea macrophylla Seringe var. Otaksa Makino was evaluated against Plasmodium yoelii 17 XL in mice. Four different fractions were prepared in the usual manner to obtain an alkaloid fraction. All mice treated with the fraction containing febrifugine and isofebrifugine mixture at 1 mg/kg twice a day for 5 consecutive days survived during the experiment, and the change of mean parasitemia level showed almost the same pattern as that from mice treated with the hot-water extract of the same plant leaves. Activity of this fraction, however, was markedly reduced compared with the hot-water extract. Furthermore, no antimalarial activity was shown in the hotwater extract from H. macrophylla var. Otaksa roots or Dichroa febrifuga Lour. leaves.
Cytokine and antibody production was investigated during the course of resolution of primary infection in Plasmodium yoelii 17XL-infected BALB/c mice treated with a mixture of febrifugine and isofebrifugine. The infected mice in an untreated control group showed a progressively increasing parasitemia, leading to mouse death. In contrast, infected mice given the mixture orally showed low parasitemia levels during administration. Following a transient increase in parasitemia in the bloodstream of the treated mice, no parasites could be detected by microscopic examination. Analysis of cytokines in plasma showed that the plasma IFN-gamma levels elevated significantly within the first week of infection in both groups. Furthermore, on day 20 the plasma IFN-gamma and IL-4 levels elevated significantly in the treated mice and the production of both cytokines was sustained until at least day 40. The production of both cytokines in the treated mice was coincident with a decrease in parasitemia. The production of parasite-specific antibodies in the course of P. yoelii 17XL infection was also monitored. In the drug-treated mice, the titers of parasite-specific IgG1, IgG2a, IgG2b and IgG3 elevated significantly from day 20; and the production of parasite-specific antibodies was coincident with a decrease in parasite numbers in the bloodstream.
The development of protective immunity to Plasmodium requires the presence of T-lymphocytes. This is obvious from many experimental models showing that parasitaernia cannot be controlled in T-cell-deficient animals. In addition, protection against plasmodia can be achieved in adoptive transfer experiments using specific T-cells from immune animals. In this brief article Jean Langhorne discusses the different responses of one particular subset of T-lymphocytes, the CD4(+) T-cells, to the parasite, emphasizing their role in the development of protective immunity to the erythrocytic stages of infection.