Browsing by Author "Maduranga, K."

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Antibacterial Polyketide from Lasiodiplodia theobromae and Pyrenula bahiana on Mangrove Ecosystems in Puttalam Lagoon, Sri Lanka
(Asian Journal of Chemistry, 2022) Paranagama, P.A.; Santhirasegaram, S.; Wickramarachchi, S.R.; Attanayake, R.N.; Weerakoon, G.; Maduranga, K.
Lasiodiplodia theobromae is one of the frequently isolated fast growing endolichenic fungus. This fungus was isolated from the lichen host, Pyrenula bahiana collected from the mangrove ecosystems in Puttlam lagoon and its identification was confirmed based on rDNA-ITS sequence homology. Secondary metabolites of L. theobromae were extracted into ethyl acetate and subjected to antibacterial assay against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) and Bacillus subtilis (ATCC6051). Crude extract at a concentration of 6.8 μg/mL showed good antibacterial activity against the bacterial strain S. aureus compared with the activity of the standard azithromycin at a concentration of 5.0 μg/mL. Active crude extract was partitioned to obtain methanol, hexane and chloroform fractions. Chloroform fraction showed the highest activity to S. aureus out of three fractions. This fraction was subjected to bioassay-guided separation on silica gel column chromatography to isolate bioactive pure compounds. The bioactive pure compound was identified as (3R)-de-O-methyllasiodiplodin using LC-MS, 1D and 2D NMR spectroscopy.
Antibacterial polyketide from Lasiodiplodia theobromae, inhabiting the lichen host, Pyrenula bahiana on mangrove ecosystems in Puttalam lagoon, Sri Lanka
(Asian Journal of Chemistry, 2022) Paranagama, P. A.; Santhirasegaram, S.; Fathima, M. M. A.; Wickramarachchi, S. R.; Attanayake, R. N.; Weerakoon, G.; Maduranga, K.
Lasiodiplodia theobromae is one of the frequently isolated fast growing endolichenic fungus. This fungus was isolated from the lichen host, Pyrenula bahiana collected from the mangrove ecosystems in Puttlam lagoon and identity was confirmed based on rDNA-ITS sequence homology. Secondary metabolites of L. theobromae were extracted into ethyl acetate and subjected to antibacterial assay against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) and Bacillus subtilis (ATCC6051). Crude extract at a concentration of 6.8 μg/ml showed good anti-bacterial activity against the bacterial strain S. aureus compared with the activity of the standard Azithromycin at a concentration of 5.0 μg/ml. Active crude extract was partitioned to obtain methanol,
Bioactive Properties and Metabolite Profiles of Endolichenic Fungi in Mangrove Ecosystem of Negombo Lagoon, Sri Lanka
(Natural Product Communications, 2022) Weerasinghe, R. H.; Maduranga, K.; Attanayake, R. N.; Shevkar, C.; Kate, A. S.; Weerakoon, G.; Kalia, K.; Paranagama, P.
Endolichenic fungi (ELF) serve as a novel source of natural products with distinctive bioactivities. A total of 58 ELF isolated from 29 lichens collected from mangrove and mangrove-associated plants of Negombo lagoon, Sri Lanka were identified using morphological and DNA barcoding techniques. Ethyl acetate extracts of 18 such identified ELF isolates were subjected to in vitro assays to determine antioxidant, anti-inflammatory, tyrosinase inhibitory and antibacterial potency. Liquid chromatography–mass spectrometry (LC–MS) dereplication was conducted on the crude extracts in order to detect the secondary metabolites present. The extracts of Daldinia eschscholtzii and Hypoxylon lividipigmentum had the highest radical scavenging activity with SC50 values 14.27 ±0.24 μg/mL and 18.34±1.37 μg/mL, respectively. D. eschscholtzii also exhibited remarkable anti-inflammatory activity (IC50 7.97 ±0.09 μg/mL). Tyrosinase inhibitory activity was highest in Cytospora xylocarpi (IC50 68.50 ±0.34 μg/mL), while the highest activity against aerobic bacterial species Escherichia coli, Bacillus subtilis, Staphylococcus aureus and the anaerobic bacterial strain Streptococcus mutans was observed in the extracts of Xylaria feegenesis and Curvularia lunata. After a thorough study of the LC–MS profiles, it was found that the chemical profiles of Neofusicoccum occulatum, H. lividipigmentum and Myramaececium rubricosum were previously poorly explored in the literature.
Bioprospecting of an Endolichenic Fungus Phanerochaete sordida Isolated from Mangrove-Associated Lichen Bactrospora myriadea
(Journal of Chemistry, 2022) Weerasinghe, R. H.; Shevkar, C. D.,; Maduranga, K.; Pandey, K. H.; Attanayake, R. N.; Kate, A. S.; Weerakoon, G.; Behera, S. K.; Kalia, K. S.; Paranagama, P. A.
