Suranga Wickramarachchi

University of Kelaniya · Department of Chemistry

This study aimed to examine the potentiality of microencapsulated cinnamon leaf oil (CNO-CS-MCs) and lemongrass oil (LGO-CS-MCs) as natural fungicides against Aspergillus flavus. Oil encapsulated microcapsules were synthesized using ionotropic gelation method. Cinnamon leaf oil (CNO) and lemongrass oil (LGO) were characterized using GC-MS. A. flavu...

Marine-derived shrimp, lobster, and crab shells have poor water solubility, hence cause environmental pollution worldwide. Chitin, comprising 15-40% of shrimp shells' dry weight, can be converted to chitosan, a biodegradable natural polymer which has many industrial applications. This study was focused on extracting chitosan, using fresh shrimp (Pe...

Chitosan, a biodegradable biopolymer from chitin, has revealed many antimicrobial properties and currently applies in food and medical industries. Chitosan was chemically extracted from fresh Penaeus monodon shell waste following a standard procedure. The chemical characteristics of the product were investigated using Fourier-transform infrared spe...

Chitosan, a biodegradable biopolymer from chitin, has revealed many antimicrobial properties and currently applies in food and medical industries. Staphylococcus aureus is a foodborne pathogen. Treating S. aureus infections is challenged by evolving antibiotic resistance to a wide array of antibiotics. Therefore, an alternative method for combating...

Abstract Background A large volume of animal byproducts remains underutilized, and low-value components such as skin, bones, feathers, heads, feet, hairs, horns, hooves, tails, cartilage, unused myofibril muscles, fins, fish scales, and whey protein are generated by meat processing industries, slaughterhouses, and milk processing industries. The ma...

Current study is based on the larvicidal effect of mycosynthesized siver nanopartices (AgNPs) from Trichoderma longibrachiatum (Tl-AgNPs) and Trichoderma viride (Tv-AgNPs) on Aedes aegypti and Aedes albopictus dengue vectors and non-targeted aquatic crustacean, Moina macrocopa. Mosquito larvae were exposed to each test concentration (10 to 50 mg L-...

This work reports the synthesis of silver nanoparticles (AgNPs) using the leaf extract of Annona glabra as a green synthetic route and assessment of its photocatalytic property using methelyne blue as a model dye and toxic effect against an aquatic model, Daphnia magna. Leaf extract prepared at 100 ºC, 1% plant extract, 1 mM of AgNO3, 3 h incubatio...

Marine-derived shrimp, lobster, and crab shells have poor water solubility, hence cause environmental pollution worldwide. Chitin, comprising 15-40% of shrimp shells' dry weight, can be converted to chitosan, a biodegradable natural polymer which has many industrial applications. This study was focused on extracting chitosan, using fresh shrimp (Pe...

Aedes aegypti and Aedes albopictus are the responsible vectors of transmitting dengue in Sri Lanka. Excessive use of chemical pesticides causes insecticide resistance. Therefore, mosquito biolarvicides remain to be an important method for mosquito control. The use of fungal metabolites can be considered a tool to overcome the issues related to inse...

Silver nanoparticles (AgNPs) are used in many applications in various fields, including biolabeling, sensors, filters, and antibacterial agents due to their specific physico-chemical and biological properties. As a result, AgNPs are released into the environment, and ultimately their transformation products, such as nanoparticulate of Ag2S, accumul...

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 eth...

The mosquito Aedes aegypti is a critical vector of infectious diseases, including dengue, chikungunya and yellow fever. Prevention of these diseases is mainly achieved through mosquito population control due to the non-availability of a commercial vaccine except for yellow fever. The use of biogenic nanoparticles to control insect vectors has been...

The biological synthesis of silver nanoparticles (AgNPs) is a novel and alternative approach to antibiotics. This study was designed to biosynthesize and characterize AgNPs and evaluate the in-vitro toxicity of AgNPs against Salmonella typhi (ATCC14028). Cell-free supernatant of 16s-rRNA sequenced Lactobacillus fermentum (L12) was provided as the r...

Ionotropic gelation using sodium tripolyphosphate (STPP) as the crosslinker was successfully used to formulate lemongrass oil containing chitosan microcapsules. Formation of oil in aqueous chitosan polymer solution was followed by crosslinking with STPP. Optimum formulation for the synthesis of microcapsules was found varying the amounts of lemongr...

