A microbial model of mammalian metabolism: biotransformation of 4,5-dimethoxyl-canthin-6-one using Cunninghamella blakesleeana CGMCC 3.970

1.?A filamentous fungus, Cunninghamella blakesleeana CGMCC 3.970, was applied as a microbial system to mimic mammalian metabolism of 4,5-dimethoxyl-canthin-6-one (1). Compound 1 belongs to canthin-6-one type alkaloids, which is a major bioactive constituent of a traditional Chinese medicine (the stems of Picrasma quassioides).

2.?After 72?h of incubation in potato dextrose broth, 1 was metabolized to seven metabolites as follows: 4-methoxyl-5-hydroxyl-canthin-6-one (M1), 4-hydroxyl-5-methoxyl-canthin-6-one (M2), canthin-6-one (M3), canthin-6-one N-oxide (M4), 10-hydroxyl-4,5-dimethoxyl-canthin-6-one (M5), 1-methoxycarbonl-β-carboline (M6), and 4-methoxyl-5-O-β-D-glucopyranosyl-canthin-6-one (M7).

3.?The structures of metabolites were determined using spectroscopic analyses, chemical methods, and comparison of NMR data with those of known compounds. Among them, M7 was a new compound.

4.?The metabolic pathways of 1 were proposed, and the metabolic processes involved phase I (O-demethylation, dehydroxylation, demethoxylation, N-oxidation, hydroxylation, and oxidative ring cleavage) and phase II (glycosylation) reactions.

5.?This was the first research on microbial transformation of canthin-6-one alkaloid, which could be a useful microbial model for producing the mammalian phase I and phase II metabolites of canthin-6-one alkaloids.

6.?1, M1?M5, and M7 are canthin-6-one alkaloids, whereas M6 belongs to β-carboline type alkaloids. The strain of Cunninghamella blakesleeana can supply an approach to transform canthin-6-one type alkaloids into β-carboline type alkaloids.     

Studies on the alkaloid constituents of Evodia rutaecarpa (Juss) Benth var. bodinaieri (Dode) Huang and their acute toxicity in mice

Six alkaloids (1–6) have been isolated from the fruits of Evodia rutaecarpa (Juss) Benth var. bodinaieri (Dode) Huang, two of which are new compounds, identified as 2-undecyl-4(1H)-quinolone (4) and 1-methyl-2-undecanone-10′-4(1H)-quinolone (5); the known compounds were identified as rutaecarpine (1), evodiamine (2), 1-methyl-2-undecyl-4(1H)-quinoline (3) and 2-undecanone-10′-4(1H)-quinolone (6). Compounds 1–5 were evaluated for their acute toxicity.     

Microsomal metabolism of N,N-diethyl-m-toluamide (DEET,DET): the extended network of metabolites

1. The aim was to set out to establish the complete network of metabolites arising from the phenobarbital-treated rat liver microsomal oxidation of N,N-diethyl-m-toluamide (DEET). The products formed from DEET and all its subsequent metabolites were identified by HPLC retention times, UV spectroscopy, mass spectrometry and by comparison with authentic standards. 2. DEET (1a) produces three major metabolites, N-ethyl-m-toluamide (1b), N,N-diethyl-m-(hydroxymethyl)benzamide (2a) and N-ethyl-m-(hydroxymethyl)benzamide (2b), and, at low substrate concentrations or extended reaction times, two minor metabolites, toluamide (1c) and N,N-diethyl-m-formylbenzamide (3a). 1b and 2a are primary metabolites and their formation follows Michaelis-Menten-type kinetics. At low DEET concentrations, ring methyl group oxidation is favoured; at saturation concentrations, methyl group oxidation and N-deethylation proceed at similar rates. The rate of formation of 2b decreases with increasing DEET concentration; 2b is therefore a secondary metabolite of DEET and DEET acts as a competitive inhibitor of the metabolism of 1b and 2a. 3. Except for the primary amides, where N-dealkylation is impossible, metabolism of all subsequent compounds, 1b,c, 2a-c, 3a-c and 4a,b, involves an N-deethylation (NEt₂ → NHEt or NHEt → NH₂) competitive with a ring substituent oxidation (CH₃ → CH₂OH, CH₂OH → CHO or CHO → CO₂H). Surprisingly, the aldehydes 3a-c are also reduced to the corresponding alcohols 2a-c (CHO → CH₂OH); CO inhibits the oxidative metabolism of 3a-c, but reduction to 2a-c continues uninhibited. 4. The outcomes of this work are that (1) previously unreported aldehydes 3b and 3c form part of the DEET network of metabolites, (2) the reduction of the aldehydes 3a-c has the potential to inhibit the formation of the more highly oxidized DEET metabolites, (3) amide hydrolysis was not observed for any substrate and (4) no evidence was obtained for N-(1-hydroxyethyl)amide intermediates.     

