Evaluation of Binding and Abrasion Properties of Grey Mangrove (Avicennia marina) Leaf Extract Against Escherichia coli K12 DNA

Background: Mangroves are globally known for their ecological importance and are found to be extensively used in traditional medicine. Avicennia marina, commonly known as grey mangroves exhibit strong antimicrobial properties and are also considered being a promising drug candidate in neutralizing pathogens. Objective: In our present study, the leaf extract from Avicennia marina was isolated using organic solvents of ascensive polarity to evaluate binding and abrasive properties in Escherichia coli K12 DNA. Methods: Samples of the pulverized leaves were used for sequential extraction using ethyl acetate, chloroform and acetone. The minimum inhibitory concentration of isolates from ethyl acetate, chloroform and acetone were quantified to be 0.125gL-1, 0.0625gL-1 and 0.125gL-1, respectively. These values were further utilized to calculate the binding constant between Escherichia coli DNA and isolates. In addition, mutagenicity of the isolates was assessed using Ames test in which the Escherichia coli K12 (strain AB1157) bacteria was cultured in minimal glucose media supplemented with isolates for assessing their DNA modifying ability. Further, DNA abrasion potential was assessed for all the isolates using Comet assay. Results: Results of Ames test showed that the isolates have DNA modifying ability, whereas the Comet assay demonstrated that isolates do not exhibit DNA degrading potential. Conclusion: In conclusion, the mechanism by which the isolates degrade the bacterial cell must be contrary to its DNA degrading potential. Experiments paved the way for further quantification and examination using bioinformatics tools to find the best drug candidate and to run clinical trials

Spatial distribution and potential ecological risk assessment of some trace elements in sediments and grey mangrove (Avicennia marina) along the Arabian Gulf coast, Saudi Arabia

To assess trace element concentrations (Zn, Cu, Pb, Cr, Cd and Ni) in the mangrove swamps along the Saudi coast of the Arabian Gulf, thirteen samples of surface sediment and leaves of grey mangrove, Avicennia marina were collected and analyzed. The detected trace element contents (μg g-1) in surface sediments were in the following descending order according to their mean values; Cr (49.18) > Zn (48.48) > Cu (43.06) > Pb (26.61) > Ni (22.88) > Cd (3.21). The results showed that the average concentrations of Cd and Pb exceeded their world average concentration of shale. The geo-accumulation, potential ecological risk and toxicity response indices demonstrated that trace elements have posed a considerable ecological risk, especially Cd. The inter-relationships between physico-chemical characters and trace elements suggests that grained particles of mud represent a noteworthy character in the distribution of trace elements compared to organic materials. Moreover, the results revealed that Zn was clearly bioaccumulated in leaf tissues A. marina. Dredging, landfilling, sewage effluents and oil pollution can be the paramount sources of pollution in the area under investigation.

Total Phenolic and Coumarin Content, Antioxidant Activity of Leaves, Fruits, and Stem Barks of Grey Mangrove (Avicennia marina)

Avicennia marina is one of the mangrove species used for traditional medicines. The leaves, fruits, and stem barks of A. marina are used for treating skin diseases. The stem barks are used for rheumatism, smallpox, and ulcers. The extract of A. marina was also reported to have antioxidant activity and indicates the presence of alkaloid, saponin, flavonoid, tannin, sterol/triterpenoid, and coumarin. However, the comparison of the antioxidant activity of leaves, fruits, and stem barks is not evaluated yet. The purpose of this study is to compare the antioxidant activity, total phenolic and coumarin content of leaves, fruits, and stem barks of A. marina. The antioxidant activity was determined using DPPH radical scavenging assay and was evaluated by spectrophotometric method at 515 nm. Quercetin was used for comparison. The fruits had the highest antioxidant activity with an IC50 value of 85.246 ppm, followed by stem barks and leaves with IC50 of 205.281 ppm and 307.037 ppm, respectively. Although the antioxidant activity of A. marina fruits was far from quercetin (IC50 of 3.789 ppm), it still categorized as a strong antioxidant. The strong antioxidant activity of fruits was followed by higher total phenolic and coumarin content than the stem barks and leaves part. Total phenolic and coumarin content of fruits were 49.119 mg GAE/ g and 8.894 x 10-3 mg CE/g, respectively. The leaves part had total coumarin content of 8.418 x 10-3 mg CE/g, but it had low IC50. It may be caused by the other secondary metabolite compounds that could reduce the antioxidant activity of coumarin.

