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Antifouling paint was introduced and utilized as a control to prevent the problem of biofouling. The Methanolic Crude Extract (MCE) and the Essential Oil (EO) were extracted from Melaleuca cajuputi. Gas Chromatography-Mass Spectrometry (GC-MS) was used to determine the metabolite profiles. An antibacterial assay was conducted via the disc diffusion technique and an antifouling assay of MCE and EO of M. cajuputi was investigated using a crystal violet assay and painted steel panels incorporating MCE and EO. Painted steel panels were immersed in the aquarium to measure the antibiofilm activity and in the natural sea environment to observe the settlement of foulers. The MCE exhibits antibacterial activity against Gram-negative bacteria, indicating narrow-spectrum activity, while EO has broad-spectrum activity against Gram-positive and −negative bacteria. The GC-MS profile showed the presence of cycloheptasiloxane, tetradecamethyl-, cyclotrisiloxane, hexamethyl-, terpinene-4-ol, caryophyllene, and 1,8-cineole in both MCE and EO of M. cajuputi. Crystal violet assay revealed that both samples reduced the attachment of biofilm form by Pseudomonas aeruginosa at 61% and 60%. Panel painted with paint incorporated 5% MCE inhibits bacteria growth in natural seawater, followed by 10% MCE, 5% EO, and 10% EO in aquarium testing. Referring to photographic observation, all the panels coated with paint incorporated with samples successfully reduced the attachment of foulers compared to Blank Paint (BP). In conclusion, these findings indicated that the MCE and EO of M. cajuputi could potentially be used as a substitute for toxic antifoulants to prevent the formation of microfoulers. [ABSTRACT FROM AUTHOR]

Melaleuca cajuputi subsp. cajuputi is one of the Australian Melaleuca species commonly found in Pulau Buru (Maluku, Indonesia). Its oil, the M. cajuputi essential oil (MCEO), has been utilized as the main flavor of the Indonesian functional food, Cajuputs Candy. However, the availability of MCEO is becoming limited. On the other hand, Indonesia has many other potential MCEO sources which can be developed as flavor ingredient. Thus, it is noteworthy to explore these new MCEO sources by studying their sensory characteristics and metabolite profiles. This study was conducted to identify potential metabolites that are correlated to sensory attributes of MCEO by using the metabolomics approach. The metabolite profiles of thirteen MCEOs from different origins were analyzed by gas chromatography-mass spectrometry while sensory analyses on Cajuputs Candy were conducted by difference-from-control and rate-all-that-apply tests. Sixty metabolites from the MCEO were annotated that includes 1,8-cineole, α-terpineol, caryophyllene, α-pinene, and γ-terpinene. Sensory analysis revealed cooling aftertaste and sweet taste as favorable attributes. Further analysis using Orthogonal Partial Least Square indicated that 1,8-cineole and γ-terpinene were correlated with cooling aftertaste, while 1,8-cineole and caryophyllene were also correlated with sweet taste. In contrast, linalool and nerolidol were associated with the feature of the most characteristic manufacturer's products which have unfavorable attributes such as floral, iodophor-like, metallic, and soapy attributes. The identification of these metabolites will be useful for the selection of MCEOs that can potentially be used as flavor. [ABSTRACT FROM AUTHOR]

