An ensemble docking-based virtual screening and molecular dynamics simulation of phytochemical compounds from Malaysian Kelulut Honey (KH) against SARS-CoV-2 target enzyme, human angiotensin-converting enzyme 2 (ACE-2).

The human angiotensin-converting enzyme 2 (ACE-2) receptor is a metalloenzyme that plays an important role in regulating blood pressure by modulating angiotensin II. This receptor facilitates SARS-CoV-2 entry into human cells via receptor-mediated endocytosis, causing the global COVID-19 pandemic and a major health crisis. Kelulut honey (KH), one of Malaysian honey recently gained attention for its distinct flavour and taste while having many nutritional and medicinal properties. Recent study demonstrates the antiviral potential of KH against SARS-CoV-2 by inhibiting ACE-2 in vitro, but the bioactive compound pertaining to the ACE-2 inhibition is yet unknown. An ensemble docking-based virtual screening was employed to screen the phytochemical compounds from KH with high binding affinity against the 10 best representative structures of ACE-2 that mostly formed from MD simulation. From 110 phytochemicals previously identified in KH, 27 compounds passed the ADMET analysis and proceeded to docking. Among the docked compound, SDC and FMN consistently exhibited strong binding to ACE-2's active site (-9.719 and -9.473 kcal/mol) and allosteric site (-7.305 and -7.464 kcal/mol) as compared to potent ACE-2 inhibitor, MLN 4760. Detailed trajectory analysis of MD simulation showed stable binding interaction towards active and allosteric sites of ACE-2. KH's compounds show promise in inhibiting SARS-CoV-2 binding to ACE-2 receptors, indicating potential for preventive use or as a supplement to other COVID-19 treatments. Additional research is needed to confirm KH's antiviral effects and its role in SARS-CoV-2 therapy, including prophylaxis and adjuvant treatment with vaccination.Communicated by Ramaswamy H. Sarma.

Effectiveness of stingless bee (Kelulut) honey versus conventional gel dressing in diabetic wound bed preparation: A randomized controlled trial.

Purpose: Kelulut honey contains trehalulose and has high antioxidant content, such as phenolic and flavonoid substances, which can promote wound healing. This study evaluated the effectiveness of Kelulut honey in diabetic wound healing compared to a commercially available conventional gel dressing (Intrasite gel). Methods: A prospective, randomized, single-blinded control trial was performed on eligible diabetic patients with full-thickness cavity wounds. Patients' demographics, size and site of wounds, and baseline routine blood investigations were recorded. The wounds were dressed every other day with Kelulut honey for the intervention group or gel for the control group. The wound size reduction and granulation tissue formation percentage were calculated every 6 days for 1 month. Results: Seventy-one patients were randomized. After 30 days of follow-up, 62 participants were available for analysis: 30 from the control group and 32 from the treatment group. The control group had increased granulation tissue at baseline and more wounds on the lower limb and posterior trunk. Both groups showed an increasing mean and median percentage of wound epithelialization and granulation tissue over time, with significantly higher values at every timepoint in the honey group (p < 0.05). However, repeated measures analysis of variance and analysis of covariance revealed no significant interaction effect between the different treatments and time, with F (2.02, 121.28) = 0.88, p = 0.417 and F (1.60, 93.95) = 0.79, p = 0.431, respectively. Conclusion: This study revealed that Kelulut honey was comparable to and as effective as the conventional gel in treating diabetic wounds in terms of promoting epithelialization and granulation tissue formation.

The anti-allergic potential of stingless bee honey from different botanical sources via modulation of mast cell degranulation.

