New ursane triterpenoids from <Emphasis Type="Italic">Ficus pandurata</Emphasis> and their binding affinity for human cannabinoid and opioid receptors

Phytochemical investigation of Ficus pandurata Hance (Moraceae) fruits has led to the isolation of two new triterpenoids, ficupanduratin A [1β-hydroxy-3β-acetoxy-11α-methoxy-urs-12-ene] (11) and ficupanduratin B [21α-hydroxy-3β-acetoxy-11α-methoxy-urs-12-ene] (17), along with 20 known compounds: α-amyrin acetate (1), α-amyrin (2), 3β-acetoxy-20-taraxasten-22-one (3), 3β-acetoxy-11α-methoxy-olean-12-ene (4), 3β-acetoxy-11α-methoxy-12-ursene (5), 11-oxo-α-amyrin acetate (6), 11-oxo-β-amyrin acetate (7), palmitic acid (8), stigmast-4,22-diene-3,6-dione (9), stigmast-4-ene-3,6-dione (10), stigmasterol (12), β-sitosterol (13), stigmast-22-ene-3,6-dione (14), stigmastane-3,6-dione (15), 3β,21β-dihydroxy-11α-methoxy-olean-12-ene (16), 3β-hydroxy-11α-methoxyurs-12-ene (18), 6-hydroxystigmast-4,22-diene-3-one (19), 6-hydroxystigmast-4-ene-3-one (20), 11α,21α-dihydroxy-3β-acetoxy-urs-12-ene (21), and β-sitosterol-3-O-β-d-glucopyranoside (22). Compound 21 is reported for the first time from a natural source. The structures of the 20 compounds were elucidated on the basis of IR, 1D (¹H and ¹³C), 2D (¹H–¹H COSY, HSQC, HMBC and NOESY) NMR and MS spectroscopic data, in addition to comparison with literature data. The isolated compounds were evaluated for their anti-microbial, anti-malarial, anti-leishmanial, and cytotoxic activities. In addition, their radioligand displacement affinity on opioid and cannabinoid receptors was assessed. Compounds 4, 11, and 15 exhibited good affinity towards the CB2 receptor, with displacement values of 69.7, 62.5 and 86.5 %, respectively. Furthermore, the binding mode of the active compounds in the active site of the CB2 cannabinoid receptors was investigated through molecular modelling.     

Alkyl phenols,alkenyl cyclohexenones and other phytochemical constituents from <Emphasis Type="Italic">Lannea rivae</Emphasis> (chiov) Sacleux (Anacardiaceae) and their bioactivity

Six novel compounds, 3-nonadec-14′-(Z)-enyl phenol (1a); 4,5-dihydroxy-4,2′-epoxy-5-[16′-Z-18′-E-heneicosenyldiene]-cyclohex-2-enone (2), 2,4,5-trihydroxy-2-[16′-Z-heneicosenyl]-cyclohexanone (3); 4S,6R-dihydroxy-6-[12′-Z-heptadecenyl]-cyclohex-2-enone (4a); 4S,6R-dihydroxy-6-[14′-Z-nonadecenyl]-cyclohex-2-enone (4b); and 1,2,4-trihydroxy-4-[16′-Z-heneicosenyl]-cyclohexane (5) were identified from the roots and stems of Lannea rivae in addition to the known cardanols, 3-heptadec-12′-Z-enyl phenol (1b), 3-pentadec-10′-Z-enyl phenol (1c) and 3-pentadecyl phenol (1d), sitosterol (6), sitosterol glucoside (7), taraxerone (8), taraxerol (9), E-lutein (10), myricetin (11), myricetin-3-O-α-rhamnopyranoside (12), myricetin-3-O-β-galactopyranoside (13) and (-)-epicatechin-3-O-gallate (14). The ketones 4a and 4b were isolated as a mixture and were qualitatively separated and identified by GCMS. Myricetin (11) and epicatechin gallate (14) displayed over 90 % DPPH radical-scavenging activity at 50 μg mL^?1, while its glycosides (12 and 13) showed percentages of over 70 % in the same assay. The same compounds 11 and 14 showed antibacterial activity similar to erythromycin and vancomycin against Gram-positive bacteria and were also active against Gram-negative bacteria, but not as much as the cefuroxime, ciprofloxacin and nalidixic acid standards. Compounds 1a–d, 4a–b and 5 were all relatively non-toxic, while 2 (the epoxy cyclohex-2-enone) and 3 (the trihydroxy cyclohexanone) showed more toxicity than the others. These two toxic compounds, 2 and 3 also showed antiplasmodial activity with IC₅₀ values between 0.48 and 2.05 μg mL^?1. The mixture of dihydroxy cyclohex-2-enones 4a and 4b, which was far less toxic than 2 and 3, also showed promising antiplasmodial activity and may be a possible lead for further investigation as an antiplasmodial drug.     

