Norhayati Muhammad

Acuminatol and Other Antioxidative Resveratrol Oligomers from the Stem Bark of Shorea acuminata

A new resveratrol dimer, acuminatol (1), was isolated along with five known compounds from the acetone extract of the stem bark of Shorea acuminata. Their structures and stereochemistry were determined by spectroscopic methods, which included the extensive use of 2D NMR techniques. All isolated compounds were evaluated for their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA) and the β-carotene-linoleic acid (BCLA) assays, and compared with those of the standards of ascorbic acid (AscA) and butylated hydroxytoluene (BHT). All compounds tested exhibited good to moderate antioxidant activity in the DPPH assay (IC50s 0.84 to 10.06 mM) and displayed strong inhibition of β-carotene oxidation (IC50s 0.10 to 0.22 mM). The isolated compounds were evaluated on the Vero cell line and were found to be non-cytotoxic with LC50 values between 161 to 830 µM.

Chemical Composition, Antioxidant and Antibacterial Properties of the Essential Oils of Shorea acuminata (Dipterocarpaceae)

Abstract Chemical composition, antioxidant and antibacterial properties of the essential oils from the stem and leaves of Shorea acuminata Dyer were investigated. The yield of the hydro-distilled essential oils obtained from stem and leaves were 0.40 % and 0.02 %, respectively. The main groups of compound found in the essential oils were sesquiterpene hydrocarbons (64.8 % and 33.4 %) and oxygenated sesquiterpenes (19.2 % and 51.7 %), which accounted for 85.6 % of the stem oil and 85.8 % of the leaf oil. Caryophyllene oxide (36.0 %) and β-caryophyllene (13.9 %) were found to be the major constituents in the leaves, whereas germacrene D (35.0 %) was the major constituent in the stem. The essential oils from the stem and leaves exhibited good antioxidant activity as measured by DPPH free radical-scavenging ability with EC50 of 0.72 mg/ml and 0.64 mg/ml respectively. In β-carotene/linoleic acid assay, the stem and leaves essential oil exhibited 88.78 % and 89.27 % antioxidant activity respectively at 9 mg/ml which was comparable to that of BHT (98.31 %). The antibacterial test results showed that the leaf oil of S. acuminata had low antibacterial activity against MRSA and S. aureus and no antibacterial activity against S. typhimurium and E. coli. The stem oil was inactive against all bacteria tested.

Polyherbal formulations with optimum antioxidant properties

The objective of this study is to determine the optimum antioxidant properties of polyherbal formulations of the aqueous extract of leaves of Strobilanthes crispus (pecah beling), Phyllanthus niruri (dukung anak), Orthosiphon aristatus (misai kucing) and Stevia rebudiana using in vitro method. There are 22 formulations consisting various proportions of the extracts designated using commercial statistical software package that is Design Expert 6.0.4. The antioxidant study of the individual extracts and their different combinations were conducted using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, Ferric Reduction Antioxidant Potential Assay (FRAP) and total phenolic content (TPC) assay. Results showed that O. aristatus has higher antioxidant properties in most of the assay when tested individually, as compared to S. crispus, P. niruri and S. rebudiana. Synergistic effect was exhibited in most of the polyherbal combinations. From the optimization process, it was revealed that the quadratic model was statistically significant for the FRAP and TPC while special cubic model was statistically significant for DPPH. The optimum mixture found for antioxidant properties was the polyherbal formulation that contain the extract of 23.96% of S. crispus, 0.62% of P. niruri and 75.42% of O. aristatus with desirability of 0.985. In conclusion, the results indicated that the formulations obtained in this present study justify the promising antioxidant properties of the polyherbal mixtures. Thus, it is sensible to use the combination of studied herbal formulation for development of any antioxidant supplement or food products in the future.The objective of this study is to determine the optimum antioxidant properties of polyherbal formulations of the aqueous extract of leaves of Strobilanthes crispus (pecah beling), Phyllanthus niruri (dukung anak), Orthosiphon aristatus (misai kucing) and Stevia rebudiana using in vitro method. There are 22 formulations consisting various proportions of the extracts designated using commercial statistical software package that is Design Expert 6.0.4. The antioxidant study of the individual extracts and their different combinations were conducted using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, Ferric Reduction Antioxidant Potential Assay (FRAP) and total phenolic content (TPC) assay. Results showed that O. aristatus has higher antioxidant properties in most of the assay when tested individually, as compared to S. crispus, P. niruri and S. rebudiana. Synergistic effect was exhibited in most of the polyherbal combinations. From the optimization process, it was revealed that the quadrat...

Optimisation of microwave-assisted processing in production of pineapple jam

Pineapples are available all year round since they are unseasonal fruits. Due to the continuous harvesting of the fruit, the retailers and farmers had to find a solution such as the processing of pineapple into jam, to treat the unsuccessfully sold pineapples. The direct heating of pineapple puree during the production of pineapple jam can cause over degradation of quality of the fresh pineapple. Thus, this study aims to optimise the microwave-assisted processing conditions for producing pineapple jam which could reduce water activity and meets minimum requirement for pH and total soluble solids contents of fruit jam. The power and time of the microwave processing were chosen as the factors, while the water activity, pH and total soluble solids (TSS) content of the pineapple jam were determined as responses to be optimised. The microwave treatment on the pineapple jam was able to give significant effect on the water activity and TSS content of the pineapple jam. The optimum power and time for the microwav...

Identification of most tolerant lichen species to vehicular traffic’s pollutants at Batu Pahat area

Bio-indicators are organisms that can be used for the identification and qualitative determination of human generated environmental factors. The decreasing population of sensitive lichens in specific regions around the world due to low air quality level has make lichens as a bio-indicator for air pollution. Lichen is a result of symbiotic association of fungus and alga and well known for having wide variety of sensitivity towards environmental stressors such as air quality and climate change. The aim of this study is to identify the most tolerant lichen species to vehicular traffic’s pollutant at Batu Pahat urban and suburban areas. This study was conducted by using Index of Atmospheric Purity (IAP) method and followed by morphological and chemicals testing for species identification. Dirinaria picta has been identified as the most tolerant lichen species against pollutants from vehicle traffic. The results also indicated that the air quality of Batu Pahat town/urban area could be considered as moderately...

Hopeanolin and other Resveratrol Oligomers from the Twigs of Shorea acuminata: Antioxidant Propertiaes and Chemotaxonomic Significance

Hopeanolin (1) was isolated from the acetone extract of the twigs of Shorea acuminata (Dipterocarpaceae), together with four resveratrol oligomers namely (-)-laevifonol, (-)-� -viniferin, (-)-vaticanol B and (-)-hopeaphenol. The structures of these compounds were established based on spectroscopic evidence, including UV, IR, NMR and mass spectra. Compound 1 showed the potent ability to protect � -carotene bleaching by linoleic acid and also to scavenge DPPH radicals with IC50s 0.18 and 6.58 mM respectively. The presence of compound 1 and the other four resveratrol oligomers in this species have great chemotaxonomic significance on the relationship between Shorea and other genera of Dipterocarpaceae especially Hopea.