Cadmium (Cd) is one of non-essential heavy metals which is released into environment naturally or anthropogenically. It is highly persistent toxic metals that are exceptionally distressing industrial and agriculture activities by contaminating soil, water and food. Its long-duration endurance in soil and water results in accumulation and uptake into plants, leading to the food chain. This becomes a serious global problem threatening humans and animals as food chain components. Living organisms, especially humans, are exposed to Cd through plants as one of the main vegetative food sources. This review paper is concentrated on the symptoms of the plants affected by Cd toxicity. The absorption of Cd triggers several seen and unseen symptoms by polluted plants such as stunted growth, chlorosis, necrosis and wilting. Apart from that, factors that affect the uptake and translocation of Cd in plants are elaborated to understand the mechanism that contributes to its accumulation. By insight of Cd accumulation, this review also discussed the phytoremediation techniques-phytoextraction, phytostimulation, phytostabilization, phytovolatization and rhizofiltration in bioremediating the Cd.

Hydrogen peroxide (H₂O₂) is defined as a reactive oxygen species (ROS), able to cause damage to a variety of cellular structures. On the other hand, recent work has demonstrated that H₂O₂ can also act as a potent signaling molecule that mediates various physiological and biochemical processes in plants. This study was carried out to investigate the effects of H₂O₂ on the growth, mineral nutrient accumulation, as well as the biologic and chemical properties of Ficus deltoidea var. deltoidea. F. deltoidea plants were spray-treated with 0- (control), 8-, 16-, 30- and 60-mM H₂O₂ under field conditions. Plant height, leaf area, chlorophyll content, net photosynthetic rate, stomatal conductance and quantum yield of the F. deltoidea plants significantly increased after treatment with 16 and 30-mM H₂O₂. The results indicate that 60-mM H₂O₂ increased the accumulation of arsenic, iron and sodium content in the leaves of F. deltoidea. On the other hand, 8-mM H₂O₂ significantly enhanced the accumulation of arsenic, iron, calcium and potassium content in the syconium of F. deltoidea plants. In addition, H₂O₂ treatment did not produce any significant effects on antimony and magnesium accumulation in the leaves or the syconium of F. deltoidea plants. The results show that the F. deltoidea plant has strong antidiabetic properties and its α-glucosidase activity increased in treated plants compared to standard acarbose. Hydrogen peroxide, particularly in concentrations of 16 and 30 mM, increased the antioxidant activity, total phenolic and flavonoid content and the vitexin and isovitexin content. There was a positive correlation between antioxidant activity with total phenol and total flavonoid content in H₂O₂-treated plants. The quantitative analysis by HPTLC indicates that the amount of vitexin and isovitexin increased with the higher concentrations of H₂O₂. From this study, it can be concluded that spraying 16 and 30-mM H₂O₂ once a week enhances growth, mineral accumulation and stimulates bioactive compounds of the F. deltoidea plants.

This study was carried out to investigate the regulatory effects of hydrogen peroxide (H₂O₂) on the growth, photosynthesis, biochemical properties, leaf anatomy and Rubisco gene expression in Ficus deltoidea var. deltoidea, a slow-growing medicinal herb. Results showed that 20-mM H₂O₂ treatment increased plant height, net photosynthetic rate, stomatal conductance and chlorophyll content of the plants by 10%, 20%, 127% and 57%, respectively, than a control plant. In addition, 20 mM H₂O₂ treatment significantly increased the carotene, total phenolic, total flavonoid and total sugar content than the control plant. The applications of H₂O₂ did not produce any negative effects on the leaf area, chlorophyll fluorescence, quantum yield or antioxidant activity of F. deltoidea plants. In regard to leaf anatomy, it was observed that the applications of H₂O₂ at 15 mM significantly improved cellular structure, leaf veins and promoted cell proliferation. Treated leaves developed a palisade layer, thickened leaf surface, the widest stomatal openings and a well-developed vascular bundle when compared to the control plant. Employing reverse transcription polymerase chain reaction (RT-PCR), the study showed that the Rubisco gene was expressed at a higher level in 15 mM H₂O₂ treatments than in 20 mM H₂O₂ treatments. The results indicate that H₂O₂ increased the Rubisco expression ratio up to 16-fold when compared to the untreated plants. It was conclusive that spraying 15 mM and 20 mM H₂O₂ twice a week enhanced growth, photosynthesis, the stomatal aperture, improved leaf anatomy and helped to regulate the expression of the Rubisco gene.