C<Subscript>21</Subscript> steroid derivatives from the Dai herbal medicine Dai-Bai-Jie,the dried roots of <Emphasis Type="Italic">Marsdenia tenacissima</Emphasis>, and their screening for anti-HIV activity

Twenty-three new C₂₁ steroidal glycosides, marstenacissides C1–C10 (1–10), D1–D7 (11–17) and E1–E6 (18–23), and four new C₂₁ steroids, 11α,12β-O-ditigloyl-tenacigenin C (24), 11α-O-benzoyl-12β-O-tigloyl-tenacigenin C (25), 11α-O-tigloyl-12β-O-benzoyl-tenacigenin C (26) and 11α-O-tigloyl-12β-O-benzoyl-marsdenin (27), were isolated from the Dai herbal medicine Dai-Bai-Jie, derived from the roots of Marsdenia tenacissima. The chemical structures of all compounds were established by spectroscopic techniques, including high-resolution mass spectrometry and NMR spectroscopy, as well as by comparison with reported spectral data. The anti-HIV activities of these compounds were screened, and the compounds obtained displayed inhibitory effects against HIV-1 with inhibition rates of 36.4–81.3% at 30 μM.     

Two new ursane-type triterpenoid saponins from <Emphasis Type="Italic">Elsholtzia bodinieri</Emphasis>

Two new ursane-type triterpenoid saponins, bodiniosides M (1) and N (2), along with three known saponins, oblonganosides I (3), pseudobuxussaponin B (4) and bodinioside A (5), were isolated from the aerial parts of Elsholtzia bodinieri. The structures of compounds 1 and 2 were characterized by spectroscopic data as well as acid hydrolysis and GC analysis as 3-O-β-d-xylopyranosyl-19α-hydroxy-23-acetoxy-urs-12(13)-en-28-oic acid 28-O-α-l-rhamnopyranosyl-(1-2)-β-d-glucopyranoside and 3-O-β-d-glucopyranosyl-2α,19α-dihydroxy-urs-12(13)-en-28,20β-lactone. Compounds 1 and 5 exhibited potent anti-HCV activities in vitro with a selective index of 6.53 and 4.41, respectively.     

Synthesis,characterization and antimicrobial activity of 4-((1-benzyl/phenyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl)methoxy)benzaldehyde analogues

A diverse series of 4-((1-benzyl/phenyl-1H-1,2,3-triazol-4-yl)methoxy)benzaldehyde analogues has been synthesized in good yield by the click reaction between 4-O-propargylated benzaldehyde and various organic bromides/azides. All the synthesized compounds were tested in vitro for their antimicrobial activity against Gram-positive bacteria (Staphylococcus epidermidis and Bacillus subtilis), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and fungi (Candida albicans and Aspergillus niger). Most of the compounds exhibited good-to-excellent antimicrobial activity. Compound 7b was found to be more potent than ciprofloxacin against B. subtilis, whereas it showed activity comparable to ciprofloxacin against E. coli. Compounds 4h and 4i showed activity comparable to fluconazole against A. niger. Further, the binding mode of compound 7b into the active site of E. coli topoisomerase II DNA gyrase B has also been investigated.     

