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Antibacterial and Antioxidant Activities of Megastigmane Glycosides from Hosta plantaginea
Abstract
A new megastigmane glycoside, together with two known compounds, has been isolated from the flowers of Hosta plantaginea. The structure elucidation of the new compound was carried out by 1D (¹H and ¹³C NMR) and 2D NMR (COSY, HSQC, HMBC, and NOESY) spectral analysis. The antibacterial and antioxidant activities of the three compounds were evaluated against various bacteria, and their radical scavenging capacity was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH).
... Two-dimensional NMR can be used in combination with traditional analytical chemical methods to deduce the structure of unknown compounds and is the cornerstone of modern structure elucidation methods [110]. Many researchers have thus discovered a variety of new substances [111][112][113][114][115][116][117][118] that can be used to develop new drugs or in biological research. ...
In the fields of medicine and health, traditional high-performance liquid chromatography or UV-visible spectrophotometry is generally used for substance quantification. However, over time, nuclear magnetic resonance spectroscopy (NMR) has gradually become more mature. Nuclear magnetic resonance spectroscopy has certain advantages in the quantitative analysis of substances, such as being nondestructive, having a high flux and short analysis time. Nuclear magnetic resonance spectroscopy has been included in the pharmacopoeiae of various countries. In this paper, the principle of nuclear magnetic resonance spectroscopy and the recent progress in the quantitative study of natural products by NMR are reviewed, and its application in the quantitative study of natural products is proposed. At the same time, the problems of using NMR alone to quantify natural products are summarized and corresponding suggestions are put forward.
In Asia, the flower of Hosta plantaginea (Lam.) Aschers (hosta flower) is both an edible food and medicine. The hosta flower is often used as a material for cooking porridge and scented tea and in combination with other plants for alleviating pharyngitis. To clarify the anti-pharyngitis effect of the hosta flower and evaluate its potential active ingredients, an ethanol extract of the hosta flower was prepared and partially purified via chromatography on a column packed with D101 macroporous resin, which was eluted with different concentrations of ethanol. The anti-pharyngitis effect of the crude extract and the various partially purified fractions was examined in an ammonia-induced acute pharyngitis rat model. The 30% ethanol-eluted fraction significantly alleviated the severity of pharyngitis in the rat, as evaluated by changes in the levels of cytokines (IL-1β, IL-6, and TNF-α) and histological changes in the pharynx tissues. Subsequent HPLC-QTOF/MS (high-performance liquid chromatography coupled with quadrupole-time of flight tandem mass spectrometry) analysis of this fraction revealed kaempferol and its glycosides as the main components. Three of the main components were isolated and identified by 1D NMR. Their pharmacokinetics were studied for the first time by UHPLC-QQQ/MS (ultrahigh-performance liquid chromatography coupled with mass spectrometry). The findings suggested that the 30% ethanol-eluted fraction of the hosta flower extract may be a potential functional food for treating pharyngitis.
A new indole alkaloid (1), together with eight known indole alkaloid derivatives (2–9), was isolated from Hosta plantaginea for the first time. The structures of compounds 1–9 were elucidated on the basis of comprehensive spectroscopic analyses and references. Compounds 1–9 were evaluated for their inhibition of steroid 5α-reductase activity in vitro. Among them, compounds 1 and 2 showed important inhibition of steroid 5α-reductase activities.
Ethnopharmacological relevance
The genus Hosta (Liliaceae family) represents an interesting source of natural bio-constituents, and the 50 species of this genus are widespread in the world. Five species have been used as traditional East Asian medicines for treating inflammation and pain-related diseases. However, the available data for this genus have not been comprehensively reviewed regarding their extracts and secondary metabolites.
Aim of the study
The present review aims to provide a deeper insight, better awareness and detailed knowledge of traditional uses, phytochemistry, pharmacology along with toxicological aspects of the genus Hosta in the past decades (February 1964 to August 2020). In addition, the relevance among traditional uses, pharmacology and phytochemistry in folk medicines were extensively discussed.
Materials and methods
The relevant information of Hosta species was obtained from several databases. Moreover, the medical books, PhD and MSc dissertations in Chinese were also used to perform this work.
