A new and rapid protocol for optimum callus production and complete plant regeneration has been assessed in Malaysian upland rice (Oryza sativa) cv. Panderas. The effect of plant growth regulator (PGR) on the regeneration frequency of Malaysian upland rice (cv. Panderas) was investigated. Mature seeds were used as a starting material for callus induction experiment using various concentrations of 2,4-D and NAA. Optimal callus induction frequency at 90% was obtained on MS media containing 2,4-D (3 mg L(-1)) and NAA (2 mg L(-1)) after 6 weeks while no significant difference was seen on tryptophan and glutamine parameters. Embryogenic callus was recorded as compact, globular and light yellowish in color. The embryogenic callus morphology was further confirmed with scanning electron microscopy (SEM) analysis. For regeneration, induced calli were treated with various concentrations of Kin (0.5-1.5 mg L(-1)), BAP, NAA and 0.5 mg L(-1) of TDZ. The result showed that the maximum regeneration frequency (100%) was achieved on MS medium containing BAP (0.5 mg L(-1)), Kin (1.5 mg L(-1)), NAA (0.5 mg L(-1)) and TDZ (0.5 mg L(-1)) within four weeks. Developed shoots were successfully rooted on half strength MS free hormone medium and later transferred into a pot containing soil for acclimatization. This cutting-edge finding is unique over the other existing publishable data due to the good regeneration response by producing a large number of shoots.

Justicia gendarussa methanolic leaf extracts from five different locations in the Southern region of Peninsular Malaysia and two flavonoids, kaempferol and naringenin, were tested for cytotoxic activity. Kaempferol and naringenin were two flavonoids detected in leaf extracts using gas chromatography-flame ionization detection (GC-FID). The results indicated that highest concentrations of kaempferol and naringenin were detected in leaves extracted from Mersing with 1591.80 mg/kg and 444.35 mg/kg, respectively. Positive correlations were observed between kaempferol and naringenin concentrations in all leaf extracts analysed with the Pearson method. The effects of kaempferol and naringenin from leaf extracts were examined on breast cancer cell lines (MDA-MB-231 and MDA-MB-468) using MTT assay. Leaf extract from Mersing showed high cytotoxicity against MDA-MB-468 and MDA-MB-231 with IC50 values of 23 μg/mL and 40 μg/mL, respectively, compared to other leaf extracts. Kaempferol possessed high cytotoxicity against MDA-MB-468 and MDA-MB-231 with IC50 values of 23 μg/mL and 34 μg/mL, respectively. These findings suggest that the presence of kaempferol in Mersing leaf extract contributed to high cytotoxicity of both MDA-MB-231 and MDA-MB-468 cancer cell lines.

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The present study was designed to evaluate the cytotoxic activity of Justicia gendarussa methanolic leaf extracts from five different locations in Johor and also two standards flavonoids (naringenin and kaempferol) as these two compounds were detected in the chromatogram. In this study, leaf extracts and compounds were tested against various human cancer cell lines (HT-29, HeLa and BxPC-3) by using MTT assay. The results showed that methanolic leaf extracts from Mersing and kaempferol were very toxic against BxPC-3 and HeLa cells with IC50 values of 16 µg/ml and 5 µg/ml, respectively. It is suggested that J. gendarussa leaf extracts from Mersing have potential cytotoxic activity on human cancer cell lines particularly BxPC-3 cells.

Heavy metal pollution leads to human health problems and represents a constant threat to the environment. Pollutant clean-up using conventional methods are often hampered by high cost and ineffective pollutant removal. Phytoremediation technique is a preferable alternative due to its minimal side effects to the environment in addition to reasonable treatment cost. In this study, we investigated the potential of Centella asiatica and Orthosiphon stamineus as phytoremediation agents. Both species were grown in contaminated soil obtained from industrial land. Plant growth response and their ability to accumulate and translocate zinc, copper and lead were assessed. From this study, root growth of C. asiatica was compromised when grown in contaminated soil. Copper was highly accumulated in C. asiatica roots while the leaves were more concentrated with zinc and lead. Conversely, all three tested metals were highly detected in the roots of O. stamineus, although the root elongation was not adversely affected. Low amount of metals in the stems of both species permits longer stem length. Correlation study showed that the accumulation of zinc, copper and lead in plant tissues varies depending on plant species and the type of metals. Based on the bioaccumulation, translocation and enrichment factor, our study showed that C. asiatica was tolerant towards zinc, copper and lead; hence suitable for phytoextraction. By contrast, O. stamineus acted as a moderate accumulator of the tested metal elements.