Syntheses of arylcinnamic acids,using Alum-Cs<Subscript>2</Subscript>CO<Subscript>3</Subscript> as precursors of new 2-heterostyrylbenzimidazoles and their antimicrobial evaluation

A simple and green methodology has been developed for the syntheses of some new 2-styrylbenzimidazoles. In this method, 2-styrylbenzimidazoles 6(a–x) were synthesized by the condensation of o-phenylenediamines 4(a–c) with cinnamic acids 3(a–h) using glycerol containing boric acid (10 mol%) as the reaction medium at 180 °C about 3–5 h. The cinnamic acids 3(a–h) were obtained by the condensation between aromatic aldehydes 1(a–h), and malonic acid using a new heterogeneous catalytic system such as alum-Cs₂CO₃ in water is described. Compounds 6(a–x) were also obtained alternatively by the condensation of 2-methylbenzimidazoles 5(a-c) with 1(a-h) using the same glycerol containing boric acid (10 mol%) as reaction medium at 180 °C for 5–6 h. The catalytic systems mentioned here were found to be highly active, stable, and recyclable under reaction conditions. All the newly synthesized compounds were characterized by IR, Mass, and NMR spectral analyses. All synthesized compounds were screened for their antimicrobial activity against the clinical strains which include gram-positive bacteria (Micrococcus luteus MTCC 2470, Staphylococcus aureus MTCC 96, Staphylococcus aureus MLS-16 MTCC 2940, Bacillus subtilis MTCC 121) and gram-negative bacteria (Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 2453, Klebsiella planticola MTCC 530, and Candida albicans MTCC 3017). The results revealed that compounds (6b, 6g, 6h, 6j, 6k, 6n, 6o, 6t) exhibited significant antibacterial activity almost equal to the standard drug, i.e., Ciprofloxacin.     

A new indole glycoside from the seeds of <Emphasis Type="Italic">Raphanus sativus</Emphasis>

A new indole glycoside, β-d-glucopyranosyl 2-(methylthio)-1H-indole-3-carboxylate, named raphanuside A (1), as well as eight known compounds, β-d-fructofuranosyl-(2 → 1)-(6-O-sinapoyl)-α-d-glucopyranoside (2), (3-O-sinapoyl)-β-d-fructofuranosyl-(2 → 1)-α-d-glucopyranoside (3), (3-O-sinapoyl)-β-d-fructofuranosyl-(2 → 1)-(6-O-sinapoyl)-α-d-glucopyranoside (4), (3,4-O-disinapoyl)-β-d-fructofuranosyl-(2 → 1)-(6-O-sinapoyl)-α-d-glucopyranoside (5), isorhamnetin 3,4′-di-O-β-d-glucoside (6), isorhamnetin 3-O-β-d-glucoside-7-O-α-l-rhamnoside (7), isorhamnetin 3-O-β-d-glucoside (8) and 3'-O-methyl-(?)-epicatechin 7-O-β-d-glucoside (9) were isolated from the seeds of Raphanus sativus. Furthermore, compounds 1–3 and 6–9, were isolated from this plant for the first time. The structures of compounds 1–9 were identified using 1D and 2D NMR, including ¹H–¹H COSY, HSQC, HMBC and NOESY spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-α stimulated MG-63 cells was also examined.     

Synthesis,structures elucidation,DNA-PK,PI3K and antiplatelet activity of a series of novel 7- or 8-(<Emphasis Type="Italic">N</Emphasis>-substituted)-2-morpholino-quinazolines