Studies on selected metabolites profiling of Orthosiphon stamineus extracts using chromatographic and spectroscopic techniques combined with chemometric tools have not been fully elucidated. Thus present study was performed to profile selected metabolites in O. stamineus leaves extracts using HPLC and FTIR combined with chemometric tools and correlated with biological activities. Five different extracts were prepared using three methods; maceration, soxhlet and reflux. The extracts were analyzed using UV-Vis, HPLC and FTIR techniques. Analysis of selected primary and secondary metabolites was also evaluated. The antioxidant and cytotoxic activities of the extracts were evaluated. Chemometric tools were employed to classify the extracts based on HPLC analysis and FTIR fingerprints. The ethanolic extract using maceration characterized high content of phenolics and flavonoids, (rosmarinic acid and eupatorin) with high antioxidant activity. Ethanolic (50 %) and methanolic extracts using soxhlet showed high proteins and glycosaponins. Water extracts using reflux and maceration showed high polysaccharides. Methanolic extract (50 %) using soxhlet and methanolic extract using maceration showed strong cytotoxic effect against MCF7 and HCT116 cell lines, respectively. Antioxidant and cytotoxic activities showed significant correlation with selected primary and secondary metabolites. HPLC fingerprints combined with chemometrics showed the extracts have been clustered based on selected major peaks profile. FTIR fingerprints combined with chemometrics showed that the extracts have been clustered based on protein and polysaccharide contents. Ten different extracts of O. stamineus have showed significant differences in the content of selected primary and secondary metabolites as well as the biological activities. Chemometric tools were able to classify and discriminate the distinctive features of extracts thus can be correlated with the biological activities.

The wax apple or jambu madu, is a non-climacteric tropical fruit from Myrtaceae family and widely cultivated in South East Asia. The limited availability of good quality seedlings of wax apple is the main problem to development of flourish it’s market share in the current fruit industry. Therefore, in order to produce good quality planting materials, a study aimed at optimizing propagation and adventitious rooting technique and survivability of wax apple air layer was conducted. In this study, four different levels of Indole-3-Butyric Acid (IBA) concentration (0, 1000, 1500 and 2000 mg L-1) and three rooting media (sphagnum moss, vermicompost and garden soil) were applied after removal of bark (phloem) on the shoot to determine the effect on rooting and survivability of the wax apple air layer under field conditions. The results showed that the wax apple shoots treated with 2000 mg L-1 IBA produced the significantly higher number of roots, increased length of root, diameter of branch, length of branch, number of leaf and leaf area of air layers. In addition, the highest chlorophyll content and stomatal aperture were recorded in 2000 mg L-1 IBA treatment compared to other treatments including control. Vermicompost medium was better than garden soil and sphagnum moss in respect of rooting and survivability of air layers. The results showed that the combination of 2000 mg L-1 IBA and vermicompost as rooting media give the best combination to root initiation, root number, root length and survival rate (100%) of wax apple air layers. From this study, it can be concluded that 2000 mg L-1 IBA and vermicompost treatment enhance the root initiation, early establishment and survivability of wax apple air layered under field conditions.

Propolis is a gum-like product that collected by bees from plants and it varies in colour range from light yellow to dark brown. The chemical composition of propolis depends on various factors such as vegetation, season and environmental conditions of the sample collection. The aim of the study was to determine the chemical profile and antioxidant properties of crude methanol extract of Geniotrigona thoracica propolis from five localities, namely Besut (BST), Dungun (DGN), Lundang (LDG), Tanah Merah (TM) and Gua Musang (GM). Phytochemical screening by thin layer chromatography (TLC) showed the presence of terpenoids, flavonoids, coumarins, essential oils and unsaturated and aromatic compounds. The extracts displayed different characteristics of chemical profile that varied from each other. The antioxidant properties of extracts were evaluated based on total phenolic content, total flavonoid content and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity. Propolis from Gua Musang (GM) exhibited the highest total phenolic content with 23.43 ± 0.50 mg GAE/g extract while propolis from Besut (BST) exhibited the highest total flavonoids content with 17.22 ± 0.16 mg QE/g extract and showed the lowest IC50 with 53 µg/mL for DPPH radical scavenging activities. As a result, Geniotrigona thoracica from Besut (BST) could be considered as a good source of antioxidant due to its antioxidant properties.