A new erythrinan alkaloid from the seed of Erythrina addisoniae

Metabolomic study of the estrogenic and anti-osteoporotic potential of Erythrina bidwillii leaf

Erythrina bidwillii Lindl., Leguminosae, constitutes a valuable crop for horticulture and medicine; however, it is rarely investigated. Menopause is a crucial transitional period in women's health. Women worldwide consider the use of phytoestrogens as a safe hormone replacement therapy to alleviate detrimental menopausal symptoms. Thus, the discovery of novel phytoestrogens is highly demanded. The present study aimed to investigate, for the first time, the metabolomic profile and the estrogenic potential of E. bidwillii Lindl. leaf. Ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry and gas chromatography-mass spectrometry metabolite profiling revealed the prevalence of alkaloids, flavonoids, isoflavonoids and fatty acids. Additionally, five erythrinan alkaloids, cristanine A (1), 8-oxoerythraline (2), (+)-erythrinine (3), (+)-erythraline (4) and 8-oxoerythrinine (5), along with the isoflavonoid genistin (6), were isolated. Erythrina bidwillii leaf extract exhibited significant in vivo estrogenic, anti-osteoporotic, anti-hyperlipidemic, hepatoprotective, and nephroprotective activities, utilizing ovariectomized rat model. Moreover, ethyl acetate and hexane fractions possessed significant in vitro estrogeic potential on MCF-7 cell lines. An in silico study of the isolated metabolites revealed that (+)-erythrinine (3) and 8-oxoerythrinine (5) exhibited the highest affinity for ERα and ERβ, respectively, modeling them as potential estrogenic lead metabolites. Therefore, E. bidwillii leaf could be employed as promising hormone replacement therapy for postmenopausal women after thorough clinical trials.

Insights into the Role of Erythrina corallodendron L. in Alzheimer's Disease: in Vitro and in Silico Approach

Alzheimer's disease (AD) is a major health problem. Cholinergic transmission is greatly affected in AD. Phytochemical investigation of the alkaloid rich fraction (AF) of Erythrina corallodendron L leaves resulted in isolation of five known alkaloids: erysodine, erythrinine, 8-oxoerythrinine, erysovine N-oxide and erythrinine N-oxide. In this study, eysovine N-oxide was reported for the second time in nature. AF was assayed for cholinesterase inhibition at the concentration of 100 μg mL-1 . AF showed a higher percent inhibition for butyrylcholinesterase enzyme (BuChE) (83.28 %) compared to acetylcholinesterase enzyme (AChE) (64.64 %). The isolated alkaloids were also assayed for their anti-BuChE effect. In-silico docking study was done for the isolated compounds at the binding sites of AChE and BuChE to determine their binding pattern and interactions, also molecular dynamics were estimated for the compound displaying the best fit for AChE and BuChE. In addition, ADME parameters and toxicity were predicted for the isolated alkaloids compared to donepezil.

Computational studies of biologically active alkaloids of plant origin: an overview

Computational studies nowadays constitute a crucial source of information for drug development, because they provide information on many molecular properties and also enable predictions of the properties of not-yet-synthesized compounds. Alkaloids are a vast group of natural products exhibiting a variety of biological activities, many of which are interesting for drug development. On the other hand, computational studies of biologically active alkaloids have so far mostly focused on few particularly relevant or “popular” molecules, such as quinine, caffeine, or cocaine, with only few works on the other molecules. The present work offers an overview of existing computational studies on alkaloid molecules, from the earliest ones to the most recent, and considering all the theoretical approaches with which studies have been performed (both quantum mechanics and molecular dynamics). The considered studies are grouped according to their objectives and outcomes, such as conformational analysis of alkaloid molecules, effects of selected solvents on their properties, docking studies aimed at better understanding of the interactions between alkaloid molecules and biological targets, studies focusing on structure activity relationships, and computational studies performed to confirm experimental results. It is concluded that it would be important that computational studies on many other alkaloid molecules are performed and their results made available, covering their different classes as well as the variety of their biological activities, to attain better understanding of the properties not only of individual molecules, but also of groups of related molecules and of the overall alkaloids family.