Metal nanoparticles are used in all phases of science, including medical fields. They still seduce scientists to explore new dimensions for their respective value, which is usually attributed to their corresponding small sizes. Among the other metallic nanoparticles, silver nanoparticles (AgNPs) aroused a keen interest. The chemical methods used to...

This study aimed to determine the DPPH free radical scavenging activity, total phenolic content (TPC) and total flavonoid content (TFC) of methanolic extract of Durio zibethinus Murr. (durian) peels and its fractions. The chemical constituents of durian peels extracted into methanol by soxhlet extraction were sequentially extracted into hexane, dic...

Essential oils have long been attracted as substitutes for synthetic chemical pesticides because of their antimicrobial properties, low mammalian toxicity and wide public acceptance. Essential oils of lemongrass and cinnamon leaf were encapsulated using chitosan, a biodegradable polymer by emulsion formation/ionotropic gelation technique. A. flavus...

This study aims to evaluate the acute toxicity of biosynthetic AgNPs produced ,tsing Annona glabra Ieaf extract, against a selected aquatic-indicator, Daphnia magna. Tine toxicity of the biosynthetic AgNPs was compared against the Ag* ion solution. Aqueous leafextrrcts of A. glabra were prepared by heating chopped leaves (20.0 g) with water (100.0...

Chemical composition of leaf The main classes of phytochemicals present in an aqueous leaf extract are flavonoids, glycolipids, alkaloids, aromatic hydrocarbons, phenols, sugars, steroids and terpenes (Fig 01). The terpenes identified in oil samples are mainly mono and sesquiterpenoids. The composition of oil is as follows 1 ; A B C D E F Figure 01...

The lichen host, Amandinea medusulina, collected from mangrove habitats in Sri Lanka, and its associated endolichenic fungi were isolated and identified by rDNA-ITS sequence analysis and morphological features. One of the fungal strains frequently isolated from the lichen thalli was identified as Xylaria psidii. This study aimed at the isolation an...

silver nanoparticles (AgNPs) have attracted high research interest because of their important applications in antimicrobial, cataiysis, and water treatment plants. They dispray totarly new and. errhanced properties compared to larger bulk material particles and these novel properties are due to the difference in specific characteristics such as par...

The accelerating pharmaceutical problem ofbacteria growing resistant to existing antibrotics forces the scientific community to search for new antibacterial compounds for antibiotic drug development. I-iterature reveals that Sri Lankan mangrove inhabiting endolichenic fungal (ELF) population is rich in nrany such bioactive compounds-Previously isol...

The present study reports mosquito larvicidal potential of green synthesized silver nanoparticles by using Annona glabra leaves (An-AgNPs). Synthesized An-AgNPs were characterized by Ultraviolet-Visible spectroscopy (UV-VIS), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS) technique and Fourier transform infrared spectroscopy (FT...

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With the revelation of intriguing bioactive properties from natural sources, the thirst to investigate more into the mysteries of nature has immensely expanded. Endolichenic fungi (ELF) became an interesting source during the recent past in this search for novel bioactive compounds and literature sources provide evidence of many such bioactive comp...

Recently metallic nanoparticles were found to possess photocatalytic activity on organic molecules under visible radiation a phenomenon which will be useful in degrading and removing hazardous organic dyes. During this study the photocatalytic activity of Annona glabra - AgNPs (bare NPs) and Tween 80-stabilized Annona glabra – AgNPs (stabilized NPs...

No: 279 Potential of using leaf extract of Annona glabra as a novel, green source for the synthesis of silver nanoparticles This study aims at investigating the potential of using the leaf extract of Annona glabra for the green synthesis of silver nanoparticles (AgNPs) and optimization of process parameters to obtain nanoparticles with narrow size...

Silver nanoparticles have been studied extensively due to their wide applications in nonlinear optics, biolabeling, reaction catalysis, antibacterial products, electrical conductors, and chemical sensing. Use of plant extracts in the synthesis of silver nanoparticles has gained much attention recently as it is very simple, rapid, eco-friendly and c...

Chitosan microcapsules containing cinnamon leaf oil were formed by ionotropic gelation of chitosan by crosslinking with sodium tripolyphosphate. The microencapsulation method for oil loading was optimized by varying the amounts of polymer, oil and cross linker. The effect of varying process parameters on the encapsulation efficience (EE), oil loadi...

