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Broussonins A and B, new phytoalexins from diseased paper mulberry
Abstract
Isolation and structure elucidation of two phytoalexins (1 and 2), produced by diseased paper mulberry and designated as broussonins A and B, are described. These phytoalexins are characterized structurally by a 1,3-diphenylpropane skeleton.
... 1,3-Diarylpropanes are a subclass of flavonoids which are precursors for flavonoid biosynthesis in plants and exhibit significant cytotoxic activity in several cancer cell lines. [1] In addition, 1,3-diarylpropanes have shown antifungal, [2] antiinflammatory, [3] antiadipogenic, [4] antitubercular, [5] antimalarial, [6] anti-Alzheimer [7] and antioxidant activities, [8] to name a few. 1,3-Diarylpropanes have also shown strong inhibition of tyrosinase and exhibited strong skin-whitening effects; therefore, these natural compounds are of growing industrial interest for the development of depigmenting agents. ...
... [16] In addition, flavanones can be extracted from citrus waste using environmentally benign techniques, so the development of processes to convert them to high-value-added products are of paramount importance from the point of view of bio-circular economy. [17] Herein we describe a practical process for catalytic hydrogenation of flavanones using a mixture of Pd/C and Pd(OH) 2 ...
A new substrate‐controlled hydrogenation of flavanones to selectively obtain different hydrogenation products is herein reported. Thus, hydrogenation of flavanones bearing different electron‐donating and electron withdrawing substituents (Cl, Br, Me, OMe, OH) provided the corresponding 1,3‐diarylpropanes in excellent yields. This procedure offers a straightforward, simple, and cost‐effective method for the preparation of glycosylated 2′‐hydroxy‐1,3‐diarylpropanes derived from natural flavanones such as Naringin and Hesperedin. On the contrary, when the hydrogenation was performed over fluorinated flavanones, the corresponding flavans were selectively obtained in excellent yields.
... The 23 known flavonoids were identified as daphnegiravone D (4) (Wang et al., 2017), 5,7,3,4-tetrahydroxy-3-methoxyflavone (5) (Zheng et al., 2008), 8-prenylquercetin-3-methyl ether (6) (Lou et al., 2019), uralenol-3-methyl ether (7) (Jia et al., 1993), isolicoflavonol (8) (Zheng et al., 2008), broussoflavonol F (9) (Fang et al., 1995), glycyrrhiza-flavonol A (10) (Hatano et al., 1997), broussoflavonol A (11) (Matsumoto et al., 1985), diosmetin (12) (Cai et al., 2000), ()-liquiritigenin (13) (Hu et al., 2010), ()-bavachin (14) (Chen et al., 2005), cathayanon H (15) (Ni et al., 2010), (2S)-7,4-dihydroxyflavan (16) (Achenbach et al., 1988), (2S)-7,3'-dihydroxy-4'-methoxyflavan (17) , (2S)-7,4-dihydroxy-3-prenylflavan (18) (Lee et al., 2001), kazinol B (19) (Li et al., 2010), daphnegiravan H (20) (Sun et al., 2016), 4,2,4-trihydroxychalcone (21) (Achenbach et al., 1988;Veitch et al., 2003), 4,4-dihydroxy-2-methoxychalcone (22) (Achenbach et al., 1988;Fu et al., 2008), broussochalcone A (23) (Ryu et al., 2012), 1-(4-hydroxy-2-methoxyphenyl)-3-(3-hydroxy-4-methoxyphenyl)-propane (24) (Garcez et al., 2006), 1-(2-hydroxy-4-methoxyphenyl)-3-(4-hydroxy-3-methoxyphenyl)-propane (25) (Martinez V and Cuca S, 1987), 1-(4-hydroxy-2-methoxyphenyl)-3-(4-hydroxyphenyl)-propane (26) (Jo et al., 2015;Takasugi et al., 1980) by comparing their spectroscopic data with those in the literature. The types of these 26 compounds were flavonols (1, 2, and 411), flavone (12), dihydroflavones (13 and 14), dihydroflavonol (15), flavans (3 and 1620), chalcones (2123), and 1,3-diarylpropanes (2426). ...