A bisamide and four diketopiperazines from a marine-derived Streptomyces sp.

A new bisamide N ₁-acetyl-N ₇-phenylacetyl cadaverine (1) and a series of diketopiperazines including a new diketopiperazine cyclo(2-hydroxy-Pro-R-Leu) (2), together with a new natural product cyclo(4-hydroxy-S-Pro-S-Trp) (3) and two known leucine-based diketopiperazines cyclo(4-hydroxy-R-Pro-S-Leu) (4) and cyclo (S-Pro-R-Leu) (5), were isolated from ethyl acetate extract of a fermentation broth of a marine-derived Streptomyces sp. Their structures were elucidated by the interpretation of spectroscopic analysis. The antitumor activities of compounds 1–3 against HL-60 cell lines were tested by MTT assay.     

A bioactive sesquiterpene from Bixa orellana

A dichloromethane extract of the air-dried leaves of Bixa orellana afforded ishwarane 1, phytol 2, polyprenol 3, and a mixture of stigmasterol 4a and sitosterol 4b by silica gel chromatography. The structure of 1 was elucidated by extensive 1D and 2D NMR spectroscopy. Compound 1 at three doses (25, 50, and 100 mg/kg BW) was tested for prophylactic, gastrointestinal motility, analgesic, hypoglycemic, and antimicrobial potentials. Results of the prophylactic assay demonstrated the anti-toxic property of 1 at 100 mg/kg BW. A 50 mg/kg BW dose of 1 resulted in a more propulsive movement of the gastrointestinal tract (88.38 ± 13.59%) compared to the negative control (78.47 ± 10.61%). Tail flick and acetic acid writhing tests indicated that 100 mg/kg BW 1 had minimal analgesic activity. Compound 1 demonstrated no hypoglycemic potential on the animals tested. Compound 1 exhibited moderate antifungal activity against C. albicans, low activity against T. mentagrophytes, and low antibacterial activity against E. coli, S. aureus, and P. aeruginosa. It was inactive against B. subtilis and A. niger.     

Further derivatives of 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carboxylic acid and their antibacterial activities

Compound 4, 5, 6, 7, and 8 were synthesized from 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carboxylic acid 1 as a starting material. The pyrazolo[4,3-d]oxazinone 4 was obtained from direct reaction of the acid 1 with hydroxylamine hydrochloride. Acid chloride 2 was converted easily into the new derivatives consisting of 1-(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-oyl)-sulfamide 5 and 3,4-dibenzoyl-1,5-diphenyl-1H-pyrazole 6. The nitrile derivative 7 was obtained by dehydration of the amide 3 in a mixture of SOCl₂ and Dimethylformamide (DMF). Cyclocondensation reaction of 7 with anhydrous hydrazine led to the formation of 7-aminopyrazolo[3,4-d]pyridazine 8 derivative. These new synthesized compounds evaluated for their antibacterial activities against Gram-positive and Gram-negative bacteria using the tube dilution method. The finding of antibacterial activity study showed that the sulfamide derivative 5 was the best compound of the series, exhibiting antibacterial activity against both Gram-positive and Gram-negative bacteria.     

