New pyranosyl cembranoid diterpenes from Sarcophyton trocheliophorum

During our continual searching programme for novel bioactive metabolites from Sarcophyton trocheliophorum, collected from Red Sea, we describe herein the isolation and structural elucidation of further two new pyrane-based cembranoid diterpenes: 9-hydroxy-7,8-dehydro-sarcotrocheliol (1) and 8,9-expoy-sarcotrocheliol acetate (2), along with the well-known sarcotrocheliol acetate (3), (+)-sarcophine (4), (+)-sarcophytoxide (5) and (-)-sarcophytoxide (6). The chemical structures of compounds 1 and 2 were determined on the basis of 1D and 2D NMR (¹H, ¹³C, ¹H–¹H COSY, HMQC, HMBC and NOE), mass spectra (ESI and HR-ESIMS) and by comparison with related structures. The antimicrobial activities of the reported compounds 1–6 were investigated. According to the molecular docking study of compounds 1–6 using 3D structure of α,β tubulin in complex with taxol (PDB code 1JFF) and epothilone A (PDB code 1TVK), sarcophine (4) displayed the highest affinity towards both crystal structures, followed by 5 and 6, meanwhile pyrane-based cembranoid diterpenes (1–3) showed less affinity.     

Phytochemical profile and biological activities of Deverra tortuosa (Desf.)DC.: a desert aromatic shrub widespread in Northern Region of Saudi Arabia

The present study describes the chemical composition of the essential oil of different plant parts of Devrra tortuosa; in vivo and in vitro biological activities of plant extract and essential oils. Apiol was found to be the major component of the oil (between 65.73% and 74.41%). The best antioxidant activities were observed for the oil of flowers (IC50 = 175 μg/ml). The samples of stems and roots exhibit lower antioxidant activity (IC50 = 201 μg/ml and 182 μg/ml, respectively). The values of IC50 showed that the extracts of methanol exhibit the highest antioxidants activities (IC50 = 64.8 102 μg/ml). EOs showed excellent antifungal activity against yeasts with low azole susceptibilities (i.e. Malassezia spp. and Candida krusei). The MIC values of oils varied between 2.85 mg/mL and 27 mg/mL. The obtained results also showed that the plant extracts inhibited the germination and the shoot and root growth of Triticum æstivum seedlings.     

1,3,4,5-四氢-7-烷氧基-2H-1-苯并氮杂(卓)-2-酮的合成及生物活性

合成了一系列1,3,4,5-四氢-7-烷氧基-2H-1-苯并氮杂(卓)-2-酮衍生物.采用最大电惊厥实验测定化合物的抗惊厥活性,其中的1,3,4,5-四氢-7-丁氧基-2H-1-苯并氮杂(卓)-2-酮(4b)具有较强的抗惊厥活性,ED_(50)为52.8 mg/kg,TD_(50)为246.2mg/kg,PI为4.7.     

Structural characterization and biological activity of galactoglucan from Castanea mollissima Blume

Abstract

A galactoglucan (HCPA) was extracted from C. mollissima Blume fruits using hot water, which was composed of glucose and galactose, with a molecular weight of 5.5?kDa. Methylation and 1?D, 2?D NMR spectroscopy analysis showed that HCPA contained [→4)-α-D-Glcp(1→], [→4,6)-α-D-Glcp(1→], [→4)-β-D-Galp(1→] and [α-D-Glcp(1→] motifs in a molar ratio of approximately 6.11:1.08:1.00:1.03. HCPA showed a spherical-like structure as detected by scanning electron microscope (SEM). HCPA biological activity was investigated in vitro. The results showed that HCPA inhibited the proliferation of HeLa, MCF-7 and MGC-803 cells, induced HeLa cells apoptosis and arrested cell cycle in G2/M phase of HeLa cells. HCPA also enhanced the viability and phagocytic ability of RAW 264.7 cells and stimulated the production of NO, TNF-α and IL-6. The results demonstrated that HCPA had a potent antitumor and immunomodulating effects in vitro, suggesting its potential use as functional food and drug products.     