The stem and root barks of Daphne giraldii Nitsche, also known as “Zushima”, is a traditional Chinese medicine with a long history of treating a variety of diseases such as rheumatism arthralgia, quadriplegia, headache, stomachache, waistache, and bruises. Chromatographic fractionation of the EtOH extracts of “Zushima” has led to the isolation of 26 flavonoids, including ten flavonols (1, 2, and 4−11), one flavone (12), two dihydroflavones (13 and 14), a dihydroflavonol (15), six flavans (3 and 16−20), three chalcones (21−23), and three 1,3-diarylpropanes (24−26). Daphgiflavones A−C (1−3) were new flavonoids. Their structures were elucidated by spectroscopic analysis. All compounds were evaluated for anti-inflammatory properties by testing their inhibitory activities against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophages. Compounds 8, 11, 21, and 23 exhibited significant inhibition on NO production with IC50 values ranging from 2.26 to 6.88 μM, being more active than the positive control quercetin (IC50: 14.16 μM).
... These compounds are precursors in the flavonoid biosynthesis and have been isolated from diverse plant species from around the globe. [1] 1,3-Diarylpropanes exhibit diverse biological activities, i. e. antifungal, [2] anti-inflammatory, [3] anticancer, [4] antiadipogenic, [5] antitubercular, [6] antimalarial, [7] and anti-Alzheimer, [8] to name a few. Owing to their wide range of bioactivities, 1,3-diarylpropanes have become of great interest to many research groups in chemistry, biomedicine as well as those in agricultural and food chemistry. ...
A solvent‐controlled hydrogenation of 2’‐hydroxychalcones to selectively obtain different hydrogenation products is herein reported. Thus, hydrogenation of 2’‐hydroxychalcones using EtOH as solvent provided the corresponding 1,3‐diarylpropanes in excellent yields. On the contrary, when the hydrogenation was performed in DCM, the corresponding dihydrochalcones were isolated. Switching the reaction solvent to n‐BuOH/H2O (1:1), afforded 1,3‐diarylpropanols from moderate to good yields. The methodology here reported offers a straightforward, simple and cost‐effective method for the preparation of a wide variety of 2’‐hydroxy‐1,3‐diarylpropanes derivatives, and was also applied to the preparation of natural Bussealins C and D.
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... 10 1,3-Diarylpropanes, homologues to dihydrostilbenes and a subclass of flavonoids (C6-C3-C6 unit) are also an important secondary metabolites of plants and exhibit diverse biological activities viz. antifungal, 11 anti-inflammatory, 12 anticancer, 13 antiadipogenic, 14 antitubercular, 13a and antimalarial, 15 to name a few. 1,3-Diarylpropanes attached with anthranilic acid were also investigated as b-amyloid aggregation inhibitors in Alzheimer's disease. ...
An efficient synthesis of dihydrostilbenes (1-5) and diarylpropanes (6-10) is achieved from the commercially available starting materials and Wittig-Horner reaction, Claisen-Schmidt condensation and hydrogenation as key steps. Later, their nitric oxide (NO) production inhibition effects were evaluated in lipopolysaccharide (LPS)-induced RAW-264.7 macrophages as an indicator of anti-inflammatory activity. All the tested compounds significantly decreased NO production in a concentration-dependent manner except compounds 2, 6 and 8 and did not show notable cytotoxicity except compound 1. Two compounds i.e., compound 9 (hindsiipropane B) (100%; IC50 = 1.84 μM) possessed the most potent NO inhibitory activity which was even stronger than the positive control, L-NMMA (90.1%; IC50 = 2.73 μM) followed by compound 4 (75.5%; IC50 = 2.98 μM) at 10 μM concentration and this finding was also further correlated by suppressed expression of LPS stimulated inducible NO synthase. Our study revealed that compound 9, a 1,3-diarylpropane scaffold with 3“,4”-dimethoxyphenyl and 3’,4’-dihydroxy 2’-methoxyphenyl motifs could be considered as potential compound or lead compound for further development of NO production-targeted anti-inflammatory agents.
... The location of the three oxygen functions on the benzene ring was deduced from HMBC correlations; thus, cross-peaks were observed between methylene protons (δ 2.57; H 2 -1) and C-2, C-3, C-2 0 , and C-6 0 , methoxyl protons and C-2 0 , H-6 0 and C-2 0 and C-4 0 , H-5 0 and C-1 0 and C-3 0 . These data closely resembled those of broussonin A and B (phytoalexins with a 1,3-diarylpropane carbon skeleton) isolated from Broussonetia papyrifera except for the appearance of the signals due to a monosubstituted benzene ring instead of a para-substituted benzene ring (14). Therefore, the structure of 1 was established as 1-(3 0 ,4 0 -dihydroxy-2 0 -methoxyphenyl)-3-(phenyl)propane (1). ...
