International conference on Frontiers in Chemical Technology 2020 (FCT 2020)
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Item Detailed evaluation of methylated and acetylated products of cinnamon leaf oil against Aedes aegypti(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Medagedara, H. K.; Paranagama, P. A.; Gunaratna, Medha J.Aedes aegypti is a known vector of several viruses including Yellow fever, Dengue, Chikungunya and Zika virus. Two potential Aedes aegypti mosquito repellents; methyl eugenol and acetyl eugenol were semi-synthesized using eugenol extracted from cinnamon leaf, which is the main constituent in cinnamon leaf as well as in other plant leaf extracts like maduruthala and clove oil. Methyl eugenol was semi-synthesized using methyl iodide as a methylation precursor and acetyl eugenol was semi-synthesized using acetic anhydride, triethylamine base and catalytic amount of DMAP. Synthesis reactions were monitored using TLC and products were purified using flash silica columns. Formations of desired products were confirmed using GC-MS analysis. A diluted series (0.6-8 mg/ mL) was prepared for these semi-synthesized compounds and for the cinnamon leaf extract using ethanol and tested separately for their mosquito repellency using arm-in-cage tests followed by standard WHO methods. Experiments were performed on twenty volunteers in triplicates. Effective dose (ED99) for each repellent was calculated using beta regression analysis. Current study suggests that all compounds tested were effective mosquito repellents. Their ED99 varied as; cinnamon leaf extract (5.80) > methyl eugenol (5.41) > acetyl eugenol (5.13). Acetyl eugenol could be a potential safe repellent as its ED99 was achieved at a lower concentration and due to the absence of any side effects on skin when applied. Both maduruthala and clove oil contained significant contents of eugenol and clove oil had slight amounts of acetyl eugenol which could be extracted to synthesize repellent compounds or use directly in future.Item Exploring bioactive compounds in the endolichenic fungus, Xylaria feejeensis, inhabiting the lichen, Graphis librata, collected from Negombo lagoon, Sri Lanka(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Gunawardhana, M. H. A. Y.; Wickramarachchi, P. A. S. R.; Weerasinghe, W. R. H.; Paranagama, P. A.The accelerating pharmaceutical problem of bacteria growing resistant to existing antibiotics forces the scientific community to search for new antibacterial compounds for antibiotic drug development. Literature reveals that Sri Lankan mangrove inhabiting endolichenic fungal (ELF) population is rich in many such bioactive compounds. Previously isolated and cultured ELF, Xylaria feejeensis; from the lichen Graphis librata inhabiting in the mangrove plant Rhizophora mucronata was cultured on 60 large potato dextrose agar medium containing petri dishes and incubated for 14 days at room temperature. After extracting secondary metabolites to ethyl acetate (EA) the resulted crude extract was tested for its antibacterial and antioxidant activity. EA crude extract showed negligible antioxidant activity in DPPH radical scavenging assay hence this assay was not proceeded further. The activity of crude extract (5 mg/ml) against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) and Bacillus subtilis (ATCC6051) was tested using agar well diffusion antibacterial assay. An inhibition zone diameter of 1.9 cm, 2.2 cm, and 2.2 cm against three bacterial strains with Azithromycin positive control (5 mg/ml) 2.2 cm, 2.2 cm and 2.3 cm was observed respectively. By partitioning of EA crude extract resulted two antibacterial active hexane and chloroform fractions and one antibacterial inactive 60% methanol in water fraction. Hexane fraction showed the highest antibacterial activity with inhibition diameter zone of 2.6 cm against E.coli with 2.6 cm diameter of inhibition zone for positive control. Further purification of hexane fraction was performed by normal phase column chromatography and 4 fractions were resulted. The highest polar fraction showed 1.4, 2.1 and 1.7 cm diameter inhibition zones of growth of E.coli, S. aureus and B. subtilis comparable with 2.2 cm Azithromycin. The other 3 fractions showed no antibacterial activity against these bacterial strains. Results suggest that further purification of active fraction and structure elucidation might result in new antibiotic lead compounds.Item Development of a herbal fairness cream using four medicinal plants(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Wimalasekera, H. N.; Paranagama, P. A.; Harapathdeniya, S.There are reports in the public domain which state that artificially synthesized fairness creams have shown side effects on humans. The purpose of a fairness cream is to get a fairer skin by blocking harmful Ultraviolet (UV) rays which can activate the melanin biosynthesis in the body. When there is an excess production of melanin, it can lead to several hyperpigmentation diseases and finally result in a darker or tanned skin. This excess melanin formation can be inhibited by avoiding exposure to UV light, using tyrosinase inhibitors and anti-oxidants, which can reduce melanin proliferation. In this research study, a herbal fairness cream was prepared using four traditional medicinal plants found in Sri Lanka to inhibit excess melanin production in the body. The four plants chosen for this study were, Hemidesmus