Alkaloids of genus Erythrina: An updated review

Genus Erythrina (Fabaceae) comprises several species, which are widely distributed in tropical and subtropical regions of the world. The plants of this genus exhibited significant role in traditional medicine targeting different diseases. Alkaloids and flavonoids were reported as the chief bioactive constituents of this genus with a wide range of biological activities. About 143 alkaloids were isolated from Erythrina sp. Anticonvulsant, anxiolytic, curare-like activity, insecticidal and cytotoxic activities were reported for Erythrina sp. alkaloids. The present work is an overview of the isolated alkaloids from Erythrina sp. with their reported biological activities.[Figure: see text]Abbreviations: CHCl3: Chloroform; CNS: Central nervous system; DCM: Methylene chloride; DPPH: 2,2-Diphenyl-1-picrylhydrazyl; E.: Erythrina; ERα/β: Estrogen receptors α/β; EtOAc: Ethyl acetate; EtOH: Ethanol; Hep-G2: Human liver carcinoma cell lines; HIV: Human immunodeficiency virus; HL-60: Human promyelocytic leukemia cells; K-562: Human immortalized myelogenous leukemia cell line; LPS: Lipopolysaccharide; MeOH: Methanol; MOLT-4: Acute lymphoblastic leukemia cell line; nAChRs: nicotinic acetylcholine receptors; NO: Nitric oxide; NREM: non-rapid eye movement; Pet. ether: Petroleum ether; RBA: Receptor binder affinity; TRAIL: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand.

The genus Erythrina L.: A review on its alkaloids, preclinical, and clinical studies

Erythrina L. genus (Fabaceae) comprises about 115 species, and it has been extensively studied, mainly because of its alkaloids, which have pharmacological properties. References demonstrated that Erythrina spp. have a potential to act in the central nervous system, presenting anxiolytic and anticonvulsant properties already established. Phytochemical investigations confirmed the presence of tetracyclic alkaloids as the major compounds. However, other alkaloid classes have also been reported, including dimeric and trimeric substances, coupled through direct polymerization or two erythrinine units via an acetyl glucose. The present review covers the relevant literature from 1990 until 2017 and outlines the current data on chemical composition and preclinical and clinical studies on Erythrina species. Additionally, the quite striking analogy in the biosynthetic route of erythrin, morphinans, and Amaryllidaceae family alkaloids was also discussed.

Hepatoprotective activity of Erythrina × neillii leaf extract and characterization of its phytoconstituents

BACKGROUND

Natural antioxidants and anti-inflammatory agents have the ability to restore normal balance to destructed liver cells. The genus Erythrina has attracted attention for its broad spectrum of physiological activities and its rich polyphenolic and alkaloid contents.

HYPOTHESIS/PURPOSE

The major phytoconstituents of Erythrina × neillii, an ornamental coral tree and a hybrid between E. herbacea and E. humeana that was not previously studied, were investigated. The hepatoprotective effect and underlying mechanisms were also assessed.

STUDY DESIGN AND METHODS

The main phytoconstituents in the different fractions of the alcoholic leaf extract (dichloromethane and ethyl acetate) were identified using high resolution high-performance liquid chromatography coupled with mass spectrometry (HR-HPLC-MS-MS) based on the fragmentation pattern and molecular formula of the identified compounds and on previous literature. In addition, the hepatoprotective, anti-inflammatory and antioxidant activities of three doses of E. × neillii alcoholic leaf extract (100, 250, 500 mg/kg) were investigated in methotrexate (MTX)-intoxicated rats and were compared with those of silymarin-treated rats. Liver function parameters were obtained, and a histopathological study was performed. In addition, the anti-inflammatory mediators and the antioxidant system in the liver tissues were assessed.

RESULTS

The dichloromethane extract revealed an abundance of alkaloids (25), in addition to tentatively identifying flavone (1), flavanone (1) and three fatty acids. Additionally, thirty-six compounds belonging to different classes of phytoconstituents with a predominance of flavonoids (21), O/C-flavone and flavonol glycosides, followed by alkaloids (9), fatty acids (4) and (2), and phenolic glycoside were identified in the ethyl acetate extract. Compared with MTX, alcoholic leaf extract (500 mg/kg) ameliorated the MTX-induced alterations by improving several biochemical marker levels, fighting oxidative stress in serum and liver tissues, and decreasing inflammatory mediators; this finding was further confirmed by the histopathological study.

