Gudrun Schröder

Bio: Gudrun Schröder is an academic researcher from Friedrich Loeffler Institute. The author has contributed to research in topics: Antimicrobial & Medicinal plants. The author has an hindex of 4, co-authored 4 publications receiving 401 citations.

In vitro Antimicrobial, Cytotoxic and Radical Scavenging Activities and Chemical Constituents of the Endemic Thymus laevigatus (Vahl)

Abstract: The leaves of Thymus laevigatus (Vahl), Lamiaceae (Labiatae), an endemic species of Yemen, are traditionally used in the treatment of various disorders including stomach and respiratory system. In a first biological and chemical study of this endemic species we investigated antimicrobial, cytotoxic and antioxidant activities of different extracts of the leaves of this plant. The preliminary phytochemical screening of extracts composition was performed by TLC while the composition of the essential oil was determined by GC-MS. Twelve constituents were detected from the essential oil, which constituted 99.6 % of the total amount. The major constituents of the oil were: carvacrol (84.3 %), p-cymene (4.1 %) p-mentha-1, 4-diene (4.0 %) and trans - anethole (3.6%). The main active components were identified by TLC as carvacrol and anethole for dichloromethane extract and as non-volatile phenols and flavonoids for the methanol extract. The methanol, dichloromethane and aqueous extracts were tested for their antimicrobial activities against five bacteria strains and six human pathogenic fungi. Both methanol and dichloromethane showed strong activities against most human pathogenic strains. In the contrast, methanol extract showed broader and stronger antibacterial activities than the dichloromethane extract, especially against the Gram-negative bacterium Pseudomonas aeruginosa . The methanol extract showed the same strong radical scavenging activity in the DPPH assay (14.9 μg/ml), when compared to the standard antioxidant, ascorbic acid. In contrast, the cytotoxic activity of the methanol against FL cells, a human amniotic epithelial cell line, was only moderate (IC 50 298, 8 μg/ml). On the contrary, the water extract did not show any biological activity. Results presented here suggest that the essential oil and extracts of Thymus laevigatus possess strong antimicrobial and antioxidant properties, and therefore, they can be used as a natural preservative ingredient in food and/or pharmaceutical industry.

Biological activities of selected basidiomycetes from Yemen.

Abstract: In a previous paper we demonstrated the results of biological screening of Yemeni basidiomycetes. The present study was aimed to investigate the antimicrobial and the antioxidant activity of further basidiomycetes collected in Yemen. Dichloromethane, methanol and aqueous extracts of the fruiting bodies of 25 species were screened in vitro for their antibacterial activities against three Gram-positive bacteria (Staphyloccocus aureus, Bacillus subtilis, Micrococcus flavus) and two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), against six human fungal pathogens (Candida albicans, Candida krusei, Aspergillus fumigatus, Mucor sp., Microsporum gypseum, Trichophyton mentagrophytes) and against one non human pathogenic fungus (Candida maltosa). The results indicated that 75 extracts exhibited activity against one or more of the bacteria. The methanol extracts of Agaricus cf. bernardii, Agrocybe pediades, Chlorophyllum molybdites, Coriolopsis polyzona, Ganoderma xylonoides, Pycnoporus sanguineus, Trametes lactinea and Trametes cingulata showed activity against all tested bacteria. The highest antibacterial activity was exhibited by methanol extracts from Chlorophyllum molybdites, Ganoderma xylonoides and Trametes cingulata and Agaricus cf. bernardii, Agrocybe pediades, Coriolopsis polyzona, Pycnoporus sanguineus and Trametes lactinea. The methanol extracts of Chlorophyllum molybdites, Ganoderma xylonoides and Pycnoporus sanguineus showed considerable antifungal activities against the tested fungal strains. Strong antioxidative effects employing the DPPH assay were exhibited by methanol extracts from Chlorophyllum molybdites, Ganoderma xylonoides, Hexagonia velutina, Pycnoporus sanguineus, Trametes lactinea and Trametes cingulata. Our previous and presented studies about 48 basidiomycetes collected in Yemen provide evidence that basidiomycetes from the Arabic region so far should attract more attention as potential source for new biologically active agents.

In-vitro cytotoxicity activity of solanum nigrum extract against hela cell line and vero cell line.

Abstract: The study was aimed to evaluation of the anticancer activity of the fruits of Solanum Nigrum on the HeLa cell line. The fruits of Solanum Nigrum methanolic extract were tested for its inhibitory effect on HeLa Cell Line. The percentage viability of the cell line was carried out by using Trypan blue dye exclusion method. The cytotoxicity of Solanum Nigrum on HeLa cell was evaluated by the SRB assay and MTT assay. Solanum Nigrum methanolic extract has significant cytotoxicity effect on HeLa Cell Line in concentration range between 10 mg/ml to 0.0196 mg/ml by using SRB assay and study also showed that inhibitory action on HeLa cell line in concentration range between 10 mg/ml to 0.0196 mg/ml by using MTT assay. IC50 value and R 2 value of Solanum Nigrum on HeLa cell and Vero cell were 847.8 and 0.8724, 9088 and 0.1017 respectively by SRB assay. IC50 value and R 2 value of Solanum Nigrum on HeLa cell was 265.0 and 0.9496 respectively by MTT assay. IC50 value of Solanum Nigrum on Vero cell was 6.862 by MTT assay. R 2 value of Solanum Nigrum was not found by MTT assay. From the performed assay, methanolic extract of these drug shows greater activity on HeLa cell line and little activity on Vero cell line and that mean Solanum Nigrum can be used as anticancer

Studies of the in vitro anticancer, antimicrobial and antioxidant potentials of selected Yemeni medicinal plants from the island Soqotra

Abstract: Recent years have witnessed that there is a revival of interest in drug discovery from medicinal plants for the maintenance of health in all parts of the world. The aim of this work was to investigate 26 plants belonging to 17 families collected from a unique place in Yemen (Soqotra Island) for their in vitro anticancer, antimicrobial and antioxidant activities. The 26 plants were extracted with methanol and hot water to yield 52 extracts. Evaluation for in vitro anticancer activity was done against three human cancer cell lines (A-427, 5637 and MCF-7) by using an established microtiter plate assay based on cellular staining with crystal violet. Antimicrobial activity was tested against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains by using an agar diffusion method and the determination of MIC against three Gram-positive bacteria with the broth micro-dilution assay. Antioxidant activity was investigated by measuring the scavenging activity of the DPPH radical. Moreover, a phytochemical screening of the methanolic extracts was done. Notable cancer cell growth inhibition was observed for extracts from Ballochia atro-virgata, Eureiandra balfourii and Hypoestes pubescens, with IC50 values ranging between 0.8 and 8.2 μg/ml. The methanol extracts of Acanthospermum hispidum, Boswellia dioscorides, Boswellia socotrana, Commiphora ornifolia and Euphorbia socotrana also showed noticeable antiproliferative potency with IC50 values 15 mm and MIC values ≤ 250 μg/ml. In addition, the methanolic extracts of Acacia pennivenia, Boswellia dioscorides, Boswellia socotrana and Commiphora ornifolia showed good antioxidant potential at low concentrations (more than 80% at 50 μg/ml). Our results show once again that medicinal plants can be promising sources of natural products with potential anticancer, antimicrobial and antioxidative activity. The results will guide the selection of some plant species for further pharmacological and phytochemical investigations.