SYNTHESIS OF NOVEL OPTICALLY ACTIVE CYCLIC PHOSPHOLIPID CONJUGATES OF TEGAFUR AND URIDINE STARTING FROM L-SERINE

Abstract

Starting from L-serine, cyclic thiophosphoramidate conjugates (2 and 3) of Tegafur and uridine were synthesized via a multiple-step procedure of esterification, cyclic phosphorylation, and sulfurization, etc. L-serinoate was N-alkylated, then cyclized with phosphorus oxychloride, and further reacted with N³-(2-hydroxyethyl) Tegafur to afford cyclic phospholipid conjugate 4. The resultants (2, 3, and 4) were successfully separated in the form of pure diastereomer by column chromatography on silica gel. Their configurations were discussed and assigned according to their NMR spectra. The asymmetric induction effects of the carbon-based chiral centre on the diastereomer preference were also observed in these two synthetic phosphorylation cyclizations. The bioassay on their antitumor activities is under investigation.     

Synthesis of 5-(7-Hydroxyheptyl)-1,2-dithiolan-3-one 1-Oxide,a Core Functionality of Antibiotic Leinamycin

5-(7-Hydroxyheptyl)-1,2-dithiolan-3-one 1-oxide was designed and synthesized in our laboratories that contain the heterocycle of 1,2-dithiolan-3-one 1-oxide, a reactive core of antibiotic leinamycin. In addition, the activated ester of 5-(7-hydroxyheptyl)-1,2-dithiolan-3-one 1-oxide was prepared, which presumably is useful for coupling this DNA-cleaving functionality to certain DNA-binding agents.     

Isoconversional Curing and Degradation Kinetics Study of Self-assembled Thermo-responsive Resin System Bearing Oxime and Iminium Groups

This paper demonstrates synthesis of a self-assembled resin system containing p-acetylpyridine oxime, formaldehyde and p-methoxyacetophenone moieties in main chain and thermally cross-linkable periphery oxime groups, and application as antimicrobial coating in biomedical applications. The post-polymerization conversion from oxime into iminium groups was observed by heating scan, with exothermic peaks being at 194 to 247°C. Various degradation models including the Flynn-Wall-Ozawa (F-W-O), Kissinger-Akahira-Sunose (K-A-S), Tang (T) and Friedman (F) methods were employed to check the thermal stability of self-assembly by computing apparent activation energy. It has also exhibited strong biocidal properties against gram-positive and gram-negative bacteria, and fungi until the macrochain retains some positive charge. The obtained results prove that the structure of links, which combine the hydrophobic pyridine rings with the hydrophilic iminium groups, is responsible for the high biocidal activity of the resin system.     

Studies on 2-Aminothiophenes: Synthesis,Transformations, and Biological Evaluation of Functionally-Substituted Thiophenes and Their Fused Derivatives

Abstract

Heterocyclic enamines1 reacted with ethyl acetoacetate to afford the corresponding amide derivatives2. Treatment of2 with carbon disulphide yielded the dipotassium salts3which reacted in-situ with a variety of α -haloketones to give the respective substituted thiophenes5,8, and13. The reactivity of the latter products towards various chemical reagents was studied to yield their fused thiophene derivatives7,10,12, and14, respectively. Some representative compounds were tested for antimicrobial activity.     

Synthesis and Biological Evaluation of Novel Tetracyclic Benzothiazepines

6-Arylidene-2,3-dimethyl-6,7,8,9-tetrahydro-benzocyclohepten-5-one 2a–l were obtained by the condensation of 2,3-dimethyl/3-methyl benzocyclohepten-5-one 1 with appropriate aromatic aldehydes, and upon condensation with 2-aminothiophenol in ethyl alcohol yielded 1,5-benzothiazepine derivatives 3a–l, respectively. Compounds 3d and 3h were found to possess antimicrobial activity when tested against B. Subtilis. Compounds 3i and 3j were found to possess moderate anti-inflammatory activity. Compound 3b was found to possess comparable antifungal activity when compared to clotrimazole against Trichomonas species.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Total synthesis of myceliothermophins A-E

Total synthesis of an antitumor compound myceliothermophin A and related compounds based on a convergent synthetic strategy was investigated. A common decalin skeleton of myceliothermophins was stereoselectively constructed by an IMDA reaction. The fully elaborated precursor of myceliothermophins was obtained via aldol reaction of N-protected γ-methoxylactam with decalin aldehyde. By using Teoc group for the protection of nitrogen atom of lactam ring, selective deprotection prior to the hydrolysis of methoxyaminal moiety was successfully achieved to obtain γ-methoxylactams (myceliothermophins C and D). Subsequent hydrolysis of these compounds afforded the corresponding γ-hydroxylactam, and myceliothermophins A and B in high yield. Myceliothermophin E was also synthesized by dehydration of the obtained γ-hydroxylactams. The absolute configurations of myceliothermophins A-E were also successfully determined.