Bioassay-guided fractionation of the ethyl acetate extract of Phanerochaete sordida, an endolichenic fungus (ELF) isolated from the host lichen Bactrospora myriadea, collected from Negombo lagoon, Sri Lanka, led to the isolation of a bioactive compound. Following the identification of the fungus using morphological and DNA barcoding techniques, the pure compound was isolated using column chromatography, preparative TLC, and semipreparative HPLC. The structure elucidation was carried out using IR, HR-ESI-MS and 1H, 13C & 2D NMR spectroscopic methods. The in vitro bioassays conducted revealed that compound 1 has a high antioxidant activity with ABTS•+ (IC5058:91 ± 1:35 μM), moderate anti-inflammatory activity (IC50254:79 ± 1:41 μM), comparable antibacterial activity against the oral-bacterial strain Streptococcus mutans (MIC 898.79 μM and MLC 1797.58μM), moderate tyrosinase inhibition (IC501713:69 ± 8:65 μM), and moderate cytotoxicity against oral cancer (IC5013:65 ± 0:02 μM), in comparison with respective positive controls. The in silico experiments conducted for tyrosinase inhibition and cytotoxicity using Schrödinger revealed results in line with the in vitro results, thus confirming the bioactivities. The molecule also satisfies the key features of drug likeliness according to pharmacokinetic studies.
Bioprospecting of an Endolichenic Fungus Phanerochaete sordida Isolated from Mangrove-Associated Lichen Bactrospora myriadea
(Journal of Chemistry,, 2022) Weerasinghe, R. H.; Shevkar, C. D.; Maduranga, K.; Pandey, K. H.; Attanayake, R. N.; Kate, A. S.; Weerakoon, G.; Behera, S. K.; Kalia, K. S.; Paranagama, P. A.
Bioassay-guided fractionation of the ethyl acetate extract of Phanerochaete sordida, an endolichenic fungus (ELF) isolated from the host lichen Bactrospora myriadea, collected from Negombo lagoon, Sri Lanka, led to the isolation of a bioactive compound. Following the identification of the fungus using morphological and DNA barcoding techniques, the pure compound was isolated using column chromatography, preparative TLC, and semipreparative HPLC. The structure elucidation was carried out using IR, HR-ESI-MS and 1H, 13C & 2D NMR spectroscopic methods. The in vitro bioassays conducted revealed that compound 1 has a high antioxidant activity with ABTS•+ (IC5058:91 ± 1:35 μM), moderate anti-inflammatory activity (IC50254:79 ± 1:41 μM), comparable antibacterial activity against the oral-bacterial strain Streptococcus mutans (MIC 898.79 μM and MLC 1797.58μM), moderate tyrosinase inhibition (IC501713:69 ± 8:65 μM), and moderate cytotoxicity against oral cancer (IC5013:65 ± 0:02 μM), in comparison with respective positive controls. The in silico experiments conducted for tyrosinase inhibition and cytotoxicity using Schrödinger revealed results in line with the in vitro results, thus confirming the bioactivities. The molecule also satisfies the key features of drug likeliness according to pharmacokinetic studies.
Chemical characterization of endolichenic fungi, Talaromyces pinophilus residing in the lichen, Arthonia sp. collected from mangroves of Sri Lanka
(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Shevkar, C.; Armarkar, A.; Maduranga, K.; Weerasinghe, R.; Pandey, K.; Kalia, K.; Paranagama, P. A.; Kate, A.
Lichens are one of the interesting symbiotic organisms comprising of algae, fungi and other microbiota. The complex miniature ecosystem of lichen provides a competitive environment to endolichenic fungi, which makes it suitable for the production of structurally diverse molecules. Mangroves of Sri Lanka are well-known for the presence of various type of lichens and hence, in this study, 32 specimens of lichen were collected from mangroves of Puttalam Lagoon of Sri Lanka. LCMS based dereplication study was carried out for the isolated 70 cultures of endolichenic fungi from lichens. Talaromin B and Ergochrome BB were present in the ethyl acetate extract of Talaromyces pinophilus along with probable novel compounds having m/z [M+H]+ 663.2321, 778.4128, 401.3029 with “no hit” in Dictionary of Natural Products (DNP). The mentioned extract showed promising anti-cancer activity having IC50 of 50.32 μg/mL tested against MCF-7 cell line (Human breast cancer cell line) by Alamar blue assay. The extract was then scaled up for further isolation of masses showing no hits in DNP. Here, 2 known and 2 new compounds were isolated with 95-98% purity from the scaled up fermentation batch including [NIPER20099_83_7/30_1] Peniazaphilin B and a macrocyclicpolyester [NIPER20099_83_7/30_2] (15G25α). Structural elucidation of two novel molecules is in process. All four molecules were tested in vitro against MCF-7 cell line and only one molecule [NIPER20099_83_7/30_3] having molecular weight 560.2045 showed promising activity with the IC50 value of 22.15μM. The study suggest Talaromyces pinophilus might serve as a source of novel cytotoxic hit. Investigating secondary metabolites of the endolichenic fungi might help us to unravel the complex ecosystems of lichen and help us understand its further therapeutic benefits.