Aromatic acid derivatives from the lateral roots of Aconitum carmichaelii

Seven new aromatic acid derivatives (1–7), together with five known analogs, were isolated from the lateral roots of Aconitum carmichaelii. Structures of the new compounds were determined by spectroscopic and chemical methods as 4-methyl ( ? )-(R)-hydroxyeucomate (1), 4-butyl ( ? )-(R)-hydroxyeucomate (2), 4-butyl-1-methyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (3), 1-butyl-4-methyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (4), dimethyl (+)-(R)-2-O-(4′-hydroxy-3′-methoxybenzoyl)malate (5), dimethyl (+)-(R)-2-O-(4′-hydroxybenzoyl)malate (6), and methyl ( ± )-3-(4′-hydroxy-3′-methoxyphenyl)-3-sulfopropionate (7), respectively. Compounds 1 and 2 are 2-benzylmalates (eucomate derivatives), 3–6 belong to 2-O-benzoylmalates, and 7 is a rare phenylpropionate containing a sulfonic acid group. The absolute configurations of eucomate derivatives were confirmed by X-ray crystallographic analysis of 4-methyl eucomate (11).     

Ergostane steroids from the ethanol extract of Dysoxylum mollissimum

Three new ergostane steroids, 7α-acetoxyl-ergosta-5,24(28)-diene-3β,4β,20S-triol (1), 7α-acetoxyl-ergosta-5,24(28)-diene-3β,4β-diol (2), and 7α-acetoxyl-ergosta-5,24(28)-3β-ol (3) were isolated from the ethanol extract of stem bark of Dysoxylum mollissimum BI. Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (¹H-¹H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. All the isolated steroids were in vitro evaluated for their anti-inflammatory activity against COX-1 and COX-2. As a result, steroids 1–3 exhibited modest selective inhibition for COX-1 (>60%).     

Simultaneous quantification by HPLC of the phenolic compounds for the crude drug of Prunus serotina subsp. capuli

Context: Prunus serotina Ehrenb. subsp. capuli (Cav.) McVaugh (Rosaceae), commonly known as “capulin”, is a native North American tree, commercialized and used in folk medicine for the treatment of the hypertension, gastrointestinal illnesses, and cough.

Objective: This work developed a suitable HPLC method for quantifying the major active constituents of the infusion of P. serotina, the most important preparation consumed by populations around the world.

Materials and methods: The analytical method was performed using a Fortis-RP column (150?mm?×?4.6?mm; film thickness 5?µm). The mobile phase consisted of an isocratic acetate buffer solution (pH 2.7; A) and methanol (B) (65:35 v/v) at a flow rate of 1.0?mL?min^?1.

Results: The proposed method was applied to the quantification of 1–3 in several samples of the leaves of P. serotina. The results indicated that amounts of 1–3 in the samples analyzed are uniform, and greater amounts of chlorogenic acid (2; 479.9?±?33.6?µg?g^?1, dry matter) along with hyperoside (1; 185.7?±?55.3?µg?g^?1, dry matter) were present. On the other hand, benzaldehyde (3; 118.2?±?12.1?µg?g^?1 dry matter) was found to be in lower concentration.

Conclusions: A simple, sensitive, precise, and reproducible HPLC method for the simultaneous quantification of 1–3 in P. serotina was developed and validated. This is the first report on the quantification of 1–3 as active principles, and compound 1 was selected as a marker of P. serotina, which could be useful to guarantee the quality of the crude drug and herbal products.     

Biotransformation of total coumarins of Radix Glehniae by Lecanicillium attenuatum W-1-9

Abstract

The biotransformation of total coumarins of Radix Glehniae by Lecanicillium attenuatum W-1-9 yielded three new products, lecaniside A (1), lecaniside B (2), and lecaniside C (3). The chemical structures of these metabolites were elucidated based on extensive spectral data, including 2D NMR and HRMS. The hydrogenation, dealkylation, glycosylation, and O-methylation reactions of these metabolites were observed in the present study. In the in vitro assays, compound 1 displayed a little PTP1B inhibitory activity.     

A new bisabolane sesquiterpenoid from Euphorbia chrysocoma

The new sesquiterpenoid (6R)-2-chloro-6-[(1S)-1,5-dimethylhex-4-en-1-yl]-3-methylcyclohex-2-en-1-one (1), together with ten known compounds, (6R)-6-[(1S)-1,5-dimethylhex-4-en-1-yl]-3-methylcyclohex-2-en-1-one (2), bauerenol acetate (3), lupenone (4), α-amyrenone (5), β-sitosterol (6), stigmasterol (7), β-amyrin (8), ursolic acid (9), betulinic acid (10), scopolin (11), have been isolated from the roots of Euphorbia chrysocoma Lévl. et Vant. Their structures have been elucidated by spectroscopic data.     

