Antioxidant and antibacterial activities and identification of bioactive compounds of various extracts of Caulerpa racemosa from Algerian coast

Objective: To evaluate the antibacterial and antioxidant activities and to identify the volatile bioactive compounds present in different crude extracts of the seaweed Caulerpa racemosa var. cylindracea.Methods: Caulerpa racemosa harvested from the intertidal zone of Mostaganem coast (N 35?54'37.94", E 0?3'17.37") was subjected to Soxhlet extraction using methanol, chloroform, and hexane solvents. Antioxidant properties were assessed by using 2,2'-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and β-carotene bleaching assays. The antibacterial activity was evaluated on six standard bacterial strains using the agar disc diffusion method. The GC-MS analysis was performed using non-polar and polar capillary columns. Results: The chloroform extract of Caulerpa racemosa exhibited higher contents of polyphenols [(123.91±1.46) mg gallic acid equivalent/g dry extract] and tannins [(59.28±5.43) mg catechin equivalent/g dry extract] (P