Phytochemical investigation of Rhus tripartita and its activity against cyclooxygenases and acetylcholinesterase

Purpose: To investigate the inhibitory activity of crude methanol extract, fractions and two pure compounds from Rhus tripartita stem cyclooxygenases (COX-1 and COX-2) and acetylcholinesterase (AChE); also, to evaluate their antioxidant properties in in-vitro assays.Methods: R. tripartita extract and fractions were examined as inhibitors of COX-1 and COX-2 and AChE. Their antioxidant properties were also evaluated using various antioxidant tests, including free radical scavenging, nitric oxide, and total antioxidant capacity.Results: Ethyl acetate fraction (RT2), aqueous fraction (RT4), subfraction RT2-II, and subfraction RT2-III had a potent inhibitory effect on AChE with low IC50 values. At the same time, a subfraction (RT2-III) was an effective COX-2 inhibitor (94.5 % at 10 μg/mL) followed by ethyl acetate fraction (RT2; 79.39 %), aqueous fraction (RT4; 70 %), total extract (RT; 66.18 %), subfraction RT2-III (64.08 %), compound 5 (epicatechin; 61.25 %), compound 2 (taxifolin; 55.63 %), subfraction RT2-II (46.85 %), and butanol fraction (RT3; 40.80%). RT2, RT4, RT2-II, RT2-III, and compound 2 each showed 100 % inhibition at 20 μg/mL.Conclusion: The ethyl acetate fraction (RT2), aqueous fraction (RT4) and subfractions RT2-II and RT2- III are effective natural inhibitors of AChE. Subfraction RT2-III is the best COX-2 inhibitor, followed by ethyl acetate fraction RT2 and aqueous fraction (RT4). These bioactive materials can be considered natural COX-2 and AChE inhibitorsKeywords: Cyclooxygenase, Anti-nflammatory, Acetylcholinesterase, Anacardiaceous, Taxifolin, Epicatechi

Population demography and global sensitivity analysis of <i>Avicennia marina</i> on the eastern and western coasts of Saudi Arabia

Mangrove ecosystems are one of the habitats that host high environmental diversity at the level of physical, geomorphological and biological features in arid regions. In Saudi Arabia, mangrove ecosystems are heavily threatened by both natural hazards and human pressure. The total estimated area of mangroves in Safwa Al Khurais, Saudi Arabia, is approximately 20 000 ha in extent and comprises two species: Avicennia marina and Rhizophora mucronata. They supply detritus to the marine food web and play a significant role in the conservation of biological diversity. The main objective of this study was to analyse the demographic population sensitivity of A. marina in two representative sites on the Red Sea and the eastern coast of Saudi Arabia. A sensitivity analysis was used to assess the contributions of the inputs to the total uncertainty in the analysis outcomes. Demographic features affecting mangroves in Saudi Arabia are complex and include various aspects. The phenological phase, tree size, density, cover, number of dead trees and pneumatophore characteristics were considered in this study. A comparative analysis of Gaussian process emulators for performing a global sensitivity analysis was used to conduct a variance-based sensitivity analysis to identify which uncertain inputs drive the output uncertainty. The results showed that the interconnections between different demographic features were predictable, but that the extent of the sensitivity was uncertain. Findings from the current study are anticipated to contribute significantly towards an inclusive mangrove demographic features assessment, and towards the subsequent conservation of mangroves in Saudi Arabia. Conservation implications: The findings of the current research are discussed in light of the application of sensitivity analyses outputs in the conservation and management of mangrove ecosystems at a national leve