CONCLUSION

This study reveals E. × neillii, a rich source of flavonoids and alkaloids, which could be further exploited to provide a promising and safe antihepatotoxic agent source.

An Update of Erythrinan Alkaloids and Their Pharmacological Activities

The period of the past 5 years has witnessed a remarkable increase in all of the number, structural variety, and complexity of erythrinan alkaloids reported. This structural diversity seems to be most pronounced in the alkaloids reported from the two species Erythrina arborescens and Erythrina variegata. Between them, work-up of these taxa yielded new polymeric (dimeric and trimeric) erythrinan alkaloids, a first example in one case where a normal 6,5,6,6-membered indoloisoquinoline spirocylic core has rearranged to a spiro-fused 6,5,7,6-skeleton. Furthermore, erythrinan alkaloids with a fifth ring containing a 2H-imidazole functionality were also reported for the first time, together with some new structures having an unusual substitution and with functionalities at positions C-3 and C-7 of the erythrinan core. This contribution has included 40 more erythrinan alkaloids that are either new or were omitted in the most recent major reviews on the same topic, leading to a total of 154 known erythrinan alkaloids to date. There are a few cases where the structures of the new alkaloids are contestable due to insufficient data having been obtained on isolation. To facilitate easier reference and identification, all structures having a common core have been placed in the same table or figure in this chapter.The reported pharmacological activities of the new and known erythrinan alkaloids documented have shown a considerable bias towards central nervous system and related activities. Other prominent activities that have been reported are antifeedant, insecticidal, cytotoxic, antiprotozoal, anti-inflammatory, antioxidant, antifungal, and antiviral effects. Erythrinan alkaloids generally seem to lack antibacterial activity. Several new polymeric alkaloids were found to lack cytotoxicity against a number of human cancer cell lines, although two of them showed moderate aphicidal activity and one exhibited weak to moderate acetylcholinesterase inhibition. The biological activity of erythrinan alkaloids seems to be influenced by basic substructural requirements, such as a conjugated diene (Δ^1,2, Δ^6,7) system and is modulated by the presence (or absence) of other groups in rings A, B, C, and D of the erythrinan core. The erythrinan core may provide potential leads to structures that eventually may be useful therapeutically.In recent years, a number of stereoselective chemical synthesis methods have been applied towards the erythinan alkaloids, and these are described in this contribution.

Flavones from Erythrina falcata are modulators of fear memory

Background

Flavonoids, which have been identified in a variety of plants, have been demonstrated to elicit beneficial effects on memory. Some studies have reported that flavonoids derived from Erythrina plants can provide such beneficial effects on memory. The aim of this study was to identify the flavonoids present in the stem bark crude extract of Erythrina falcata (CE) and to perform a bioactivity-guided study on conditioned fear memory.

Methods

The secondary metabolites of CE were identified by high performance liquid chromatography combined with a diode array detector, electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI/MSⁿ) and nuclear magnetic resonance (NMR). The buthanolic fraction (BuF) was obtained by partitioning. Subfractions from BuF (BuF1 – BuF6) and fraction flavonoidic (FfA and FfB) were obtained by flash chromatography. The BuF3 and BuF4 fractions were used for the isolation of flavonoids, which was performed using HPLC-PAD. The isolated substances were quantified by HPLC-DAD and their structures were confirmed by nuclear magnetic resonance (NMR). The activities of CE and the subfractions were monitored using a one-trial, step-down inhibitory avoidance (IA) task to identify the effects of these substances on the acquisition and extinction of conditioned fear in rats.

