Siti Amrah Sulaiman

The antibacterial properties of Malaysian tualang honey against wound and enteric microorganisms in comparison to manuka honey.

BackgroundAntibiotic resistance of bacteria is on the rise, thus the discovery of alternative therapeutic agents is urgently needed. Honey possesses therapeutic potential, including wound healing properties and antimicrobial activity. Although the antimicrobial activity of honey has been effectively established against an extensive spectrum of microorganisms, it differs depending on the type of honey. To date, no extensive studies of the antibacterial properties of tualang (Koompassia excelsa) honey on wound and enteric microorganisms have been conducted. The objectives of this study were to conduct such studies and to compare the antibacterial activity of tualang honey with that of manuka honey.MethodsUsing a broth dilution method, the antibacterial activity of tualang honey against 13 wound and enteric microorganisms was determined; manuka honey was used as the control. Different concentrations of honey [6.25-25% (w/v)] were tested against each type of microorganism. Briefly, two-fold dilutions of honey solutions were tested to determine the minimum inhibitory concentration (MIC) against each type of microorganism, followed by more assays within a narrower dilution range to obtain more precise MIC values. MICs were determined by both visual inspection and spectrophotometric assay at 620 nm. Minimum bactericidal concentration (MBC) also was determined by culturing on blood agar plates.ResultsBy visual inspection, the MICs of tualang honey ranged from 8.75% to 25% compared to manuka honey (8.75-20%). Spectrophotometric readings of at least 95% inhibition yielded MIC values ranging between 10% and 25% for both types of honey. The lowest MBC for tualang honey was 20%, whereas that for manuka honey was 11.25% for the microorganisms tested. The lowest MIC value (8.75%) for both types of honey was against Stenotrophomonas maltophilia. Tualang honey had a lower MIC (11.25%) against Acinetobacter baumannii compared to manuka honey (12.5%).ConclusionTualang honey exhibited variable activities against different microorganisms, but they were within the same range as those for manuka honey. This result suggests that tualang honey could potentially be used as an alternative therapeutic agent against certain microorganisms, particularly A. baumannii and S. maltophilia.

Honey: A Novel Antioxidant

The global prevalence of chronic diseases such as diabetes mellitus, hypertension, atherosclerosis, cancer and Alzheimers disease is on the rise. These diseases, which constitute the major causes of death globally, are associated with oxidative stress. Oxidative stress is defined as an “imbalance between oxidants and antioxidants in favor of the oxidants, potentially leading to damage”. Individuals with chronic diseases are more susceptible to oxidative stress and damage because they have elevated levels of oxidants and/or reduced antioxidants. This, therefore, necessitates supplementation with antioxidants so as to delay, prevent or remove oxidative damage. Honey is a natural substance with many medicinal effects such as antibacterial, hepatoprotective, hypoglycemic, reproductive, antihypertensive and antioxidant effects. This review presents findings that indicate honey may ameliorate oxidative stress in the gastrointestinal tract (GIT), liver, pancreas, kidney, reproductive organs and plasma/serum. Besides, the review highlights data that demonstrate the synergistic antioxidant effect of honey and antidiabetic drugs in the pancreas, kidney and serum of diabetic rats. These data suggest that honey, administered alone or in combination with conventional therapy, might be a novel antioxidant in the management of chronic diseases commonly associated with oxidative stress. In view of the fact that the majority of these data emanate from animal studies, there is an urgent need to investigate this antioxidant effect of honey in human subjects with chronic or degenerative diseases.

Phenolic Acid Composition and Antioxidant Properties of Malaysian Honeys

The phenolic acid and flavonoid contents of Malaysian Tualang, Gelam, and Borneo tropical honeys were compared to those of Manuka honey. Ferric reducing/antioxidant power assay (FRAP) and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activities were also quantified. All honey extracts exhibited high phenolic contents (15.21 ± 0.51- 42.23 ± 0.64 mg/kg), flavonoid contents (11.52 ± 0.27- 25.31 ± 0.37 mg/kg), FRAP values (892.15 ± 4.97- 363.38 ± 10.57 μM Fe[II]/kg), and high IC₅₀ of DPPH radical-scavenging activities (5.24 ± 0.40- 17.51 ± 0.51 mg/mL). Total of 6 phenolic acids (gallic, syringic, benzoic, trans-cinnamic, p-coumaric, and caffeic acids) and 5 flavonoids (catechin, kaempferol, naringenin, luteolin, and apigenin) were identified. Among the Malaysian honey samples, Tualang honey had the highest contents of phenolics, and flavonoids, and DPPH radical-scavenging activities. We conclude that among Malaysian honey samples, Tualang honey is the richest in phenolic acids, and flavonoid compounds, which have strong free radical-scavenging activities.