Protective effects of hesperidin derivatives and their stereoisomers against advanced glycation end-products formation

Context: Maillard reaction is implicated in the development of pathophysiology in age-related diseases. The search for newer Maillard reaction inhibitors is a priority among strategies to combat diabetes complications.

Objective: To evaluate the inhibitory potential of hesperidin, its derivatives and their stereoisomers against advanced glycation end-products (AGEs) formation.

Materials and methods: Hesperidin and hesperetin were chirally separated and the inhibitory effects of 1:1 mixture of (2S)- and (2R)-hesperidin (1), (2S)-hesperidin (2), (2R)-hesperidin (3), 1:1 mixture of (S)- and (R)-hesperetin (4), (S)-hesperetin (5), (R)-hesperetin (6), and monoglucosyl hesperidin (7) [1:1 mixture of (2S)-glucosyl hesperidin (8) and (2R)-glucosyl hesperidin (9)] at a concentration of 1 mM on protein glycation reaction have been revealed using the newly constructed RNase A-methylglyoxal (MGO) assay for the early stage and the bovine serum albumin (BSA)-glucose assay for the late stage of Maillard reaction.

Results: This study has demonstrated that hesperidin and its derivatives possessed relatively strong activity against the formation of AGEs. (S)-Hesperetin (5) possessed the highest inhibitory rate up to 57.4% in BSA-glucose assay, 38.2% in RNase A-MGO assay.

Discussion and conclusion: The new RNase A-MGO assay system could be used for the screening of AGEs inhibitors and hesperidin, and its derivatives could be promising candidate adjuvants for the treatment of diabetes complication, and age-related chronic diseases.     

Concise synthesis and PTP1B inhibitory activity of (R)- and (S)-dihydroresorcylide

The present study was designed to develop a concise synthetic route for macrolide, with the purpose of confirming the absolute configuration of natural dihydroresorcylide (1) and making it more easily accessible for biological evaluation. The absolute configuration of C-3 in natural 1 was revised to be R by comparison of the rotation sign of synthetic (R)- and (S)-1. The synthetic (R)-1 was found to be a novel highly specific PTP1B inhibitor with an IC₅₀ value of 17.06 μM.     

New cycloartanes and new iridoids from Dolichandrone spathacea collected in the mangrove forest of Soc Trang province,Vietnam

Abstract

Two new cycloartanes, named dolichandrone A (1) and dolichandrone B (2), as well as two new iridoids, named [6-O-[(E)-4-methoxycinnamoyl]-1β-hydroxy-dihydrocatalpolgenin (3) and 6-O-[(E)-4-methoxycinnamoyl]-1α-hydroxy-dihydrocatalpolgenin (4), together with four known iridoids (5–8), were isolated from the leaves and barks of Dolichandrone spathacea. Their structures were elucidated by means of extensive analysis of their HRESIMS, 1D and 2D NMR spectroscopic data. All of these compounds have been isolated for the first time from this plant. Compounds 1, 2, 5, and 7 were evaluated for their cytotoxic activity in vitro against four human cancer cell lines KB, Lu, HepG2, and MCF7. The results showed that only compound 2 exhibited a good cytotoxicity against KB cell line with IC₅₀ of 18.77 μM.     

Activity against Plasmodium falciparum of Lactones Isolated from the Endophytic Fungus Xylaria sp.

Three lactones were isolated from the culture medium of the endophytic fungus Xylaria sp. Grev. (Xylariaceae). The major compound, which showed weak activity (13 μ g/mL) against a chloroquine-resistant strain of Plasmodium falciparum, was identified as (+)-phomalactone (1). The others were 6-(1-propenyl)-3,4,5,6-tetrahydro-5-hydroxy-4H-pyran-2-one (2) and 5-hydroxymellein (3). Compounds 1 and 2 are reported for the first time as constituents of Xylaria. Also, this is the first report of the activity of the compounds 1–3 against a chloroquine-resistant Plasmodium falciparum strain.     