Chemical investigation of a red-type Mexican propolis sample has led to the isolation of three new compounds, 1-(3',4'-dihydroxy-2'-methoxyphenyl)-3-(phenyl)propane (1), (Z)-1-(2'-methoxy-4',5'-dihydroxyphenyl)-2-(3-phenyl)propene (2) and 3-hydroxy-5,6-dimethoxyflavan (3), together with seven known flavanones, isoflavans, and pterocarpans. Structural determination, was accomplished by spectroscopic analysis, particularly 2D NMR and ESI-MS/MS techniques. The present study appears to be the first report on the occurrence of isoflavonoids in Mexican propolis. In addition, the presence of compounds with a 1,3-diarylpropane and 1,3-diarylpropene carbon skeleton were found for the first time in propolis. Isolated compounds 1-10 indicated the possible relation between red Mexican propolis and the genus Dalbergia.
Six hundred forty natural compounds were tested for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Of those, sargachromanol I (SCI) and G (SCG) isolated from the brown alga Sargassum siliquastrum, dihydroberberine (DB) isolated from Coptis chinensis, and macelignan (ML) isolated from Myristica fragrans, potently and effectively inhibited AChE with IC50 values of 0.79, 1.81, 1.18, and 4.16 µM, respectively. SCI, DB, and ML reversibly inhibited AChE and showed mixed, competitive, and noncompetitive inhibition, respectively, with Ki values of 0.63, 0.77, and 4.46 µM, respectively. Broussonin A most potently inhibited BChE (IC50 = 4.16 µM), followed by ML, SCG, and SCI (9.69, 10.79, and 13.69 µM, respectively). In dual-targeting experiments, ML effectively inhibited monoamine oxidase B with the greatest potency (IC50 = 7.42 µM). Molecular docking simulation suggested the binding affinity of SCI (-8.6 kcal/mol) with AChE was greater than those of SCG (-7.9 kcal/mol) and DB (-8.2 kcal/mol). Docking simulation indicated SCI interacts with AChE at Trp81, and that SCG interacts at Ser119. No hydrogen bond was predicted for the interaction between AChE and DB. This study suggests SCI, SCG, DB, and ML be viewed as new reversible AChE inhibitors and useful lead compounds for the development for the treatment of Alzheimer's disease.
Mulberry (Morus spp.) foliage is an exclusive source of nutrition for silkworms (Bombyx mori L.). The host plant is affected by many diseases that cause destruction of leaf tissue. Phytoalexins (PAs) produced in response to infection are known to impart resistance to the host. The current knowledge about PAs as one of the post-infectional defense mechanisms in mulberry and related plants, may help to secure the host plants from microbial attack. The PAs of mulberry consist of chemical compounds belonging to the class of benzofuran and stilbenes. Kuwanon C and ethyl β rescrylate were the antifungal compounds detected in mulberry roots, which completely inhibited the growth of pathogens-Rosellinia necatrix and Helicobasidium mompa. When mulberry was affected by 'dogare' and twig blight diseases, a few antimicrobial substances were identified as prenylflavon compounds viz., kuwanon C and E, morusin, albanin A~H and albafuran A~C in shoot epidermis. The cortex tissue produced moracin compounds A~Z, whereas, 1 the xylem produced stilbene compounds viz., oxyresveratrol, 4-prenyloxyresveratrol and moracin-M. Chalcomoracin, the benzofuran compound found in the mulberry leaves was observed to inhibit the growth of Fusarium solani f. sp. mori. This review provides an overview of phytoalexins in mulberry under pathogenecity.
Plant-derived drugs are of major importance to the health and well-being of mankind. Although many of these useful drugs have been synthesized, very few are produced commercially by synthesis. Thus, the plant source remains extremely important, not only in producing drugs, but in providing novel biologically active model compounds from which potentially more potent and less toxic drugs may be synthesized (171, 575).