The DNA-dependent protein kinase and phosphoinositide 3-kinase family is one of the most frequently activated enzymes in a wide range of human cancers; consequently, inhibition of DNA-dependent protein kinase and phosphoinositide 3-kinase represents an approach for cancer therapy. In this work, we have designed and synthesized a series of novel 7- or 8-(N-substituted)-2-morpholino quinazolines 3a–f, 5a–e, 7a–e, and 9 from 7- or 8-amino-2-morpholino quinazolin-4-ones (2a, 4a), the 3-methyl analogues (2b, 4b) and the 4-alkyloxy analogues (6a–b, 8). The compounds were subsequently assayed for DNA-dependent protein kinase and phosphoinositide 3-kinase activity. Most compounds were less active than expected in spite of the strong structural resemblance to the previously studied 7- or 8-(O-substituted)-2-morpholino-1,3-benzoxazine inhibitors. Loss of DNA-dependent protein kinase activity for the quinazolin-4-ones (3a–d and 5a–d) has been attributed to tautomerization to the aromatic enol (4-OH) tautomers. Aromatization of the heterocyclic ring could alter the conformation, and thus binding position, resulting in reduced compound-receptor hydrogen bonding of the morpholine oxygen and 4-carbonyl oxygen. The hetero-aromatic compounds 7a–e and 9 also did not show any DNA-dependent protein kinase activity at 10?µM, which supports the above hypothesis. Compound 7c (R=CH₂(pyridine-4-yl)) displayed selective phosphoinositide 3-kinase delta activity with 80?% inhibition at 10?µM. Similarly, compounds 5a (8-N-substituted, R=CH₂Ph) and 3a (7-N-substituted, R=CH₂Ph) showed selective phosphoinositide 3-kinase beta activity with 69 and 61?% inhibition, respectively. Antiplatelet inhibition assays showed that compound 7e with the 4-O-benzyloxy group and 8-CH₂(pyridine-3-yl) substituents was found to be the most active (IC₅₀ 35?µM).     

Antioxidant <Emphasis Type="Italic">C</Emphasis>-glycosylflavones of <Emphasis Type="Italic">Drymaria cordata</Emphasis> (Linn.) Willd

A new C-glycosylflavone, drymaritin E (6-C-(3-keto-β-digitoxopyranosyl)-4′-O-(β-d-glucopyranosyl)-7-methoxyl-5,4′-dihydroxylflavone) 1 was isolated from the oily upper phase (SU) of the MeOH extract from aerial parts of Drymaria cordata together with two known compounds (cassiaoccidentalin A 2 and anemonin 3) and an inseparable mixture of two known C-glycosylflavones 5,4′-dihydroxy-7-methoxyflavone-6-C-(2′′-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside 4a and 5,7,3′,4′-tetrahydroxyflavone-6-C-(2′′-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside 4b. The alkaline hydrolysis of 3 led to a new hemisynthetic derivative, sodium anemonate (sodium 2-((1’E) 2′-sodium-carboxylate-vinyl)-5-oxo-cyclohex-1-ene carboxylate) 3a. The chemical structures were determined by spectroscopic methods (¹H NMR, ¹³C NMR, ¹H-¹H COSY, HMBC, HSQC, and NOESY) and mass spectrometry (ESI–MS). C-glycosylflavones had significant free radical-scavenging activities on the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). However, SU and compounds 3 and 3a exhibited no activity. In particular, compound 1 exhibited a concentration-dependent radical scavenging activity on DPPH with EC₅₀ of 31.43 µg/mL.     

Chemical structures of constituents from the leaves of <Emphasis Type="Italic">Polyscias balfouriana</Emphasis>

A new pyrrolidine derivative, (5S)-hydroxyethyl 2-oxopyrrolidine-5-carboxylate (1), a new flavonol glycoside, tamaraxetin 3,7-di-O-α-l-rhamnopyranoside (2), and a new triterpene saponin, polyscioside A methyl ester (3), along with six known compounds (4–9) were isolated from the leaves of Polyscias balfouriana. Their chemical structures were elucidated on the basis of extensive spectroscopic analysis.     