indicus (Heen Iramusu), Ixora coccinea (Rathmal), Hibiscus rosa sinensis (Pokuru Wadamal) and Citrus reticulata (Heen Naran). The plant extracts and the cream were separately subjected to anti-oxidant (DPPH and ABTS) assays and anti-tyrosinase assay. In addition, the anti-bacterial activity of this cream was studied. The methanol extracts of these four plant species displayed a high antioxidant activity and a significant tyrosinase inhibitory activity. The herbal cream was formulated using equal proportions of these extracts. Anti-tyrosinase studies of the cream revealed that it has a good anti-tyrosinase activity compared to the positive standard, Kojic acid. In addition, anti-bacterial studies revealed that the cream can inhibit bacteria Staphylococcus aureus and Bacillus subtilis. The ABTS assay showed that this polyherbal cream can act as an excellent antioxidant (IC50: 0.54±3.86) with respect to the control BHT (IC50:9.99±1.76). The cream was prepared using 100% natural ingredients which helped to enhance the therapeutic benefits of this cream. Thus, this cream can be used as a substitute for the synthetic fairness creams already available in the market.Item The OSMAC effect on the production of secondary metabolites by the endolichenic fungus, Curvularia trifolii(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Lekamwasam, C. J.; Paranagama, P. A.; Gunaratna, Medha J.Fungi are a very diverse group of organisms that can produce a vast number of pharmacologically active secondary metabolites. Fungi also have the ability to produce numerous secondary metabolites from a single strain. In this study, the One Strain Many Compounds (OSMAC) approach was used to observe the biosynthetic potential of endolichenic fungus, Curvularia trifolii isolated from Usnea sp. in Sri Lanka. Under the OSMAC approach, the variation of the metabolic profile of the fungus when cultured in different culture media was investigated. Culturing in Potato Dextrose Broth (PDB) medium resulted in the elution of two peaks in High- Performance Liquid Chromatographic (HPLC) study while four major peaks resulted from Yeast Potato Dextrose Broth (YPDB) medium cultures. Five major peaks eluted from Oatmeal extract broth (OEB) medium cultures and two major peaks from Rice-Yeast Broth (RYB) medium cultures. The bioactivities of crude extracts from each culture media were investigated using antioxidant, antibacterial, and anti-inflammatory assays and analyzed using Graph Pad Prism software. The crude extract of OEB showed a comparatively high antioxidant activity with ABTS radical scavenging assay with an IC50 value of 0.501 ± 0.036 mg mL-1 while the crude extract of YPDB showed a comparatively high anti-inflammatory activity with human red blood cell stabilization assay with an IC50 value of 0.151 ± 0.026 mg mL-1. The crude extract of RYB showed the highest antibacterial activity against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis bacterial strains upon analysis using agar-well diffusion method. The study confirms the variation of metabolic products and associated bioactivities of Curvularia trifolii with the variation of its culture medium.Item 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.Item Polyethylene degradation capability of Schizophyllum commune(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Perera, T. W. N. K.; Attanayake, R. N.; Paranagama, P. A.Tremendous increases in the manufacture and consumption of polyethylene, over recent decades have led to numerous environmental and economic concerns. This is the first comprehensive research on determination of Endolichenic Fungi (ELF), capable of degrading polyethylene substrates. The objective of this study was to identify the ability of various ELF, for the degradation of polyethylene in liquid media. Commercially available Low Density Polyethylene (LDPE) bags were used as the test material. ELF isolates cultured on Potato Dextrose Agar, were introduced into Mineral Salt Medium Broth containing LDPE strips. The isolate, Schizophyllum commune showed a positive growth response in the broth medium. The strips treated with this isolate, were tested for the reduction in dry weight, changes in peaks of Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy, reduction in tensile strain at break and changes in Scanning Electron Microscopic analyses. Results showed that isolate, reduced the weight of LDPE strip by 10.54%, after 21 days of incubation, while control showed 0% reduction. The control LDPE strip on ATR-FTIR analysis showed prominent peaks at 2916 cm-1, 2848 cm-1, 1463 cm-1 and 720 cm-1. Changes visible in sample infrared spectra after 21 days of incubation, were the fluctuations in the percentage transmittance of above peaks and formation of new peaks at 1740 cm-1, 1215 cm-1 and 1046 cm-1. The tensile strain at break, of treated strips, reduced by 27.41%, after 21 days of incubation while control showed 0% reduction. The presence of pits and cavities, in Scanning Electron Micrographic images, suggested the penetration of fungi, into the LDPE matrix, during degradation. The occurrence of several nonuniformly scattered whitened areas and erosion zones, indicated the surface erosion of LDPE strips, in degradation. These changes were not observed in the control LDPE strips. This study provides insight into the role of Schizophyllum commune towards solving the dilemma of polyethylene wastes, through biodegradation.