Most biotic, foliar diseases of trees are caused by fungi. In order to establish infection, the fungal pathogen must overcome natural host defense mechanisms. Disease resistance is the ability of the host to prevent or resist disease. In foliar diseases of trees, host and nonhost resistance is dependent on the characteristics of the entire leaf including both biochemical and structural mechanisms as preexisting barriers or induced responses from host-pathogen interactions. The apoplast, or the extracellular matrix that includes cell wall, intercellular spaces, and xylem, is considered to have a central role in the interface of plants with the environment and in the defense of plants against pathogens (Bowles 1990). Studies on plant resistance have focused on either preinfectional host mechanisms that prevent and inhibit pathogen penetration or postinfectional host responses to disease development.
This chapter is intended to cover compounds which do not fit into the preceding chapters of this book. Since the authors of the present volume have taken a rather broad view of their topics, not too much is left for this chapter. I am very grateful to the authors of other chapters, especially to Dr Lawrence Porter, for furnishing me with references. Even so, the following lists will not be comprehensive, because for most of these compounds there are no generally accepted generic names. This makes a systematic search impossible, and I must apologize for any omissions.
Aim: To study the chemical constituents of leaves of Broussonetia papyrifera. Methods: The chemical components were isolated and purified by silica gel column and Sephadex LH-20 as well as recrystallization. The chemical structures were elucidated on the basis of physico-chemical properties and spectral data. Results: Eleven compounds were isolated and identified as apigenin(1), cosmosiin (2), vitexin (3), luteolin (4), luteolin-7-O-β-D-glucopyranoside (5), 7-methoxycoumarin (6), scopoletin (7), 1-hentriacontanol(8), quercetin(9), 7-methoxyapigenin (10) and daucosterol (11). Conclusion: Compounds 1 - 8 have been obtained from the plant for the first time.
Chemical markers, to be useful in macrosystematics, must be considered in order of decreasing generality. Thus the discovery of evolutionary relationships among the families of plants requires attention to be paid initially to the ubiquitous flavonoids. Within this biosynthetic class of metabolites the flavonol myricetin and the proanthocyanidins jointly classify the dicotyledons into three major blocks formed, if Takhtajan’s (1969) associations of families into subclasses is adopted in first approximation, by (1) Magnoliidae, Ranunculidae, and Caryophyllidae; (2) Hamamelidae, Dilleniidae, and Rosidae; and (3) Asteridae (Table 1). The present overview comprises comments on the three subclasses of block 1 and on the first subclass of block 2.
Bioassay-guided fractionation of an ethyl acetate-soluble extract from the whole plants of Broussonetia papyrifera, using an in vitro aromatase inhibition assay, led to the isolation of five new active compounds, 5,7,2',4'-tetrahydroxy-3-geranylflavone (1), isogemichalcone C (8), 3'-[gamma -hydroxymethyl-(E)-gamma -methylallyl]-2,4,2',4'-tetrahydroxychalcone 11'-O-coumarate (9), demethylmoracin I (10), and (2S)-2',4'-dihydroxy-2 "-(1-hydroxy-1-methylethyl)dihydrofuro[2,3-h]flavanone (11), and 10 known (12-21) compounds which were also found to be active. Of these compounds, the most potent were 9 (IC50 0.5 muM), 11 (IC50 0.1 muM), isolicoflavonol (12, IC50 0.1 muM), and (2S)-abyssinone II (13, IC50 0.4 muM). Additionally, six new compounds, 5,7,3',4'-tetrahydroxy-6-geranylflavonol (2), 5,7,3',4'-tetrahydroxy-3-methoxy-6-geranylflavone (3), (2S)7,4'-dihydroxy-3'-prenylflavan (4), 1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)propane (5), 1-(2,4-dihydroxy-3-prenylphenyl)-3-(4-hydroxyphenyl)propane (6), and 1-(4-hydroxy-2-methoxyphenyl)-3-(4-hydroxy-3-prenylphenyl)propane (7), were isolated and characterized, but proved to be inactive as aromatase inhibitors, as were an additional 21 known compounds. The structures of the new compounds (1-11) were elucidated by spectroscopic methods. Structure-activity relationships in the aromatase assay were determined for the benzofurans, biphenylpropanoids, coumarins, and various types of flavonoids (chalcones, flavans, flavanones, and flavones) obtained among a total of 42 constituents of B. papyrifera.
The stereoselective synthesis of trisubstituted alkenes containing a benzyl substituent has been achieved by employing Friedel-Craft reaction of aromatic compounds with unactivated Baylis-Hillman adducts in the presence of Fe3+-K-10 montmorillonite clay as a heterogeneous catalyst. The catalyst can be recovered and reused.
