The effects of 6-Benzylaminopurine (BA), different basal medium, sucrose concentration and gelling agent were investigated for shoot induction and multiplication of Acacia auriculiformis. Nodal explants derived from 5-month-old seedlings yielded the highest shoot multiplication rate in Murashige and Skoog medium (MS) with 0.44 µM BA, 30 g/L sucrose and 2 g/L Gelrite. The highest mean number of shoots (10) and mean length of shoots (5.07mm) were also obtained in this medium. Qualitative observation of the shoots cultured in 0.44 µM BA were greener and vigorous in growth as compared to shoots cultured on higher concentrations of BA (22.2 µM). MS medium produced a significantly higher number of shoots (18) compared to Woody Plant Medium (WPM) (11) and B5 medium (10). Media solidified with different gelling agents also produced a significantly different number of shoots with 2 g/L Gelrite produced the highest number of shoots (23). The highest percentage of shoots rooted was found in the MS medium without any growth regulators (40.0%) followed by medium supplemented with Indole-3-butyric acid (IBA) at 9.84 µM and the combination of 9.84 µM IBA with 5.37 µM α-naphthalene acetic acid (NAA) (33.3%). MS medium without any plant growth regulators produced the highest mean root length (84.33mm), whereas medium supplemented with 9.84 µM IBA produced the highest mean number of roots per shoot (4.33). Out planting of in vitro rooted shoots in shredded coconut husk as the substrate gave the highest percentage of survival (90%) during acclimatization in the greenhouse.

This study aimed at exploring the feasibility of using the mesocarp and exocarp of Cocus nucifera as a natural colorant using microwave-assisted extraction in which often regarded as a waste materials. The effects of microwave power and heating time on the yield of colorant, pH and colour determination were investigated. The highest colorant yield in mesocarp and exocarp was found to be 6.0% (8 min of extraction at 100 W) and 6.8% (12 min of extraction at 300W), respectively. While the control, extraction of colorant by conventional method (90 min at 90 º C), showed a percentage of 5.2% (mesocarp) and 3.6% (exocarp) yield of colorant. Meanwhile, pH of all extracts fluctuated throughout the experiment. The results proved that heating time and microwave power slightly affected the pH of all samples due to pH being inconsistent throughout the experiment. In colour determination, lightness (L*) was slightly decreased for all samples which extracted at all microwave power which indicated that the longer the heating time the darker colour was extracted. Overall, the colour of exocarp was darker than mesocarp extract due to L*, c* and h* values were lower than the mexocarp extract. The utilization of microwave-assisted extraction has significant improvement in the extraction of natural colorant compared to traditional boiling method. In fact, application of microwave irradiation method proved to be a rapid and improved technique for natural colorant extraction and extensively reduced the extraction time.

Phytochemical analysis was carried out on the natural colorant extracted using the microwave-assisted extraction which performed at a microwave power of 300 watts for 2 minutes. The pigment compound was extracted from mesocarp and mesocarp of Cocos nucifera by using 0.1 M NaOH as extracting agent. The qualitative analysis that was carried out for these natural colorants confirmed that flavonoids, terpenoids, cardiac glycosides and phenol/ tannins were present in both plant parts (mesocarp and exocarp) tested whereas alkaloids, saponins, steroids and anthraquinone were not detected. Quantitative analysis showed that tannin content was significantly (p < 0.05) higher (134.82 mg TAE/g) in the mesocarp extract compared to the exocarp extract (33.90 mg TAE/g). The amount of flavonoids was low in both extracts (mesocarp: 15.48 mg QE/g and exocarp: 28.45 mg QE/g, respectively). The antimicrobial study discovered that the mesocarp and the exocarp extract were not effective as antibacterial agents.

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