Revised structures for senegalensin and euchrenone b(10)

An overview of techniques and strategies for isolation of flavonoids from the genus Erythrina

Plants in the genus Erythrina is a potential source of chemical constituents, one of which is flavonoids, which have diverse bioactivities. To date, literature on the flavonoids from the genus Erythrina has only highlighted the phytochemical aspects, so this review article will discuss isolation techniques and strategies for the first time. More than 420 flavonoids have been reported in the Erythrina genus, which are grouped into 17 categories. These flavonoid compounds were obtained through isolation techniques and strategies using polar, semi-polar, and non-polar solvents. Various chromatographic techniques have been developed to isolate flavonoids using column flash chromatography, quick column chromatography, centrifugally accelerated thin-layer chromatography, radial chromatography, medium-pressure column chromatography, semi-preparative high-performance liquid chromatography, and preparative high-performance liquid chromatography. Chromatographic processes for isolating flavonoids can be optimized using multivariate statistical applications such as response surface methodology with central composite design, Box-Behnken design, Doehlert design, and mixture design.

Antidiabetic and Cytotoxic Activities of Rotenoids and Isoflavonoids Isolated from Millettia pachycarpa Benth

A phytochemical investigation of the root and leaf extracts of Millettia pachycarpa Benth resulted in the isolation and identification of 16 compounds, including six rotenoids (1-6) and 10 prenylated isoflavonoids (7-16). Compound 4 was isolated as a scalemic mixture, which was resolved by chiral HPLC to afford (-)-(6aS,12aS)-12a-hydroxy-α-toxicarol (4) and (+)-(6aR,12aR)-12a-hydroxy-α-toxicarol (4). (+)-(6aR,12aR)-Millettiapachycarpin (3) and (-)-(6aS,12aS)-12a-hydroxy-α-toxicarol (4) were isolated as new compounds. The absolute configuration of (-)-(6R)-pachycarotenoid (2), (+)-(6aR,12aR)-millettiapachycarpin (3), (-)-(6aS,12aS)-4 and (+)-(6aR,12aR)-12a-hydroxy-α-toxicarol (4), (+)-(6aS,12aS)-(5), and (-)-(6aS,12aS,2″R)-sumatrol (6) were identified by electronic circular dichroism (ECD) data. (-)-(6aS,12aS,2″R)-Sumatrol (6) was also confirmed by X-ray diffraction analysis using Cu-Kα radiation. Antidiabetic activities, including α-glucosidase and α-amylase inhibitory activities, and cytotoxicities against lung cancer A549, colorectal cancer SW480, and leukemic K562 cells of some isolated compounds were evaluated. Of these, isolupalbigenin (11) exhibited the highest α-glucosidase inhibitory activity, with an IC₅₀ value of 11.3 ± 0.2 μM, whereas the scalemic mixture of 12a-hydroxy-α-toxicarol (4) displayed the best α-amylase inhibitory activity, with an IC₅₀ value of 106.9 ± 0.2 μM. Euchrenone b10 (15) exhibited the highest cytotoxicity against lung cancer A549, colorectal cancer SW480, and leukemic K562 cells, with IC₅₀ values of 40.3, 39.1, and 15.1 μM, respectively. In addition, molecular docking simulations of α-glucosidase inhibition of the active compounds were studied.

Anti-diabetic potential of Masclura tricuspidata leaves: Prenylated isoflavonoids with α-glucosidase inhibitory and anti-glycation activity

Investigation of chemical constituents of Masclura tricuspidata leaves resulted in the isolation of 47 isoflavonoids possessing prenyl groups with different numbers and structures. Among them, sixteen compounds named cudracusisoflavones A-P (1-16) were first isolated from nature. The isoflavonoids isolated from M. tricuspidata leaves showed anti-diabetic effects as measured by inhibition on α-glucosidase activity and advanced glycation end-products (AGEs) formations. Especially, cudracusisoflavone L (12), a new compound, together with gancaonin M (27), erysenegalensein E (41) and millewanin G (44) showed strong α-glucosidase inhibition with IC₅₀ values <10.0 μM. In addition, cudracusisoflavones A (1), D (4), M (13) and N (14), together with known prenylated isoflavonoids efficiently inhibited methylglyoxal (MGO)- or glyoxal (GO)-induced AGE formations. Structure activity relationship together with molecular docking analysis suggested the importance of hydroxy group and linear type of prenyl moiety for α-glucosidase inhibition. Conclusively, diverse prenylated isoflavonoids in M. tricuspidata leaves might ameliorate glycotoxicity-induced metabolic diseases.

Flavonoids and other Non-alkaloidal Constituents of Genus Erythrina: Phytochemical Review

BACKGROUND

Genus Erythrina belongs to family Fabaceae, which is widely distributed in tropical and subtropical areas. It has been used in both traditional herbal medicines and pharmacological applications. Original research articles and publications on the overview of alkaloids related to this genus are available, but a supportive systematic review account which highlighted phytochemical aspects of other types of secondary metabolites is currently insufficient.