The fungus-inoculated Broussonetia papyrifera shoot cortical tissues produced eight minor antifungal compounds: two flavans named broussinol and demethylbroussin, four 1,3-diphenylpropanes named broussonin C–F, and two chalcones. Isolation and structure elucidation of these compounds are described.
The ubiquitin–proteasome proteolytic pathway plays a major role in selective protein degradation and regulates various cellular
events, including cell cycle progression, transcription, DNA repair, signal transduction, and immune response. In this pathway,
ubiquitin, a highly conserved small protein in eukaryotes, attaches to a target protein prior to degradation. The polyubiquitin
chains are recognized by the 26S proteasome, and the protein portion is degraded by the proteolytic active sites in a cavity
in the 26S proteasome. The potential of specific proteasome inhibitors, which act as anti-cancer agents, is now under intensive
investigation, and bortezomib (PS-341, Velcade), a proteasome inhibitor, was approved by the FDA for multiple myeloma treatment
in 2003. Since ubiquitination of proteins requires the sequential action of three enzymes—ubiquitin-activating enzyme (E1),
ubiquitin-conjugating enzyme (E2), and ubiquitin-protein ligase (E3)—and polyubiquitination is a prerequisite for proteasome-mediated
protein degradation, inhibitors of E1, E2, and E3 are reasonably thought to be drug candidates for treatment of diseases related
to ubiquitination. In the course of our search for new classes of inhibitors against the ubiquitin–proteasome proteolytic
pathway from natural resources for drug development, we succeeded in isolating agosterols, secomycalolides A, and 1,3-diphenylpropane
derivatives as inhibitors of chymotrypsin-like activity of the proteasome, himeic acid A as an E1 inhibitor, and (−)-hexylitaconic
acid as an inhibitor of p53–HDM2 interaction. In addition, we found that girolline, an anticancer compound, is the first agent
inhibiting the recruitment of polyubiquitinated p53 to the proteasome.
Phytoalexins accumulated in selected woody plants in response to microbial attack or stress are reviewed and listed with respect to their chemical structure and probable biogenetic origin. The host-pathogen systems from which they have been isolated are described. The review also considers the antimicrobial activity of the phytoalexins to the causal pathogens and other microorganisms.
Isoflavonoid phytoalexins are a major class of low molecular weight, inhibitory compounds synthesized by certain plants, notably members of the Leguminosae. Accumulation of these isoflavonoids is often very marked following infection. This review summarizes their biosynthesis, elicitation and biological properties. Consideration is also given to their inferred function of limiting microbial invasion in plant tissues.
The genus Broussonetia of the Moraceae (mulberry family) is of both ethnomedical and industrial interest. Of the approximately 30 species in this genus, only three have been subjected to previous phytochemical investigation, namely, B. kazinoki, B. papyrifera, and B. zeylanica. From over 100 compounds isolated from these species, the major secondary metabolites reported thus far are alkaloids of the pyrrolidine type and several types of flavonoids. Some of these compounds have exhibited various biological activities, such antioxidative, aromatase inhibitory, cytotoxic, glycosidase inhibitory, and platelet aggregation inhibitory effects. The biologically active constituents of the species in the genus Broussonetia are discussed in detail.
A new phenolic compound, broussonone A (1) were isolated from the stem barks of Broussonetia kanzinoki (Moraceae), together with two diphenylpropanes, broussonin A (2), broussonin B (3), two flavans, 7,4'-dihydroxyflavan (4), 3',7-dihydroxy-4'-methoxyflavan (5), and two flavones, 3,7-dihydroxy-4'-methoxyflavone (6), 3,7,3'-trihydroxy-4'-methoxyflavone (7). Compound 1 showed noncompetitive inhibitory activity on pancreatic lipase with an IC(50) of 28.4 μM. In addition, compounds 1-5 significantly inhibited adipocyte differentiation in 3T3-L1 cells as measured fat accumulation using Oil Red O assay.
