Antimicrobial activities of stembark and wood extracts from Nauclea subdita against pathogenic microorganisms

Aims: The aim of the study was to investigate the antimicrobial activity of Nauclea subdita (Korth) Steud against six pathogenic microorganisms. Methodology and results: Young and matured trees of N. subdita were cut and separated into bark and wood parts, respectively, prior to extraction process. Phytochemical screening tests, antimicrobial activity, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were determined. Preliminary screening for phytochemical components showed that both young and matured tree had similar constituents. Extracts from matured tree showed more potency in terms of the zones of inhibition sizes than the young tree. Extract of N. subdita was more potent to both marine bacteria, Vibrio parahaemoliticus and V. alginolyticus, while Candida albican and Aspergillus niger were resistant to it. The sensitivity test showed that 500 μg/mL is the optimum concentration for extract of bottom sapwood of mature tree to act as bactericidal. Conclusion, significance and impact study: The results from this study suggest that N. subdita bark and wood extracts may serve as potential source of antimicrobial agents for future development in medicine applications

Effect of post-thermal treatment on the density profile of rubberwood particleboard and its relation to mechanical properties

The objective of the study was to investigate the effect of heat treatment on the changes in density profile of rubberwood particleboard samples. The relationship between density profile and mechanical properties of particleboard samples was determined using regression analysis. Single layer particleboard made from rubberwood particles with dimensions of 340 mm × 340 mm × 12 mm and targeted density of 700 kg m-3 was heat-treated using oven and hot press at three different temperature levels, namely, 100, 150 and 200 °C for 30 min. All density profile attributes were significantly affected by heat treatment. Bending properties, internal bond strength and hardness were influenced by treatment temperature. However, samples treated using hot press had better mechanical properties compared with those treated using oven. Mean and peak densities exerted profound effects on mechanical properties of the samples

ORIGINAL ARTICLE Total phenolic contents and free-radical scavenging activities from methanolic extracts of Nauclea subdita (Korth) Steud. heartwood

Fatin Ruzanna Jamaluddin, Razak Wahab, Jamaluddin M. Daud and Shafiqur Rahman; Total phenolic contents and free-radical scavenging activities from methanolic extracts of Nauclea subdita (Korth) Steud. heartwood ABSTRACT Investigation on the total phenolic content (TPC) and free-radical scavenging activity of Nauclea subdita (Korth) Steud. were carried out. Information on these activities might reflect the potency of the plant extract as an antioxidant. Young and matured trees of N. subdita were harvested and cut into three heartwood parts (top, middle and bottom) and grounded into powdered forms. Soxhlet extraction of the heartwood samples using polar (methanol) and non-polar (hexane) solvents, and phytochemical screening tests were carried out. The total phenolic contents of the methanolic crude extracts from heartwood parts were determined by colorimetry at 760 nm using Folin-Ciocalteau's reagent, and gallic acid was used as standard. The methanolic extracts were also checked for primary antioxidant activities using an in vitro method, measured by free-radical scavenging activity of 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) radical. The absorbances were measured at 517 nm by UV/VIS spectrophotometer and compared with standards Trolox and butylated hydroxyanisole (BHA). The results from this study suggest that N. subdita heartwood extract may serve as a potential source of natural antioxidant for future development in food and nutraceutical applications

Total phenolic contents and free-radical scavenging activities from methanolic extracts of Nauclea subdita (Korth) Steud. heartwood

Investigation on the total phenolic content (TPC) and free-radical scavenging activity of Nauclea subdita (Korth) Steud. were carried out. Information on these activities might reflect the potency of the plant extract as an antioxidant. Young and matured trees of N. subdita were harvested and cut into three heartwood parts (top, middle and bottom) and grounded into powdered forms. Soxhlet extraction of the heartwood samples using polar (methanol) and non-polar (hexane) solvents, and phytochemical screening tests were carried out. The total phenolic contents of the methanolic crude extracts from heartwood parts were determined by colorimetry at 760 nm using Folin-Ciocalteau’s reagent, and gallic acid was used as standard. The methanolic extracts were also checked for primary antioxidant activities using an in vitro method, measured by free-radical scavenging activity of 2, 2’-diphenyl-1- picrylhydrazyl (DPPH) radical. The absorbances were measured at 517 nm by UV/VIS spectrophotometer and compared with standards Trolox and butylated hydroxyanisole (BHA). The results from this study suggest that N. subdita heartwood extract may serve as a potential source of natural antioxidant for future development in food and nutraceutical applications

Antimicrobial activities of stembark and wood extracts from Nuclea subdita against pathogenic microorganisms

The aim of the study was to investigate the antimicrobial activity of Nuclea subdita (Korth) Steud against six pathogenic microorganisms. Methodology and results: Young and maturedtrees ao N. subdita were cut and separated into bark and wood parts, respectively, prior to extraction process. Phytochemical screening tests, antimicrobial activity, minimal inhibitory concentration (MIC) and minimal bacterial concentration (MBC) values were determined. Preliminary screening for phytochemical components showed that both young and matured tree had similar constituents. Extracts from matured tree showed more potency in terms of the zones of inhibition sizes than the young tree. Extract of N. subdita was more potent to both marine bacteria, Vibrio parahaemoliticus and V. alginolyticus, while Candida albican and Aspergillus niger were resistant to it. The sensitivity test showed that 500 ug/mL is the optimum concentration for extract of bottom sapwood of mature tree to act as bactericidal. Conclusion, significance and impact study: The results from this study suggest that N. subdita bark and wood extracts may serve as potential source of antimicrobial agents for future development in medicine applications