Phenylacylphenol derivatives with anti-melanogenic activity from <Emphasis Type="Italic">Stewartia pseudocamellia</Emphasis>

Three new phenylacylphenol derivatives, stewartianol (1), deoxystewartianol-4′-O-arabinoglucoside (2), and stewartianol-3-O-glucoside (3), along with nine known compounds, methylesculin (4), fraxoside (5), fraxetin (6), scopletin (7), (+)-dihydromyricetin (8), (+)-taxifolin-7-O-β-d-glucose (9), (+)-taxifolin (10), (+)-dihydrokaempferol-7-O-β-d-glucose (11), and 3-acetyl-ursolic acid (12), were isolated from the twigs of Stewartia pseudocamellia; commonly used as folk medicine in Korea. The structures of the isolated compounds were identified using spectroscopic analysis, including 1D, 2D NMR, MS and compared with published data. The compounds were tested for their anti-melanogenic activity in cultured murine B16 melanoma cells. Stewartianol (1) and stewartianol-3-O-glucoside (3) showed an inhibitory effect significantly on melanogenesis in a concentration-dependent manner.     

Microwave-assisted synthesis,molecular docking and antimicrobial activity of novel 2-(3-aryl,1-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-4-yl)-8<Emphasis Type="Italic">H</Emphasis>-pyrano[2,3-f]chromen-4-ones

An efficient synthetic protocol of microwave-assisted synthesis of some novel 2-(3-aryl,1-phenyl-1H-pyrazol-4-yl)-8H-pyrano[2,3-f]chromen-4-ones 6a–j in excellent yields starting from 3-(3-aryl,1-phenyl-1H-pyrazol-4-yl)-1-(5-hydroxy-2H-chromen-6-yl)-propenones 5a–j was described. This approach offers the advantages of short reaction time (3–5 min), mild reaction conditions, high yields (80–88 %) and convenient operation. All the synthesized compounds were tested in vitro for their antimicrobial activity. The compounds 5h (Ar = 3-ethoxyphenyl), 6c (Ar = 4-chlorophenyl), 6e (Ar = 4-hydroxyphenyl) and 6i (Ar = 3,4-methoxyphenyl) were found to be potent against tested bacterial strains, and compounds 5g (Ar = 4-ethoxyphenyl), 6c (Ar = 4-chlorophenyl) and 6i (Ar = 3,4-methoxyphenyl) were found to be potent against tested fungal strains. The final compounds were subjected to molecular docking studies for the inhibition of enzyme DNA gyrase. The in silico molecular docking results are matching with the in vitro antimicrobial studies, and they may be considered as good inhibitor of DNA gyrase.     

Synthesis,antimicrobial and nematicidal evaluation of a new class of triazolo[4,3-<Emphasis Type="Italic">c</Emphasis>]quinazolinylthiazolidinones

In an attempt to find a new class of antimicrobial and nematicidal agents, a series of 2-aryl/heteryl-3-(5-phenyl[1,2,4]triazolo[4,3-c]quinazolin-3-yl)-1,3-thiazolidin-4-ones 5a-k was prepared by one-pot three-component reaction, involving 5-phenyl[1,2,4]triazolo[4,3-c]quinazolin-3-amine 4, aryl/heteroaryl aldehydes and thioglycolic acid, and characterized by physicochemical as well as spectral means. All the newly synthesized compounds 5a–k were tested in vitro for their antimicrobial activity against three representative Gram-positive (Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus), Gram-negative (Proteus vulgaris, Salmonella typhimurium, Escherichia coli) bacteria and four fungal strains (Candida albicans, Aspergillus fumigatus, Trichophyton rubrum, Trichophyton mentagrophytes). These compounds 5a–k, were also evaluated for their nematicidal activity against two nematodes (Ditylenchus myceliophagus, Caenorhabditis elegans). Except phenyl substituted, all the ten aryl/heteroaryl substituted compounds 5b–k showed significant antimicrobial and nematicidal properties against tested microorganisms. Particularly, compounds 5b, 5c, 5g, 5h, 5j and 5k containing electron-withdrawing substituents like chlorophenyl, nitrophenyl, furyl and 1,3-benzodioxole exhibited promising activity comparable to employed standards Ampicillin, Amphotericin B and Levamisole, and emerged as potent antimicrobial and nematicidal agents.     