Plants belonging to the genus Broussonetia (Moraceae), which grow naturally in Asian and Pacific countries, have long been used in traditional Chinese medicine to treat various conditions, particularly tinea, dysentery, hernia and oedema. Various parts of plants of this genus such as the fruits, bark, leaves, flowers and roots are used medicinally. According to Flora of China, the inner bark fibre is used in making paper, and the wood is used for furniture. Several active compounds including coumarins, polyphenols, alkaloids, flavonoids, glycosides, lignans and diterpenes have been isolated from the plants of this genus in the past few years, and some members of these constituents have been demonstrated to exert antioxidant, antiinflammatory, antiplatelet, antityrosinase, antimicrobial and antinociceptive effects. Antidiabetic and antitumoural properties seem possible, but need further support. Due to the lack of clinical trials, there are few published reports on target-organ toxicity or side effects. Currently, some East Asian nations such as China, South Korea and Japan have shown increased interest in these plants. This article reviews the phytochemical and potential beneficial therapeutic effects of plants of this genus reported since 2000.
Natural products continue to be a source of inspiration for chemists and biologists alike. The search for biologically active natural prodcuts has provided troves of information about biological processes, and natural products continue to be some of the most powerful and useful probes of biological processes available. Complex and unusual molecular architectures provide the impetus for new reaction development and push the limits of known synthetic chemistry. In addition to serving as tools for basic research, natural products represent starting points for drug discovery efforts in many cases. This review details the impressive chemical diversity present in the family of molecules that inhibit the proteasome and other aspects of the ubiquitin-proteasome pathway. To date, over 60 natural products that inhibit the ubiquitin-proteasome pathway have been identified. Although early work recognized inhibitors of the proteasome itself, more modern research has revealed that inhibition of many aspects of this critical pathway is possible. One powerful example of this is the inhibition of the interaction between p53 and MDM2 (an E3 ubiquitin ligase). Natural product proteasome inhibitors have served as powerful tools to unravel the intricacies of the ubiquitin-proteasome and related pathways. Several of these natural products have been developed into anticancer drug candidates, and one proteasome inhibitor has already been approved for the treatment of multiple myeloma. Despite the wealth of information available about naturally occurring proteasome inhibitors and related compounds, it is clear that exciting research about this class of molecules will continue well into the future.
Three new phenolic compounds, (E)-4'-demethyl-6-methyleucomin (1), anemarcoumarin A (2), and anemarchalconyn (3), were isolated from an ethyl acetate extract of the rhizomes of Anemarrhena asphodeloides, together with seven known compounds (4-10). The structures of the new compounds (1-3) were determined on the basis of spectroscopic data interpretation. Compound 3 exhibited a potent inhibitory effect against the differentiation of preadipocyte 3T3-L1 cells with an IC50 value of 5.3 μM. © 2009 American Chemical Society and American Society of Pharmacognosy.
Moraceae comprise a large family of sixty genera and nearly 1400 species (1), including important groups such as Artocarpus, Morus, and Ficus. In particular, Morus (mulberry) is a small genus of trees and shrubs found in temperate and subtropical regions of the Northern Hemisphere and has been widely cultivated in China and Japan for its leaves which serve as indispensable food for silkworms. Many varieties of Morus are cultivated in Japan; these varieties are described as belonging to three species: Morus alba
l. (“ Karayamaguwa” in Japanese), M. bombycis Koidz. (“ Yamaguwa” in Japanese), and M. lhou (ser.) Koidz. (“ Roguwa” in Japanese) (2). In addition, the root bark of the mulberry tree (Mori Cortex, Morus alba
l. and other plants of the genus Morus) has been used as an antiphlogistic, diuretic, and expectorant in Chinese herbal medicine (3, 4), and the crude drug is known as “Sohakuhi” in Japanese. In the pharmaceutical field, a few papers have been published reporting the hypotensive effect of this extract (5–11). The first of these reports was presented by Fukutome in 1938 who asserted that oral administration of the hot water extract of the mulberry tree showed a remarkable hypotensive effect in rabbits (5). Ohishi reported the hypotensive effect of the ethanol extract of mulberry root bark (6), while Suzuki and Sakuma (7) reported that the hypotensive activity seemed to be due to phenolic substances and that the effect disappeared on acetylation. Later, Katayanagi
et al. reported that the ether extract of the root bark given to rabbits (6 mg/ Kg, iv) showed a marked hypotensive effect and that the active constituents seemed to be a mixture of unstable phenolic compounds (8). Tane-Mura ascribed the activity of mulberry tree root bark to acetylcholine and its analogues presumably contained in the alcohol soluble fraction, and that the hypotensive constituents produced a yellowish-brown precipitate on treatment with Dragendorff reagent (9).
