Browsing by Author "Jayasinghe, J. M. S."

Now showing 1 - 3 of 3

Alpha-amylase and alpha-glucosidase inhibitory activities of a novel compound isolated from Murraya koenigii
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Sampath, S. N. T. I.; Jayasinghe, J. M. S.; Attanayake, A. P.; Karunaratne, V.
Herbal plants are composed of a vast amount of novel antidiabetic drugs for the management of diabetes mellitus. The leaves of Murraya koenigii L. Sprengel. which belongs to Family- Rutaceae (Common name- curry leaves) plant is known to be a promising source of natural bioactive compounds. In this research, we report the isolation and characterization of a new compound from hexane extract of leaves of M. koenigii and its in vitro antidiabetic activity. The new compound was identified as 3,3',5,5',8-pentamethyl-3,3'-bis (4-methylpent-3-en-1-yl)-3,3',11,11'-tetrahydro-10,10'-bipyrano [3,2-a] carbazole and the structure was elucidated based on extensive 13C and 1H NMR, high-resolution mass spectrometry (HRMS) and 2D NMR analysis. Investigated the in vitro antidiabetic activity of the new dimer using alpha-amylase and alpha-glucosidase enzyme inhibition activities. The compound exhibited significant alpha-amylase activity (IC50 = 30.32 ±0.34 ppm) and the alpha-glucosidase inhibition activity (IC50 = 30.91 ±0.36 ppm) when compared with the acarbose at 0.05 significant level. These results revealed that the new compound isolated from the hexane extract of leaves of M. koenigii could act as an antidiabetic agent.
The effect of O-alkylated chain length on in-vitro anti-hyperglycemic and anti-obesity activity of garcinol derivatives
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Thennakoon, T. M. T. D.; Jayasinghe, J. M. S.; Karunaratne, N. L. V. V.
Type 2 Diabetic Mellitus has become one of the major global health issue, while obesity being a major risk factor for its development. Natural product and their semi-synthetic derivatives have shown promising therapeutic potential, with fewer side effects compared to synthetic drugs. Garcinol is one such potent anti-hyperglycemic and anti-obesity secondary metabolite rich in genus Garcinia. However, there have been no reported studies on its semi-synthetic analogs. Hence, the present study was aimed to synthesize O-alkylated derivatives and evaluate the effect of the alkyl chain length on its in-vitro anti-hyperglycemic and anti-obesity properties. Garcinol was isolated from the acetone-water (9:1) extract of dried fruit rinds of Garcinia quaesita and characterized by spectroscopic methods and melting point data. Three novel O-alkylated derivatives of garcinol were synthesized using RX (C2H5I (Product 1), C3H7Br (Product 2), C6H13Br (Product 3)) and a mild base; K2CO3(acetone). The products were characterized by spectroscopic data (Mass, NMR and FTIR). The in-vitro anti-hyperglycemic activity was assessed by α-amylase and α-glucosidase enzyme inhibition assays while, the anti-obesity activity was evaluated by pancreatic lipase enzyme inhibition assay. Product 1 showed no significance difference (p > 0.05) in α-amylase (IC50 28.45 ± 1.17 mg L-1) and α-glucosidase (IC50 12.48 ± 0.28 mg L-1) inhibitory potential while Product 2 and Product 3 showed significantly lower (p < 0.05) α-amylase and α-glucosidase inhibitory activity compared to garcinol (α-amylase; IC50 37.81 ± 1.48 mg L-1 and α- glucosidase; IC50 17.18 ± 1.53 mg L-1). Product 1 (IC50 53.36 ± 1.23 mg L-1) showed significantly lower (p < 0.05) pancreatic lipase inhibitory potential while product 2 (IC50 31.75 ± 0.32 mg L-1) showed no significant difference (p>0.05) in pancreatic lipase inhibitory activity compared to garcinol (IC50 38.93 ± 0.63 mg L-1). Further, the Product 3 (IC50 27.13 ± 1.62 mg L-1) exhibited significantly higher (p < 0.05) pancreatic lipase inhibitory potential compared to garcinol (IC50 38.93 ± 0.63 mg L-1). Based on this study, it can be concluded that O-alkylated chain length has positive effect on anti-obesity potential, and a negative impact on anti-hyperglycemic potential. However, future studies are required to confirm this trend with more examples.
In vitro antidiabetic activity of fractionated extracts of Coccinia grandis (L.) Voigt
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Wasana, K. G. P.; Attanayake, A. P.; Jayasinghe, J. M. S.; Weeraratna, T. P.; Jayatilaka, K. A. P. W.
The Paspanguwa herbal formulation is commonly consumed as a traditional medicine in Sri Lanka. Paspanguwa consists of five ingredients, namely the rhizome of Zingiber officinale (Inguru), leaves and stem of Hedyotis corymbosa (Pathpadagam), dried berries of Solanum xanthocarpum (Katuwalbatu), dried stem of Coscinium fenestratum (Venivalgata), and dried seeds of Coriandrum sativum (Koththamalli). The importance and objective of this study was to prove the antioxidant and anti-inflammatory properties of traditionally used decotion, Paspanguwa claimed to have. In the present study, water extracts of the individual ingredient and the Paspanguwa decoction were screened for their total soluble phenolic content (TPC), total soluble flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and their ability to inhibit protein denaturation (anti-inflammatory activity). The highest and the lowest TPC was seen in Coriander and ginger as 12.76 ± 1.00 and 7.89 ± 0.86 mg Gallic acid equivalent/g dry weight, respectively. The highest and the lowest TFC was seen in Katuwalbatu and Pathpadagam as 778.19 ± 1.40 and 282.14 ± 1.49 µg Catechin equivalent/g of dry weight, respectively. The lowest and the highest IC50 values for the DPPH assay was seen in Paspanguwa decoction and Katuwalbatu as 253.4 ± 8.2 and 609.7 ± 5.6 µg/mL, respectively, while the standard ascorbic acid showed 111.0 ± 6.1 µg/mL. The highest and lowest reducing power percentages were seen in Paspanguwa decoction and coriander as 94.74 ± 1.31 and 22.95 ± 0.96 while the standard ascorbic acid showed 109.89 ± 0.96. The ability to inhibit protein denaturation varied in the order of: Acetylsalicylic acid (standard) > Paspanguwa decoction > ginger > coriander > Venivalgata > Katuwalbatu > Pathpadagam at all the three concentrations (625, 1250, and 2500 µg/mL). These results suggest that Paspanguwa water extract is a good source of antioxidants with TFC and TPC with a higher ability to inhibit protein denaturation. Our findings corroborate with the previous in vitro studies of the antioxidant activity of Paspanguwa. However, our study is the first to reveal the anti-inflammatory action, total flavonoid content, and reducing power of the Paspanguwa herbal formula. Further, this study validated the use of Paspanguwa as a good source of antioxidants together with anti-inflammatory activity in traditional Ayurvedic medicine.