Hypoglycemic and Antioxidant Effects of Honey Supplementation in Streptozotocin-induced Diabetic Rats

OBJECTIVES Oxidative stress plays a crucial role in the development of diabetic complications. The aims of this study were to investigate whether honey could reduce hyperglycemia and ameliorate oxidative stress in kidneys of streptozotocin-induced diabetic rats. METHODS Diabetes was induced by a single dose of STZ (60 mg/kg; i. p.). Diabetic rats were randomly grouped and administered distilled water (0.5 mL/day) and honey (0.2 g/kg/day, 1.2 g/kg/day and 2.4 g/kg/day) by oral gavage for four weeks. Each group consisted of six rats. RESULTS Total antioxidant status (TAS), activities of catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST) were significantly reduced, while superoxide dismutase (SOD) activity was up-regulated in kidneys of diabetic rats. Lipid peroxidation (TBARS) and fasting plasma glucose (FPG) were significantly elevated while body weight was reduced in diabetic rats. Honey significantly increased body weight, TAS, activities of CAT, GPx, GR, and GST in diabetic rats. It significantly restored SOD activity, and reduced FPG and TBARS levels in diabetic rats. Histopathological examinations of the kidneys revealed that mesangial matrix expansion and thickening of glomerular basement membrane were reduced in the honey-treated diabetic rats. CONCLUSIONS Honey exerts a hypoglycemic effect and ameliorates oxidative stress in kidneys of streptozotocin-induced diabetic rats.

Antioxidant Protective Effect of Glibenclamide and Metformin in Combination with Honey in Pancreas of Streptozotocin-Induced Diabetic Rats

Hyperglycemia exerts toxic effects on the pancreatic β-cells. This study investigated the hypothesis that the common antidiabetic drugs glibenclamide and metformin, in combination with tualang honey, offer additional protection for the pancreas of streptozotocin (STZ)-induced diabetic rats against oxidative stress and damage. Diabetes was induced in male Sprague Dawley rats by a single dose of STZ (60 mg/kg; ip). Diabetic rats had significantly elevated levels of lipid peroxidation (TBARS), up-regulated activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) while catalase (CAT) activity was significantly reduced. Glibenclamide and metformin produced no significant effects on TBARS and antioxidant enzymes except GPx in diabetic rats. In contrast, the combination of glibenclamide, metformin and honey significantly up-regulated CAT activity and down-regulated GPx activity while TBARS levels were significantly reduced. These findings suggest that tualang honey potentiates the effect of glibenclamide and metformin to protect diabetic rat pancreas against oxidative stress and damage.

Physicochemical and Antioxidant Properties of Algerian Honey

The aim of the present study was to characterize the physical, biochemical and antioxidant properties of Algerian honey samples (n = 4). Physical parameters, such as pH, moisture content, electrical conductivity (EC), total dissolved solids (TDS), color intensity, total sugar and sucrose content were measured. Several biochemical and antioxidant tests were performed to determine the antioxidant properties of the honey samples. The mean pH was 3.84 ± 0.01, and moisture the content was 13.21 ± 0.16%. The mean EC was 0.636 ± 0.001, and the mean TDS was 316.92 ± 0.92. The mean color was 120.58 ± 0.64 mm Pfund, and the mean 5-hydroxymethylfurfural (HMF) content was 21.49 mg/kg. The mean total sugar and reducing sugar contents were 67.03 ± 0.68 g/mL and 64.72 ± 0.52 g/g, respectively. The mean sucrose content was 2.29 ± 0.65%. High mean values of phenolic (459.83 ± 1.92 mg gallic acid/kg), flavonoid (54.23 ± 0.62 mg catechin/kg), ascorbic acid (159.70 ± 0.78 mg/kg), AEAC (278.15 ± 4.34 mg/kg), protein (3381.83 ± 6.19 mg/kg) and proline (2131.47 ± 0.90) contents, as well as DPPH (39.57% ± 4.18) and FRAP activities [337.77 ± 1.01 µM Fe (II)/100 g], were also detected, indicating that Algerian honey has a high antioxidant potential. Strong positive correlations were found between flavonoid, proline and ascorbic acid contents and color intensity with DPPH and FRAP values. Thus, the present study revealed that Algerian honey is a good source of antioxidants.

