Antimicrobial, total phenolic and total flavonoid properties of leaves and seed of Jatropha curcas, Piper nigrum L. and Piper betle methanolic crude extracts

Aims: Herbal and medicinal plants bioactive compounds of Jatropha curcas, Piper nigrum and P. betle have been shown to possess therapeutic properties. This study investigates the presence and characterization of phytochemical compounds as well as to evaluate the antimicrobial activities of the methanolic crude extract of the leaves and seeds of J. curcas, P. nigrum L. and P. betle. Methodology and results: The study on antibacterial and antifungal efficacy of the crude extracts of leaves and seeds were carried out using standard disc diffusion method. The crude extracts were found to exhibit an average response of antimicrobial activity with the inhibition zones ranged from 3% to 28% for antibacterial and from 21% to 79% for antifungal activity. Among all extracts, the leaf extract of P. betle showed a good antibacterial activity against Staphylococcus aureus and excellent antifungal properties against Aspergillus niger and A. flavus. The phytochemical screening analysis revealed the presence of saponin, tannins, glycosides, terpenoids, reducing sugar, flavonoid and anthraquinones. However, phlobatannins was not present. Total phenolic content (TPC) and total flavonoid content (TFC) were highly detected in the crude extract of P. betle and recorded as 13.33 mg of gallic acid equivalents, GAE (mg/ 100 mg sample) and 0.88 mg of RE (mg/100 mg sample), respectively. GC-MS analysis of the bioactive compounds reveals the presence of diethyl phthalate, 2-hexadecen-1-ol (Phytol), hexadecanoic acid, piperine, phenol and other minor compounds. Conclusion, significance and impact of study: The study suggested that P. betle has a potential as a source for antimicrobial agent from plants extracts. Nevertheless, further studies are needed to elucidate their precise mechanism of action.

Factors affecting toxic lead(Ii) ion bioremediation by Fusarium equiseti isolated from the mangrove soil environment of southeast Borneo

Aims: Electronic waste (e-waste) is an inorganic pollutant which causes a serious environmental problem since it contains toxic heavy metals, which cannot be removed from contaminated sites easily. The use of biomaterials for removing heavy metals from contaminated soil and wastewater has emerged as a potential alternative method to the conventional techniques. The present study were aimed to isolate efficient lead tolerant fungi from mangrove soil environment and measure its capability for lead removal from aqueous solution. Methodology and results: Lead tolerant fungal strains were isolated from soil samples using PDA (Potato Dextrose Agar) supplemented with varied concentrations of lead ions (100-500 mg/L). The most tolerant fungal strain was successfully isolated and identified molecularly as Fusarium equiseti KR706303. The isolated fungus was used for biosorption studies using Potato dextrose broth (PDB) supplemented with lead ions. The effects of pH, temperature, initial metal concentration, biomass dose and age, agitation and contact time to the Pb(II) removal efficiency were monitored in the study. The results showed that the optimal parameters for the removal of lead ions such as heavy metal concentration and pH were 300 mg/L, with a maximum Pb(II) adsorption of 97.9% observed at pH 4 and temperature of 30 °C during the batch biosorption experiments. The optimal parameters for biomass dose, agitation speed, contact time and biomass age were observed at 0.04 g, 150 rpm, 60 min and fifth day; respectively. Conclusion, significance and impact of study: The observation in this study revealed that the biomass of the isolated Fusarium equiseti KR706303 has the potential to be used as a biosorbent for heavy metal particularly Pb(II) removal from the contaminated sites. The technology is simple, efficient, cost effective and environmental friendly.

In Vitro Antagonism of Phytophthora capsici And Fusarium solani by Bacterial Isolates from Sarawak

Aims: Phytophthora capsici and Fusarium solani are common fungal pathogens causing severe diseases that lead to economic loss in pepper industry, especially in Sarawak. In response to the infections, chemical approach is more common; nevertheless, biological control is more favorable to control fungal pathogens. Biological control approach greatly reduces the problems associated with chemical applications and it restores balance of the natural environment. Here we present the ongoing work to study the action of antagonistic bacteria, Bacillus sp. and Pseudomonas sp., that produce volatile and non-volatile antifungal compounds against P. capsici and F. solani on pepper plants. Methodology and results: A total of seven bacterial candidates were isolated from different locations and tested for their antagonistic properties against P. capsici and F. solani in a dual culture assay and extracellular metabolite test. Extracellular hydrolytic enzymes production was also monitored and followed by genotypic indentification. Preliminary antagonism tests indicated that bacterial isolate Pep3 and Pep4 inhibit up to 50% of the growth of P. capsici and F. solani as compared to the control. Subsequent investigation on extracellular hydrolytic enzyme production revealed that both bacterial isolates are capable of secreting hydrolytic enzymes. Microscopic and genotypic analyses identified the bacterial isolates Pep3 as Bacillus amyloliquefaciens (KJ461444) and Pep4 as Pseudomonas pachastrellae (KM460937). Conclusion, significance and impact of study: B. Amyloliquefaciens (KJ461444) and P. pachastrellae (KM460937) inhibited the growth of P. capsici and F. solani thus reflecting the potential of the produced metabolites to be purified and used in combating plant pathogenic fungi.