Context: Endolichenic fungi are the microorganisms living inside the thalli of the lichen and found to be a new source of bioactive secondary metabolites. This is an underutilized source of bioactive compounds and has not been studied extensively. Genus, Parmotrema is one of the foliose lichens with largely rounded lobes and occurs on rocks of rain...

In this study, an eco-friendly, simple, rapid and a cost effective biological method for reducing Ag + ions into silver nanoparticles (AgNPs) using the leaf extract of Annona glabra (A. glabra) plant has been developed. Although a number of plant extract mediated synthesis of AgNPs have been reported in the literature no previous attempt has been m...

The present investigation is an attempt to synthesize silver nanoparticles (AgNPs) from Annona glabra leaf extract as a novel source of reducing agent of Ag+ into AgNPs. No previous studies reported on the use of Annona glabra in the green synthesis of AgNPs. AgNO3 was added to aqueous plant leaf extract drop wise and left at room temperature for t...

Aflatoxins, produced by Aspergillus flavus which is a major storage fungus, are known to possess carcinogenic properties and may occur in raw and stored food. Rice is the staple food among Sri Lankans and due to the specific climatic conditions, fungal growth, including A. flavus, is promoted in stored rice. Many plant derivatives have shown to be...

Aflatoxins, produced by Aspergillus flavus which is a major storage fungus, are known to posses carcinogenic properties and may occur in raw and stored food. Rice is the staple food among Sri Lankans and due to the specific climatic conditions, fungal growth, including A. flavus, is promoted in stored rice. Many plant derivatives have shown to be e...

In this paper, the in vitro antimicrobial activity of Alpinia malaccensis rhizome oil was investigated in its pure form and incorporated into chitosan films, against Colletotrichum musae, Staphylococcus aureus and Escherichia coli. Dry rhizome oil of A. malaccensis was extracted using steam distillation. Chitosan films enriched with the oil were pr...

Two new polyketides (compounds 1 and 2) were isolated from the EtOAc extract of an endolichenic fungus, Curvularia trifolii obtained from Usnea sp. in Sri Lanka. The structures of these compounds were elucidated on the basis of spectroscopic methods (UV, IR, MS, 1D NMR and 2D NMR). The bioactivity of the compounds 1 and 2 were studied using DPPH an...

Bioassay guided fractionation of the ethyl acetate extract of a laboratory culture of Penicillium citrinum, an endolichenic fungal strain isolated from a Parmotrema species in Sri Lanka, led to the isolation of two new fungal polyketides (1 and 2). The structures of these compounds were determined on the basis of their 1D NMR, 2D NMR and FABMS spec...

Chitosan stabilized silver nanoparticles (AgNPs) were synthesized using gamma ray irradiation. Four different sample solutions were prepared [1 mM AgNO 3 in 0.1% (w/v) chitosan, 1 mM AgNO 3 in 0.5% (w/v) chitosan, 2 mM AgNO 3 in 0.1% (w/v) chitosan 2 mM AgNO 3 in 0.5% (w/v) chitosan] with controls maintaining dose of radiation at 20±2 kGy. The form...

Raman spectroscopy has been used to identify solid – solid phase transitions in the symmetrically branched alkane, C120H241CH(C195H391)C119H23 during real-time heating. The vibrational modes in the region from 1700 to 200 cm-1 were studied. A single phase transition was identified at 87°C ± 5°C in this alkane based on the changes in the band intens...

The demand for the pesticide free products prompted investigating the potential of chitosan to be used as an antifungal agent to reduce anthracnose disease on banana var. embul. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of chitosan against Colletotricum musae were determined via a series of experiments using Pois...

The potential of chitosan (unirradiated and irradiated) to be used as an antifungal agent to reduce anthracnose disease on banana var. embul and thereby to improve its shelf life was investigated. Chitosan was irradiated using gamma radiation and a low dose of 5 kGy was used to determine the potential of using lower doses to irradiate chitosan in a...

Three chitosan concentrations (1%, 3%, 5% w/v) were tested for their root growth promotion properties in air-layering of three popular ornamental Ficus species namely Ficus triangularis, Ficus microcarpa and Ficus benjamina. Subsequently, these treatment responses were compared with a rooting hormone (naphthalic acetic acid) and an organic root pro...

Successive heat annealing and cooling of the extended chain form of C198H398 leads to a “perfecting” of the chains, on the evidence of FTIR data. A similar sample of CD3(CD2)11(CH2)192(CD2)11CD3 allows the deuterated end segments to be analysed separately. It is shown that the end segments develop better register, while the chain interior is scarce...