Background: The aim of the present study was to evaluate the physical, biochemical and antioxidant properties of four Malaysian monofloral types of honey (gelam, longan, rubber tree and sourwood honeys) compared to manuka honey. Several physical parameters of honey, such as pH, moisture content, electrical conductivity (EC), total dissolved solids (TDS), color intensity, total sugar and sucrose content, were measured. A number of biochemical and antioxidant tests were performed to determine the antioxidant properties of the honey samples. Hydroxymethylfurfural (HMF) levels were determined using high performance liquid chromatography. Results: The mean pH, moisture content, EC and TDS of Malaysian honey were 3.90 ± 0.12, 17.01 ± 3.07%, 0.59 ± 0.17 mS/cm and 294.87 ± 81.96 ppm, respectively. The mean color and HMF level was 102.07 ± 41.77 mm Pfund and 49.51 ± 0.12 mg/kg, respectively. Sourwood honey contained the highest contents of phenolics (580.03 ± 0.38 mg_{galic acid}/kg) and flavonoids (156.82 ± 0.47 mg_catechin/kg) with high DPPH radical scavenging activity (59.26 ± 3.77%) as well as ferric reducing power [648.25 ± 0.90 μM Fe (II)/100 g]. Sourwood honey also exhibited the highest color intensity. Several strong positive correlations were observed amongst the different antioxidant parameters and the various antioxidant tests. Conclusion: This is the first time that the antioxidant potential of both sourwood and rubber tree honeys have been reported. Our results indicated that Malaysian honey (specifically sourwood honey and longan honey) is a good source of antioxidants compared to Manuka honey.

Background: Withania somnifera, also known as ashwagandha, is an important herb in ayurvedic and indigenous medical systems. The present study was designed to evaluate the antioxidant and antibacterial activities of an 80% aqueous methanolic extract of W. somnifera roots (WSREt), fruits (WSFEt) and leaves (WSLEt). Methods: Several assays were performed to determine the antioxidant properties of this herb including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, ferric reducing antioxidant power (FRAP), ferrous chelation and inhibition of β-carotene bleaching. Results: The values for DPPH, FRAP, ferrous chelation and inhibition of β carotene bleaching for the three types of extracts ranged from 101.73-801.93 μg/ml, 2.26-3.29 mM Fe/kg, 0.22-0.65 mg/ml and 69.87-79.67%, respectively, indicating that W. somnifera, particularly the leaves, possesses significant antioxidant properties. The mean ascorbic acid content was 20.60-62.60 mg/100 g, and the mean anthocyanin content was 2.86-12.50 mg/100 g. Antibacterial activities were measured using the agar well diffusion method and five pathogenic Gram-negative bacteria: Escherichia coli, Salmonella typhi, Citrobacter freundii, Pseudomonas aeruginosa and Klebsiella pneumoniae. The leaf extracts displayed the highest activity against S. typhi (32.00 ± 0.75 mm zone of inhibition), whereas the lowest activity was against K. pneumoniae (19.00 ± 1.48 mm zone of inhibition). The lowest minimum inhibitory concentration value was 6.25 mg/ml, which was against S. typhi, followed by 12.5 mg/ml against E. coli. Conclusion: In addition to its antioxidant properties, W. somnifer a exhibited significant antibacterial activities against Gram-negative bacteria, particularly S. typhi.

Background: There is no available information on physicochemical and antioxidant properties on Bangladeshi honey. We investigated five different monofloral and three different multifloral honey samples collected from different parts of Bangladesh. Methods: The levels of phenolics, flavonoids, ascorbic acid, ascorbic acid equivalent antioxidant content (AEAC), proline, protein and antioxidants were determined in the honey samples using ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. Results: The highest level of phenolic was 688.5 ± 5.9 mg Gallic acid/kg, and the highest level of flavonoid was 155 ± 6.9 mg Catechin/kg. The highest color intensity was 2034.00 ± 17.5 mAU, and the highest protein content was 8.6 ± 0.0mg/g. High levels of proline (2932.8 ± 3.7 mg/kg), ascorbic acid (154.3 ± 0.3 mg/kg), AEAC (34.1 ± 1.4mg/100 g) and FRAP (772.4 ± 2.5 μmol Fe (II)/100 g) were detected in some of the samples, especially the multifloral honey samples, indicating good antioxidant properties. A strong positive correlation was found between phenolics, flavonoids, DPPH, FRAP and color intensity, indicating that in addition to total phenolic and flavonoid concentrations, color intensity and amino acid are good indicators of the antioxidant potential of honey. Except for a single sample (BDH-6), the honey samples stored for 1.5 years at room temperature still had 5-hydroxymethylfurfural (HMF) values within the recommended range (mean = 10.93 mg/kg), indicating that the rate of HMF production in Bangladeshi honey samples is low. Conclusion: It is postulated that the low rate of HMF formation could be attributed to the acidic and low moisture content in the samples. In general, multifloral honeys have higher antioxidant properties based on their high levels of phenolics, flavonoids, AEAC, DPPH and FRAP when compared to monofloral honeys. We also found that monofloral honey samples from Guizotia abyssinica and Nigella sativa had high antioxidant properties.