Results
Comprehensive analysis of the afore-mentioned databases, medical books and dissertations confirmed that ethnomedical uses of Hosta genus plants had been recorded in China, Japan, Korea and other countries. To date, only eight species have been studied for chemical constituents, and a total of 200 secondary metabolites (not include essential oil constituents), including steroids, flavonoids, alkaloids, furan derivatives, phenylpropanoids, phenethyl derivatives, terpenoids, aliphatics, and others. The crude extracts and isolated chemical constituents exhibited anti-inflammatory and analgesic, antioxidant, anti-tumor, anti-viral, acetylcholinesterase inhibitory, antimicrobial, anti-chronic prostatitis, and other effects. Moreover, only the n-butanol fraction of H. ventricosa (Salisb.) Stearn roots showed moderate acute toxicity in mice. In addition, the relevance among traditional uses, pharmacology and phytochemistry in folk medicines were extensively discussed.
Conclusions
Hosta spp. are plants rich in steroids and flavonoids with valuable medicinal properties; though, there are several gaps in understanding the traditional uses in the current available data. More high scientific quality preclinical studies with new methodology are necessary to assess the safety, efficacy and mechanism of these plants.
Five new compounds hostines A-E (1-5), together with eighteen known compounds (6-23), were obtained from the flowers of Hosta plantaginea (Lam.) Aschers, a traditional folk herbal medicine widely used in Mongolian. The structures of the undescribed compounds were determined by using detailed spectroscopic (1D/2D NMR) and HR-ESI-MS data analysis. The biological evaluation revealed that hostine C (3), hostine D (4), hostine E (5), stellarine (16), and phenethyl-O-β-d-glucopuranoside (19) possessed the significant anti-inflammatory activities, these compounds significantly inhibited the NO release of RAW 264.7 cells induced by LPS. The possible mechanism of NO inhibition of new bioactive compounds was also investigated using molecular docking, which revealed the interactions of bioactive compounds with the iNOS protein.
Hosta plantaginea (Lam.) Aschers, as a traditional folk medicine, has been widely used both as a single herb and in prescriptions in Asia mainly due to its anti-inflammatory and analgesic effects. A total of 101 compounds including steroids, flavonoids, alkaloids and others have been isolated from H. plantaginea. Modern pharmacology has revealed that H. plantaginea possesses various therapeutic effects such as anti-inflammatory, analgesic and antibacterial effects both in vitro and in vivo. Although a number of reports on the chemical constituents and pharmacological activities of this plant are available, there is limited research on the bioactive constituents and the mechanism of the biological activities of H. plantaginea. Thus, it is essential to strengthen the research on bioactive constituents and their mechanisms as well as their structure–function relationships in H. plantaginea. Up to now, only three compounds have been established for the quality control of H. plantaginea. However, a comprehensive review on the botany, traditional use, phytochemistry, quality control and pharmacology information about this plant has not been reported so far; thus, a systematic and comprehensive review is very necessary. Therefore, this paper provided a comprehensive overview on the botany, traditional use, phytochemistry, quality control and pharmacology of H. plantaginea and also provided evidence for its further research and clinical applications.
Two new glycosides of ionone derivatives, icarisides B3 (2) and B4 (3), as well as a new phenylethanoid glycoside, icariside D1 (4), and two new lignan glycosides, icarisides E1 (12) and E2 (13), have been isolated from Epimedium grandiflorum MORR. var. thunbergianum (MIQ.) NAKAI, together with eight known glycosides. The structures of the new compounds were established on the basis of chemical evidence and spectral data.
Four new steroidal glycosides, named capsicosides A-D together with proto-degalactotigonin, were isolated from the roots and seeds of Capsicum annuum var. conoides and Capsicum annuum var. fasciculatum. On the basis of detailed chemical and spectroscopic evidence, the structures of capsicosides A-D were shown to be furostanol glycosides corresponding to gitogenin and tigogenin oligoglycosides. Capsicoside A was regarded as the same compound as the previously described capsicoside, whose structure now needs to be revised according to the data presented in this report.