Two new <Emphasis Type="Italic">β</Emphasis>-carboline alkaloids from the stems of <Emphasis Type="Italic">Picrasma quassioides</Emphasis>

Two new β-carboline alkaloids, 1-acetyl-4-methoxy-8-hydroxy-β-carboline (1) and 1-acetyl-4,8-dimethoxy-β-carboline (2), together with 10 known compounds; seven β-carboline alkaloids (3–9), two canthin-6-one alkaloids (10 and 11), and one quassinoid (12) were isolated from the stems of Picrasma quassioides. The structure of the new compounds 1 and 2 were determined by spectroscopic analyses including 1D- and 2D-NMR and HRMS interpretation. All the isolates (1–12) were evaluated for their cytotoxicity against human ovarian carcinoma A2780 and SKOV3 cell lines using MTT assays. Of the isolates, compounds 5–7 exhibited the most potent cytotoxicity on both A2780 and SKOV3 cell lines in vitro.     

Synthesis,molecular docking,antiproliferative, and antimicrobial activity of novel pyrano[3,2-<Emphasis Type="Italic">c</Emphasis>]carbazole derivatives

A new series of pyrano[3,2-c]carbazole derivatives which are biologically valuable and synthetically challenging frameworks have been synthesized by domino Knoevenagel-hetero-Diels-Alder reaction. The key strategy involve copper iodide catalyzed cyclization of O-propargyl derivative of N-Boc-carbazole-3-carboxaldehyde with cyclic 1,3-diketones or pyrazol-5-ones to afford N-Boc-pyrano[3,2-c]carbazole derivatives. The antiproliferative activity of the all synthesized compounds on three cancer cell lines such as PANC 1 (pancreatic), HeLa (cervical), and MDA-MB-231 (breast cancer) was investigated. The results clearly demonstrated that compounds 11b, 11d, and 13d were displayed pronounced antriproliferative activity. In addition, antimicrobial activity of these compounds also assayed against three representative gram-positive organisms and gram-negative organisms. Specifically, compound 11c exhibited significant antimicrobial activity. Molecular docking studies revealed that compound 13d selectively occupy the colchicine binding site of the tubulin polymer.     

Comparative enzyme inhibition study of 1-deazapurines

A series of nitrogen heterocycles including the derivatives of 1-deazapurines, were studied for miscellaneous enzyme inhibition activities in search of the potent enzyme inhibitor. The hyperactive enzymes like carbonic anhydrase-II, phosphodiesterase-I, xanthine oxidase, α-glucosidase, and β-glucuronidase were selected for the study. The compounds 1, 2, 3, 6, 8, 11–13 and 15–17, showed significant and selective activities against different enzymes. The compounds 11 and 12 were found the most potent against carbonic anhydrase-II, α-glucosidase and β-glucuronidase in comparison to their standard compounds. These selective inhibitors can be used as lead compounds for development of drugs against various diseases associated with these enzymes.     

Design,synthesis and biological activity of <Emphasis Type="Italic">N</Emphasis>-(3-substituted-phenyl)benzenesulfonamides as selective and reversible LSD1 inhibitors

Lysine specific demethylase 1 plays a crucial role in regulating histone methylation at residues K4 and K9 on histone H3 and over-expresses in a variety of cancers. Here we designed, synthesized and evaluated a series of N-(3-substituted-phenyl)benzenesulfonamides as reversible lysine specific demethylase 1 inhibitors. All the compounds exhibited lysine specific demethylase 1 inhibition with the half maximal inhibitory concentration (IC₅₀) values between 7.5 and 68?μM. Three most active compounds 2a, 2c and 2i displayed only modest effect on flavin adenine dinucleotide-dependent enzymes mono-amine oxidases A and B, and their reversibilities of lysine specific demethylase 1 inhibition were confirmed. Molecular docking was also carried out to predict the binding mode of 2a into the active site of lysine specific demethylase 1. Taken together, N-(3-substituted-phenyl)benzenesulfonamides including 2a represent a new class of selective and reversible lysine specific demethylase 1 inhibitors with pharmaceutical research.     

