TERPENOIDS FROM RHIZOMES OF FOUR CURCUMA SPECIES (ZINGIBERACEAE) AND THEIR ANTIBACTERIAL ACTIVITY

• Main Author: Diastuti, Hartiwi
• Format: Dissertations
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/32830
• Institution: Institut Teknologi Bandung

Development of bacterial resistance has stimulated researchers to find new antibiotics either by synthesis or from natural compounds, of particularly is from plants. One of potential plant that produces antibacterial compounds is the genus Curcuma belongs to Zingiberaceae family. Curcuma is one of important Indonesian medicinal plant to cure various diseases, such as skin infections, rheumatism, inflammation of the kidneys and liver disorders. Phytochemical study on the Curcuma rhizomes showed that they contain two major types of secondary metabolites, namely diarylheptanoids (curcuminoids) and terpenoids, mainly sesquiterpenes and diterpenes. The biological properties of the curcuminoids have been widely investigated, such as for antimicrobial, antiinflammation, hepatoprotector, anticholesterol, antioxidant and anticancer. However, investigation of biological activity of the terpenoids constituents is still limited. The essential oils and several terpenoids of Curcuma was reported to inhibite the growth of some bacteria and fungi. It suggests that terpenoids of Curcuma have potential as antibacterial agents. In this research, the phytochemical studies of four species of Indonesian Curcuma rhizomes, namely C. aeruginosa, C. heyneana, C. mangga dan C. xanthorrhiza have been conducted. The samples were collected from Solo, Central Java. Antibacterial activity of isolated compounds was carried out on the isolated compounds against eight pathogenic bacteria, i.e. Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa, Salmonella typhi, Shigella dysentriae, Vibrio cholerae, Bacillus subtilis, and Staphylococcus aureus. Isolation of secondary metabolites involved a number of laboratory work, including extraction, solvent partition, fractionation, and purification using various chromatographic technique. The molecular structures of the isolated compounds were determined on the basis of 1-D and 2-D NMR spectroscopic data. The antibacterial activity was carried out using a microdillution method. The phytochemical investigation of four species of Curcuma rhizomes has successfully isolated sixteen terpenoid derivatives, including twelve sesquiterpenes, i.e two bisabolane sesquiterpens, namely ar-curcumene (1) and xanthorrhizol (2), six germacrane sesquiterpenes including isomers of (4S,5S)- germacrone-4,5-epoxide (6) that streochemically is a new compound, germacrone (3), dehydrocurdione (4), curdione (5), furanodiene (7) dan furanodienone (8), four guaian sesquiterpenes namely 4-epicurcumenol (9), procurcumenol (10), aerugidiol (11) and zedoarandiol (12), and four labdanes diterpene, namely, 15,16-bisnorlabda-13-one (13), labda-8(17)-diene-15,16-dial (14), zerumin A (15) and zerumin (16). The isolation of sixteen terpenoids from Curcuma rhizomes is an important chemical data on the phytochemistry of the genus Curcuma. The presence of the same sesquiterpenes, such as ar-curcumene (1) that was isolated from C. aeruginosa, C. heyneana and C. xanthorrhiza, indicated that they have a closely chemotaxonomic relationship. In addition, the presence of labdanes diterpene in C. mangga can explain the chemotaxonomic relationship between Curcuma and Alpinia in the Zingiberaceae family. The antibacterial evaluation of extracts and fractions of Curcuma rhizomes showed that C. aeruginosa, C. heyneana, and C. xanthorrhiza rhizomes had high activities with their MIC dan MBC values in the range of 7.8–15.6 ?g/mL, whereas the extracts and fractions C. mangga was only active against B. subtilis with MIC dan MBC values were 31.2- 62.5 ?g/mL. The antibacterial activity of the isolated compounds showed that xanthorrhizol (2), labda-8(17)-diene-15,16- dial (14) and zerumin (16) had high activities againts B. Subtilis dan S. aureus with MIC dan MBC values were less than 10 ?g/mL. Germacrone (3) and zerumin A (15) were potential as an antibacterial agent due to their MIC dan MBC values were relatively low at 15.6–31.2 ?g/mL againts P. aeruginosa dan B. subtilis. However, the other isolated compounds showed only moderately and weakly antibacterial activities. Based on the phytochemical study of four species of Curcuma rhizomes and antibacterial evaluation of the isolated compounds, it can be concluded that terpenoids from Curcuma rhizomes are potential to be developed as antibacterial agents