Chemical composition, antioxidant and antimicrobial activities of Moroccan species of Psidium guajava extracts

Background. During the recent years, appropriate attention has been paid to the oxidative stress which damages the body’s cells, proteins, and DNA. Therefore, the need of antioxidants becomes a therapeutic and preventive priority. In addition, microbial infections also constitute a public health problem. Objective. To find efficient, reliable and safe alternatives sources to synthetic antioxidants, antibiotics and antifungals drugs. Materials and methods. Extract and essential oil of Psidium guajava were screened for their antioxidant and antimicrobial activities against gram positive bacteria (Enterococcus faecalis and Staphylococcus aureus), gram negative bacteria (Citrobacter freundii, Escherichia coli and Pseudomonas sp) and fungi (Candida albicans,Candida tropicalis and Cryptococcus neoformans), as well as to determine the functional groups of phytochemicals present in the essential oil by Fourier transform infrared spectroscopy (FTIR). Results. The results indicate that P. guajava leaves extract demonstrated very high antioxidant activity and P.guajava essential oil showed the highest polyphenols content. The antioxidant capacity showed a significant negative linear correlation to total polyphenolic content (TPC) with Pearson’s correlation coefficients. P. guajava essential oil shows high antibacterial and antifungal activity against all the studied bacteria and fungi.The FTIR analysis of P. guajava essential oil showed the presence of several functional groups (ethers, esters, ketones, terpenes, alkanes, aldehydes, aromatic hydrocarbons, alcohols, and phenols). The relationship between the chemical composition and antimicrobial activity of P.guajava essential oil suggests that the attribution of its antimicrobial activity to a particular compound or a synergistic effects between its different constituents remains difficult. Conclusions. The present study demonstrated that Psidium guajava is a valuable source of active compounds with anti- oxidant and antimicrobial activities. This finding suggests the new use of the fruits and the leaves extracts of this plant in the treatment of bacterial and fungal infections, as well as for the extraction of new antioxidants. Therefore, it is necessary to be carried out in another study to identify the active(s) compound(s) in P.guajava essential oil with respect to their mechanisms and synergistic actions

Seasonal and geographical variation range of antifungal activity of sponge extracts from the Moroccan Atlantic coasts.

Peer reviewe

Evaluation of Bacteriological Parameters of Water Quality in The Bouregreg Estuary Along the Moroccan Atlantic Coast

On the Morrocan Atlantic coast, the Bouregreg estuary was submitted to many anthropic effects. After the dam Sidi Mohammed ben Abdellah was built in 1974, the flow became almost null. The waters of the estuary are meant for recreational activities, fishing, but at the same time they receive water collecting domestic and industrial wastewater. The waste in old landfills was not treated and leaked into the river water. The matter gets worse with the action of tides which make it difficult to escape the pollution load (physicochemical, bacteriological, heavy metals, etc.). The main objective of this study is to monitor the bacteriological quality of the surface waters from Bouregreg estuary (Moroccan Atlantic coast). The bacteriological parameters were determined upstream (S1, S2 and S3) and downstream (S4, S5 and S6) of the Bouregreg estuary. The parameters studied are fecal coliform (FC), fecal streptococci (FS), Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa. The evaluation of the bacterial contamination of the studied water samples shows that the rate of contamination by fecal coliforms is very high in station S3 compared to other stations. This is explained by the emplacement of this station which is located next to a main rejection of Oued Akrach. The bacterial loads are maximal in this station: 7 103 CF/100ml for fecal coliforms and 2 103 SF/100ml for fecal streptococci. The ratio values (CF/SF) for the different stations show that the fecal pollution observed at the studied estuary is of mixed origin with human dominance. The search for pathogenic bacteria namely Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa, was negative for all the studied samples