Browsing by Author "Hettiarachchi, C. M."

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    Antioxidant, anti-inflammatory and antibacterial potentials of aqueous leaf extract of Pouteria campechiana (Kunth) Baehni (Ratalawulu)
    (Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Hettiarachchi, O. I.; Deraniyagala, S. A.; Hettiarachchi, C. M.
    Antioxidants are of dietary importance in preventing oxidative stress due to the production of excess free radicals in our body leading to many diseases including cancer, atherosclerosis and diabetes as well in aging. Despite the advances in modern medicine, plant -based remedies play an important role in healthcare due to less side effects. Due to the side effects of NSAIDS and antibiotics, plant -based remedies would be beneficial. This study was conducted to assess the potential use of P. campechiana (Ratalawulu) as an antioxidant, anti-inflammatory and antibacterial agent. The aqueous leaf extract of Ratalawulu was prepared according to the method of decoction preparation in ayurvedic medicine. All assays were carried out according to previously published procedures. Aqueous leaf extract of P. Baehni showed a Total Phenolic Content of 230.71±7.62 mg (PGE)/g in the Folin-Ciocalteu method. Total flavonoid content was 140.98 ± 98.46 mg (QE)/g according to AlCl3 colorimetric assay [PGE- Pyrogallol equivalence, QE- Quercetin equivalence]. 2,2-Diphenyl-1-picrylhydrazyl radical scavenging activity of aqueous leaf extract of P. Baehni ranged between 1.4%-17.8% for concentration between 0.01-0.1 mg/ml whereas ascorbic acid showed 2.46%-43.93% for the same concentration range. Ferric ion reducing assay for aqueous leaf extract of P. Baehni showed gradual increase in reducing property relating to antioxidant action by donating a hydrogen atom to break free radical chains. Hydroxyl scavenging activity showed 5.73%-44.03% for concentration series of 20-100 mg/ ml whereas, Ascorbic acid ranged from 9.40%-47.06%. Hydroxyl radical is one of the potent reactive oxygen species in the biological system. Nitric oxide scavenging anti-inflammatory assay showed 58.06%-75.36% whereas ascorbic acid showed 80.73%-91.76% for concentration series of 0.4-6.4 mg/ ml. In the human red blood cell assay, percentage protection by aqueous leaf extract of P. Baehni was 15.0%-62.4% and that of ascorbic acid was 12.1%-72.8% for 6.0-300 μg/ml. Aqueous leaf extract of P. Baehni also showed antibacterial activity against Staphylococcus aureus. Taken together, these results suggest the potential use of aqueous leaf extract of P. Baehni as an antioxidant, anti-inflammatory and antibacterial agent, and merit further related investigation.
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    Transcriptomic analysis of cyclotides in Sri Lankan Viola betonicifolia
    (Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Rajendran, Sanjeevan; Slazak, Blazej; Mohotti, Supun; Göransson, Ulf; Hettiarachchi, C. M.; Gunasekera, Sunithi
    Plants belong to Violaceae family are known to contain stable bioactive cyclic peptides known as cyclotides. Eight species of Violaceae plants can be found in Sri Lanka: three from genus Rinorea, three from genus Viola and two from genus Hybanthus. Rinorea species were thought to be extinct in Sri Lanka until the recent discovery of Rinorea decora and Rinorea bengalensis. However, the chemical constituents and bioactivities of Sri Lankan Viola plants have not been investigated. Aim of the study was to characterize cyclotides in Sri Lankan Viola plants using a complementary tool of transcriptomics. Out of all Violaceae plants, V. betonicifolia was selected for transcriptome de novo sequencing and analysis to identify cyclotide sequences. RNA from V. betonicifolia plant tissues were extracted and sequenced by the platform Illumina HiSeq 2000 sequencing system with the library TruSeq RNA. Analysis of precursor sequences and putative processing sites provides further insight into cyclotide biosynthesis in V. betonicifolia and may also help to distinguish cyclotides from other cysteine-rich plant proteins. A total of 28 new (vibe 1-28) and three known (kalata S, viba 17, viba 11) cyclotide sequences were identified, which includes acyclotide and both cyclotide subfamilies Möbius and bracelet. Three precursors differ significantly in these common processing sites; vibe 10, vibe 22 and vibe 25 lack the common asparagine or aspartic acid in their cyclotide domain at C termini, vital for cyclisation. BLAST search of cyclisation enzyme, asparagine endopeptidase in the V. betonicifolia transcriptome showed most similar to the predicted enzyme from V. uliginosa transcriptome (93%) followed by butelase 1 (71%) and OaAEP1b (68%).