In vitro anticancer and antibacterial potentials of selected medicinal plants and isolation and characterization of a natural compound from Withania coagulans

In the current study, five different plants, Syzygium Cumini, Fagonia cretica, Acacia modesta, Withania coagulans, and Olea europaea aqueous extracts were prepared and applied against the anticancer and antibacterial activities. It was observed that O. Europaea extract shows the highest anticancer activity with cell viability of 21.5%. All the five plants extract was also used against the inhibition of Bacillus subtilis where O. Europaea extract shows a promising inhibitory activity of 3.2 cm followed by W. coagulans. Furthermore, W. coagulans was subjected to the process of column chromatography as a result a withanolide was isolated. The fast atom bombardment mass spectrometry (FAB-MS) and high resolution fast atom bombardment (HRFAB-MS) [M + 1] indicated molecular weight at m/z 453 and molecular formula C28H37O5. The UV–Vis. spectrum shows absorbance at 210 nm suggesting the presence of conjugated system, and Fourier-transform infrared spectroscopy (FTIR) was recorded to explore the functional groups. Similarly, 1D and 2D NMR spectroscopy techniques such as 1H, 13C NMR, correlation spectroscopy (COSY-45°), heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC) and Nuclear Overhauser effect Spectroscopy (NOESY) techniques was carried out to determine the unknown natural product. The collective data of all these techniques established the structure of the unknown compound and recognized as a withanolide.

Efficient and regioselective synthesis of dihydroxy-substituted 2-aminocyclooctane-1-carboxylic acid and its bicyclic derivatives

The first synthesis of 2-amino-3,4-dihydroxycyclooctane-1-carboxylic acid, methyl 6-hydroxy-9-oxo-8-oxabicyclo[5.2.1]decan-10-yl)carbamate, and 10-amino-6-hydroxy-8-oxabicyclo[5.2.1]decan-9-one starting from cis-9-azabicyclo[6.2.0]dec-6-en-10-one is described. cis-9-Azabicyclo[6.2.0]dec-6-en-10-one was transformed into the corresponding amino ester and its protected amine. Oxidation of the double bond in the N-Boc-protected methyl 2-aminocyclooct-3-ene-1-carboxylate then delivered the targeted amino acid and its derivatives. Density-functional theory (DFT) computations were used to explain the reaction mechanism for the ring opening of the epoxide and the formation of five-membered lactones. The stereochemistry of the synthesized compounds was determined by 1D and 2D NMR spectroscopy. The configuration of methyl 6-hydroxy-9-oxo-8-oxabicyclo[5.2.1]decan-10-yl)carbamate was confirmed by X-ray diffraction.

Exploring the Phytochemicals of Acacia melanoxylon R. Br.

Invasive species are currently a world menace to the environment, although the study of their chemistry may provide a means for their future beneficial use. From a study of Portuguese Acacia melanoxylon R. Br. five known compounds were isolated: lupeol, 3β-Z-coumaroyl lupeol, 3β-E-coumaroyl lupeol (dioslupecin A), kolavic acid 15-methyl ester and vomifoliol (blumenol A). Their structures were elucidated by 1D and 2D NMR spectroscopy and mass spectrometry, and as a result some corrections are made to their previous 13C NMR assignments. Cytotoxicity of 3β-E-coumaroyl lupeol (dioslupecin A) and kolavic acid 15-methyl ester was evaluated against HCT116 human colorectal cancer cells although biological activity was not evident.

Novel Harziane Diterpenes from Deep-Sea Sediment Fungus Trichoderma sp. SCSIOW21 and Their Potential Anti-Inflammatory Effects

Five undescribed harziane-type diterpene derivatives, namely harzianol K (1), harzianol L (4), harzianol M (5), harzianol N (6), harzianol O (7), along with two known compounds, hazianol J (2) and harzianol A (3) were isolated from the deep-sea sediment-derived fungus Trichoderma sp. SCSIOW21. The relative configurations were determined by meticulous spectroscopic methods including 1D, 2D NMR spectroscopy, and HR-ESI-MS. The absolute configurations were established by the ECD curve calculations and the X-ray crystallographic analysis. These compounds (1, and 4–7) contributed to increasing the diversity of the caged harziane type diterpenes with highly congested skeleton characteristics. Harzianol J (2) exhibited a weak anti-inflammatory effect with 81.8% NO inhibition at 100 µM.