Meiobenthic assemblage of the grey mangrove (Avicennia marina) along the Saudi Arabian coast of the Red Sea with emphasis on free-living nematodes

Spatial variability in the population density of meiofauna and the assemblage of free-living marine nematodes was studied at 20 mangrove sites located along the Saudi Arabian coast of the Red Sea. The total abundance of meiofauna varied between the locations and ranged from 119 to 1380 ind. 10 cm−2. A total of seven main taxa were recorded. Nematodes dominated (64.3%) in all sediment samples. They were followed by harpacticoid copepods (13.2%) and polychaetes (12.9%) with significant differences in their density between the locations surveyed (p < 0.001). The Pearson correlation analysis showed significant positive correlations between the sand fraction and nematodes, harpacticoid copepods and turbellarians. Twenty-five genera of free-living nematodes belonging to 15 families were recorded in the study area. Microlaimidae were the most abundant family, while Xyalidae, Desomodridae and Chromidoridae were the most diverse families. Microlaimus, Halalaimus and Terschellingia were the most frequent genera. ANOSIM values obtained for the distribution of different nematode genera in various habitats showed no significant differences. Feeding types of different nematode genera were also documented and the epistrate feeders along with the deposit feeders were found to be the common feeding types in the present study.

Bio-accumulation of Polycyclic Aromatic Hydrocarbons in the Grey Mangrove (Avicennia marina) along Arabian Gulf, Saudi Coast

The Arabian Gulf is considered as one of the most important sources for the crude oil all over the world. Due to the vast oil exploration and exploitation, huge amounts of organic pollutants infiltrate to the gulf. An important class of organic pollutants is polycyclic aromatic hydrocarbons (PAHs). One of the marine habitats in Arabian Gulf area is the mangrove stands, that are undoubtedly impacted by all anthropogenic factors like oil industries and sewage discharge. In the monitoring framework for mangrove ecosystem along Saudi coasts, nine mangrove stands were examined for the accumulation of PAHs in the Arabian Gulf coast. PAHs were measured using Gas Chromatography-Mass Spectrometry. The mean values detected for total PAHs in mangrove sediments, roots and leaf were 105.39, 680.0 and 282.4 ng/g, respectively. The trend of total PAHs concentrations in all sites showed the descending order: roots > leaf > sediments. Despite the sandy nature and low organic carbon contents of the mangrove sediments, moderate values of PAHs were detected in the major sites. PAH bio-accumulation factors for roots are higher than that in leaf. The diagnostic ratios revealed that the sources of PAHs are mainly pyrogenic, except for Damam and Damam Port that were found to be petrogenic.

Bio-concentration of Polycyclic Aromatic Hydrocarbons in the grey Mangrove (Avicennia marina) along eastern coast of the Red Sea

There are numerous sources of chemical pollutants which can impact the mangrove ecosystem through adjacent waters, industrial and sewage discharges and air depositions. Polycyclic aromatic hydrocarbons (PAHs) are semi volatile ubiquitous anthropogenic pollutants detected in all environmental compartments. In the monitoring framework for the mangrove ecosystem along the Red Sea coast of Saudi Arabia, nine mangrove stands were examined for the accumulation of PAHs. Polycyclic aromatic hydrocarbons were measured using Gas Chromatography-Mass Spectrometry (GC-MS). The mean values detected for total PAHs in sediments, roots and leaf were 2.98, 8.57 and 23.43 ng/g respectively. The trend of the total PAHs concentration in all sites showed the descending order: leaf > roots > sediments. Beside the sandy nature of the sediments, the presences of all stands in remote areas fare from the direct anthropogenic effects lead to these relative low values. PAH bio-concentration factors for leaf are two to three magnitudes higher than that in roots, suggesting atmosphere deposition /leaf uptake mechanism in addition to the sediment/root mechanism. The diagnostic ratios revealed that the sources of PAHs are mainly pyrogenic.