Browsing by Author "Napagoda, M. T."

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Comparative analysis of anticandidal potential between Cinnamomum zeylanicum (Ceylon Cinnamon) leaf and bark extracts against clinically isolated Candida species
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Wanigasekara, D. N.; Wickramasinghe, S. S.; Wijayaratne, G. B.; Napagoda, M. T.
Antifungal resistance has emerged as a major concern, hindering the treatment of fungal infections and prompting the development of new therapeutic options. Plant extracts have received attention for their potential as novel antifungal agents due to their various chemical entities and traditional use in indigenous medicinal systems. Cinnamomum zeylanicum (Ceylon cinnamon) has demonstrated promising antibacterial effects due to its extensive phytochemical profile. This study focuses on the antifungal properties of C. zeylanicum leaf and bark extracts against various Candida species, comparing their Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs) to fluconazole, a conventional antifungal agent. Candida species tested included C. albicans, C. parapsilosis, C. krusei, C. glabrata, C. tropicalis, C. famata, C. rugosa, C. dubliniensis, C. utilis, and C. guilliermondii. The obtained MICs depict that C. zeylanicum leaf extract has significant antifungal activity against numerous Candida species, with MIC values ranging from 0.0016 to 0.0102 mg/mL. In contrast, the bark extract had slightly higher MICs for most species, ranging from 0.0040 mg/mL to 0.0256 mg/mL. Fluconazole exhibited MIC values ranging from 0.0016 mg/mL to 0.0102 mg/mL for most species but was ineffective against C. glabrata, which was resistant to fluconazole. Notably, C. zeylanicum leaf extract has very low MICs against C. glabrata and C. krusei, indicating potency comparable to fluconazole. Furthermore, the MFCs of C. zeylanicum extracts demonstrate anticandida activity. MFCs in the leaf extract range from 0.0016 mg/mL to 0.1600 mg/mL, but in the bark extract, they range from 0.0040 mg/mL to 0.1600 mg/mL. These findings support the leaf extract's capacity to successfully kill Candida, while the bark extract likewise exhibits fungicidal activity across all tested species. In conclusion, C. zeylanicum leaf extract exhibits remarkable antifungal efficacy against various Candida species, indicating its potential as a natural alternative or adjuvant to conventional antifungal medications. The found efficacy against fluconazole-resistant species such as C. glabrata and C. krusei emphasizes the necessity of further investigation into C. zeylanicum extracts for therapeutic uses. Future studies should focus on understanding the mechanisms of action and performing clinical trials to validate these findings in real-world healthcare settings.
Determination of total phenolic content (TPC) of Nymphaea nouchali and Nymphaea pubescens by Folin Ciocalteu method
(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Sundaram, T. M.; Napagoda, M. T.; Wijesekera, K. D.; Wijayaratne, Gaya Bandara
Nymphaea nouchali (Nil Manel) and Nymphaea pubescens (Olu) are aquatic plants, and have a long history of use as food and folk medicine in many countries. Many phenolic compounds isolated from these two plant species have exhibited antioxidants properties and some simple phenolic compounds have shown to possess various pharmacological activities, including anti-inflammatory, antiproliferative, antioxidant and pro-apoptotic potential. The aim of the present study was to determine the content of total phenol in an extract from N. nouchali and N. pubescens flowers collected from Galle, Sri Lanka, by a UV/Vis spectrophotometric method. Aqueous methanol (80%) was used as the solvent to extract flowers including petals, stamens and pistil and all extracts were analyzed for TPC by Folin Ciocalteu method. Results were expressed in terms of gallic acid equivalence in (GAE)/g dry weight (DW) of flower part. N. pubescens petals contained 49.780 ± 0.626, stamens 37.581 ± 0.477 and pistil 31.889 ± 0.711, while N. nouchali petals showed 22.536 ± 0.383, stamens 38.702 ± 1.112 and pistil 30.119 ±1.116 GAEg-1. N. pubescens showed higher TPC in every plant part tested compared to N. nouchali and petal extract of N. pubescens showed highest TPC. Hence, N. pubescens flowers are a good source of antioxidants. Results emphasized that N. nouchali and N. pubescens extracts have high phenolic content and the importance of the use of natural products to treat pathological conditions.
Evaluation of photoprotective property and antioxidant property of Clitoria ternatea (Katarolu)
(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Jayashan, T. W. K. S. S.; Wijesekara, Kanchana; Napagoda, M. T.
