Comparative screening of anti-dengue activity in aqueous and ethanol extracts of mangrove plants from Sabah

Aims@#Dengue virus is a global pathogen that lacks an effective vaccine or therapy. Screening medicinal plants for anti-dengue properties provides a promising avenue to identify potent compounds. Mangroves, known for their resilience in harsh conditions, produce a diverse range of natural products with unique biochemical profiles, which hold potential for anti-dengue treatments. This study aims to evaluate the anti-dengue activity of selected mangrove plant species from Sabah against DENV2 NS2B-NS3pro, utilizing an enzymatic protease assay. @*Methodology and results @#Six mangrove species (Avicennia marina, Bruguiera gymnorrhiza, Ceriops tagal, Rhizophora apiculata, Rhizophora mucronata and Xylocarpus granatum) were investigated, with various plant parts subjected to aqueous and ethanol extraction. The results demonstrated significant anti-dengue activity in both aqueous and ethanolic extracts of the mangroves against DENV2 NS2B-NS3pro, with IC50 values ranging from 0.95 µg/mL to 6.24 µg/mL. Notably, the ethanolic extract of R. apiculata leaves exhibited the highest inhibition, with an IC50 value of 0.95 µg/mL. @*Conclusion, significance and impact of study@#These findings suggest that the ethanolic extracts from R. apiculata leaves hold promise as potential candidates for dengue treatment. This study underscores the importance of natural products as valuable sources for the development of novel anti-dengue treatments, highlighting the need to explore mangroves in the quest for effective therapeutic options.

Efficacy of pyroligneous acid from Rhizophora apiculata on pathogenic Candida albicans.

Rhizophora apiculata pyroligneous acid which is a crude condensate produced from the distillation of smoke generated in the process of charcoal making has the potential to be used as antifungal agent especially to treat candidal infections. In this study, pyroligneous acid (PA), concentrated pyroligneous acid (CPA), Dichloromethane extracts of CPA namely DCM A and B were tested against four pathogenic strains of Candida albicans. The results exhibited significant inhibition zones within the range of 7.00 -8.00 mm for PA, 16.00- 17.00 mm for CPA, 16.00-18.00 mm for DCM A and 19.00-22.00 mm for DCM B. The results also revealed that extract DCM B of CPA was the most potential to be used as anticandidal agent with the minimum inhibitory concentration values between 3.13-6.25 mg/mL. Scanning electron micrographs of DCM B treated C. albicans cells confirmed the damaged cells caused by the extract.

Gallic acid: An anticandidal compound in hydrolysable tannin extracted from the barks of Rhizophora apiculata Blume.

A research was conducted to study the anticandidal compound of tannin extracted from the barks of a mangrove tree, Rhizophora apiculata Blume. Tannin obtained from the barks of Rhizophora apiculata Blume was further separated into condensed and hydrolysable tannins. A strong anticandidal activity was detected in the hydrolysable tannin, which exhibited minimal inhibitory concentration (MIC) of 6.25 mg/ml, and it was found to have yeastostatic activity at lower concentration (below MIC value) and yeastocidal activity at higher concentration (more than the MIC value). Furthermore, the isolation of the bioactive compound in hydrolysable tannin that responsible for the anticandidal activity was also determined using thin layer chromatography and high-performance liquid chromatography (HPLC). The results obtained confirmed that gallic acid was the bioactive compound that plays role in inhibiting and killing the Candida albicans cells.

Accumulation of lead and copper in Rhizophora apiculata from Setiu mangrove forest, Terengganu, Malaysia.

The accumulative partitioning of Pb and Cu in the Rhizophora apiculata was studied randomly in the Setiu mangrove forest, Terengganu. Samples of leaves, barks and roots were collected randomly from the selected studied species. Sediments between the roots of the sampled mangrove plants were also collected. The results from analysis for Rhizophora apiculata shows that the concentration of Pb and Cu were accumulated higher in root tissue compared to bark and leaf tissue but lower than surrounding sediment level. The average concentration of Cu for Rhizophora apiculata in leaf, bark, root and sediment was 2.73 , 3.94 , 5.21 and 9.42 mg l-1, respectively. Meanwhile, the average concentration of Pb in leaf, bark, root and sediment was 1.43 , 1.38 , 2.05 and 11.66 mg l-1, respectively. Results of concentration factors (CF) show that the overall the concentration of Pb and Cu were accumulated much higher in roots system of Rhizophora apiculata.