International Journal of Engineering and TechnologyVol. 1, No.4 , October, 2009 ISSN: 1793-8236 - 282 - Chong Khim Phin, Rossall S. and Markus Atong Abstract - This paper discusses the in vitro synergy effect of syringic acid, caffeic acid and 4-hydroxybenzoic acid which found in oil palm root. Experiments were observed for fourteen days, repeated at least three times and data were recorded daily. The synergy effect of the phenolics against Ganoderma boninense were expressed in inhibition of radial growth of G. boninense on PDA ameliorated with the combination of either two or three different phenolics with concentration of 0.5 to 2.5 mg/ml. Several combinations showed strong fungitoxicity effect to G. boninense. Combinations of 4-hydroxybenzoic acid, syringic acid and caffeic acid up to 2.5 mg/ml strongly inhibited the growth of G. boninense in comparison to the control. Index Terms - Ganoderma boninense, Syringic acid, Caffeic acid, 4-hydroxybenzoic acid I. INTRODUCTION The Malaysian palm oil industry recorded a satisfactory performance in 2008. Export earnings of oil palm products rose to record RM 65.2 billion. The total oil palm planted area in the country increased by 4.3% to 4.48 million hectares in 2008. The expansion in planted area occurred mainly in Sabah and Sarawak with a combined growth of 7% compared to 2% in Peninsular Malaysia. Sabah remained the largest oil palm planted state, accounting for 1.33 million hectares or 30% of the total planted area in the country [7]. Optimal yield production of oil palm in Malaysia and other countries of South East Asia is hampered by the presence of devastating Basal Stem Rot (BSR) disease caused by Ganoderma boninense. Oil palm has an economic life span of 25-30 years. Basal stem rot can kill more than 80 percent of stands by the time they are half-way through normal economic life [1]. In the late 1960s and early 1970s in Sumatra, there was little decline in the yield of oil palm until the surviving stand had fallen to about 115 palm/ha, but in more recent plantings, any loss of palm was associated with a loss of yield [4]. Yield of infected palms was also reduced by 20-40% compared to the year before infection was detected [8]. Palms with Ganoderma yielded between 13 and 21% less than healthy palms at the same age [12]. Heavily infected field yielded 26% less at 11 years after planting, and 46% less at 15 years by which time incidence was 67% [6]. There is Manuscript received September 10, 2009. Chong Khim Phin (corresponding author; phone: 6-088-320000 x5655; fax: 6-088-320278) and Markus Atong are with School of Sustainable Agriculture, Universiti Malaysia Sabah Stephen Rossall is with Division of Plant and Crop Sciences, University of Nottingham currently no effective cure for G. boninense infection in an existing stand. Preventive and ameliorative treatments which are commonly carried out show various degrees of effectiveness [13]. Determination of total phenolic content in G. boninense infected and healthy oil palm roots showed susceptible palm roots at week four had low phenolic content, whereas week one had high phenolic content. Gallic acids concentrations decreased in the four weeks old roots of infected susceptible palms compared to healthy roots. Determination of total phenolic content in infected palm seedlings root (D X P) also showed low phenolic content compared to the non infected palm seedlings root. This indicate phenolic compounds are involved in oil palm resistance against Ganoderma [11].To identify the possibility of oil palm resistance against G. boninense in certain circumstances need further investigation. However, if resistance in oil palm against G. boninense is possible, it may contribute to tackling the problem. In a collaborative experiment to this research, we found syringic acid, caffeic acid and 4-hydroxybenzoic acid present in oil palm roots in natural condition or after elicitation. In this paper, we present the works on in vitro synergy effect of syringic acid, caffeic acid and 4-hydroxybenzoic acid to G. boninense. II. MATERIALS AND METHODS A. Ganoderma boninense Cultures were provided by Borneo Samudera Sdn Bhd, Sabah, Malaysia, maintained at 25oC on Potato Dextrose Agar (PDA). B. In vitro bioassay A series of 0, 0.5, 1.0, 1.5, 2.0 and 2.5 mg/ml of syringic acid, caffeic acid and 4-hydroxybenzoic acid from Sigma® were ameliorated into the PDA with the combination as table 1. The phenolics were first dissolved in Acetone: Water (50:50; v/v). Solvent was served as positive control. The growth of the pathogen was expressed in centimeter of radial growth. Table 1: Combination of different phenolics in different concentration for in vitro synergy effect experiments. Combination Phenolics & Concentration 1 Sy0.5mg/ml + Caff0.5mg/ml 2 Sy0.5mg/ml + Caff2.5mg/ml 3 Sy1.0mg/ml + Caff0.5mg/ml 4 Sy1.0mg/ml + Caff2.5mg/ml 5 Sy2.5mg/ml + Caff2.5mg/ml 6 Sy0.5mg/ml + Hy2.5mg/ml In Vitro Synergy Effect of Syringic Acid, Caffeic Acid and 4-hydroxybenzoic Acid against Ganoderma boninense