Cytotoxic Bioxanthracene and Macrocyclic Polyester from Endolichenic Fungus Talaromyces pinophilus: In-Vitro and In-Silico Analysis
(Indian J Microbiol, 2022) Shevkar, C.; Armarkar, A.; Weerasinghe, R.; Maduranga, K.; Behera, S.K.; Kalia, Kiran; Paranagama, P.; Kate, A. S.; Pandey, K.
Lichens are used in folklore medicines across the globe for wound healing and to treat skin disorders and respiratory diseases. They are an intricate symbiosis between fungi and algae with the domination of fungal counterparts. Recent research studies pointed out that yeast is a third major partner in lichens. Endolichenic fungi (ELF) are also a part of this complex miniature ecosystem. The highly competitive environment of lichens compels ELF to produce toxic metabolites which are comparatively less explored for their chemical diversity and use. Here, we investigated 31 ELF isolated from 32 lichens found on mangrove plants at Puttalam Lagoon of Sri Lanka to find cytotoxic molecules by applying LC-UV-HRMS analysis and in vitro bioassays. The studies resulted in the identification of three potent cytotoxic molecules from endolichenic fungi Talaromyces pinophilus isolated from host lichen Porina tetracerae. The ethyl acetate extract of this fungus showed moderate cytotoxicity against the breast cancer cell line. Chemical characterization of ethyl acetate extract of T. pinophilus produced peniazaphilin B, 152G256a-1, and ES-242-3. The structures of these molecules were confirmed by NMR and MS data. We are reporting ES-242-3 for the first time from the genus Talaromyces and peniazaphilin B and 152G256a-1 from T. pinophilus. The isolated compounds were evaluated for their anticancer potential against breast, oral and cervical cancer cell lines. Compound 152G256a-1 showed potent cytotoxicity against oral cancer (CAL-27 cell line) with an IC50 value of 2.96 ± 0.17 lM while ES-242-3 showed the best activity against breast cancer (MCF-7 cell line) and cervical cancer (HeLa cell line) with IC50 value 14.08 ± 0.2 lM and 4.46 ± 0.05 lM respectively. An insilico analysis was carried out to predict the mechanism of in-vitro activity, drug likeliness, and pharmacokinetic profile of the isolated compounds. The study confirms the potential of ELF T. pinophilus to produce diverse bioactive scaffolds and encourages the researchers to further explore the fungus and its metabolites with newer technologies to produce potent anticancer leads.
Molecular phylogeny and bioprospecting of Endolichenic Fungi (ELF) inhabiting in the lichens collected from a mangrove ecosystem in Sri Lanka
(PLoS ONE 13(8): e0200711. https://doi.org/ 10.1371/journal.pone.0200711, 2018) Maduranga, K.; Attanayake, R.N.; Santhirasegaram, S.; Weerakoon, G.; Paranagama, P.A.
Endolichenic fungi (ELF) are unexplored group of organisms as a source for the production of bioactive secondary metabolites with radical scavenging activity, antilipase and amylase inhibitory activities. Endolichenic fungi in lichens collected from mangrove or mangrove associated plants are least known for their fungal diversity and potential to produce bioactive compounds. A total of 171 ELF strains were isolated from the lichens collected from mangrove and mangrove associated plants in Puttalam lagoon. Out of this collection, 70 isolates were identified using rDNA-ITS region sequence homology to the GenBank accessions and a phylogenetic analysis was performed. Commonly isolated genera of ELF from lichens were Aspergillus, Byssochlamys, Talaromyces, Diaporthe, Phomopsis, Endomelanconiopsis, Schizophyllum, Cerrena, Trichoderma, Xylaria, Hypoxylon, Daldinia, Preussia, Sordaria, Neurospora, and Lasiodiplodia. In the present study, the effectiveness of ethyl acetate extracts of the ELF isolates were investigated against antioxidant activity, antilipase activity and α-amylase inhibition activity in in-vitro conditions. The results revealed that the extracts of Daldinia eschscholtzii, Diaporthe musigena and Sordaria sp. had the highest radical scavenging activity with smaller IC50 values (25 μg/mL to 31 μg/mL) compared to the IC50 values of BHT (76.50±1.47 μg/mL). Antilipase assay revealed that 13 extracts from ELF showed promising antiobesity activity ranged between 25% to 40%. Amylase inhibitory assay indicated that the test extracts do not contain antidiabetic secondary metabolites.