SEPARATION, IDENTIFICATION, AND ANTIMICROBIAL ACTIVITY ASSAY OF SEAWEED EXTRACTS Gracilaria verrucosa AND Ulva fasciata

• Main Author: Ayuwulanda, Aditya
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/33930
• Institution: Institut Teknologi Bandung

One of biological resources derives from Indonesia’s sea is seaweed. Seaweed contains many chemical compounds as primary metabolites which are used as food and secondary metabolites that have activity as an antimicrobial, anticancer, antioxidant, antiinflammatory, antiviral, etc. Study of antimicrobial activity will discover and further understanding one of the potencies of sea weeds. This study was conducted to determine the antimicrobial activity of seaweed extracts Gracilaria verrucosa and Ulva fasciata that derived from Sayang Heulang Beach, Pamengpeuk, District of Garut, West Java. Antimicrobial assay of seaweed extracts was conducted to against four bacteria, which is Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus. Antimicrobial activity assay was performed by disc diffusion method. To obtain the seaweed extract, it was extracted with modified Folch method (methanol to chloroform to phosphate buffer, 2:1:0.8 (v/v)). The methanol phase extract rendement isolated from Gracilaria verrucosa and Ulva fasciata were 10.21% and 35.61% respectively, while those of the chloroform phase extract were 2.49% and 0.79% (dry weight, w/w) respectively. Both crude extracts from Gracilaria verrucosa have antimicrobial activity while only those of methanol extract from Ulva fasciata showed antimicrobial activity. Antimicrobial activity towards E. coli, P. aeruginosa, S. aureus, and B. cereus have shown by the development of clear zone diameter. Crude chloroform extracts of G. verrucosa showed highest activity against B. cereus (4.3 ± 1.52 mm), while those of U. fasciata showed highest activity againsts E. coli and P. aeruginosa (5.33 ± 0.57 mm). The average clear zone was analyzed by statistical test. T-test analysis showed that chloroform extracts from both seaweeds give the same effect toward S. aureus, B. cereus, and P. aeruginosa, while different effect were shown when studied upon E. coli. The crude extracts for chloroform phase were separated by chromatography column and eluted with step gradient of hexane and acetone (proportion of hexane to acetone were 7:3, 1:1, 3:7, and 1:9 (v/v)). Column chromatography fractions were analyzed by UV-Vis spectrometry. Extract of G. verrucosa separated into 11 fractions with six of them have antimicrobial activity, while extract of U. fasciata separated into 7 fractions with two of them have the activity. Among them G. verrucosa chromatography column extracts fraction 2 (FG-2) and fraction 4 (FG- 4) showed the highest antimicrobial activity. Such activity showed distict value againsts E. coli and P. aeruginosa with the average clear zone diameter was 3.5 ± 0.70 mm. For those of U. fasciata, fraction 2 (FU-2) showed the highest antimicrobial activity against E. coli with the average clear zone diameter was 4 ± 0.70 mm. The active fraction of seaweed extracts was identified by observing the absorbance peak at 380-780 nm. FG-2 showed peaks at wavelength of 410 nm, 505 nm, 535 nm, 609 nm, and 668 nm which are the typical peak for phaeophytin. FG-4 showed peaks at wavelength of 417 nm, 455 nm, 538 nm, 607 nm, and 666 nm which are the peaks for the mixture of chlorophyll and phaeophytin. FU-2 showed peaks at wavelength of 412 nm, 435 nm, 536 nm, 606 nm, and 662 nm which are the typical peaks for chlorophyll. FU-5 showed peaks at wavelength of 412 nm, 435 nm, 506 nm, 535 nm, 604 nm, and 666 nm which are the peaks for the mixture of chlorophyll and phaeophytin.