BACKGROUND: Allergy is an inflammatory disorder affecting around 20% of the global population. The adverse effects of current conventional treatments give rise to the increased popularity of using natural food products as complementary and alternative medicine against allergic diseases. Stingless bee honey, commonly known as Kelulut honey (KH) in Malaysia, has been used locally as a traditional remedy to relieve cough and asthma. This study evaluated the anti-allergic potential of KH collected from four different botanical sources on phorbol ester 12-myristate-3-acetate and calcium ionophore-activated human mast cells. METHODS: The present study examined the inhibitory effects of all collected honey on the release of selected inflammatory mediators, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-4, IL-6, IL-8, histamine, and ß-hexosaminidase in an activated HMC. Besides that, all honey's total phenolic content (TPC) was also examined, followed by using liquid chromatography with tandem mass spectrometry (LC-MS/MS) to identify the phytochemicals in the honey. Further examination of the identified phytochemicals on their potential interaction with selected signaling molecules in an activated mast cell was conducted using computational methods. RESULTS: The results indicated that there were significant inhibitory effects on all selected inflammatory mediators' release by KH sourced from bamboo (BH) and rubber tree (RH) at 0.5% and 1%, but not KH sourced from mango (AH) and noni (EH). BH and RH were found to have higher TPC values and were rich in their phytochemical profiles based on the LC-MS/MS results. Computational studies were employed to determine the possible molecular target of KH through molecular docking using HADDOCK and PRODIGY web servers. CONCLUSIONS: In short, the results indicated that KH possesses anti-allergic effects towards an activated HMC, possibly by targeting downstream MAPKs. However, their anti-allergic effects may vary according to their botanical sources. Nevertheless, the present study has provided insight into the potential application of stingless bee honey as a complementary and alternative medicine to treat various allergic diseases.

Utilizing machine learning techniques to predict the blood-brain barrier permeability of compounds detected using LCQTOF-MS in Malaysian Kelulut honey.

Current in silico modelling techniques, such as molecular dynamics, typically focus on compounds with the highest concentration from chromatographic analyses for bioactivity screening. Consequently, they reduce the need for labour-intensive in vitro studies but limit the utilization of extensive chromatographic data and molecular diversity for compound classification. Compound permeability across the blood-brain barrier (BBB) is a key concern in central nervous system (CNS) drug development, and this limitation can be addressed by applying cheminformatics with codeless machine learning (ML). Among the four models developed in this study, the Random Forest (RF) algorithm with the most robust performance in both internal and external validation was selected for model construction, with an accuracy (ACC) of 87.5% and 86.9% and area under the curve (AUC) of 0.907 and 0.726, respectively. The RF model was deployed to classify 285 compounds detected using liquid chromatography quadrupole time-of-flight mass spectrometry (LCQTOF-MS) in Kelulut honey; of which, 140 compounds were screened with 94 descriptors. Seventeen compounds were predicted to permeate the BBB, revealing their potential as drugs for treating neurodegenerative diseases. Our results highlight the importance of employing ML pattern recognition to identify compounds with neuroprotective potential from the entire pool of chromatographic data.

Phytochemical Compounds of Raw Versus Methanol-Extracted Kelulut, Tualang, and Manuka Honeys.

Honey has been widely used for medicinal purposes since ancient times. It is produced by stinging bees or stingless bees by processing the collected nectar or plant sap in their bodies into raw honey. Extraction of honey will result in the pooling of crude volatile bioactive materials that could enhance its benefits. This work aims to compare the phytochemical characteristics of raw and methanol-extracted honeys in the Kelulut, Tualang and Manuka honeys. All types of raw honey samples were extracted by using the methanol extraction method and both groups were analysed using gas chromatography/mass spectrometry (GC/MS) at the National Poison Centre, Universiti Sains Malaysia, Malaysia. The findings showed that 23 compounds were identified in raw Kelulut honey and 18 compounds in methanol-extracted Kelulut honey; 28 compounds were identified in raw Tualang honey and 29 compounds in methanol-extracted Tualang honey; 19 compounds in raw Manuka honey and 22 compounds in methanol-extracted Manuka honey. There were differences in the phytochemical substances detected in raw and methanol-extracted honeys. The major compounds in raw honeys were mostly from the ketone, alcohol, and ester groups, whereas the ketone group was dominant in methanol-extracted honeys. Most bioactive substances identified in the methanol-extracted variant of honeys were more concentrated than the raw variant. A majority of these substances have antimicrobial characteristics.

Protective Role of Kelulut Honey against Toxicity Effects of Polystyrene Microplastics on Morphology, Hormones, and Sex Steroid Receptor Expression in the Uterus of Rats.