OBJECTIVE

With the utilization of data and information from SCI-Finder, Google Scholar, the Web of Science, Scopus, Science Direct, PubMed, Chemical Abstracts, ACS journals, Springer, Taylor Francis, Bentham Science and IOP Science, the reliable material sources of this systematic review paper were obtained from the literature published from the 1980s to now.

CONCLUSION

A vast amount of data showed that the non-alkaloidal secondary metabolites were obtained from genus Erythrina with various classes of chemical structures. Herein, approximately five hundred constituents were isolated, comprising flavonoids, terpenoids, saponins, phytosterols, phenols, arylbenzofurans, coumarins, alcohols, ceramides, mono-sugars and fatty acid derivatives. In agreement with the previous phytochemical reports on the plants of the family Fabaceae, flavonoids reached a high amount in the plants of genus Erythrina. Numerous biological activity investigations such as anti-bacteria, anti-cancer, anti-virus using isolated compounds from Erythrina species suggested that secondary metabolites of Erythrina plants are now becoming the promising agents for drug developments.

Erythrina suberosa: Ethnopharmacology, Phytochemistry and Biological Activities

Plants are a great and irreplaceable source of medicines, fuel, food, energy and even cosmetics. Since prehistory, humans have learned to use plants for survival, growth and proliferation and still today it relies on natural and cultivated vegetables for food and the source of novel compounds with pharmacological activity. Not only herbs and flowers, but also trees are used. Indeed, Erythrina suberosa Roxb. is a deciduous tree of the family Fabaceae, common in Southeast Asia. In India, E. suberosa is called the “corky coral tree” or simply the “Indian coral tree”, given its peculiar red-orange flowers that can flower throughout the year and its corky irregular bark covered by prickles. It is a plant commonly used as an ornamental tree, but it also holds ethnopharmacological and socioeconomic uses. This article explored phytobiological features of E. suberosa, analysing its taxonomy, examining its traditional and common uses and investigating its bioactive components and pharmacological properties.

Isoflavones with neuroprotective activities from fruits of Cudrania tricuspidata

Ten isoflavones, cudraisoflavones B-K (1-10), together with 27 known isoflavones, were isolated from the EtOAc soluble extract of fruits of Cudrania tricuspidata. The structures of compounds 1-10 were elucidated on the basis of MS and NMR spectroscopic data, including 2D NMR experiments. Compounds 7-9 and three known (11-13) compounds showed neuroprotective activity against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells, with EC50 values of 0.5-9.2 μM.

Assessing sub-Saharan Erythrina for efficacy: traditional uses, biological activities and phytochemistry

The genus Erythrina comprises more than 100 species, widely distributed in tropical and subtropical areas. In Africa, 31 wild species and 14 cultivated species have been described. In sub-Saharan Africa, Erythrina species are used to treat frequent parasitic and microbial diseases, inflammation, cancer, wounds. The rationale of these traditional uses in African traditional medicine was established by screening several species for biological activities. Promising activities were found against bacteria, parasites (Plasmodium), human and phytopathogenic fungi, some of which were multidrug resistant (MDR) micro organisms. Some species also exhibited antioxidant, anti-inflammatory activities and enzymes inhibitory properties. Most of the species chemically investigated were reported to contain flavanones, prenylated isoflavones, isoflavanones and pterocarpans. Some phytochemicals (vogelin B, vogelin C, isowightcone, abyssinin II, derrone) were the active principles as antibacterials, antifungals, antiplasmodials and inhibitors of enzyme borne diseases (PTP1B, HIV protease, DGAT). This review highlights the important role of Erythrina species as sources of lead compounds or new class of phytotherapeutic agents for fighting against major public health (MDR infections, cancer, diabetes, obesity) in sub-Saharan Africa.

A new prenylated isoflavone from Derris scandens Benth

The phytochemical study of the whole plant of Derris scandens (Leguminosae) has resulted in the isolation of a new isoflavone derivative, scandinone A (11), together with 11 known compounds (1-10, 12). Structural elucidations of these compounds were performed using spectroscopic methods especially 1D, 2D NMR, and mass spectral analyses. The alpha-glucosidase-inhibitory activity of the isolates was also evaluated.

Flavonoids from Erythrina vogelii (Fabaceae) of Cameroon

A new flavone, vogeol, and a new isoflavone, vogliiol, have been isolated from Erythrina vogelii, a Cameroonian medicinal plant, along with seven known constituents (salvigenin, carpachromene, euchrenone b10 scandenone, 5,4′-dihydroxy-8-(3″″-methylbut-2″″-enyl)-2″′-(4″′-hydroxy-4″′-methylethyl)-furano-[4″′,5″′:6,7] isoflavone, erythrivarone C, and 5,7,4′-trihydroxy-6-[3″″-methylbut-3″″-enyl]-flavone). Their structures were elucidated by spectroscopic methods.

