Quantification of gallic acid and tannic acid from quercus infectoria (Manjakani) and their effects on antioxidant and antibacterial activities

Effects of different types of solvent on the antioxidant and antibacterial activity of Quercus infectoria extract have not been well documented. Therefore, extraction process was conducted using conventional Soxhlet extraction with six different types of solvent (100% methanol, ethanol, acetone, water and 70% methanol, and ethanol). High performance liquid chromatography was implemented to identify gallic acid and tannic acid in the extracts. Water extracts contained the highest concentration of both gallic acid and tannic acid compared to other types of solvent; 51.14 mg/g sample and 1332.88 mg/g sample of gallic acid and tannic acid. Meanwhile, antioxidant and antibacterial activity were tested using DPPH free radicals scavenging and disc diffusion assay. Results demonstrated that water extracts gave the highest antioxidant activity (approximately 94.55%), while acetone extract gave the largest inhibition zone for disc diffusion assay (19.00mm respectively). The results also revealed rich sources of gallic acid and tannic acid in Q.infectoria which might provide a novel source of these natural antioxidant and antibacterial activity

Isolation and Identification of Marine Algae (Oscillatoria Sp.) From Kuantan Coastal Region Malaysia and Studies on Their Bioactive and Antibacterial Properties

Marine algae is an incredible group of prokaryotic organisms that produce a variety of industrially and clinically important secondary metabolites. In this study explore the marine cyanobacteria (Oscillatoria Sp.) was isolated from the Kuantan coastal area and on their anti-microbial activity and bioactive compounds. The ethanolic Oscillatoria Sp. extract was subjected to GC-MS analysis to determine the bioactive compounds. Also the ethanolic extract used for antibacterial activity by disk diffusion assay using four different types of pathogenic bacteria such as P. aurogenosa, Bacillus subtilis, Staphylococcus aureus and Escherichia coli. The zone of inhibition was observed and measured in the experimental petri plates. The antibacterial activity showed that the ethanol extract of Oscillatoria Sp. was effective against P. aeruginosa the 16mmzone of inhibition was observed. The microalgae crude extract was highly significant in against tested gram-positive bacteria. Moreover, GC-MS analysis data shows the present of several compounds such as phenol derivatives and fatty acid derivatives in the sample. The compounds are mainly responsible for controlling the gram positive bacteria