Browsing by Author "Udukala, D. N."

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Determination of Antioxidant Activity of the Aqueous Extract of Corm of Musa paradisiaca L.
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Yatawatta, Y. M. G. A. I.; Udukala, D. N.
Most often grown in tropical and subtropical regions, Musa paradisiaca L. is renowned for its excellent nutritional content. Corm of Musa paradisiaca is known to be used in treating many diseases in traditional medicine in Sri Lanka. In this study the antioxidant properties of the aqueous extract which was prepared according to the method preparing decoction (“Kasaya”) was evaluated using the (DPPH) free radical scavenging assay. Antioxidant-rich decoction which contains six therapeutic herbs such as Musa paradisiaca L., Sida cordofolia L., Phyllanthus emblem L., Santalum album L., Tribulus terrestris L., and Salacia reticulata L. are used to make the decoction. These plants already contain antioxidant properties in certain of their parts. IC50 values calculated for the standard, aqueous extract and decoction were 0.052±0.012 mg/mL, 0.096±0.015 mg/mL and 0.056±0.111 mg/mL respectively. At higher concentrations, the percentage free radical scavenging activity in the aqueous plant extract and the decoction displayed similar values, but at lower concentrations, the free radical scavenging activity of the decoction was noticeably higher than that of the corm of Musa paradisiaca's aqueous extract. In addition, total phenolic content and total flavonoid content of both the aqueous extract and the decoction were examined compared with the respective standards. The Folin-Ciocalteu method is used to calculate the total phenolic content in the extracts as Gallic acid equivalents (GAE). The phenolic content of the Aqueous extract and decoction showed as 23.80±0.06 mg GAE/g and 56.04 ±0.07 mg GAE/g respectively. The decoction has a noticeably higher total phenolic content than the aqueous extract. The amount of total flavonoids in the extracts was measured using Quercetin equivalents (QE). The flavonoid content of the aqueous plant extract resulted in 52.39± 0.06 mg QE/g and the decoction resulted as 76.04±0.07 mg QE/g. In comparison, the flavonoid content of the decoction was significantly higher than that of the aqueous plant extract.
Evaluation of in vitro and in-silico anti-bacterial activities of novel para substituted methoxy and chloro derivatives of quinazolinone
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Ravishan, M. G. K.; Udukala, D. N.; Gunaratna, M. J.
Among the plethora of microorganisms encountered daily, some exhibit pathogenic qualities while others offer benefits. The ongoing battle against pathogenic microorganisms escalates considering increasing antibiotic resistance, prompting the need for novel strategies to impede or eradicate these entities. A main approach in the realm of antimicrobial tactics involves targeting DNA gyrase, a protein pivotal for processes such as replication, repair, and growth. Among the vast range of existing antibacterial drugs Quinazolinone based compounds are much prominent. This research focused on the synthesis of novel 6-bromo-2-phenylquinazolin-4(3H)-one, 6-bromo-2-(4-methoxyphenyl)quinazolin- 4(3H)-one and 6-bromo-2-(4-chlorophenyl)quinazolin-4(3H)-one and the evaluation of their antimicrobial activities against Escherichia coli (ATCC 25921). The selection of functional groups for the derivatives, based on their electron-withdrawing and donating properties, was geared towards augmenting antimicrobial efficacy by impeding crucial processes like cell wall formation and replication. The structures of the synthesized analogues were confirmed using spectroscopic techniques such as FT-IR, 1H NMR, 13C NMR, High Resolution Mass Spectroscopy and by determining the melting points of the compounds. In-silico investigations utilizing molecular docking strategies done through auto dock vina have unveiled encouraging findings, showcasing strong binding affinities with DNA gyrase of E.coli. Both 6-bromo-2-(4-methoxyphenyl)quinazolin-4(3H)-one and 6-bromo-2-(4- chlorophenyl)quinazolin-4(3H)-one compounds and the standard ciprofloxacin gave binding affinities higher than -7.0 kcal/mol indicating their higher interactions with DNA gyrase in inhibition of cell wall synthesis of the micro-organism. However, the synthesized compounds failed to demonstrate noteworthy antimicrobial efficacy against E.coli in the well diffusion test, contrary to the favourable molecular docking results. The para substituted compounds 6-bromo-2-(4-methoxyphenyl)quinazolin- 4(3H)-one and 6-bromo-2-(4-chlorophenyl)quinazolin-4(3H)-one showed positive activity (maximum zone of inhibition values of 15.0 ± 1.00 mm and 13.0 ± 0.58 mm respectively) compared to the 6- bromo-2-phenylquinazolin-4(3H)-one showcasing that electron donating or electron withdrawing effects at para position showed no considerable difference, concluding that para position substitution may enhance the anti-bacterial activity of the compound. Hence this study demonstrates the easy synthesis of 6th position brominated 2-phenyl-3H-quinazolin-4-one derivatives through oxidative cyclocondensation of 2-amino-5-bromobenzamide with an aryl aldehyde and determination of their antibacterial activities showcasing the need of further modifications and accurate methods for in-silico and in-vitro evaluations.
