Martina Wurster

Synthesis and antimicrobial activity of 4-hydroxy-4-(pyridyl)alk-3-en-2-ones

4-Hydroxy-4-(pyridyl)alk-3-en-2-ones were prepared by base-mediated condensation of ketones with pyridinecarboxylates. Several derivatives show weak antimicrobial activity against Gram-positive and Gram-negative bacteria.

Triterpene glycosides from the leaves of Pittosporum angustifolium.

Phytochemical investigation of the leaves of Pittosporum angustifolium resulted in the isolation and structural elucidation of nine new triterpene saponins, named pittangretosides A-I (1-9), together with a known compound (10). Mainly by NMR and HRESIMS experiments, eight compounds were identified as A1-barrigenol glycosides (1-7, 10), whereas two compounds exhibited an unusual 17,22-seco-backbone of oleanolic acid (8, 9). All compounds were evaluated for their in vitro cytotoxicities against human urinary bladder carcinoma cells (5637). Only compounds with an angeloyl-residue at C-22 of the aglycone (1-4 and 10) showed antiproliferative effects with IC50 values of 4.1, 5.2, 2.1, 17.9, and 2.4 µM, respectively.

Cylindrofridins A–C, Linear Cylindrocyclophane-Related Alkylresorcinols from the Cyanobacterium Cylindrospermum stagnale

A rapid and exhaustive one-step biomass extraction as well as an enrichment and cleanup procedure has been developed for HPLC-UV detection and quantification of closely related [7.7]paracyclophanes and structural derivatives based on a two-phase solvent system. The procedure has been validated using the biomass of the carbamidocyclophane- and cylindrocyclophane-producing cyanobacterium Nostoc sp. CAVN2 and was utilized to perform a screening comprising 102 cyanobacterial strains. As a result, three new cylindrocyclophane-related alkylresorcinols, cylindrofridins A-C (1-3), and known cylindrocyclophanes (4-6) were detected and isolated from Cylindrospermum stagnale PCC 7417. Structures of 1-3 were elucidated by a combination of 1D and 2D NMR experiments, HRMS, and ECD spectroscopy. Cylindrofridin A (1) is the first naturally occurring [7.7]paracyclophane-related monomeric derivative. In contrast, cylindrofridins B (2) and C (3) represent dimers related to 1. Due to chlorination at the alkyl carbon atom in 1-3, the site of [7.7]paracyclophane macrocycle formation, the cylindrofridins represent linearized congeners of the cylindrocyclophanes. Compounds 1-3 were not toxic against nontumorigenic HaCaT cells (IC50 values >25 μM) compared to the respective cylindrocyclophanes, but 1 was the only cylindrofridin showing moderate activity against methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pneumoniae with MIC values of 9 and 17 μM, respectively.

Chemical Composition of Essential oil from the Oleogum Resin of Commiphora habessinica (Berg.) Engl. from Yemen

Abstract The essential oil extracted from the oleogum resin of the Yemeni Commiphora habessinica (Berg.) Engl. was analyzed by gas chromatography-mass spectrometry (GC-MS) and 13 constituents were identified. The major constituents were β-elemene (32.1 %), α-selinene (18.9 %), cadina-1,4-diene (7.5 %), germacrene B (3.6 %), α-copaene (3.5 %), t-muurolol (3.0 %) caryophyllene oxide (2.9 %) and α-cadinol (2.6 %).

Cytotoxic saponins from the seeds of Pittosporum angustifolium.

Three new acylated R1-barrigenol triterpene glycosides, 1 - 3, were isolated from the seeds of Pittosporum angustifolium Lodd. together with four known glycosides, 4 - 7, containing R1- and A1-barrigenol backbones. On the basis of spectroscopic, spectrometric, and chemical analyses the novel compounds were named pittangretosides N- P and established as 21ß-acetoxy- 22α-angeloyloxy- (1), 21ß-acetoxy-22α-(2-acetoxy-2-methylbutyroyloxy)- (2), and 21ß-(2-methylbutyroyloxy)- 22α-acetoxy-3ß-[b-D-glucopyranosyl- (1→2)]-[α-L-arabinopyranosyl-(1→3)]-[α- L-arabinofuranosyl-(1!4)]-ß-D-glucuronopyranosyloxyolean-12-ene-15α,16α,28-triol (3). Evaluation of the in vitro cytotoxicity against three tumour cell lines and one non-tumourigenic cell line revealed antiproliferative effects with IC50 values in a range of 1:74 - 34:1 μM

Differential effects of Helenalin, an anti-inflammatory sesquiterpene lactone, on the proteome, metabolome and the oxidative stress response in several immune cell types.