Identification of cytoprotective constituents of the flower buds of <Emphasis Type="Italic">Tussilago farfara</Emphasis> against glucose oxidase-induced oxidative stress in mouse fibroblast NIH3T3 cells and human keratinocyte HaCaT cells

A new cytoprotective compound, 1-[(4S)-3,4-dihydro-4-hydroxy-2,2-dimethyl-2H-1-benzopyran-6-yl]-ethanone (1) was isolated from the flower buds of Tussilago farfara L. (Compositae), together with eight known compounds, 3,4-dicaffeoyl isoquinic acid (2), trans-cinnamic acid (3), 4-hydroxyacetophenone (4), 4,5-dicaffeoylquinic acid methyl ester (5), 3,5-dicaffeoylquinic acid methyl ester (6), 4-hydroxybenzoic acid (7), isoquercetrin (8), and ligucyperonol (9). Compounds 2–4 were found in this plant for the first time. The isolates 1–9, were tested for their cytoprotective activities against glucose oxidase-induced oxidative stress in mouse fibroblast NIH3T3 cells and human keratinocyte HaCaT cells. Among them, 1 and 3 showed significant cytoprotective activities as determined by MTT assay and lactate dehydrogenase leakage, indicating their possibility as the potent cytoprotective agents. The structure of 1 was determined by spectroscopic data analysis including 1D- and 2D-NMR experiments, and its absolute configuration was elucidated by a circular dichroism.     

Two new naphthalenic lactone glycosides from <Emphasis Type="Italic">Cassia obtusifolia</Emphasis> L. seeds

Two new naphthalenic lactone glycosides, (3S)-9,10-dihydroxy-7-methoxy-3-methyl-1-oxo-3,4-dihydro-1H-benzo[g]isochromene-3-carboxylic acid 9-O-β-d-glucopyranoside (1) and (3R)-cassialactone 9-O-β-d-glucopyranoside (2) were isolated from seeds of Cassia obtusifolia Linn., along with five known compounds: (3R)-cassialactone 9-O-β-d-gentiobioside (3), emodin 1-O-β-gentiobioside (4), 1-hydroxyl-2-acetyl-3,8-dimethoxy-naphthalene 6-O-β-d-apiofuranosyl-(1?→?2)-β-d-glucopyranoside (5), rubrofusarin 6-O-β-d-gentiobioside (6), rubrofusarin 6-O-β-d-triglucoside (7). Structures of 1 and 2 were elucidated by NMR and HR-ESI-MS spectroscopic analysis. Their stereochemistry was determined by CD experiment. All compounds were tested for their ability to inhibit the formation of advanced glycation end-products in vitro. Compounds 1, 2, 3, 5, and 6 showed significant in vitro inhibitory activities (IC₅₀ values of 11.63, 23.40, 7.32, 89.03, and 38.89 µM, respectively).     

Microbial transformation of naringenin derivatives

Microbial transformations of (±)-7-O-prenylnaringenin (7-PN, 1) and (±)-7-O-allylnaringenin (7-AN, 2) have isolated four metabolites (3–6). Structures of these novel compounds were identified as 5,4′-dihydroxy-7-O-[(2E)-4-hydroxy-3-methyl-2-buten-1-yl]flavanone (3), 5,4′-dihydroxy-7-O-(2,3-dihdroxy-3-methylbutyl)flavanone (4), 5,4′-dihydroxy-7-O-(2,3-dihdroxypropyl)flavanone (5), and 5-O-β-D-glucopyranosyl-7-O-allyl-4′-hydroxyflavanone (6) based on spectroscopy. Compounds 1–6 were evaluated for their radical scavenging capacity using DPPH (2,2-diphenyl-1-picrylhydrazyl). The derivatives 3–6 exhibited more potent antioxidant activity than their corresponding substrates 1 and 2.