BACKGROUND: Microplastics (MPs) are an emerging global pollutant. Previous studies have revealed that chronic exposure to MPs can affect animal and human reproductive health, particularly by impairing the reproductive system's normal functions, which may increase the risk of infertility in both males and females. Kelulut honey (KH), an excellent source of antioxidants, has been used to counteract the disruptive effects of Polystyrene microplastics (PS-MPs) in the rat uterus. Thus, this study aimed to investigate the potential protective effects of Kelulut honey against PS-MPs-induced uterine toxicity in pubertal rats. METHODS: Prepubertal female Sprague Dawley rats were divided into four groups (n = 8): (i) normal control group (NC: treated with deionized water), MPs-exposed group (M: exposed to PS-MPs at 2.5 mg/kg), (iii) Kelulut honey group (DM: pretreated with 1200 mg/kg of KH 30 minutes before they were administered with PS-MPs at 2.5 mg/kg), and (iv) Kelulut honey control group (DC: only treated with KH at 2.5 mg/kg). The rats were treated orally once daily for six consecutive weeks. RESULTS: Uterine abnormalities in PS-MPs-exposed rats were significantly improved after concurrent treatment with Kelulut honey. Morphology improvement was observed and luminal epithelial cells seemed thicker with more goblet cells, glandular cells had a more regular and circular shape, stromal cell increased in size, interstitial gaps between stromal cells expanded, and the myometrium layer was thicker. Kelulut honey treatment also effectively normalized the suppressive effect of PS-MPs on the expression and distribution of sex steroid receptors (ERα and ERß), as well as the level of serum gonadotropin (LH and FSH) and sex steroid (estradiol and progesterone) hormones. CONCLUSION: Kelulut honey can protect the female reproductive system against the disruptive effects of PS-MPs. The phytochemical properties of Kelulut honey might be responsible for these beneficial benefits. However, future studies are warranted to identify the mechanisms involved.

Tualang and Kelulut Honey Reduced Lipopolysaccharidesstimulated Inflammatory Responses of Mic

@#Microglial activity is crucial in maintaining the central nervous system (CNS) homeostasis. However, prolonged microglial activation have been implicated in the pathology of neurodegenerative diseases. Activated microglia will increase the production of inflammatory cytokines, reactive oxygen species (ROS) and alter their surface marker expression levels. This study used Malaysian honey, Tualang honey (TH), and Kelulut honey (KH) to determine lipopolysaccharide (LPS)-stimulated inflammatory responses of microglia. TH and KH at 0.1% were used in the current study as our findings showed no significant difference in the cell viability between BV2 cells treated with 0.1 % of TH and KH and control group. TH and KH reduced the ROS level significantly by 41.62±1.06% and 49.16±0.63%, respectively, and slightly reduced the expression of co-stimulatory molecules, CD40 and CD11b in LPS-activated BV2 cells. Our preliminary findings proposed an in-depth future study on the anti-inflammatory effect of TH and KH on microglial activation.

Kelulut Honey Improves Folliculogenesis, Steroidogenic, and Aromatase Enzyme Profiles and Ovarian Histomorphology in Letrozole-Induced Polycystic Ovary Syndrome Rats.

Polycystic ovary syndrome (PCOS) has been linked to aberrant folliculogenesis and abnormalities in the aromatase enzyme (Cyp19a1) and the steroidogenic enzyme, 17-alpha-hydroxylase (Cyp17a1) expression. It has been demonstrated that Kelulut honey (KH) improves both female and male reproductive system anomalies in animal studies. Here, we examined the effects of isolated and combined KH, metformin, and clomiphene in improving folliculogenesis, aromatase, and steroidogenic enzyme profiles and ovarian histomorphology in letrozole-induced PCOS rats. Letrozole (1 mg/kg/day) was administered to female Sprague-Dawley (SD) rats for 21 days to induce PCOS. PCOS rats were subsequently divided into six experimental groups: untreated, treatment with metformin (500 mg/kg/day), clomiphene (2 mg/kg/day), KH (1 g/kg/day), combined KH (1 g/kg/day) and metformin (500 mg/kg/day), and combined KH (1 g/kg/day) and clomiphene (2 mg/kg/day). All treatments were given orally for 35 days. We found that KH was comparable with clomiphene and metformin in improving the expression of Cyp17a1 and Cyp19a1, apart from enhancing folliculogenesis both histologically and through the expression of folliculogenesis-related genes. Besides, the combination of KH with clomiphene was the most effective treatment in improving the ovarian histomorphology of PCOS rats. The effectiveness of KH in restoring altered folliculogenesis, steroidogenic, and aromatase enzyme profiles in PCOS warrants a future clinical trial to validate its therapeutic effect clinically.