Cumulative lifetime dose of ultra violet (UV) radiation has increased significantly due to many natural and artificial consequences. UV-A and UV-B radiation are considered as the major risk factors for photo dermal pathogenesis. Many herbal extracts and herbal preparations have served as effective sunscreen agents as they have UV absorption, scattering, reflecting and excellent free radical scavenging activity. Clitoria ternatea (Katarolu) is a plant known for its versatility in therapeutic and cosmeceutical applications over thousands of years due its remarkable bioactivity and rich phytochemical composition. Therefore, the study is concentrated on determining photo protective property and antioxidant profiles of acidified aqueous alcoholic floral extracts of C. ternatea. Invitro photo protective property of crude extract was evaluated using 0.2 mg/mL methanolic solution and expressed in terms of spectrophotometric SPF according to Mansur equation. Stability of photo protective property was evaluated for 21 days. Antioxidant activity of the floral extract was evaluated by DPPH radical scavenging activity, nitric oxide (NO) radical scavenging and ferricyanide reducing assays. Alcoholic extract of C. ternatea petal (0.2 mg/mL) exhibited excellent photo protective activity and SPF value was 20.4916±0.653 and shown promising photo stability in terms of spectrophotometric SPF value. Antioxidant capacity of the crude floral extract was 1418.27±125.89 mg ascorbic acid equivalents/100g DW mg ascorbic acid equivalents/ 100g DW of the with reference to the standard curve (y = 0.7328x - 0.1471, R² = 0.9979). % NO radical scavenging capacity of floral extract (1mg/mL) was 40.379±5.478. Reducing power of the floral extract was 2345.412±215.258 mg and 3345.91±456.34 mg ascorbic acid equivalents/ 100g DW, respectively with reference to the standard curve (y = 0.0042x + 0.0971, R² = 0.9988). Hence, C.ternatea can be successfully served as a natural sunscreen agent in herbal and natural cosmeceuticals.
Interactions between penicillin and aqueous extracts of Plectranthus amboinicus and Plectranthus zeylanicus against Staphylococcus aureus.
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Hafsa, M. F. F.; Darshana, D.; Wickramasinghe, S. S.; Tennakoon, S. H.; Napagoda, M. T.
Penicillin, the pioneering antibiotic, has declined in effectiveness against Staphylococcus aureus due to increasing resistance, highlighting the urgent need for alternative strategies. Combining penicillin with medicinal plant extracts, such as Plectranthus amboinicus (Kapparawalliya) and Plectranthus zeylanicus (Iriveriya), rich in antibacterial compounds, offers a promising approach to revitalising its therapeutic efficacy. This study aimed to evaluate the potential interactions between penicillin and the aqueous extracts from P. amboinicus (PA) and P. zeylanicus (PZ) against both Methicillin-sensitive S. aureus (MSSA) and Methicillin-resistant S. aureus (MRSA). Whole plants of PA and PZ were macerated in distilled water for 24 hours at room temperature to prepare aqueous extracts. In the preliminary screening, the antibacterial activity of the aqueous extracts (500 mg/mL), and penicillin (3 mg/mL) were evaluated individually using the well-diffusion method. Ciprofloxacin (2 mg/mL) and distilled water were used as positive and negative controls, respectively. Subsequently, the minimum inhibitory concentration (MIC) of penicillin against MSSA and MRSA was determined using the broth microdilution method, followed by subculturing to determine minimum bactericidal concentrations (MBC). Aqueous extracts of PA and PZ were combined with different penicillin concentrations (2×MIC, MIC, 1/2×MIC, 1/4×MIC). The antibacterial activity of these combinations against MSSA and MRSA was evaluated using the well-diffusion method (well-diameter = 6 mm), measuring the inhibition zone diameter (IZD). The IZD of MIC of penicillin was compared with the IZD of penicillinPA and penicillin-PZ combinations to determine the interactions. Results showed that the aqueous extracts of PA and PZ did not demonstrate inhibition zones against MSSA and MRSA. The MIC and MBC of penicillin against MSSA were determined as 0.052 µg/mL and 100 µg/mL, respectively. However, the MIC of penicillin against MRSA was indeterminable, with an MBC exceeding 100 µg/mL. Notably, most combinations of penicillin with PA and PZ exhibited significantly higher IZD compared to MIC of penicillin alone (no inhibition zones), against both MSSA and MRSA (p < 0.05). Among all the combinations, the highest IZD was observed with the MIC+PZ combination against both MSSA and MRSA (IZD = 12.78 mm and 11.89 mm respectively). Potentiation was observed for the penicillin-PA combination, at penicillin concentration corresponding to the MIC against MSSA and at MIC, 1/2×MIC, 1/4×MIC against MRSA. With PZ, potentiation against MSSA and MRSA occurred at a penicillin concentration equivalent to the MIC. Additionally, penicillin combined with PZ demonstrated significantly stronger potentiation (p < 0.05) compared to penicillin-PA combinations, at equal penicillin concentrations, against both strains. In conclusion, the aqueous extracts from PA and PZ potentiated the antibacterial effectiveness of penicillin against MSSA and MRSA. This underscores the promise of these combinations for potent antibacterial therapies, suggesting a potential avenue for repurposing and reintroducing penicillin in combination with plant extracts to address antibiotic resistance. Further research should focus on understanding the mechanisms that enhance the effectiveness of penicillin when combined with PA and PZ.