In this study, the total phenolic and flavonoid contents, the 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging ability and the ferric reducing power (FRAP) of Aloe vera were measured to determine the antioxidant activity of this species. The in vivo antidiabetic effects of the plant were also investigated using streptozotocin-induced type 2 diabetic model rats that were divided into five groups based on the treatment received: (1) water (WC); (2) glibenclamide; (3) concentrated gel extract (Gel-C); (4) ethanol (80%) gel extract (Gel-Et); and (5) ethanol (80%) skin extract of Aloe vera (Skin-Et). Skin-Et, which contained the highest level of total phenolics (62.37 ± 1.34 mg_{gallic acid}/kg) and flavonoids (20.83 ± 0.77 mg/kg), exhibited the highest scavenging activity (85.01 ± 0.52%) and the greatest reducing power (185.98 ± 0.41 µM), indicating that the skin contained the highest level of antioxidants. The oral consumption of Gel-Et for 4 weeks a caused significant reduction in the fasting serum glucose levels of the rats. The rats in the Gel-C-, Gel-Et- and Skin-Et-treated groups experienced a reduction in their total cholesterol levels by 11%, 17% and 25%, respectively and a reduction in their LDL cholesterol levels by 45%, 3% and 69%, respectively. The in vivo experimental antioxidant parameter MDA is strongly correlated with the in vitro antioxidant parameters of flavonoids and polyphenols, namely the DPPH and FRAP values (r = 0.94, 0.92, 0.93, 0.90), thus confirming the antioxidant potential of the Aloe vera extracts.

This study was conducted to evaluate the effects of evaporation, gamma irradiation and temperature on the total polyphenols, flavonoids and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities of Tualang honey samples (n = 14) following storage over three, six or twelve months. The mean polyphenol concentrations of the six gamma irradiated honey samples at three, six and twelve months, respectively, were 96.13%, 98.01% and 102.03% higher than the corresponding values of the eight non-gamma irradiated samples. Similarly, the mean values for flavonoids at three, six and twelve months were 111.52%, 114.81% and 110.04% higher, respectively, for the gamma irradiated samples. The mean values for DPPH radical-scavenging activities at three, six and twelve months were also 67.09%, 65.26% and 44.65% higher, respectively, for the gamma irradiated samples. These data indicate that all gamma irradiated honey samples had higher antioxidant potential following gamma irradiation, while evaporation and temperature had minor effects on antioxidant potential.

Bioconversion of cellulosic components into fermentable sugars has currently been accomplished with the help of the microbial enzyme, cellulase. In this study, Pleurotus ostreatus (Jacquin ex Fr.) Kummer and Pleurotus sajor-caju (Fr.) Singer were tested for cellulase production by solid state fermentation (SSF) using saw dust, sugarcane bagasse, and paddy straw as substrate. To enhance production, the substrates were pretreated with 1% and 4% NaOH solutions. Supernatants of extracted enzyme solutions were used to estimate reducing sugar and soluble protein, as well as enzyme activities. Maximum production of reducing sugar and soluble protein were recorded in 12 and 10 day fermented products, respectively. In the production of reducing sugars, P. ostreatus (42.8 mg g^{-1}) was found to be more efficient than P. sajor-caju (10.9 mg g^{-1}), while P. sajor-caju was more efficient in soluble protein production (40.2 mg g^{-1}) compared to P. ostreatus (3.1 mg g^{-1}). P. ostreatus was found to be more efficient in the individual components of cellulase enzyme production than P. sajor-caju. All the enzyme activities were found to attain a peak at 10 days of fermentation. The highest activities of endoglucanase, exoglucanase, and \beta-glucosidase were recorded as 7.08, 7.36, and 3.60 units (µmole of glucose released/min/g substrate), respectively, for P. ostreatus, while that of P. sajor-caju were 1.9, 2.03, and 2.63 units, respectively. Total cellulase activity was found to reach a maximum at 10 days of fermentation for both strains. For P. ostreatus it was recorded as 3.51 units, while for P. sajor-caju it was 0.82 units. This study suggests P. ostreatus as an important source of cellulase enzymes.