Antimicrobial effect of medicinal plants used in traditional Indonesian medicine

Andreas Romulo, M.Sc.

Doctoral thesis

Abstract:

In many regions of Indonesia, there are numerous traditional herbal preparations for the treatment of infectious diseases. Despite the well-documented traditional use of the plants, their antimicrobial potential has been poorly studied by modern laboratory methods. Therefore, this study investigated: 1) antimicrobial effect of ethanol plant extracts using broth microdilution method, 2) antimicrobial and antistaphylococcal effects of essential oil (EO) of Curcuma mangga by broth microdilution volatilisation and modified broth microdilution methods, and 3) chemical composition of antimicrobially active essential oil of C. mangga using gas chromatography-mass spectrometry (GC-MS) and gas chromatography with quadrupole and time of flight mass spectrometry (GC-QTOF-MS). The results showed that the extract of Orthosiphon aristatus leaf produced the strongest antimicrobial effect, inhibiting the growth of Candida albicans at minimum inhibitory concentration (MIC) of 128 μg/mL, Staphylococcus aureus at MIC of 256 μg/mL, Enterococcus faecalis at MIC of 256 μg/mL and Pseudomonas aeruginosa at MIC of 256 μg/mL. The leaf extract of Woodfordia floribunda also exhibited significant effect against C. albicans (MIC 128 μg/mL), S. aureus (MIC 256 μg/mL) and E. faecalis (MIC 256 μg/mL). The analysis of rhizome of C. mangga EO using broth microdilution volatilisation method and modified standard broth microdilution method showed that the EO exhibited antistaphylococcal activity with the MIC ranging from 128 to 1024 μg/mL, whereas tetracycline-resistant S. aureus was the most sensitive strain (MIC 128 μg/mL). The identification of C. mangga EO by GC-MS and GC-QTOF-MS revealed the major constituents of C. mangga were 15,16-dinorlabda-8(17),11-dien-13-one (22.76/13.70%), followed by ambrial (14.90/9.52%), 13-nor-eremophil-1(10)-en-11-one (6.64/5.39%), 15,16-dinorlabda-8(17),12-dien-14-al (5.71/6.68%), and aromadendrene oxide (5.53/3.27%). The findings suggest that O. aristatus and W. floribunda leaves extract and the EO of C. mangga rhizome as promising agents for the development of traditional medicine based anti-infective preparation. However, further researches focused on the isolation and characterisation of antimicrobially effective constituents of O. aristatus and W. floribunda and the safety and in vivo efficacy of C. mangga EO, will be needed before its possible use.

Keywords

anti-Candidal, antistaphylococcal, Antimicrobial, Curcuma mangga, essential oil, GC-MS, GC-QTOF-MS, Orthosiphon aristatus, plant extract, Woodfordia floribunda

Language used: English

Date on which the thesis was submitted / produced: 13. 9. 2018

Thesis defence

• Supervisor: prof. Ing. Ladislav Kokoška, Ph.D.
• Reader: Přemysl Landa, externi, Jaroslav Havlík, externi, Kateřina Macáková, externi

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Doctoral programme / field:
Agricultural Specialization / Tropical and Subtropical Agriculture