The effects of tualang honey on female reproductive organs, tibia bone and hormonal profile in ovariectomised rats - animal model for menopause

BackgroundHoney is a highly nutritional natural product that has been widely used in folk medicine for a number of therapeutic purposes. We evaluated whether Malaysian Tualang honey (AgroMas, Malaysia) was effective in reducing menopausal syndrome in ovariectomised female rats; an animal model for menopause.MethodsThe rats were divided into two control groups and three test groups. The control groups were sham-operated (SH) and ovariectomised (OVX) rats. The SH and OVX control rats were fed on 0.5 ml of distill water. The rats in the test groups were fed with low dose 0.2 g/kg (THL), medium dose, 1.0 g/kg (THM) and high dose 2.0 g/kg (THH) of Tualang honey in 0.5 ml of distill water. The administration was given by oral gavage once daily for 2 weeks. The reproductive organs (uterus and vagina), tibia bone and aorta were taken for histopathological examination while serum for hormonal assays.ResultsAdministration of Tualang honey for 2 weeks to ovariectomised rats significantly increased the weight of the uterus and the thickness of vaginal epithelium, restored the morphology of the tibia bones and reduced the body weight compared to rats in the ovariectomised group. The levels of estradiol and progesterone, in honey treated groups were markedly lower than that in the OVX group. At low doses (0.2 g/kg; THL group) of Tualang honey there was an increased in serum free testosterone levels compared to OVX group (P < 0.01). Progesterone concentrations was significantly decreased in the OVX group as compared to SHAM group (P < 0.05).ConclusionsTualang honey was shown to have beneficial effects on menopausal (ovariectomised) rats by preventing uterine atrophy, increased bone density and suppression of increased body weight. Honey could be an alternative to HRT.

High 5-hydroxymethylfurfural concentrations are found in Malaysian honey samples stored for more than one year.

5-Hydroxymethylfurfural (HMF) content is an indicator of the purity of honey. High concentrations of HMF in honey indicate overheating, poor storage conditions and old honey. This study investigated the HMF content of nine Malaysian honey samples, as well as the correlation of HMF formation with physicochemical properties of honey. Based on the recommendation by the International Honey Commission, three methods for the determination of HMF were used: (1) high performance liquid chromatography (HPLC), (2) White spectrophotometry and (3) Winkler spectrophotometry methods. HPLC and White spectrophotometric results yielded almost similar values, whereas the Winkler method showed higher readings. The physicochemical properties of honey (pH, free acids, lactones and total acids) showed significant correlation with HMF content and may provide parameters that could be used to make quick assessments of honey quality. The HMF content of fresh Malaysian honey samples stored for 3-6 months (at 2.80-24.87 mg/kg) was within the internationally recommended value (80 mg/kg for tropical honeys), while honey samples stored for longer periods (12-24 months) contained much higher HMF concentrations (128.19-1131.76 mg/kg). Therefore, it is recommended that honey should generally be consumed within one year, regardless of the type.

Antioxidant protection of Malaysian tualang honey in pancreas of normal and streptozotocin-induced diabetic rats

Glucotoxicity contributes to beta-cell dysfunction through oxidative stress. Our previous study demonstrated that tualang honey ameliorated renal oxidative stress and produced hypoglycemic effect in streptozotocin (STZ)-induced diabetic rats. This present study investigated the hypothesis that hypoglycemic effect of tualang honey might partly be due to protection of pancreas against oxidative stress. Diabetes was induced by a single dose of STZ (60 mg/kg; ip). Diabetic rats were randomly divided into two groups and administered distilled water (0.5 ml/d) and tualang honey (1.0 g/kg/d). Similarly, two groups of non-diabetic rats received distilled water (0.5 ml/d) and tualang honey (1.0 g/kg/d). The animals were treated orally for 28 days. At the end of the treatment period, the honey-treated diabetic rats had significantly (p<0.05) reduced blood glucose levels [8.8 (5.8)mmol/L; median (interquartile range)] compared with the diabetic control rats [17.9 (2.6)mmol/L]. The pancreas of diabetic control rats showed significantly increased levels of malondialdehyde (MDA) and up-regulation of superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Catalase (CAT) activity was significantly reduced while glutathione-S-transferase (GST) and glutathione reductase (GR) activities remained unchanged in the pancreas of diabetic rats. Tualang honey significantly (p<0.05) reduced elevated MDA levels. Honey treatment also restored SOD and CAT activities. These results suggest that hypoglycemic effect of tualang honey might be attributed to its antioxidative effect on the pancreas.

Antioxidant Properties of Honey and Its Role in Preventing Health Disorder

Honey is being used since long time both in medical and domestic needs, but only recently its antioxidant property has come to limelight. With increasing demand for antioxidant supply in the food, honey is becoming popular as a source of antioxidant since it is rich in phenolic acids and flavonoids and other antioxidants including glucose oxidase, catalase, ascorbic acid, carotenoid derivatives, organic acids, amino acids and proteins. The antioxidants have several pre- ventative effects against different diseases like cancer, cardiovascular diseases, inflammatory disorders, neurological de- generation, wound healing, infectious diseases and aging, which led to search for foods rich in antioxidants. Various stud- ies on antioxidant properties of honey have been done. The present article is a short review on the antioxidant properties of honey and its role against health disorder.