Acorenone C: A New Spiro-Sesquiterpene from a Mangrove-Associated Fungus, Pseudofusicoccum sp. J003

Mangrove-derived endophytes are rich in bioactive secondary metabolites with a variety of biological activities. Recently, a fungus Pseudofusicoccum sp. J003 was first isolated by our research group from mangrove species Sonneratia apetala Buch.-Ham. The subsequent chemical investigation of the methanol extract of the culture broth of this strain has led to the isolation of a new sesquiterpenoid named acorenone C (1), two alkaloids (2–3), four phenolic compounds (4–7), and four steroid derivatives (8–11). The new structure of 1 was established by extensive spectroscopic analysis, including 1D, 2D NMR spectroscopy, and HRESIMS. Its absolute configuration was elucidated by experimental ECD and ECD calculation. The in vitro AChE inhibitory, anti-inflammatory, and cytotoxic activities of the selected compounds were evaluated. The results showed that compound 1 showed mild AChE inhibitory activity, with an inhibition rate of 23.34% at the concentration of 50 μM. Compound 9 exerted a significant inhibitory effect against nitric oxide (NO) production in LPS-stimulated RAW 264.7 mouse macrophages, with an inhibition rate of 72.89% at the concentration of 25 μM, better than that of positive control L-NMMA. Compound 9 also displayed obvious inhibition effects on the growth of two human tumor cell lines, HL-60 and SW480 (inhibition rates 98.68 ± 0.97% and 60.40 ± 4.51%, respectively). The antimicrobial activities of the compounds (1–11) against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa were also tested; however, none of them showed antimicrobial activities.

Purification, Characterisation and Synthesis of Glycerolipids Extracted from L. plantarum and B. longum subsp. infantis

<p>Glycolipids from the cell wall of Gram-positive bacteria have been the topic of my PhD. It is well known that many bacterial glycolipids (e.g. LPS, TDMs and PIMs) have profound immunological effects, and therefore the characterisation, biological testing and synthesis of gram-positive bacterial glycolipids is of interest. The first part of this thesis includes a description of the extraction and characterisation of glycolipids from gut bacteria including Bifidobacterium and Lactobacillus genus and the second part focussed on the chemical synthesis of Streptococcus sp. DSM 8747 glycolipids and lipoteichoic acid analogues (LTA). Members of the genus Lactobacillus are common in the gut microbiota and are often used as probiotics. As lactobacilli are known to have benefits to human health, compounds on its surface are of high interest. To date, the structures of the glycolipids from L. plantarum have not been conclusively assigned. Thus, for the first time, the full characterisation of the four principal glycolipids of the L. plantarum cell wall was reported using sugar, linkage and FAME analysis, as well as ESI-MS/MS and 1D- and 2D-NMR spectroscopy. The major glycolipids were identified as: α-D-Glcp-diglyceride, α-D-Galp-(1→2)-α-D-Glcp-diglyceride, β-D-Glcp-(1→6)-α-D-Galp-(1→2)-6-O-acyl-α-D-Glcp-diglyceride and β-D-Glcp-(1→6)-α-D-Galp-(1→2)-α-D-Glcp-diglyceride. These glycolipids showed weak activation of murine bone marrow macrophages in an initial biological screen. After having identified the structures of the glycolipids from L. plantarum, the glycolipids from Bifidobacterium, a dominant member of the gut microbiota in infants, were extracted. Bifidobacteria are considered to be important in the development of a healthy immune system and they are believed to exhibit anticancerous properties, alleviate the symptoms of irritable bowel syndrome, and are thought to reduce atopic disease. Despite this, the chemical nature of immunomodulatory compounds on the surface of bifidobacteria has not been well documented. Thus, glycolipids were extracted from B. longum subsp. infantis, fractionated chromatographically and analyzed using NMR spectroscopy, constituent sugar and linkage analysis, and fatty acid analysis. These analyzes revealed a novel glycolipid, containing an unprecedented mixed acetal moiety and a galactofuranose moiety as a head group. However, like L. plantarum glycolipids, bifidobacterial glycolipids were shown only to induce little macrophage activity when tested. Having successfully characterised a novel glycolipid present in bifidobacteria, analogues of this glycolipid as well as poly(glycerophosphate) lipotechoic acids analogues (LTAs) were then synthesised. Much debate still remains about the role of LTAs during Gram-positive bacterial infection. This is partly due to differences in the biological activities of extracted versus synthesised LTAs and highlights the need for structurally defined non-contaminated LTAs when investigating the effect of these glycolipids on the innate immune response. An efficient synthesis of the core lipoteichoic acid (LTA) anchor of the Streptococcus species DSM 8747, and derivatives thereof, was achieved. These Streptococcus glycolipids contain a galactofuranose moiety and thus have similarities to the novel glycolipid that was found in bifidobacteria. The syntheses, which commence with readily available D-galactose, are short (7-9 steps), convergent, and high-yielding (33-37% overall yield). In total 11 different targets were synthesised. The biological activity of these compounds was also investigated, with several analogues (particularly the sn-1,2-di-acylglycerol LTA anchors) found to induce macrophage activation.</p>

Purification, Characterisation and Synthesis of Glycerolipids Extracted from L. plantarum and B. longum subsp. infantis