This chapter discusses the experimental approaches to antifungal chemotherapy. Fungal diseases in general occur in all parts of the world and affect all ages, though a number of particular species are restricted geographically in their incidence. It goes without saying that a systemic fungal infection will require systemic treatment. When however the fungus is confined to the skin or mucosal membranes, then the possibility exists of applying a topical treatment to the affected area, or alternatively treating the infection systemically, getting the parasite from “behind.” With a topical treatment the patient may feel he is doing something positive by applying the medication to the lesion whereas an oral treatment may give the feeling of irrelevance. On the other hand there would seem little point in applying a messy treatment to an already messy lesion if an alternative oral treatment were available.
Antifungal activity of medicinal plants against Aspergillus niger was evaluated using Bio-Cell Tracer (BCT). By this system enabled the real time determination of hyphal growth rate could be done in the presence or absence of Chinese herbal extracts. Of the 41 herbal extracts with 60% acetone extracts tested by the present method, 26 were found to contain active components against A. niger hyphal growth. In contrast, by conventional methods, no active component was detected from every herbal extract except 3 herbal extracts. From the extract of Anemarrhena asphodeloides, one of active components was isolated and its structure determined by NMR, UV, and mass spectroscopy. The compound was identified as broussonin A (2-3-(4-hydroxyphenyl)propyl)-5-methoxy-phenol) which was formerly reported as a phytoalexin of Broussonetia papyrifera Vent.
A new butenylflavanone, (2S)-5-hydroxy-7-methoxy-8-[(E)-3-oxo-1-butenyl]flavanone (1), and a new rotenoid, 4',5'-dihydro-11,5'-dihydroxy-4'-methoxytephrosin (2), as well as three active flavonoids of previously known structure, isoliquiritigenin (3), genistein (4), and chrysoeriol (5), along with nine known inactive compounds, alpha-toxicarol (6), sumatrol, 6a,12a-dehydro-alpha-toxicarol, 11-hydroxytephrosin, obovatin, marmesin, lupenone, benzyl benzoate, and benzyl trans-cinnamate, were isolated from an ethyl acetate-soluble extract of the stems of Tephrosia toxicaria, using a bioassay based on the induction of quinone reductase (QR) in cultured Hepa 1c1c7 mouse hepatoma cells to monitor chromatographic fractionation. The structures of compounds 1 and 2 were elucidated by spectroscopic data interpretation. All isolates were evaluated for their potential cancer chemopreventive properties utilizing an in vitro assay to determine quinone reductase induction. Selected compounds were tested in a mouse mammary organ culture assay to evaluate the inhibition of 7,12-dimethylbenz[a]anthracene (DMBA)-induced preneoplastic lesions.
Three known phenolic compounds, (-)-(R)-nyasol (= 4,4'-(1Z,3R)-Penta-1,4-diene-1,3-diyldiphenol; 1), its derivative 2, and broussonin A (3)--isolated from the rhizomes of Anemarrhena asphodeloides--were for the first time identified as the active principles capable of efficient respiratory-syncytial-virus (RSV) inhibition. The IC50 values of 1-3 against the RSV-A2 strain, propagated in HEp-2 cells, were determined, their activities being higher than that of the standard antiviral drug ribavirin (IC50 = 1.15 microM). In addition, the known, but inactive, compound 'trans-N-(para-coumaroyl)tyramine' (= (2E)-3-(4-hydroxyphenyl)-N-[2-(4-hydroxyphenyl)ethyl]prop-2-enamide; 4) was isolated from this plant for the first time.
While the flavonoids are biosynthetically and constitutionally a homogeneous group of compounds, the neoflavonoids, as presently defined, may be biosynthetically and are constitutionally a heterogeneous group. Biogenetic considerations which lead to these conclusions and reviews on occurrence, structural elucidation and synthesis are presented for 1,3‐diarylpropanes and flavans (flavonoids), as well as for cinnamylphenols and 2‐aryl‐3‐methylbenzofurans (neoflavonoids), with the purpose of providing addenda to the 1975 monograph, The Flavonoids, edited by Harborne, Mabry and Mabry for Chapman and Hall, London.
The heartwood of Pterocarpus santalinus contains two major red pigments, santalin-A and santalin-B which are partial methyl ethers of the same polyphenol (santalin). For locating the position of the methoxyl groups, alkali fission and permanganate oxidation of the mixed ethyl methyl ethers are the most convenient. By this method santalin-A has been shown to be 9,1O,12- tri-O-methylsantalin and santalin-B, 9,10,12,4′-tetra-O-methylsantalin.