Synthesis and antibacterial activities of cyclodimers of styrene oxides

A simple synthetic procedure for preparation of 1,4-dioxanes or 1,3-dioxolanes from styrene oxides is described. Electron-donating groups on the aromatic ring of the styrene oxides were found to favour formation of 1,4-dioxanes while electron-withdrawing groups favoured formation of 1,3-dioxolanes. Antibacterial activities of the prepared cyclodimers are reported. KEY WORDS: Dioxanes, Dioxolanes, Styrene, Epoxidation, Cyclodimerization, Antibacterial activities Bull. Chem. Soc. Ethiop. 2011, 25(2), 299-304

Pharmacology and phytochemistry studies in Peltophorum africanum

Peltophorum africanum Sond is an ethnomedicinal plant in the family Fabaceae. This literature report captures information about the ethnomedical uses, pharmacology and phytochemistry of P. africanum within the last four decades. The literature surveyed revealed the presence of different types of polyphenols whose content was higher in the bark and roots than the leaves. The plant polar extracts are rich in phenolic compounds and shows high antioxidant properties. The root and stem extracts are active against bacteria, parasites and HIV. There were no reports on the quality control of P. africanum as a herbal drug, nor a systematic identification of which phytochemicals are responsible for most of the pharmacological activities. Betulinic acid found in the bark is a known anti HIV agent. The reports on the pharmacological functions and the phytochemical studies which were started based on the traditional uses and botanical information justify the ethnomedicinal uses of the tree

Umbelliferone: Sources, chemistry and bioactivities review

Umbelliferone is a 7-hydroxycoumarin that is a pharmacologically active agent. It is widely distributed within the Rutaceae and Apiaceae (Umbelliferae) families and is efficiently extracted using methanol. Umbelliferone is a fluorescing compound used as a sunscreen agent. It is synthesized using the Pechmann condensation reaction of resorcinol and formyl acetic acid. Biosynthetically it is synthesized using the phenylpropanoid pathway. Umbelliferone is a synthon for other coumarins and heterocycles with improved biological activities. In the Literature modest antibacterial and antifungal activities are reported with MIC values of 500â1000 μg/mL, but exhibited good E. coli anti-biofilm formation. Umbelliferone shows good inhibitions of DPPH, hydroxyl, superoxide anion and ABTS radicals. Other reported activities are anti-inflammatory, anti-hyperglycaemic, molluscicidal and anti-tumor activities. Keywords: Umbelliferone, Anti-bacterial, Anti-tumor, Cytotoxicity, Synthesis, Biosynthesi

Antimicrobial activity of Mystroxylon aethiopicum leave extracts and isolated 3-O-acetyloleanolic acid

464-469Mystroxylon aethiopicum (Thumb.) Loes subsp. schlechteri (loes.) R. H. Archeris, a member of the Celastracea family, is widely used in traditional medicine to treat several diseases, such as hemorrhagic diarrhoea and respiratory tract infections. The study aimed to isolate the biologically active compounds from the leaves of M. aethiopicum. The leaves were ground to a fine powder and sequentially extracted with n-hexane, dichloromethane, acetone and methanol using serial exhaustive extraction (SEE) method. The bioautography and broth micro-dilution methods were used to analyse the antibacterial activities. The bioautography assay revealed that the compounds in the n-hexane, dichloromethane and acetone extracts have activity against all tested microorganisms. In contrast, the methanol extracts exhibited no antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli. The n-hexane extract had the lowest average MIC of 0.08 mg/mL, followed by the acetone (0.71 mg/mL) and dichloromethane (0.82 mg/mL) extracts. The bioassay-guided fractionation of dichloromethane and acetone extracts led to the isolation of 3-Oacetyloleanolic acid. The structure of the isolated compound was elucidated using NMR data and comparison with literature data. This is the first report on the isolation of 3-O-acetyloleanolic acid from the leaves of M. aethiopicum

Terminalia Prunioides pods herbal tea: Antioxidant activity, proximate, and metal content analysis

Growth in the demand for herbal teas has led to an increase in their research and commercial activities. In this study, the quantitative assessment of Motsiara (Terminalia prunioides) pods herbal tea was performed by determining antioxidant activity, total phenolic content, proximate and metal content. The studied extracts had a significant amount of phenolic content and antioxidant activity. The proximate analysis of ash, moisture, fat, crude fiber, protein, and carbohydrates gave results within the permissible limits for plant materials and teas. For metal analysis the following elements were at permissible values: K, Ca, Mg, Na, Mn, Ni, and Fe, while As, Cu, Cr, Co, Zn, and Pb were found at higher values. The preliminary data shows that T. prunioides pods are a potential source of natural antioxidants and minerals that can be useful in herbal tea formulations

Nickel mixed ligand complexes against drug resistant bacteria: Synthesis, characterization, antibacterial activities and molecular docking studies

Five new nickel complexes of the type NiCl2L2 where (L is 4-picolylchloride (4PY), pyridin-4-ylmethyl 4-nitrobenzoate (L1), 4-(pyridine-4-ylmethoxy)aniline (L2), pyridin-4-ylmethyl 4-aminobenzoate (L3) and 4-((4-nitrophenoxy)methyl)pyridine (L4)) were synthesized, characterized, and evaluated for their ability to inhibit bacterial growth. Four of the complexes were synthesized using a green method of co-grinding using a pestle and mortar. All the complexes synthesized by the mechanochemical method were recovered at favorable yields between 70 and 78%, while Ni4PY was recovered at 47.1%. The thermal studies showed the different transformations of the complexes and their thermal stability through Differential Scanning Calorimetry (DSC), while Thermogravimetric analysis (TGA) showed the loss of different components of the complexes cementing their successful synthesis. FTIR data revealed all the significant functional groups originating from the ligands in the new complexes. The characterization results demonstrated the successful synthesis of these complexes. Electronic spectra and magnetic susceptibility studies showed all the complexes to be d8 tetrahedral, except NiL1 which showed a partial d8 octahedral geometry. To better understand the biological activities, molecular docking calculations against the PBP2a proteins from S. aureus, OmpK36 proteins from K. pneumoniae, and DHPS proteins were also carried out. According to the results, the active nickel complexes should have had better activity than the control drug AgSD, however their activity was decreased due to solubility issues