<p>Glycolipids from the cell wall of Gram-positive bacteria have been the topic of my PhD. It is well known that many bacterial glycolipids (e.g. LPS, TDMs and PIMs) have profound immunological effects, and therefore the characterisation, biological testing and synthesis of gram-positive bacterial glycolipids is of interest. The first part of this thesis includes a description of the extraction and characterisation of glycolipids from gut bacteria including Bifidobacterium and Lactobacillus genus and the second part focussed on the chemical synthesis of Streptococcus sp. DSM 8747 glycolipids and lipoteichoic acid analogues (LTA). Members of the genus Lactobacillus are common in the gut microbiota and are often used as probiotics. As lactobacilli are known to have benefits to human health, compounds on its surface are of high interest. To date, the structures of the glycolipids from L. plantarum have not been conclusively assigned. Thus, for the first time, the full characterisation of the four principal glycolipids of the L. plantarum cell wall was reported using sugar, linkage and FAME analysis, as well as ESI-MS/MS and 1D- and 2D-NMR spectroscopy. The major glycolipids were identified as: α-D-Glcp-diglyceride, α-D-Galp-(1→2)-α-D-Glcp-diglyceride, β-D-Glcp-(1→6)-α-D-Galp-(1→2)-6-O-acyl-α-D-Glcp-diglyceride and β-D-Glcp-(1→6)-α-D-Galp-(1→2)-α-D-Glcp-diglyceride. These glycolipids showed weak activation of murine bone marrow macrophages in an initial biological screen. After having identified the structures of the glycolipids from L. plantarum, the glycolipids from Bifidobacterium, a dominant member of the gut microbiota in infants, were extracted. Bifidobacteria are considered to be important in the development of a healthy immune system and they are believed to exhibit anticancerous properties, alleviate the symptoms of irritable bowel syndrome, and are thought to reduce atopic disease. Despite this, the chemical nature of immunomodulatory compounds on the surface of bifidobacteria has not been well documented. Thus, glycolipids were extracted from B. longum subsp. infantis, fractionated chromatographically and analyzed using NMR spectroscopy, constituent sugar and linkage analysis, and fatty acid analysis. These analyzes revealed a novel glycolipid, containing an unprecedented mixed acetal moiety and a galactofuranose moiety as a head group. However, like L. plantarum glycolipids, bifidobacterial glycolipids were shown only to induce little macrophage activity when tested. Having successfully characterised a novel glycolipid present in bifidobacteria, analogues of this glycolipid as well as poly(glycerophosphate) lipotechoic acids analogues (LTAs) were then synthesised. Much debate still remains about the role of LTAs during Gram-positive bacterial infection. This is partly due to differences in the biological activities of extracted versus synthesised LTAs and highlights the need for structurally defined non-contaminated LTAs when investigating the effect of these glycolipids on the innate immune response. An efficient synthesis of the core lipoteichoic acid (LTA) anchor of the Streptococcus species DSM 8747, and derivatives thereof, was achieved. These Streptococcus glycolipids contain a galactofuranose moiety and thus have similarities to the novel glycolipid that was found in bifidobacteria. The syntheses, which commence with readily available D-galactose, are short (7-9 steps), convergent, and high-yielding (33-37% overall yield). In total 11 different targets were synthesised. The biological activity of these compounds was also investigated, with several analogues (particularly the sn-1,2-di-acylglycerol LTA anchors) found to induce macrophage activation.</p>

Multicomponent Synthesis of 2-(2,4-Diamino-3-cyano-5H-chromeno[2,3-b]pyridin-5-yl)malonic Acids in DMSO

Dimethyl sulfoxide is a widely used solvent in organic synthesis and in the pharmaceutical industry because of its low cost, stability, and low toxicity. Multicomponent reactions are an advanced approach that has become an efficient, economical, and eco-friendly substitute for the conventional sequential multi-step synthesis of various biologically active compounds. This approach was adopted for the synthesis of previously unknown 2-(2,4-diamino-3-cyano-5H-chromeno[2,3-b]pyridin-5-yl)malonic acids via transformation of salicylaldehydes, malononitrile dimer, and malonic acid. It was shown that the use of DMSO at room temperature makes it possible to synthesize previously unavailable compounds. The investigation of the reaction mechanism using 1H-NMR monitoring made it possible to confirm the proposed mechanism of the transformation. The structure of synthesized 5H-chromeno[2,3-b]pyridines was confirmed by 2D-NMR spectroscopy.

Apoptotic Activity of New Oxisterigmatocystin Derivatives from the Marine-Derived Fungus Aspergillus nomius NC06

Sponge-derived fungi have recently attracted attention as an important source of interesting bioactive compounds. Aspergillus nomius NC06 was isolated from the marine sponge Neopetrosia chaliniformis. This fungus was cultured on rice medium and yielded four compounds including three new oxisterigmatocystins, namely, J, K, and L (1, 2, and 3), and one known compound, aspergillicin A (4). Structures of the compounds were elucidated by 1D and 2D NMR spectroscopy and by high-resolution mass spectrometry. The isolated compounds were tested for cytotoxic activity against HT 29 colon cancer cells, where compounds 1, 2, and 4 exhibited IC50 values of 1.21, 2.23, and 5.62 µg/mL, respectively. Under the fluorescence microscope by using a double staining method, HT 29 cells were observed to be viable, apoptotic, and necrotic after treatment with the cytotoxic compounds 1, 2, and 4. The result shows that compounds 1 and 2 were able to induce apoptosis and cell death in HT 29 cells.