Evaluation of total phenolic content and antioxidant activity of Tabernaemontana dichotoma
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Weerathunga, R. M.; Udukala, D. N.
Sri Lanka is recognized as a global biodiversity hotspot, which possesses a diverse range of fruits, yet a significant portion of them is underutilized. Numerous phytochemicals found within plants have a wide variety of medicinal applications including acting as antioxidants. Phenolic compounds are excellent oxygen radical scavengers, because the electron reduction potential of phenolic radicals is lower than the electron reduction potential of oxygen radicals. Therefore, the objective of this study was to evaluate the total phenolic content and the antioxidant activity of Tabernaemontana dichotoma, a plant species commonly known as “Divi kaduru” or “Eve’s apple” collected from Gampaha district, Sri Lanka. This plant was chosen for this research because it was easily found, frequently used in traditional medicine, and has not been researched before. Crude extracts of the fruit and seed of T. dichotoma were prepared by sequential extraction using hexane, ethyl acetate and methanol at room temperature for 48 hours for each solvent respectively. Spectrophotometric technique using Folin - Ciocalteu reagent was performed to evaluate the total phenolic content of the extracts and results were expressed as Gallic acid equivalents (GAE) per gram of dry weight of the sample. Then the 2,2- diphenyl-1- picrylhydrazyl (DPPH) free radical scavenging activity was carried out to determine the antioxidant activity based on the scavenging ability of the stable DPPH free radical. Ethyl acetate extract of the seed exhibited the highest total phenolic content 0.8717 ± 0.003 mg GAE/g, followed by the methanol extract of the fruit (0.4065 ± 0.004 mg GAE/g), methanol extract of the seed (0.2947 ± 0.009 mg GAE/ g) and ethyl acetate extract of the fruit (0.1991 ± 0.089 mg GAE/g). These results were obtained using gallic acid as the standard (R2 = 0.9911). Crude ethyl acetate extract of seed showed the highest antioxidant activity among all four extracts (199.35 ± 0.056 mg/L), yet lower activity compared to that of standard L-Ascorbic acid (IC30 value; 35.45 mg/L). Additionally, the extracts showed a moderate correlation between the total phenolic content and antioxidant capacities of ethyl acetate and methanol extracts (p = 0.2582 and p = 0.6371) respectively. This study provides insight into the variation of phytochemical composition and antioxidant potential across different parts of the plant Tabernaemontana dichotoma. Further studies of these plant extracts could lead to an effective drug development from these plant extracts.
Volatiles from host plant brinjal attract the brinjal Fruit and Shoot Borer -Leucinodes orbonalis Guenee
(Journal of Asia-Pacific Entomology, 2021) Nusra, M. S. F.; Udukala, D. N.; Amarasinghe, L. D.; Paranagama, P. A.
