Justicia gendarussa methanolic leaves extract from four different locations in Southern region of Malaysia and distribution
of two flavonoids, naringenin and kaempferol in plant organs (young and mature leaves) were determined using gas
chromatography-flame ionization detector (GC-FID) analysis. Naringenin and kaempferol contents were detected
and quantified in leaves extract. The results indicated that mature leaves contained more naringenin and kaempferol
compared to young leaves. The highest concentration of naringenin and kaempferol were recorded in mature leaves from
Skudai and Muar regions which were 507.692 and 1226.964 mgkg-1, respectively. Data analysis showed that naringenin
content was directly proportional to the amount of kaempferol in the leaf extracts. In conclusion, this study suggested
geographical variation among plant samples and physiological stage of organ parts could contribute to variation in
flavonoids concentration in a plant species.
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.