Ent-kaurene and ent-beyerene diterpenoids and other constituents of Thecacoris batesii

Two novel diterpenoids, thecacorins A (1) and B (2), were isolated from Thecacoris batesii and their structures were established as ent-3b,20-epoxy-16-kaurene-3a,12b-diol and ent-15-beyerene-2b,3b-diol, respectively, on the basis of extensive spectroscopic analysis, especially, 1D NMR spectra, in conjunction with 2D experiments, COSY, NOESY, HMQC and HMBC. KEY WORDS: Diterpenoids, Thecacorin A, Thecacorin B, Ent-3b,20-epoxy-16-kaurene-3a,12b-diol, Ent-15-beyerene-2b,3b-diol, Thecacoris batesii  Bull. Chem. Soc. Ethiop. 2007, 21(1), 89-94

Antimycobacterial, antibacterial and antifungal activities of Terminalia superba (Combretaceae)

The methanol extract from the stem bark of Terminalia superba (TSB), fractions (TSB1 - 7) and two compounds isolated following bio-assay guided fractionation namely 3,4'- di-O-methylellagic acid 3'-O-β-D-xylopyranoside (1) and 4'-O-galloy-3,3'-di-O-methylellagic acid 4-O-β-D-xylopyranoside (2) were evaluated for their antimycobacterial, antibacterial and antifungal activities. The broth microdilution, microplate Alamar Blue assay (MABA) and agar disc diffusion methods were used for the investigations. The results of the antimycobacterial assays showed that the crude extract, fraction TSB5-7 and compound 1 were able to prevent the growth of all the studied mycobacteria. The lowest minimal inhibitory concentration (MIC) value of 39.06 μg/ml for this extract was recorded on both M. smegmatis and M. tuberculosis MTCS2. The corresponding values were 19.53 μg/ml and 4.88 μg/ml for fractions and compounds respectively. The MIC determinations results on other organisms indicate values ranging from 19.53 to 78.12 μg/ml for TSB and compound 2 on 90.9% of the tested organisms, meanwhile compounds 1 as well as fractions TSB 6 and 7 exhibited detectable MIC values on all studied microorganisms. The overall results provide promising baseline information for the potential use of the crude extract from Terminalia superba, fractions 6-7 and the tested compounds in the treatment of tuberculosis, bacterial and fungal infections

Cytotoxicity, antimicrobial and antioxidant activity of eight compounds isolated from Entada abyssinica (Fabaceae)

BACKGROUND : Entada abyssinica is a plant traditionally used against gastrointestinal bacterial infections. Eight compounds including three flavonoids, three terpenoids, a monoglyceride and a phenolic compound isolated from E. abyssinica were investigated for their cytotoxicity, antibacterial and antioxidant activity. RESULTS : Compounds 7 and 2 had remarkable activity against Salmonella typhimurium with the lowest respective minimum inhibitory concentration (MIC) values of 1.56 and 3.12 μg/mL. The antioxidant assay gave IC50 values varied from 0.48 to 2.87 μg/mL in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, from 2.53 to 17.04 μg/mL in the 2,2′-Azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) assay and from 1.43 to 103.98 μg/mL in the FRAP assay. Compounds had relatively low cytotoxicity (LC50 values ranging from 22.42 to 80.55 μg/mL) towards Vero cells. Ursolic acid had the most potent cytotoxicity against THP-1 and RAW 264.7 cells with LC50 values of 9.62 and 4.56 μg/mL respectively, and selectivity index values of 7.32 and 15.44 respectively. CONCLUSION : Our findings suggest that among the terpenoid and flavonoid compounds studied, entadanin (compound 7) possess tremendous antibacterial activity against S. typhimurium and could be developed for the treatment of bacterial diseases.The National Research Foundation (NRF) and Medical Research Council (MRC).The University of Pretoria provided a postdoctoral fellowship to JPD.http://www.biomedcentral.com/bmcpublichealtham2017Paraclinical Science

Antihepatotoxic and Antioxidant Activities of Methanol Extract and Isolated Compounds from Ficus chlamydocarpa

Free radicals, in particular radical oxygen species (ROS), play an important role in the aetiology and pathogenesis of various diseases. Current research in many countries focuses on the use of local medicinal plants as a promising source of liver protective agents. This paper describes the hepatoprotective effects of the methanol extract and four isolated compounds from Ficus chlamydocarpa on CCl4-induced liver damage, as well as the possible antioxidant mechanisms involved in this protection. The DPPH test, along with the ß-Carotene-Linoleic Acid Model System and Ferric-Reducing Antioxidant Power assays, as well as the inhibition of microsomal lipid peroxidation were used to measure radical-scavenging and antioxidant activities. Pretreatment of rats with the methanol extract of F. chlamydocarpa before CCl4administration, significantly prevented serum increase of hepatic enzyme markers, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), in a dose-dependent manner. The hepatoprotection was also associated with a significant enhancement in hepatic reduced glutathione (GSH) and a marked decrease of liver malondialdehyde (MDA). Among the four compounds 1-4, isolated from the methanol extract, α-amyrin acetate (1) and luteolin (4) showed a significant hepatoprotective activity, as indicated by their ability to prevent liver cell death and lactate dehydrogenase (LDH) leakage during CCl4intoxication

Further alkaloids of arauopsis tabouensis: the structure of araliopsinine and the presence of dimeric 2-quinoline alkaloids

Bull.Chem.Soc.Ethiop.,2(1), 21-28 (1988)

Further alkaloids of <i>arauopsis tabouensis</i>: the structure of araliopsinine and the presence of dimeric 2-quinoline alkaloids

Bull.Chem.Soc.Ethiop.,2(1), 21-28 (1988)