Crop Science

Our recent study on Artocarpus odoratissimus (Moraceae) has resulted in the purification of a new prenylated pyranoflavone derivative artosimmin (1) and traxateryl acetate (2). Details of structural elucidations associated with 1 and 2 are reported by combining 1D, 2D NMR and mass spectrometric methods. Compound 2 is obtained for the first time from this species. Furthermore, the biological assay results exhibited compound 1 to be significantly cytotoxic against cancer cell lines (HL-60 & MCF-7) and also possessed antioxidant properties toward 1,1-diphenyl-2-picrylhydrazyl radical (DPPH).

Problem statement: Coptotermes curvignathus (Isoptera: Rhinotermitidae) is a common termite pest found in oil palm plantation planted on peat. Currently, the control methods focus on using insecticides that lead to high cost and adverse effect to the environment. Approach: Biological control like the use of entomopathogens provides an alternative control method for termite infestation problem. However, several factors need to be investigated in order to obtain a virulent strain with potential to be developed into a biopesticide. Results: Three local isolates (MG, LR2 and TA) of Metarhizium anisopliae were obtained and identified as M. anisopliae var. anisopliae using molecular techniques. Growth performance of isolates on four basal media namely, Potato Dextrose Agar (PDA), Potato Dextrose Agar with 1% yeast extract (PDAY), Sabaroud Dextrose Agar (SDA) and Sabaroud Dextrose Agar with 1% yeast extract (SDAY) was assessed. The pathogenicity of each isolate was tested against subterranean termite Coptotermes curvignathus at three concentrations of 1×10 6 , 1×10 7 and 1×10 8 conidia mL −1. Infections of the isolates were examined using electron microscopy technique. The growth performance of each isolate differed significantly. Among all basal media, only SDAY was able to produce high growth performance and thick conidia mats with all isolates. The most pathogenic isolate was LR2, which caused 100% mortality at 1×10 7 conidia mL −1 within 3 days post-inoculation. Conclusion/Recommendations: All three isolates were pathogenic against C. curvignathus as they were able to germinate and penetrate into the termite cuticle within 15 hours post-inoculation. The three local isolates of M. anisopliae var. anisopliae have potential to be developed as biopesticides to control termites, C. curvignathus in oil palm plantations.

Boric acid (H 3 BO 3) is detrimental to human health if consumed in excess. However, it continues to be used in the production of food especially noodles and some processed seafood such as fish ball. Five kinds of noodles and a type of fish ball were collected over a period of four weeks from a random sample of manufacturers in Bintulu, Sarawak, Malaysia. The boric acid in these food samples were analyzed by the curcumin-acetic acid method using 2-ethyl-1, 3-hexanediol (EHD) extraction. Results showed that yellow noodles contained highest concentration of boric acid throughout the four weeks with a mean of 2.034 µg g −1. In general, the mean concentrations in most food types were inconsistent throughout the sampling period and were relatively low compared to studies reported in Peninsular Malaysia. Although it is not a permitted food preservative or additive, this study showed that local food manufacturers were still using boric acid.

The oil palm industry of Malaysia has expanded into peat area in Sarawak. Problem statement: The subterranean termite Coptotermes curvignathus was a serious pest of oil palm on peat. Control of this termite has resorted to heavy usage of chemicals which was deemed uneconomical and hostile to the environment. Baiting system has inconsistent success due to the limited knowledge of the behavior of the pest. Approach: This study was to investigate damage and nesting characteristic of the pest. Infested palm in the peat area was dissected using a chainsaw and observation was made on the endoecie and damage. Microclimate inside the palm was recorded using a data logger and acid insoluble lignin from 3 different infested palms was determined. Results: Dissection of infested palm revealed that termite generally attacked the palm from the spear in immature palm or basal region in mature palm due to the energy requirement and level of water table. Spear region infestation was possible because of the moist environment provided by the proximity of the fronds and leaf sheaths. The high lignin content (42-45%) in the thin laminae indicated the concentration of lignin or incorporation of peat in nest construction. Wood stump residues remained in the plantation was one of the main reasons of termite infestation. The stability and protection of the wood stump encouraged termite breeding. A C. curvignathus queen was discovered in the endoecie under the wood stump and was seen mobile. Conclusion: The pest was generally available in area where wood stumps and moisture were available. Manipulation of water table for certain period after spraying of chemical may help reduce infestation by the termite.

Sago starch is usually chemically modified to overcome and improve the unstable properties of native sago starch during processing. In this study, sago starch was treated in hydrochloric acid in the presence of methanol, ethanol and 2-propanol at 45 0 C for 1 hour. Granule size, granular structure and solubility of the modified starch were investigated. Results showed that recovery yields of the modified starch were in excess of 57% with a maximum recovery of 94%, and the average granule size of the starch ranged from 24.8 to 30.1 µm. Images under light microscope revealed some internal fissures in starch granules after acid-alcohol treatment. Acid concentration had a pronounced effect on the degree of polymerization. The degree of polymerization progressively decreased as the carbon number of the alcohol increased. This study showed that sago starch can be modified through hydrolysis and alcoholysis to give various limit dextrins with high solubility.

