STUDY OF ANTIOXIDANT AND ANTIBACTERIAL ACTIVITY OF EXTRACTS, FRACTIONS, SUBFRACTIONS AND ACTIVE COMPOUNDS OF MOBE (ARTOCARPUS LACUCHA BUCH. -HAM)

• Main Author: Pertiwi, Dewi
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83345
• Institution: Institut Teknologi Bandung

Infection causes many health problems. One of the causes of infection is pathogenic bacteria that can be treated with antibiotics. However, inappropriate use of antibiotics causes antibiotic resistance resulting in the failure of therapy for infection. Nowadays, research on antibacterials and antioxidants in plants is often conducted, due to the content of phenol and flavonoid compounds that can act as antibacterials and antioxidants. Reactive oxygen species (ROS), which are free radicals, can cause various degenerative diseases such as atherosclerosis, diabetes, cardiovascular and aging. Because of these problems, searching for new candidate medicinal plants is necessary. Mobe (Artocarpus lacucha) is one of the plants from the Artocarpus genus that is traditionally used by the community as a seasoning for cooking and to treat diseases such as stomach pain, wound healing and deworming. Various research results obtained information that this plant has antioxidant, antimicrobial, anti-inflammatory and antiglycation activities. This study aims to assess the antioxidant and antibacterial activity of mobe. The plant parts used were leaves, barks, twigs and fruits. From the four parts, the barks was chosen to evaluate for the next step because it had the best antioxidant activity (antioxidant capacity by DPPH method 7.19 ± 0.10 mg AEAC/g extract and by CUPRAC method 91.32 ± 3.77 mg AEAC/g extract) and the best antibacterial against 6 of 9 test bacteria (inhibition diameter at a concentration of 750 µg/disk against MRSA bacteria, S. aureus, C.acnes, S.mutans, S.epidermidis and B.subtillis were 10.20 ± 0.001; 10.40 ± 0.69; 9.80 ± 0.34; 8.85 ± 0.26; 8.20 ± 0.17; 7.27 ± 0.37 mm respectively, minimum inhibitory concentration (MIC) of the six bacteria at concentrations of 1.56; 12.5; 25; 12.5; 25 and 12.5 mg/mL. Multistage extraction steps of stem barks involved n-hexane, ethyl acetate and ethanol as solvents. The ethyl acetate extract was selected to proceed to the fractionation stage because it had the best antioxidant activity (antioxidant capacity by DPPH method 70.91 ± 2.60 mg AEAC/g extract and by CUPRAC method 179.74 ± 2.52 mg AEAC/g extract) and the best antibacterial against 6 of 9 test bacteria (inhibition diameter at a concentration of 750 µg/disk against MRSA bacteria, S. aureus, C.acnes, S.mutans, S.epidermidis and B.subtillis were 9.13 ± 0.03; 9.88 ± 0.02; 9.63 ± 0.03; 8.03 ± 0.03; 8.53 ± 0.02; 6.83 ± 0.03 mm, respectively, MIC of the six bacteria at concentrations of 3.125; 3.125; 1.56; 1.56; 6.25 and 3.125 mg/mL, respectively). At the fractionation process, 8 combined fractions were obtained. Based on the yield, chromatogram pattern, antioxidant activity and antibacterial activity by TLC- bioautography, fraction F6 was selected to continue in the subfractionation. Antioxidant activity of fraction F6 gave antioxidant capacity by DPPH method 57.63 ± 0.98 mg AEAC/g extract and by CUPRAC method 70.55 ± 0.32 mg AEAC/g extract and TLC-bioautography results concluded that fraction F6 with concentration of 50 µg gave clear zone on S. aureus, MRSA, C. acnes and S. epidermidis. At the subfractionation process, 9 combined subfractions were obtained. Subfraction SF5 gave the best antioxidant activity (antioxidant capacity with DPPH method 69.72 ± 0.09 mg AEAC/g extract and with CUPRAC method 209.65 ± 0.18 mg AEAC/g extract). TLC - bioautography concluded that subfraction SF5 with concentration of 50 µg showed clear zone on S. aureus, MRSA, C. acnes and S. epidermidis. MIC by SF5 subfraction against S. aureus, MRSA, C. acnes at a concentration of 625 µg/mL and against S. epidermidis at 1250 µg/mL. Furthermore, SF5 subfraction was analyzed using LC-HRMS-MS, SEM and TEM. The LC-HRMS-MS results were six major compounds with similarity ?90%, namely kaempferol, piceatannol, isorhamnetin, 4- methylumbeliferon, oleamide and (2R,3R)-2-(2,6-dihydroxyphenyl)-3,5,7-trihydroxy-2,3-dihydro4H-chromen-4-one. SEM and TEM results showed that SF5 subfraction at MIC could damage the cell walls of 4 test bacteria. Three selected compounds kaempferol, piceatannol and isorhamnetin were tested in silico and concluded that the three compounds had potential as antibacterial to S. aureus, MRSA, C. acnes and S. epidermidis. In this study, the determination of kaempferol content in ethyl acetate extract of stem bark, fraction F6 and subfraction SF5 was also carried out and the kaempferol content were 0.18 ± 0.05; 0.07 ± 0.01 and 0.04 ± 0.02 %, respectively. From this study, it was concluded that mobe bark extract had the potential to be developed as an antioxidant and antibacterial, especially for Gram-positive bacteria.