Three new spirostanol saponins and two new furostanol saponins were isolated from the underground parts of Hosta longipes. Their structures were determined to be (25R)-5 alpha-spirostane-2 alpha, 3 beta-diol (gitogenin) 3-O-{O-alpha-L -rhamnopyranosyl-(1-->2)-beta-D-galactopyranoside}, gitogenin 3-O-{O-alpha-L-rhamnopyranosyl-(1-->2) -O-[beta-D-glucopyranosyl-(1-->4)]-beta-D-galactopyranoside-, (25R)-5 alpha-spirostan-3 beta-ol (tigogenin) 3-O-{O-alpha-L-rhamnopyranosyl-(1-->2) -O-[beta-D-glucopyranosyl-(1-->4)]-beta-D-galactopyranoside-, 26-O-beta-D-glucopyranosyl-22-O-methyl-(25R)-5 alpha-furostane-2 alpha,3 beta, 22 xi,26-tetrol 3-O-{O-alpha-L-rhamnopyranosyl -(1-->2)-beta-D-galactopyranoside} and 26-O-beta -D-glucopyranosyl-22-O-methyl-(25R)-5 alpha-furostane-2 alpha,3 beta,22 xi,26-tetrol 3-O-{O-alpha-L -rhamnopyranosyl-(1-->2)-O-[beta-D-glucopyranosyl -(1-->4)]-beta-D-galactopyranoside}, respectively. The isolated saponins and their derivatives were examined for inhibitory activity on 12-O-tetradecanoylphorbor-13-acetate-stimulated 32P-incorporation into phospholipids of HeLa cells as the primary screening test to find new antitumour-promoter compounds.
A new C22-steroid glycoside was isolated from the underground parts of Hosta plantaginea var. japonica, together with a known furostanol saponin and three known spirostanol saponins. The structure of the new steroid glycoside was characterized by spectroscopic analysis and acid-catalysed hydrolysis as 2 alpha, 3 beta, 16 beta-trihydroxy-5 alpha-pregn-20(21)-ene-carboxylic acid gamma-lactone 3-O-¿O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1--> 4)-beta-D-galactopyranoside¿. The isolated compounds were assayed for their cytostatic activity on leukaemia HL-60 cells. The spirostanol saponins showed cytostatic activity in a dose-dependent manner with the IC50 values ranging between 1 and 3 micrograms ml-1.
A total of eighteen steroidal saponins were isolated from the rhizomes of Hosta sieboldii, one of which appeared to be the first isolation from a plant source and six to be new compounds. The structures of the new saponins were determined by spectral data and a few chemical transformations to be (25R)-2 alpha, 3 beta-dihydroxy-5 alpha-spirostan-12-one (manogenin) 3-O-¿O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl -(1-->4)-beta-D-galactopyranoside¿, (25R)-2 alpha,3 beta-dihydroxy-5 alpha-spirost-9-en-12-one (9,11-dehydromanogenin) 3-O-¿O-beta-D-glucopyranosyl-(1-->2)-O-beta-D- glucopyranosyl-(1-->4)-beta-D-galactopyranoside¿, 9,11-dehydromanogenin 3-O-¿O-beta-D-glucopyranosyl-(1-->2)-O-[O-alpha-L- rhamnopyranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->3)]-O-beta-D- glucopyranosyl-(1-->4)-beta-D-galactopyranoside¿, (25R)-2 alpha,3 beta-dihydroxy-26-beta-D-glucopyranosyloxy-22-methoxy-5 alpha-furostan-12-one 3-O-¿O-beta-D-glucopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O- beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside¿, (25R)-2 alpha, 3 beta-dihydroxy-26-beta-D-glucopyranosyloxy-22-methoxy-5 alpha-furost-9-en-12-one 3-O-¿O-beta-D-glucopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O- beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside¿ and (25R)-5 alpha-spirostan-2 alpha,3 beta,12 beta-triol 3-O-¿O-alpha-L- rhamnopyranosyl-(1-->2)-beta-D-galactopyranoside¿, respectively. Cytostatic activity of the isolated saponins on leukaemia HL-60 cells was examined.