Three new isoflavanones from Erythrina costaricensis

Three new isoflavanones, 5,7,3'-trihydroxy-4'-methoxy-6,5'-di(gamma, gamma-dimethylallyl)-isoflavanone (1), 5,3'-dihydroxy-4'-methoxy-5'-gamma,gamma-dimethylallyl-2'',2''-dimethylpyrano[5,6 : 6,7]isoflavanone (2) and 5,3'-dihydroxy-2'',2''-dimethylpyrano[5,6 : 6,7]-2''',2'''-dimethylpyrano[5,6 : 5,4]isoflavanone (3), along with two known isoflavonoids, cristacarpin and euchrenone b(10), were isolated from the stems of Erythrina costaricensis. Their structures were established on the basis of spectroscopic evidence. Compound 3 is a rare isoflavanone possessing two 2,2-dimethylpyran moieties. Among the new isoflavanones, compound 1 showed potent antibacterial activity against methicillin-resistant Staphylococcus aureus.

Prenylated and benzylated flavonoids from the fruits of Cudrania tricuspidata

Three new prenylated isoflavones, 5,7-dihydroxy-6-(2''-hydroxy-3''-methylbut-3''-enyl)-4'-methoxylisoflavone (1), 5,4'-dihydroxy-6-(3''-methylbut-2''-enyl)-2'''-(4'''-hydroxy-4'''-methylethyl)-3'''-methoxydihydrofurano-[4''',5''';7,8]isoflavone (2), and 5,4'-dihydroxy-8-(3''-methylbut-2''-enyl)-2'''-(4'''-hydroxy-4'''-methylethyl)furano-[4''',5''';6,7]isoflavone (3), a benzylated dihydroflavonol, 5,7,4'-trihydroxy-8-p-hydroxybenzyldihydroflavonol (4), and eight known flavonoids (5-12) were isolated from the fruits of Cudrania tricuspidata. The structures of these compounds were determined on the basis of MS and (1)H and (13)C NMR spectroscopic data, including 2D NMR experiments. Compounds 2, 3, 6, 7, 8, 10, 11, and 12 inhibited LPS-induced nitric oxide production, with IC(50) values of 11.8-41.8 microM.

Two new isoflavanones from Erythrina costaricensis

Two new isoflavanones, 5,3'-dihydroxy-4'-methoxy-5'-(3-methyl-1,3-butadienyl)-2'',2''-dimethylpyrano[5,6:6,7]isoflavanone (1) and 5,3'-dihydroxy-5'-(3-hydroxy-3-methyl-1-butenyl)-4'-methoxy-2'',2''-dimethylpyrano[5,6:6,7]isoflavanone (2), together with two known isoflavonoids, cristacarpin, and euchrenone b10, were isolated from the stems of Erythrina costaricensis. Their structures were established on the basis of spectroscopic evidence. These new compounds are rare isoflavanones, possessing both a 2,2-dimethylpyran substituent and a prenyl analog. The antibacterial activities of 1 and 2 against the methicillin-resistant Staphylococcus aureus were examined.

Isoflavonoids of the leguminosae

Isoflavonoids are found predominantly in subfamily Papilionoideae of the Leguminosae. This review describes more than 420 new examples of Leguminosae isoflavonoids, giving details of their source, identification, biological activity, synthesis, and ecological or chemosystematic significance. Other topics addressed include the application of hyphenated analytical techniques to the characterisation of legume-derived isoflavonoids, and advances made in biosynthetic studies. A checklist of new compounds by species is given, and 404 references are cited.

Four New Isoflavonoids from the Stem Bark of Erythrina variegata

Bioassay-directed fractionation of the stem bark extract of Erythrina variegata L. has resulted in the isolation of three new isoflavones: 5,4'-dihydroxy-8-(3,3-dimethylallyl)-2''-methoxyisopropylfurano[4,5:6,7]isoflavone (1), 5,7,4'-trihydroxy-6-(3,3-dimethylallyloxiranylmethyl)isoflavone (2), 5,4'-dihydroxy-8-(3,3-dimethylallyl)-2''-hydroxymethyl-2''-methylpyrano[5,6:6,7]isoflavone (3) and a new isoflavanone, 5,4'-dihydroxy-2'-methoxy-8-(3,3-dimethylallyl)-2'',2''-dimethylpyrano[5,6:6,7]isoflavanone (4) together with seven known compounds, euchrenone b10 (5), isoerysenegalensein E (6), wighteone (7), laburnetin (8), lupiwighteone (9), erythrodiol (10), and oleanolic acid (11). The structures were determined on the basis of spectroscopic analyses and chemical evidence. The effect of these compounds on the proliferation of rat osteogenic sarcoma (UMR106) is also reported.