J. ISSAAS Vol. 18, No. 1:62-69 (2012)
ANTIFUNGAL ACTIVITY OF TEAK (TECTONA GRANDIS L.F) LEAF EXTRACT AGAINST ARTHRINIUM PHAEOSPERMUM (CORDA) M.B. ELLIS, THE CAUSE OF WOOD DECAY ON ALBIZIA FALCATARIA (L.) FOSBERG Ni Putu Adriani Astiti1 and Dewa Ngurah Suprapta2,* 1
Laboratory of Plant Physiology, Department of Biology, Faculty of Mathematic and Natural Science, Udayana University, Bali, Indonesia. 2 Laboratory of Biopesticide, Faculty of Agriculture, Udayana University, Bali, Indonesia * Corresponding author: [email protected]
(Received: December 7, 2011; Accepted: March 30, 2012)
ABSTRACT Arthrinium phaeospermum (Corda) M.B. Ellis is one of the fungi which causes decay on Albizia falcataria (L.) Fosberg wood. Synthetic fungicides are commonly applied to reduce wood decay, however, its improper use may cause environmental and health problems. The extract of higher tropical plants were proven by previous workers to possess antimicrobial activities against plant pathogenic fungi. In this study, the antifungal activity of teak leaf extract was tested against A. phaeospermum, the cause of wood decay in A. falcataria . The air-dried leaves of teak, Tectona grandis were extracted with methanol and evaporated in a rotary evaporator. Antifungal activity of the leaf extract was tested based on well diffusion method on potato dextrose agar (PDA). Leaf extracts, 0.5 %, 1 %, 2 % and 4 % (w/v) were tested in this study. Sterile distilled water containing 0.2% Tween-80 was used as solvent and control. The results of this study showed that the teak leaf extract at a concentration as low as 0.5% (w/v) suppressed significantly the growth of A. phaeospermum by 81.4%, with minimum inhibitory concentration (MIC) of 0.4 % (w/v). The leaf extract inhibited significantly the fungal radial growth, total biomass and sporulation. Key words : antimicrobial activity, tropical plants, pathogenic fungi.
INTRODUCTION Albizia falcataria is one of the important wood trees that is used for many purposes. In Bali, the wood of this tree is widely used for furniture and wood carvings, particularly for modern art. However, this wood is susceptible to fungal wood decay. Several types of fungi have been reported to be associated with the wood decay such as Serpula lacrymans, Coniophora puteana, Amyloporia xantha, Chaetomium globosum, Cladosporium spp, Penicillium spp., Monilia sp. and Arthrinium phaeospermum (Astiti, 1998; Novianto, 2009; Singh, 2010). Arthrinium phaeospermum is one of the causal agent of wood decay of A. falcataria. The infection by this fungus reduces the durability and quality of wood (Novianto, 2009). Synthetic chemical fungicides has been used as preservatives to control this wood decay however, an increase in the awareness on the negative impacts of these chemicals particularly on human health and environment has made this preservative unsuitable. Many chemical wood preservatives have been prohibited for use on wood (Priadi, 2005). Exploration of the higher plants to produce wood preservative agents that are environmentally friendly and safe to the human health is necessary.
Antifungal activity of teak (Tectona grandis L.f) leaf extract….. Higher tropical plants can produce diverse anti-microbe and anti-insect substances (Downum et al., 1993; Lis-Balchin et al., 1996; Nakamura et al., 1996). Substances such as flavonoids, alkaloids, terpenoids are the secondary metabolites produced by the plants as chemical defense against pests and diseases attacks. It is estimated only 10% of these tropical plants have been investigated for their pesticidal activity. Teak is one of these plants which produces secondary metabolic products containing phenolic compounds. Manoharachary and Gourinath (1988) determined the efficacy of some tropical plant extracts against four pathogenic fungi, i.e. Curvularia lunata, Cylindrocarpon lichenicola, Fusarium solani and Myrothecium leuchotrichum. The plants tested were Calatropis, Datura, Ocimum, Ricinus and Thidax. Among the plant parts tested, extracts of roots and flowers were found to be effective in inhibiting sporulation and growth of fungi. Bandara and Wijayagunasekeya (1988) evaluated three rhizomatous herbs, i.e. Acorus calamus (Araceae), Zingiber zerumbet and Curcuma longa (Zingiberaceae) for their antifungal activity against Cladosporium sp., Btryodiplodia theobromae, Fusarium solani, Phytophthora infestans, Pythium sp., and Pyricularia oryzae. Their results revealed that extracts of A. calamus and Z. zerumbet had profound effect on growth of all fungi tested. Fifteen plant species of different families were evaluated for antifungal acitivity by Suprapta et al. (2001) to control Ceratocystis fruit rot on snake fruit (Salacca edulis). Their findings revealed that root extract of Alpinia galanga and the leaf extract of Carica papaya significantly inhibited the growth of Ceratocystis sp. both on PDA medium and on snake fruit. The leaf extract of Pometia pinnata was found to contain antifungal activity against Phytophthora infestans, the causal agent of late blight of potato (Suprapta et al., 2002). The application of the leaf extracts of Piper betle and root extract of Alpinia galanga controlled significantly the wilt disease of banana caused by Fusarium oxysporum and Pseudomonas solanacearum under field conditions (Arya et al., 2001) Appropriate technological improvement, which result in more effective use of natural resources is required to preserve the wood particularly against the attack of fungi. Astiti (1998) found that the water extract of teak leaf obviously inhibited