Results

Six subclasses of flavonoids were identified for the first time in CE. According to our behavioral data, CE, BuF, BuF3 and BuF4, the flavonoidic fractions, vitexin, isovitexin and 6-C-glycoside-diosmetin improved the acquisition of fear memory. Rats treated with BuF, BuF3 and BuF4 were particularly resistant to extinction. Nevertheless, rats treated with FfA and FfB, vitexin, isovitexin and 6-C-glycoside-diosmetin exhibited gradual reduction in conditioned fear response during the extinction retest session, which was measured at 48 to 480 h after conditioning.

Conclusions

Our results demonstrate that vitexin, isovitexin and diosmetin-6-C-glucoside and flavonoidic fractions resulted in a significant retention of fear memory but did not prevent the extinction of fear memory. These results further substantiate that the treatment with pure flavonoids or flavanoid-rich fractions might represent potential therapeutic approaches for the treatment of neurocognitive disorders, improvement of memory acquisition and spontaneous recovery of fear.

Leishmanicidal evaluation of tetrahydroprotoberberine and spirocyclic erythrina-alkaloids

Leishmaniasis is one of the World’s most problematic diseases in developing countries. Traditional medicines to treat leishmaniasis have serious side effects, as well as significant parasite resistance problems. In this work, two alkaloids 1 and 2 were obtained from Corydalis govaniana Wall and seven alkaloids 3–9, were obtained from Erythrina verna. The structures of the compounds were confirmed by mass spectrometry and 1D- and 2D-NMR spectroscopy. The leishmanicidal activity of compounds 1–9 against Leishmania amazonensis was tested on promastigote forms and cytotoxicity against J774 (macrophage cell line) was assessed in vitro. Compound 1 showed potent activity (IC₅₀ = 0.18 µg/mL), compared with the standard amphotericin B (IC₅₀ = 0.20 µg/mL). The spirocyclic erythrina-alkaloids showed lower leishmanicidal activity than dibenzoquinolizine type alkaloids.

Erythrina variegata Linn: A review on morphology, phytochemistry, and pharmacological aspects

This review gives an account of the current knowledge on the morphology, phytochemistry, and pharmacological aspects of Erythrina variegata. E. variegata also called Erythrina indica is a thorny deciduous tree growing to 60 feet tall. A wide range of chemical compounds have been isolated, mainly alkaloids, flavonoids, triterpenoids, and lectin. Different parts of the plant have been used in traditional medicine as nervine sedative, collyrium in opthalmia, antiasthmatic, antiepileptic, antiseptic, and as an astringent. The alkaloids extracted from the leaves of E. variegata are reported to have anti-inflammatory and analgesic activity. Isoflavonoids isolated from E. variegata having antibacterial and anthelmintic activity. E. variegata shows several other characteristic pharmacological effects like neuromuscular blocking, smooth muscle relaxant, CNS depressant, and hydrocholeretic, which are consistent with the reported uses of the plant extracts in the indigenous system of medicine. Hence the present article includes the detailed exploration of morphology, phytochemistry, and pharmacological aspects of E. variegata in an attempt to provide a direction for further research.

Nicotinic acetylcholine receptor-based blockade: applications of molecular targets for cancer therapy

The nicotinic acetylcholine receptor (nAChR) was first characterized in 1970 as a membrane receptor of a neurotransmitter and an ion channel. nAChRs have been shown to be involved in smoking-induced cancer formation in multiple types of human cancer cells. In vitro and in vivo animal studies have shown that homopentameric nAChR inhibitors, such as methyllycaconitine and α-Bgtx, can attenuate nicotine-induced proliferative, angiogenic, and metastatic effects in lung, colon, and bladder cancer cells. Recent publications have shown that α9-nAChR is important for breast cancer formation, and in many in vivo studies, α9-nAChR-specific antagonists (e.g., α-ImI, α-ImI, Vc1.1, RgIA, and It14a) produced an analgesic effect. Vc1.1 functions in a variety of animal pain models and currently has entered phase II clinical trials. For cancer therapy, natural compounds such as garcinol and EGCG have been found to block nicotine- and estrogen-induced breast cancer cell proliferation through inhibition of the α9-nAChR signaling pathway. A detailed investigation of the carcinogenic effects of nAChRs and their specific antagonists would enhance our understanding of their value as targets for clinical translation.