• The narrow-sense heritability were low for growth traits, moderate for 1,8-cineole content and high for leaf essential oil concentration. • The genetic relationships between growth, oil concentration and 1,8-cineole content were independent. • Simultaneous improvement of oil concentration and 1,8-cineole in M. cajuputi subsp. cajuputi breeding program was possible by using index selection. • The index selection simultaneously improving 1,8-cineole content by 2.18% and leaf oil concentration by 27.36%. Melaleuca cajuputi is a multi-purpose tree, best known as an aromatic and medicinal plant for the production of medicinal essential oil that has been commercially used. Among three subspecies cajuputi , cumingiana and platyphylla , M. cajuputi subsp. cajuputi is the main source of cajuput oil industry. Breeding program of M. cajuputi subsp. cajuputi aimed to improve leaf oil yield and 1,8-cineole content has been implemented for the last two decades. In this study, genetic parameters for growth (height and diameter), leaf oil concentration and 1,8-cineole content in the full-sib family progeny trial including 39 families planted in Playen, Gunungkidul, Yogyakarta, Indonesia were examined. Narrow-sense heritability were low for growth traits (h i 2 = 0.10 – 0.13) but high for leaf essential oil concentration (0.50) and moderate for 1,8-cineole content (0.21). There were no genetic correlations among growth, oil concentration and 1,8-cineole content. Index selection was used to improve simultaneously both oil concentration and 1,8-cineole content in the M. cajuputi subsp. cajuputi breeding program. The genetic gains for oil concentration increased from −1.19 to 29.67% while the gains for 1,8-cineole content decreased from 6.19 to 0.07%. The scenario that improved 1,8-cineole content by 2.18% was the most optimal selection as genetic responses of leaf oil concentration reached 27.36%. [ABSTRACT FROM AUTHOR]

Due to the rice production problem, control of paddy weeds with the use of allelopathy as active compounds serve as new alternative for sustainable weeds management. The volatile oil from Melaleuca cajuputi which has possible active allelopathy compound present is extracted and analyzed. Response Surface Methodology (RSM) with central composite rotatable design (CCRD) is used to design the experiment for optimization of supercritical carbon dioxide (SC-CO 2 ) extraction of volatile oil from Melaleuca cajuputi leaves for maximum oil yield. Three factors which included carbon dioxide (CO 2 ) flow rate (4–7 ml/min), temperature (40–55  ℃ ) and pressure (14–26 MPa) were investigated. The regression model shows a good prediction with coefficient of determination, R 2 of 0.9607. The optimum condition of SC-CO 2 extraction is determined to be at CO 2 flow rate of 5.88 ml/min, temperature of 43.10 ℃ and pressure of 24.91 MPa with the prediction yield of 1.24 wt%. The optimum condition is validated with experimental runs which gives an average yield of 1.26 wt% which indicates good agreement between the measured and predicted value. The chemical composition of the volatile oil at optimized condition is analyzed using Gas Chromatography Mass Spectrometry (GC–MS) and Gas Chromatography with Flame Ionization Detector (GC-FID). Caryophyllene and humulene are the two major sesquiterpenes detected from the optimized condition. Thus, volatile oil extract from the foliage of Melaleuca cajuputi can be considered as potential source for bio-herbicides due to the presence of caryophyllene which has allelopathic effect. Kinetics studies are also studied with modified Reverchon-Sesti Osseo as the model fitting. [ABSTRACT FROM AUTHOR]

Seedlings of Melaleuca cajuputi (M. caj) and Eucalyptus camaldulensis (E. cam) were grown in acidic (pH 4.2) solution culture medium. Half of the plants in each species were subjected to Al toxicity (160 μM {Al3+}) for 31 days, and the effects of this stress on root and shoot growth, uptake of Ca, K, P, Fe and Al, and leaf area were studied at intervals. In comparison to M. caj, E. cam was less tolerant to Al toxicity and exhibited symptoms of leaf necrosis after the first 10 days of exposure. The dry mass of various plant parts of E. cam increased during the pre-necrotic period and declined significantly in the post-necrotic period in response to Al toxicity. Al toxicity significantly reduced the Ca, Fe, P and K concentration in the roots of E. cam; the effect was more severe in the post-necrotic period compared with the pre-necrotic period. Although the shoot and roots of the Al-tolerant M. caj accumulated more Al, growth and mineral concentration in these organs were less affected in comparison to the sensitive E. cam. In the post-necrotic period, leaf area and number and chlorophyll concentration were reduced and peroxidation of lipid increased significantly in the newly developing leaves of Al-stressed E. cam. The mechanism of Al induced stress influence on E. cam has been discussed in the context of growth promotion due to relief from proton-induced stress in the pre-necrotic period and reduction of growth due to membrane damage in the post-necrotic period. [Copyright &y& Elsevier]