Othman Abd. Samah

Antimicrobial activity and essential oils of Curcuma aeruginosa, Curcuma mangga, and Zingiber cassumunar from Malaysia

OBJECTIVE To analyze the chemical composition of the essential oils of Curcuma aeruginosa (C. aeruginosa), Curcuma mangga (C. mangga), and Zingiber cassumunar (Z. cassumunar), and study their antimicrobial activity. METHODS Essential oils obtained by steam distillation were analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the essential oils was evaluated against four bacteria: Bacillus cereus (B. cereus), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa); and two fungi: Candida albicans (C. albicans) and Cyptococcus neoformans (C. neoformans), using disc-diffusion and broth microdilution methods. RESULTS Cycloisolongifolene, 8,9-dehydro formyl (35.29%) and dihydrocostunolide (22.51%) were the major compounds in C. aeruginosa oil; whereas caryophyllene oxide (18.71%) and caryophyllene (12.69%) were the major compounds in C. mangga oil; and 2,6,9,9-tetramethyl-2,6,10-cycloundecatrien-1-one (60.77%) and α-caryophyllene (23.92%) were abundant in Z. cassumunar oil. The essential oils displayed varying degrees of antimicrobial activity against all tested microorganisms. C. mangga oil had the highest and most broad-spectrum activity by inhibiting all microorganisms tested, with C. neoformans being the most sensitive microorganism by having the lowest minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 0.1 μL/mL. C. aeruginosa oil showed mild antimicrobial activity, whereas Z. cassumunar had very low or weak activity against the tested microorganisms. CONCLUSIONS The preliminary results suggest promising antimicrobial properties of C. mangga and C. aeruginosa, which may be useful for food preservation, pharmaceutical treatment and natural therapies.

Antifungal activity of Andrographis paniculata extracts and active principles against skin pathogenic fungal strains in vitro

Context: Andrographis paniculata Nees. (Acanthaceae) is an annual herbaceous plant widely cultivated in southern Asia, China, and Europe. It is used in the treatment of skin infections in India, China, and Malaysia by folk medicine practitioners. Objective: Antifungal activity of the whole plant extracts and isolation of active principles from A. paniculata were investigated. Materials and methods: Dichloromethane (DCM) and methanol (MEOH) extracts of A. paniculata whole plant were screened for their antifungal potential using broth microdilution method in vitro against seven pathogenic fungal species responsible for skin infections. Active principles were detected through bioguided assays and isolated using chromatography techniques. Structures of compounds were elucidated through spectroscopy techniques and comparisons were made with previously reported data for similar compounds. Results: DCM extract revealed lowest minimum inhibitory concentration (MIC) value (100 μg/mL) against Microsporum canis, Candida albicans, and Candida tropicalis, whereas MEOH extract revealed lowest MIC (150 µg/mL) against C. tropicalis and Aspergillus niger. DCM extract showed lowest minimum fungicidal concentration (MFC) value (250 µg/mL) against M. canis, C. albicans, C. tropicalis and A. niger, whereas MEOH extract showed lowest MFC (250 µg/mL) against Trichophyton mentagrophytes, Trichophyton rubrum, M. canis, C. albicans, C. tropicalis and A. niger. Bioassay guided isolation from DCM and MEOH extract afforded 3-O-β-d-glucosyl-14-deoxyandrographiside, 14-deoxyandrographolide, and 14-deoxy-11,12-didehydroandrographolide as antifungal compounds. The lowest MIC (50 µg/mL) and MFC (50 µg/mL) was exerted by 14-deoxyandrographolide on M. canis. Discussion and conclusion: This is first report on the isolation of antifungal substances through bioassay-guided assay from A. paniculata. Our finding justifies the use of A. paniculata in folk medicines for the treatment of fungal skin infections.

Andrographis paniculata (Burm.f) Wall. ex Ness: A Potent Antibacterial Plant

Antibacterial agents of plant origin have vast therapeutic potential. They are valuable in the treatment of infectious diseases while simultaneously extenuating many of the side effects that are often associated with synthetic antibacterial agents. The beneficial medicinal effects of plant materials typically result from the combinations of secondary metabolites such as alkaloids, steroids, tannins, phenol compounds, flavonoids and resins fatty acids gums which are capable of producing definite physiological action on body (Paul et al., 2006). Nowadays, multiple drug resistance has developed due to indiscriminate use of commercial antimicrobial drugs commonly used in the treatment of infectious disease. In addition to this problem, antibiotics are sometimes associated with adverse side effects on the host including hypersensitivity, immune-suppression and allergic reactions. This situation forced scientists to search for new antimicrobial substances. Giving the alarming incidence of antibiotic resistance in bacteria of medical importance, there is a constant need for new and effective therapeutic agents. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases from medicinal plants. Biodiversity is a precious source for modern biotechnology. It is a source which potentially holds innovative and sustainable solutions to a broad range of important problems for modern society. Improved cooperation between the natural product chemists and the microbiologists is a productive step to speed up the process of evaluating these potentialities. Moreover, microbiologists and natural product chemists in tropical countries, with the richest flora and fauna placed right at their door step have a very central position. They are essential for building up international scientific cooperation, with the objective of expanding our understanding of biological and biochemical diversity, and based on this bringing forward more biological solutions. The entire process is built on a principle of fairness and equity in sharing of the benefits and respecting the States sovereign right to its own resources. After figuring out the chemical structures of secondary metabolites, it is considered crucial to know how useful these molecules might be in terms of medicinal properties. During the past 40 years, numerous novel compounds have been isolated from different plants and marine organisms and many of these have been reported to have core biological activities, some of which are of interest from the point of view of potential drug development (Lene, 1996; Gerald, 2001). Antimicrobial Agents 346 In this context, Andrographis paniculata (Burm.f.) Wall. ex Nees., could be a potential source to develop new efficacious antibacterial drugs. A. paniculata (Acanthaceae) (King of Bitters) is an annual herbaceous plant and is widely cultivated and traditionally used in Southern Asia, China and some parts of Europe. A. paniculata has been effectively used in traditional Asian medicines for centuries. In traditional medicine, A. paniculata is widely used to get rid of a body heat, dispel toxins from the body, prevents common cold, upper respiratory tract infections including sinusitis and fever (Gabrielian et al., 2002) and as an antidote against snakes and insects poisons (Samy et al., 2008). A. paniculata has been reported to exhibit various mode of biological activities in vivo as well as in vitro viz., antiviral (Wiart et al., 2000), anti-inflammatory (Wen et al., 2010), antihuman immunodeficiency virus (HIV) (Calabrese et al., 2000), immunomodulating/immunostimulatory (Iruretagoyena et al., 2005), anticancer activity (Li et al., 2007; Geethangili et al., 2008) and antibacterial activity.