Extracts of Arnica spp. are traditionally used due to their anti-inflammatory effects for the topical treatment of e.g. haematoma or muscle distortions. One of the main active compounds is Helenalin, a sesquiterpene lactone that can be found in various Asteraceae. However, immunotoxic effects of the compound are only poorly analysed. In this study, a 2D gel electrophoresis based proteomic approach together with a membrane based proteomic assay, metabolomics and the detection of intracellular reactive oxygen species (iROS) were used to investigate potential immunotoxic properties of Helenalin on the human immune cell lines Jurkat and THP-1 and on human peripheral blood mononuclear cells (PBMC). The study revealed a dose-dependent cytotoxicity towards both tested cell lines and the PBMC. However, the cell lines were less sensitive to the Helenalin treatment than the PBMC. The proteomic assays showed strong effects on the carbohydrate metabolism and the protein folding in THP-1 cells but only weak impact on Jurkat cells. Metabolomic studies as well as iROS detection in THP-1 cells verified the results of the proteomic analysis. In summary, the approaches used in this study were able to identify target pathways of Helenalin especially in THP-1 monocytes and thus enable a risk assessment of the substance.

A proteomic approach for the identification of immunotoxic properties of Tulipalin A

The immune system is permanently exposed to several environmental influences that can have adverse effects on immune cells or organs leading to immunosuppression or inappropriate immunostimulation, called direct immunotoxicity. The natural compound Tulipalin A (TUPA), a lactone with α‐methylene‐γ‐butyrolactone moiety, can influence the immune system and lead to allergic contact dermatitis. This in vitro study focused on effects of TUPA using two immune cell lines (Jurkat T cells and THP‐1 monocytes). To evaluate the immunotoxic potential of the compound, a proteomic approach applying 2D gel electrophoresis and MALDI‐TOF/TOF‐MS in combination with metabolomic analysis was used after exposure of the cells to IC10 of TUPA. THP‐1 cells showed a strong robustness to TUPA treatment since only five proteins were altered. In contrast, in Jurkat T cells an increase in the abundance of 66 proteins and a decrease of six proteins was determined. These intracellular proteins were mapped to biological processes. Especially an accumulation of chaperones and an influence on the purine synthesis were observed. The changes in purine synthesis were confirmed by metabolomic analysis. In conclusion, the data indicate possible target processes of low doses of TUPA in Jurkat T cells and provides knowledge of how TUPA affects the functionality of immune cells.

Taraxastane-type triterpene saponins isolated from Pittosporum angustifolium Lodd.

Abstract Two new taraxastane-type triterpene saponins, named pittangretosides L (1) and C1 (2), were isolated from the leaves of Pittosporum angustifolium Lodd. Their structures were established by NMR spectroscopic, mass spectrometric and chemical means. The in vitro cytotoxicity was evaluated against four cell lines. The compounds exhibited no cytotoxic activity up to a concentration of 130 μm.

New Mono- and Bisdesmosidic Triterpene Glycosides from Pittosporum angustifolium Lodd

Abstract Fifteen new mono- and bisdesmosidic triterpene saponins, named pittangretosides J, K, M, Q- Z, A1, and B1, along with three known compounds were isolated from the leaves of Pittosporum angustifolium. By spectroscopic, mass spectrometric and chemical evidence, their structures were established as glycosides of A1- and R1-barrigenol, barringtogenol C and camelliagenin A backbones

Chemical Composition, Antimicrobial and Antioxidant Activities of the Volatile Oil of Ganoderma pfeifferi Bres

In a first study of the volatile oil of the mushroom basidiomycete Ganoderma pfeifferi Bres., the chemical composition and antimicrobial and antioxidant activities of the oil were investigated. The volatile oil was obtained from the fresh fruiting bodies of Ganoderma pfeifferi Bres. By hydrodistillation extraction and analyzed by GC-MS. The antimicrobial activity of the oil was evaluated against five bacteria strains and two types of fungi strains, using disc diffusion and broth microdilution methods. In addition, the antioxidant activity of the oil was determined using DPPH assay. Four volatile compounds representing 90.5% of the total oil were identified. The majority of the essential oil was dominated by 1-octen-3-ol (amyl vinyl carbinol) 1 (73.6%) followed by 1-octen-3-ol acetate 2 (12.4%), phenylacetaldehyde 3 (3.0%) and 6-camphenol 4 (1.5%). The results showed that the Gram-positive bacteria species are more sensitive to the essential oil than Gram-negative bacteria. The oil showed strong antimicrobial activity against Staphylococcus aureus as well as Candida albicans. Moreover, the oil exhibited strong radical scavenging activity in the DPPH assay. This first report on the chemical composition and biological properties of G. pfeifferi volatile oil makes its pharmaceutical uses rational and provides a basis in the biological and phytochemical investigations of the volatile oils of Ganodermataceae species.