Investigation of 6-O-methyl-scutellarein metabolites in rats by ultra-flow liquid chromatography/quadrupole-time-of-flight mass spectrometry

Context Scutellarin (1) has been widely used in China to treat acute cerebral infarction and paralysis induced by cerebrovascular diseases. However, scutellarin (1) has unstable metabolic characteristics.

Objective The metabolic profile of 6-O-scutellarein was studied to determine its metabolic stability in vivo.

Materials and methods In this study, a method of UFLC/Q-TOF MS was used to study the 6-O-methyl-scutellarein metabolites in rat plasma, urine, bile and faeces after oral administration of 6-O-methyl-scutellarein (3). One hour after oral administration of 6-O-methyl-scutellarein (3) (34?mg/kg), approximately 1?mL blood samples were collected in EP tubes from all groups. Bile, urine and faeces samples were collected from eight SD rats during 0–24?h after oral administration. The mass defect filtering, dynamic background subtraction and information dependent acquisition techniques were also used to identify the 6-O-methyl-scutellarein metabolites.

Results The parent compound 6-O-methyl-scutellarein (3) was found in rat urine, plasma, bile and faeces. The glucuronide conjugate of 6-O-methyl-scutellarein (M1, M2), diglucuronide conjugate of 6-O-methyl-scutellarein (M3), sulphate conjugate of 6-O-methyl-scutellarein (M4), glucuronide and sulphate conjugate of 6-O-methyl-scutellarein (M5), methylated conjugate of 6-O-methyl-scutellarein (M6) were detected in rat urine. M1, M2 and M3 were detected in rat bile. M1 was found in rat plasma and M7 was detected in faeces.

Discussion and conclusion Because the parent compound 6-O-methyl-scutellarein (3) was found in rat urine, plasma, bile and faeces, we speculate that 6-O-methyl-scutellarein (3) had good metabolic stability in vivo. This warrants further study to develop it as a promising candidate for the treatment of ischemic cerebrovascular disease.     

Two pairs of unusual melibiose and raffinose esters from Scrophularia ningpoensis

A pair of unusual melibiose esters (1α/1β) and a pair of unusual raffinose esters (2α/2β), were isolated from Scrophularia ningpoensis. Structures of them were established by detailed spectroscopic analyses to be 6-O-(E)-cinnamoyl-α-d-galactopyranosyl-(1→6)-α(β)-d-glucopyranose (1α/1β) and 6-O-(E)/(Z)-cinnamoyl-α-d-galactopyranosyl-(1→6)-α-d-glucopyranosyl-(1→2)-β-d-fructofuranose (2α/2β), respectively. All these compounds were evaluated for antifouling activity against the settlement of Balanus amphitrite larvae, along with the cytotoxic effect against the proliferation of HeLa cell lines.     

Three new alkaloids from the seeds of Nigella glandulifera

Three new alkaloids namely 8-(4-hydroxyphenyl)-6-methoxy-3,4-dihydroisoquinolin-1(2H)-one (1), 4-aminonigellidine (2), and N-[(4-hydroxy-2-isopropyl-5-methyl)]phenylurea (3), along with six known ones (4–9), were isolated from the seeds of Nigella glandulifera. The structures of 1–3 were determined through spectroscopic analyses (HRESIMS, 1D/2D NMR). Compound 1 was a rare isoquinolinone alkaloid with phenyl substituted at C-8.     

Trans-dimer D,a novel dimeric sesquiterpene with a bis-bisabolene skeleton from a Hainan sponge Axinyssa variabilis

A novel bisabolene sesquiterpene dimer named trans-dimer D (1) and its diastereoisomer trans-dimer C (2) reported in our previous work have been isolated as an inseparable mixture in a ratio of 1.5:1 from the South China Sea sponge Axinyssa variabilis. The structure of 1 was determined on the basis of extensive spectroscopic analysis and by comparison of its NMR spectral data with those of structurally related compounds. Compound 1 represents the fourth example of a sesquiterpene dimer with a bis-bisabolene skeleton.