The compatibility and synergy in efficacy of the termiticide fipronil with a biocontrol agent Metarhizium anisopliae, alone or in combination, against the subterranean termite, Coptotermes curvignathus were investigated. Sublethal doses of fipronil were found relatively less detrimental to fungal growth of M. anisopliae local isolates in a compatibility test. The fungus-insecticide bait formulation showed the greatest synergistic effect that increased termite mortality as well as reduced the lethal time at a sublethal dose of 0.05 mg a.i./l fipronil with conidia concentrations of 10 7 conidia/g bait (χ² = 48.80) at LT 50 value of 6.46 days, followed by 10 8 conidia/g bait (χ² = 5.09) at LT 50 value of 4.89 days compared to the use of these control agents alone. The insecticidal stress caused by sublethal fipronil in the formulated bait may weaken the termites and reduce their defence mechanism, which facilitates fungus infection on termites. The observed synergism treatments show the potential for integrated fungus-insecticide control method and need to be further investigated on termite infested oil palm trees.

Pellitorine (1), which was isolated from the roots of Piper nigrum , showed strong cytotoxic activities against HL60 and MCT-7 cell lines. Microbial transformation of piperine (2) gave a new compound 5-[3,4-(methylenedioxy)phenyl]-pent-2-ene piperidine (3). Two other alkaloids were also found from Piper nigrum. They are (E)-1-[3',4'-(methylenedioxy)cinnamoyl]piperidine (4) and 2,4-tetradecadienoic acid isobutyl amide (5). These compounds were isolated using chromatographic methods and their structures were elucidated using MS, IR and NMR techniques.

Phytate complexes in whole grain rice are indigestible by human but can be broken down by endogenous phytase enzyme. The inherent phytate content and phytase activity could influence the nutritional quality of whole grain rice. This work aims to determine and identify their variability with genotypes, growing areas and grain morphology. It was found that the whole rice grain was largely high in phytate content (18.20 to 32.36 g/kg) but low in phytase activity (4.77 to 102.65 U/kg), with significant variation among cultivars. Phytate content was marginally different between growing locations but, with no significant difference among their genotypes and grain morphology. This variation could be due to locality factors such as cropping and fertilization practices in the cultivation site. Meanwhile, phytase activity appeared to be determined by genotype, grain width and grain length-to-width ratio. A relatively high phytase activity could be selected from the whole grain rice based on rounded grain and in the genotypic category of L. These types of rice cultivars could reduce the inherent phytate level and improve the nutritional quality of the whole grain rice.

Solid state fermentation has been used for mass production of Metarhizium anisopliae many years ago. However, solid state fermentation was time consuming, costly and unable to produce in large amount. We examined the suitability of liquid state fermentation to mass produce M. anisopliae and the effect of culture medium on fungal pathogenicity. Three different liquid medium selected for this study was Jenkins medium, Leland medium and MPOB medium. The fungus was cultured for 5 days to examine the growth rate. Yield of submerged conidia in different medium was assessed on day 3. Fungal virulence was bioassayed on termite Coptotermes curvignathus. The results indicated that Jenkins medium yielded significantly lower growth rate and dry weight (1.472 mg mL −1), but the fungus exhibited highest virulence (100% mortality on day 4) among the 3 medium studied. MPOB medium had the highest growth rate and DW yield (1.961 mg mL −1) but achieved 100% mortality only on day 6. The LC 50 result showed Jenkins medium yielded the most virulent fungus culture compared to Leland medium and MPOB medium.

In our recent investigation on Morinda citrifolia as a potential larvicide against the larvae of Aedes aegypti, we found 1-hydroxy-2-methyl anthraquinone (1) to have good larvicidal activity. Extracts of the roots of Morinda citrifolia were also found to be larvicidal.

The health advantages of whole grain rice are largely associated with the bioactive food components namely, ferulic acid (FA), gamma oryzanol (GO) and gamma aminobutyric acid (GABA) in the germ and bran of grain kernel. This study was aimed to determine the content of these health-promoting compounds among 53 local rice cultivars and their relation to bran colours. There was remarkable amount of health-promoting compounds in the rice collection, especially "Segerit", "Merah" from Rumah Ulat and "Keladi" from Menitam. FA was the highest with an average of 1034.0 µg/g followed by GO 757.90 µg/g and GABA 191.16 µg/g. Rice with pigmented bran stored more FA and GO than their non-pigmented counterparts. An analysis of variance and Pearson's student correlation showed that FA responded significantly with rice bran colour (r= 0.75) but no significant relations was found for GO and GABA. This result indicated that bran colour could be a quick indicator of FA content in whole grain rice. Whole grain rice rich in bioactive compounds is a good material for the development of nutraceutical products and functional food.

Oil palm is one of the most important plantation crops in Malaysia. The sustainability of oil palm is threatened by Ganoderma species. It is commonly known that Ganoderma boninense is the causal pathogen for basal stem rot (BSR) in oil palm. However, little is known about the threats by other species of Ganoderma or upper stem rot (USR), which is associated with a similar pathogen. A total of 46 isolates of Ganoderma were isolated from BSR and USR infected oil palms. The isolates were identified using a multiplex PCR, and its genetic heterogeneity was determined using a somatic compatibility test. It was found that BSR and USR coexisted in the plantations, and USR emerged as one of the major diseases. The diseases were associated with similar pathogens, namely G. zonatum (71.7%), followed by G. boninense (26.1%), and G. miniatocinctum (2.2%). Somatic compatibility test indicated that all the isolates were genetically heterogeneous. These results show that G. zonatum and the transmis...