Curcumin, the yellow color pigment of turmeric, is produced industrially from turmeric oleoresin. The mother liquor after isolation of curcumin from oleoresin contains approximately 40% oil. The oil was extracted from the mother liquor using hexane at 60 degrees C, and the hexane extract was separated into three fractions using silica gel column chromatography. These fractions were tested for antibacterial activity by pour plate method against Bacillus cereus, Bacillus coagulans, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Fraction II eluted with 5% ethyl acetate in hexane was found to be most active fraction. The turmeric oil, fraction I, and fraction II were analyzed by GC and GC-MS. ar-Turmerone, turmerone, and curlone were found to be the major compounds present in these fractions along with other oxygenated compounds.
We recently showed that zerumbone, a sesquiterpene found in subtropical ginger, suppresses colonic tumor marker formation in rats and induces apoptosis in colon cancer cell lines. In our present study, the anti-tumor initiating and promoting activities of zerumbone in mouse skin were evaluated using a conventional 2-stage carcinogenesis model. A single topical pretreatment to mouse skin (2 micromol) 24 hr before application of dimethylbenz[a]anthracene (0.2 micromol) markedly suppressed tumor incidence by 60% and the number of tumors by 80% per mouse. Repeated pretreatment (16 nmol) twice weekly during the post-initiation phase reduced the number of 12-O-tetradecanoylphorbol-13-acetate (TPA, 1.6 nmol)-induced tumors by 83% as well as their diameter by 57%. Multiple reverse transcriptase (RT) PCR experiments revealed that zerumbone (2 micromol) enhanced the mRNA expression level of manganese superoxide dismutase, glutathione peroxidase-1, glutathione S-transferase-P1 and NAD(P)H quinone oxidoreductase in the epidermis, but not that of cytochrome p450 1A1 or 1B1. Further, it diminished TPA-induced cyclooxygenase-2 protein expression and phosphorylation of extracellular signal-regulated kinase 1/2, while pretreatment(s), in either the priming or activation stage or both, reduced double TPA application-induced hydrogen peroxide formation and edema induction by 29% to 86%, respectively. Histologic examination revealed that pretreatment(s) with zerumbone suppressed leukocyte infiltration and reduced proliferating cell nuclear antigen-labeling indices. Together, our results indicate that zerumbone is a promising agent for the prevention of both tumor initiating and promoting processes, through induction of anti-oxidative and phase II drug metabolizing enzymes as well as attenuation of proinflammatory signaling pathways.
A synthesis of optically active vomifoliol stereoisomers 1-4 and their glucosides, roseoside stereoisomers 5-8, was accomplished via alpha-acetylenic alcohol 11a or 11b effectively prepared by an asymmetric transfer hydrogenation of alpha,beta-acetylenic ketone 10. Simultaneous separation of these stereoisomers by HPLC was also performed.
Five new benzylphenethylamine alkaloids, hostasine (1), 8-demethoxyhostasine, 8-demethoxy-10-O-methylhostasine, 10-O-methylhostasine, and 9-O-demethyl-7-O-methyllycorenine, along with 12 known compounds, were isolated from Hosta plantaginea by bioassay-guided fractionation. The structures of the new alkaloids were established by means of extensive spectroscopic methods, and the relative configuration of 1 was further confirmed by single-crystal X-ray diffraction. 7-Deoxy-trans-dihydronarciclasine (IC(50) = 1.80 microM), a known alkaloid, showed strong activity against tobacco mosaic virus by the half-leaf method. Some of these alkaloids were also evaluated for their inhibitory activity against acetylcholinesterase. 8-Demethoxy-10-O-methylhostasine was found to possess significant activity, with an IC(50) of 2.32 microM.
Hostasinine A (1), a benzylphenethylamine alkaloid with an unprecedented skeleton featuring a C-4-C-6 linkage and a nitrone moiety, was isolated from Hosta plantaginea. Its structure was established on the basis of spectroscopic data, and was further confirmed by single-crystal X-ray diffraction. The alkaloid was postulated biogenetically from haemanthidine via N-oxidation and aza-aldol-type condensation and was synthesized biomimetically. The inhibitory activities of 1 on acetylcholinesterase (AChE) and two tumor cell lines (K562 and A549) were also evaluated.