Chandrika Nanayakkara

Serpulanines A to C, N-Oxidized Tyrosine Derivatives Isolated from the Sri Lankan Fungus Serpula sp.: Structure Elucidation, Synthesis, and Histone Deacetylase Inhibition

Serpulanines A (1), B (2), and C (3) have been isolated from extracts of the rare Sri Lankan macrofungus Serpula sp. The structures of 1, 2, and 3 were elucidated by a combination of spectroscopic and single-crystal X-ray diffraction analyses. Serpulanines A (1) and B (2) both contain the rare (E)-2-hydroxyimino hydroxamic acid functional group array. A proposed biogenesis for serpulanine B (2) suggests that its (E)-2-hydroxyimino hydroxamic acid moiety arises from a diketopiperazine precursor. Synthetic serpulanine A (1) inhibited class I/II histone deacetylases in murine metastatic lung carcinoma cells with an IC50 of 7 μM.

Rapid degradation of FOG discharged from food industry wastewater by lipolytic fungi as a bioaugmentation application

ABSTRACT Fats, oils and grease (FOG) congregate in grease traps and are a slowly biodegradable particulate organic matter, which may require enzymatic or hydrolytic conversion to form readily biodegradable soluble organic matter. The existing treatment methods employ water-based hydrolysis of FOG to form long-chain fatty acids (LCFAs). The LCFAs discharged into wastewater treatment system create functional difficulties, especially the inhibitory effect caused by accumulation of LCFAs. This study aims to find an effective treatment method for this persistent problem encountered in conventional wastewater treatment system. Solid-state degradation by lipolytic fungi was performed in a tray-type reactor as a novel approach of bioaugmentation. Grease trap waste samples were dried to have moisture content of 25–35% and mixed with coir fiber (1% w/v) for proper aeration. Each 10 mg/g dry weight of substrate was inoculated with 1 mL of spore suspension (1 × 10⁷ spores/mL) of lipolytic fungi. Thereafter, moisture content in the reactor was increased to 65%, and incubated at 30°C. Within 72 h of post incubation, degradation efficiency of about 50% was recorded by fungal isolates. The feasibility of using developed protocol for FOG degradation was tested with a laboratory-scale prototype reactor.

Antioxidant potential and content of the polyphenolic secondary metabolites of white rot macrofungi; Flavodon flavus (Klotzsch.) and Xylaria feejeensis (Berk.)

White rots are a variety of wood-decay fungi that digests moist wood, causing it to rot. White rot fungi produce structurally diverse polyphenolic secondary metabolites which are known to responsible for the renowned antioxidative system of this fungal category. The current study was aimed at investigating the antioxidant properties of terrestrial white rots F. flavus and X. feejeensis harvested from the dry zone forest reserves in Dambulla and Mahiyanganaya areas of Sri Lanka for the first time. Furthermore, the contribution of phenolic and flavonoid substances towards the antioxidant properties of studied white rots were determined. Studied white rot species exhibited a strong antioxidant capacity implying that studied forms possess an effectual antioxidative system. Furthermore, analyzed species also contained high contents of phenolic and flavonoid substances suggesting that phenolic and flavonoid substances secreted by F. flavus and X. feejeensis contribute to their prominent antioxidant activity.

Cytotoxic effects of ergone, a compound isolated from Fulviformes fastuosus

BackgroundMushrooms inspired the cuisines of many cultures and conventional medicaments for cancer. However, a substantial number of mushroom species are yet unexplored, possessing an unknown chemical, biological and pharmacological profiles. Fulviformes fastuosus is a terrestrial mushroom, which is commonly found in Sri Lankan woodlands. The current study was aimed at isolation and characterization of a potent cytotoxic compound from F. fastuosus and investigating the apoptotic effect induced by the active principle against cancer and normal cell lines.MethodsBioactivity guided isolation of active principles from the methanol extract of F. fastuosus was performed by a rapid extraction and isolation method using different chromatographic techniques. Potential cytotoxic compound was identified using one and two dimensional nuclear magnetic resonance spectroscopy and mass spectrometry. Isolated compound was screened for in vitro cytotoxicity against Hepatocellular carcinoma (HepG-2), Muscle rhabdomyosarcoma (RD) and Rat Wistar liver normal (CC-1) cell lines using 3 4, 5-(dimethylthiazol-2-yl) 2-5-diphenyl tetrazolium bromide (MTT) cell viability assay. Apoptotic features of cells were observed via microscopic examination and ethidium bromide/acridine orange fluorescent staining.ResultsThe interpretation of spectral data resulted in the identification of the chemical structure as ergosta-4,6,8 (14),22-tetraen-3-one (ergone). Ergone exhibited promising cytotoxic properties against RD cells with less cytotoxicity effect on CC-1 cells. In addition, ergone also possesses a strong cytotoxic effect against HepG-2 cells showing low toxic level for CC-1 cells. Apoptotic features of treated cells were detected via morphological characterization and ethidium bromide/acridine orange staining.ConclusionThe present study elaborates the isolation of a potent cytotoxic compound; ergone, from F. fastuosus via a rapid and efficient isolation method. Importantly, ergone has exhibited greater cytotoxic activity against RD cells with high selectivity index compared to cytotoxicity against HepG-2 cells. Ergone can be used in the development of therapeutic strategies for curbing rhabdomyosarcoma.

Synthesis, Characterization, and Antimicrobial Activity of Novel Sulfonated Copper-Triazine Complexes

Metallotriazine complexes possess interesting biological and medicinal properties, and the present study focuses on the synthesis, characterization, and antimicrobial activity of four novel copper-triazine derivatives in search of potent antibacterial and antifungal drug leads. In this study, 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4,4′-disulfonic acid monosodium salt (L1, ferrozine) and 3-(2-pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5,5′-disulfonic acid disodium salt (L2, ferene) have been used as ligands to study the complexation towards copper(II). The synthesized complexes, [CuCl2(ferrozine)]·7H2O·MeOH (1), [CuCl2(ferrozine)2]·5H2O·MeOH (2), [CuCl2(ferene)]·H2O·MeOH (3), and [CuCl2(ferene)2]·H2O·MeOH (4), have been characterized spectroscopically, and preliminary bioassays have been carried out. FTIR spectroscopic data have shown that N=N and C=N stretching frequencies of complexes have been shifted towards lower frequencies in comparison with that of the ligands, confirming new bond formation between Cu and N, which in turn lowers the strength of N=N and C=N bonds. In addition, a bathochromic shift has been observed for UV-visible spectra of complexes (1), (2), (3), and (4). Furthermore, elemental analysis data have been useful to obtain empirical formulas of these complexes and to establish the purity of each complex. Complexes (1) and (2) have shown antibacterial activity for both S. aureus (ATCC® 25923) and E. coli (ATCC® 25922) at 1 mg/disc concentration, and ferrozine has shown a larger inhibition zone against the clinical sample of C. albicans at 1 mg/disc concentration in comparison with the positive control, fluconazole.