Browsing by Author "Kandiah, R."

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Injecting Drug Users in Sri Lanka
(University of Kelaniya, 2005) Senanayake, B.; Kandiah, R.; Ratnayake, Y.
An exploratory descriptive study on Injecting Drug Users (IDUs) in Sri Lanka was undertaken in the light of the increase in the number of IDUs between 1998 and 2002. The aim of the study was to understand the nature and the extent of injecting drug use in the country in 2003-2004. A non-probable ‘snow-ball’ sample of IDUs was studied from the correctional institutions and the community. The case histories and interviews were conducted taking into consideration the physical signs of drug injecting, body language and verbal expressions. The IDUs were males aged mostly between 20 and 40 years, mostly from Colombo and adjacent urban areas. Majority them were form a lower social strata, employed as smallscale entrepreneurs or manual workers. The IDUs could be broadly categorised into 3 groups by their drug injecting: regular injectors, intermittent injectors and those injected once or few occasions. Many regular IDUs had a criminal record. Periods of social and political instability or high profile drug law enforcement appear to have enhanced the spread of injecting drug use. During the crisis period, the street level supply of heroin had been severely hampered, which had forced the heroin chasers (Chinese method users) to switch to injecting as a means of survival. Sharing of injecting equipment was minimal among IDUs. Many of the IDUs had engaged in unprotected sex with multiple partners including commercial sex-workers in countries of high seroprevalence of HIV/AIDS and STDs. Many IDUs believed that injecting heroin could enhance their sexual libido, which had been proven otherwise within 3 months of regular injecting. However, this had been a major reason for initiating injecting drug use. Sri Lanka at present is a low prevalence country for injecting drug use and HIV/AIDS. A scenario of decrease in accessibility to heroin due to high price, and law level of purity possibility of increase in the prevalence of injecting drug use could increase in seroprevalence of HIV/AIDS and other blood and STD. Hence, the injecting drug use has to be closely monitored to prevent this situation in Sri Lanka.
Isolation of bioactive secondary metabolites from the endolichenic fungi, Neosartorya sp. inhabiting the lichen Parmotrema sp. in Sri Lanka
(Faculty of Graduate Studies, University of Kelaniya, 2015) Manthrirathna, M.A.T.P.; Kandiah, R.; Gunasekara, D.S.; Paranagama, P.A.
Natural products are a potential source of novel pharmaceutical agents. Therefore, isolation and identification of bioactive compounds from organisms adapted to various biotopes and unraveling their bioactivities in search for new pharmacophores has a mounting interest. Fungi are known to be prominent producers of useful metabolites. Endolichenic fungi (ELF) that occur asymptomatically within the lichen thalli are one of the ecological groups of fungi. ELF in Sri Lanka remain almost unexplored as a source of useful bioactive compounds. The objective of this study is to isolate bioactive secondary metabolites from ELF Neosartorya sp. isolated from Parmotrema sp. that occur in Hakgala Botanical Garden. ELF Neosartorya sp. was cultivated on 48 PDA plates and incubated at room temperature. Secondary metabolites were extracted into ethyl acetate from 9 days old cultures. Antibacterial activity of the crude extract was evaluated against Bacillus subtilis (BS) and Staphylococcus aureus (SA) using agar well diffusion method. Standard antibiotic Azithromycin was used as the positive control and Dimethyl sulfoxide as the negative control. Since the crude extract showed antibacterial activity against both BS and SA, it was partitioned with hexane, chloroform (CHCl3) and aqueous methanol. All three fractions showed activity against SA, with the CHCl3 fraction having higher activity compared to the other two fractions. Chloroform and methanol fractions showed significant activity against BS, while CHCl3 fraction showed activity comparable with Azithromycin. Chloroform fraction of Neosartorya sp. was further fractionated using bio-assay guided fractionation (silica gel column chromatography). Pure compounds were isolated using preparative TLC. One major pure compound was isolated from CHCl3 fraction and the characterization still in progress.
A secondary metabolite with in vitro radical scavenging activity from endolichenic fungus Daldinia eschscholzii found in lichen, Parmotrema sp. in Sri Lanka
(Journal of the National Science Foundation of Sri Lanka, 2020) Manthrirathna, M.; Kandiah, R.; Gunasekera, D.; Samanthi, K.; Welideniya, D.; Maduranga, H.; Paranagama, P.
Endolichenic fungi, an unexplored group of microorganisms, are a promising source of bioactive compounds. Secondary metabolites were isolated from the chloroform fraction of crude ethyl acetate extract of endolichenic fungus Daldinia eschscholzii inhabiting the lichen, Parmotrema sp. in Sri Lanka. Two pure compounds, 1 and 2 were isolated and the structures were identified using 1H-, 13C-, 2D- nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) data. Compound 1 did not show any radical scavenging activity in DPPH assay. Compound 2, identified as 8-methoxynaphthalen-1-ol showed strong radical scavenging ability in the DPPH assay with a half maximal inhibitory concentration (IC50) of 10.2 ± 5.8 µg/ mL. The activity of compound 2 was higher than that of the standard, butylated hydroxy toluene (BHT).
Secondary Metabolites with Radical Scavenging Activity from Daldinia Eschcholzii, Isolated from The Lichen Parmotrema Sp. In Sri Lanka-Isolation and Structure Determination
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Manthrirathna, M.A.T.P.; Kandiah, R.; Gunasekara, D.S.; Paranagama, P.A.
Natural products are promising leads for novel therapeutic agents. Isolation and characterization of bioactive compounds in search for potential pharmocophores has acquired a developing interest in on-going research. Although Endolichenic fungi (EF) are a rich source of bioactive secondary metabolites, they still remain almost unexploited. The present study is focused on isolation and structure elucidation of compounds with radical scavenging activity from the EF, Daldinia eschscholzii that occur in the lichen Parmotrema sp. in Hakgala Botanical Garden, Sri Lanka. Daldinia eschscholzii cultivated on 48 large petri dishes with PDA were incubated at room temperature for one week. Mycelia were cut in to small pieces along with the medium and extracted with ethyl acetate twice. The radical scavenging activity of the crude extract was evaluated using DPPH assay. Standard antioxidant, Butylated Hydroxy Toluene (BHT) and MeOH were used as the positive control (IC50= 38.2 ± 4.0 μg/ mL) and negative control respectively. The crude extract with high radical scavenging activity (IC50 = 77.9 ± 5.1 μg/ mL), was partitioned with hexane, chloroform and aqueous methanol. All three organic extracts were then subjected to DPPH assay. Chloroform fraction with the highest activity (IC50= 63.8 ± 4.8 μg/ mL) was further fractionated using silica gel, sephadex column chromatography and preparative TLC to isolate two pure compounds. The structures of the compounds were elucidated using 1H, 13C, 2D NMR and MS data. The compounds were identified as 7-hydroxy- 2-methylchroman-4-one (1) and 5-methoxynaphthalen-1-ol (2). Compound 1 showed no activity in the assay. Compound 2 showed higher activity than the standard BHT, with IC50 value of 10.2 ± 5.8 μg/ mL.