Brinjal Fruit and Shoot Borer- Leucinodes orbonalis Guenee is a major insect pest on brinjal- Solanum melongena worldwide. An effective strategy used in developing pest controlling agents is the synergism between insect pheromones and host plant volatiles, which can increase the attraction of insect pest. The present study was aimed at investigating the chemical constituents and attractant effects of the volatiles extracted from different parts of the host plant brinjal on the behavior of adult L. orbonalis. Bioassay using Y-shaped olfactometer revealed that the one-day old virgin female, gravid female and male insects respond positively to the host plant volatiles extracted from fruits, leaves and shoots but not to that of flowers. It was shown that the gravid females were significantly attracted to all three volatiles (p < 0.05). Bioassay using X-shaped olfactometer identified that all three types of insects highly preferred the volatiles from fruits (p < 0.05). Gas chromatography-mass spectrometry analysis of volatiles indicated that brinjal plant produces volatile secondary metabolites, which include 2,2′ -(Ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl) dibenzoate (12.11%), 3,7-dimethylocta-1,6-dien-3-ol (22.38%), Benzyl alcohol (22.9%) and Benzyl alcohol (27.06%) as major constituents from fruits, shoots, leaves and flowers respectively. Responses of insects to the volatiles from host plant in the absence of visual cues direct us to focus on the importance of host plant volatiles to locate the plant. Results of this study emphasize the major role that host plant volatiles play in the attraction of insect pests towards the plant.
Volatiles from host plant brinjal attract the brinjal Fruit and Shoot Borer -Leucinodes orbonalis Guenee
(Journal of Asia-Pacific Entomology, 2021) Nusra, M. S. F.; Udukala, D. N.; Amarasinghe, L. D.; Paranagama, P. A.
Brinjal Fruit and Shoot Borer- Leucinodes orbonalis Guenee is a major insect pest on brinjal- Solanum melongena worldwide. An effective strategy used in developing pest controlling agents is the synergism between insect pheromones and host plant volatiles, which can increase the attraction of insect pest. The present study was aimed at investigating the chemical constituents and attractant effects of the volatiles extracted from different parts of the host plant brinjal on the behavior of adult L. orbonalis. Bioassay using Y-shaped olfactometer revealed that the one-day old virgin female, gravid female and male insects respond positively to the host plant volatiles extracted from fruits, leaves and shoots but not to that of flowers. It was shown that the gravid females were significantly attracted to all three volatiles (p < 0.05). Bioassay using X-shaped olfactometer identified that all three types of insects highly preferred the volatiles from fruits (p < 0.05). Gas chromatography-mass spectrometry analysis of volatiles indicated that brinjal plant produces volatile secondary metabolites, which include 2,2′ -(Ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl) dibenzoate (12.11%), 3,7-dimethylocta-1,6-dien-3-ol (22.38%), Benzyl alcohol (22.9%) and Benzyl alcohol (27.06%) as major constituents from fruits, shoots, leaves and flowers respectively. Responses of insects to the volatiles from host plant in the absence of visual cues direct us to focus on the importance of host plant volatiles to locate the plant. Results of this study emphasize the major role that host plant volatiles play in the attraction of insect pests towards the plant.
Volatiles from host plant brinjal attract the brinjal Fruit and Shoot Borer -Leucinodes orbonalis Guenee
(2021) Nusra, M. S. F.; Udukala, D. N.; Amarasinghe, L. D.; Paranagama, P. A.
Blinjal Fruit and Shoot Borer- Leucinodes orbo11alis Guenee is a major insect pest on brinjal- Sola11u111 111elo11ge11a worldwide. An effective strategy used in developing pest controlling agents is the synergism between insect pheromones and host plant volatiles, which can increase the attraction of insect pest. The present study was aimed at investigating the chemical consti tuents and attractant effects of the volatiles extracted from different parts of the host plant brinjal on the behavior of ad ult L. orbo11alis. Bioassay using Y-shaped olfactometer revealed that the one-day old virgin female, gravid female and male insects respond positively to the host plant volatiles exU'acted from fruits, leaves and shoots but not to that of flowers. It was shown that the gravid females were significantly attracted to all three volatiles (p < 0.05). Bioassay using X-shaped olfactometer identified that all three types of insects highly preferred the volatiles from fruits (p < 0.05). Gas chromatography-mass specuomeuy analysis of volatiles indicated that brinjal plant produces volatile seconda1y metabolites, which include 2,2' -(Ethane-l ,2-diylbis(oxy))bis(ethane-2,1-diyl) di benzoate (12.11 %), 3,7-dimethylocta-1,6-dien-3-ol (22.38%), Benzyl alcohol (22.9%) and Benzyl alcohol (27.06%) as major constituents from fruits, shoots, leaves and flowers respectively. Responses of insects to the volatiles from host plant in the absence of visual cues direct us to focus on the importance of host plant volatiles to locate the plant. Results of this study emphasize the major role that host plant volatiles play in the attraction of insect pests towards the plant.