the growth of Monilia sp., the cause of wood decay. The methanol crude extract of the leaf of Tectona grandis at concentration 5 mg ml-1 inhibited the sporulation of Alternaria cajani and Helminthosporium sp. by 86.8% and 90.0%, respectively (Shalini and Srivastava, 2008). This study was conducted to evaluate the antifungal potential of teak leaf extracts particularly against A.phaeospermum, the cause of wood decay on A. falcataria. MATERIALS AND METHODS Sample Collection and Extraction Mature Tectona grandis leaves were collected from Bukit, Jimbaran Denpasar Bali, Indonesia. The leaves were washed in tap water, and cut into small pieces of about 2 mm x 2 mm in size and air dried for three days under room temperature (28 ± 2o C). The leaves were ground using a blender to powder form and extracted with methanol (PA grade) by soaking for 48 h in the dark under room temperature (28 ± 2o C). The extract was then filtered through two layers of cheese cloth and followed by Whatman No.1 filter paper. The filtrates were evaporated in a rotary evaporator (Iwaki, Tokyo Japan) and the crude extract was used for antifungal testing against A. phaeospermum. Determination of Minimum Inhibitory Concentration The fungus, A. phaeospermum was isolated from rotten wood and maintained in the Laboratory of Microbiology, Faculty of Science Udayana University. The fungus was re-cultured on PDA medium to allow it to produce mycelia and spores. The propagules (spores and mycelia) were harvested in sterile distilled water. Propagule suspension (200 l) were spread on melted PDA 63
J. ISSAAS Vol. 18, No. 1:62-69 (2012) medium in a laminar flow. After the medium become solid, a diffusion well was made in the center of PDA using cork borer (5 mm diam.). Into the well, 20 l crude extract of teak leaf was applied using a micro pipette at concentrations 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2% and 4% (w/v). For control, 20 l sterile distilled water containing 0.2% Tween-80 was used. Five Petri dishes were prepared for each concentration. The cultures were then incubated for 48 h in the dark under room temperature. The formation of inhibition zone around the diffusion well was observed and was used to determine the antifungal activity. The lowest concentration in which the leaf extract of teak leaf produced inhibition zone is known as minimum inhibitory concentration (MIC). Effect of Extract on Radial Growth The teak leaf extract at various concentrations (0.5%, 1%, 2% and 4%, w/v) were applied on Petri dishes and 10 ml melted PDA medium was added. The sterile distilled water containing 0.2% Tween-80 was used as control. The Petri dishes were shaken gently to allow the extract to distribute evenly. After the medium solidified, a mycelial plug (5 mm diam.) of A. phaeospermum, taken from the edge of a 3-day old culture was put in the center of the PDA. Five Petri dishes were prepared for each concentration. The cultures were incubated for 7 days in the dark under room temperature. The diameter of fungal colony was measured daily. The inhibitory activity to the radial growth (IR) was determined according to the following formula (Pinto et al., 1998): IR (%) = dc – dt x 100 Dc where: IR = inhibitory activity to the radial growth dc = average increase in mycelia growth in control plates dt = average increase in mycelia growth in treated plates. Effect of Extract on Sporulation Spores were harvested in sterile distilled water from a culture maintained in slant PDA. The suspension was passed through a filter paper (Whatman No.2) to separate the spore and mycelia or hypae. A 200 l spore suspension (2 x 105 spores/ml-1) was added into 10 ml potato dextrose broth in a test tube containing various concentrations of teak leaf extract, i.e. 0%, 0.5%, 1%, 2% and 4% (w/v). The cultures were incubated in the dark under room temperature for five days. The number of spores were counted using haemocytometer under light microscope. The inhibitory activity to the spore formation (IS) was calculated according to the following formula : IS (%) = dc – dt x 100 dc where: IS = inhibitory activity to the sporulation dc = spore’s density on control (without extract treatment) dt = spore’s density with extract treatment. Effect of Extract on Fungal Biomass The determination of the effect of teak leaf extract on fungal biomass was done in 100 ml potato-dextrose broth (PDB) medium that was placed in a 200-ml Erlenmeyer flask. The teak leaf extract was added into the flask at concentration varied from 0%, 0.5%, 1%, 2% and 4% (w/v). The medium was then inoculated with 1 ml of spore suspension (the spore density was 2 X 105 spores/ml). The final volume of the culture was 100 ml with five flasks for each concentration. The cultures were incubated in the dark for 8 days under room temperature. The biomass was harvested
Antifungal activity of teak (Tectona grandis L.f) leaf extract….. through centrifugation at 5,000 rpm for 5 minutes. The pellet (biomass) was taken and placed on glass filter paper and dried in an oven at 60oC until constant weight. The inhibitory activity against the fungal biomass (IB) was calculated according to the formula : IB (%) = WC – WT x 100 W Where: IB = inhibitory activity to the fungal biomass WC = dry weight of biomass on control (without extract treatment) WT = dry weight of biomass with extract treatment. RESULTS AND DISCUSSION The teak leaf extract suppressed significantly the growth of A. phaeospermum with a minimum inhibitory concentration (MIC) of 0.4 % (not shown). This extract inhibited significantly (P