Kelulut Honey Ameliorates Oestrus Cycle, Hormonal Profiles, and Oxidative Stress in Letrozole-Induced Polycystic Ovary Syndrome Rats.

Kelulut honey (KH) has been proven to have excellent antioxidative and anti-inflammatory properties with unique physicochemical characteristics. Therefore, we investigated the isolated and combined effects of KH, metformin, or clomiphene in alleviating oxidative stress and reproductive and metabolic abnormalities in polycystic ovary syndrome (PCOS). Female Sprague-Dawley (SD) rats were given 1 mg/kg/day of letrozole for 21 days to induce PCOS. PCOS rats were then divided into six treatment groups: untreated, metformin (500 mg/kg/day), clomiphene (2 mg/kg/day), KH (1 g/kg/day), combined KH (1 g/kg/day) and metformin (500 mg/kg/day), and combined KH (1 g/kg/day) and clomiphene (2 mg/kg/day). All treatments were administered orally for 35 days. The physicochemical characteristics of KH were assessed through hydroxymethylfurfural, free acidity, diastase number, moisture content, sugar profile, metals, and mineral compounds. Additionally, we determined the semivolatile organic compounds present in KH through gas chromatography-mass spectrometry (GC/MS) analysis. KH and its combination with metformin or clomiphene were shown to improve the oestrus cycle, hormonal profile, and oxidative stress in PCOS rats. However, KH did not reduce the fasting blood glucose, insulin, and body weight gain in PCOS rats. These findings may provide a basis for future studies to discover the potential use of KH as a complementary treatment for women with PCOS.

Effects of Kelulut Honey on Oestrus Cycle Regulation and Histomorphological Changes in Letrozole-Induced Polycystic Ovary Syndrome Rats: A Preliminary Study.

Polycystic ovary syndrome (PCOS) is a complex reproductive, metabolic, and endocrine disorder that affects women of reproductive age. Kelulut honey is stingless bee honey that possesses anti-inflammatory, anti-cancer, anti-diabetic, and potent antioxidative activities in most conditions. However, its value in improving PCOS remains to be elucidated. Thus, this preliminary study aimed to determine the effective dose of Kelulut honey in oestrus cycle regulation and ovarian histomorphological changes in letrozole-induced PCOS rats. PCOS was induced in all-female Sprague Dawley (SD) rats with 1 mg/kg/day of letrozole except for the control group for 21 days. Kelulut honey was then orally administered to the PCOS rats at the dose of 0.5, 1, or 2 g/kg/day, respectively, for 35 days. The oestrous cycle was determined through vaginal smears, while ovarian histomorphological changes were observed by haematoxylin and eosin (H&E) staining. The untreated PCOS rats were characterised by irregular oestrous cyclicity, hyperglycaemia, and aberrant ovarian histology. In this study, Kelulut honey (1 g/kg/day) increased the number of corpus luteum and antral follicles (p < 0.05), improved the cystic follicle, and normalised the oestrus cycle (p < 0.05). This preliminary study demonstrated that Kelulut honey, particularly at a dose of 1 g/kg/day, has the potential to alleviate oestrus cycle dysregulation and ovarian histomorphological changes occurring in PCOS.

Botanical Origin Differentiation of Malaysian Stingless Bee Honey Produced by Heterotrigona itama and Geniotrigona thoracica Using Chemometrics.

Stingless bee honey, specifically honeydew honey, is generally valued for its better health benefits than those of most blossom types. However, scientific studies about the differentiation of stingless bee honey based on honeydew and blossom origins are very limited. In this study, 13C NMR spectroscopy was employed to quantify the seven major sugar tautomers in stingless bee honey samples, and the major sugar compositions of both honeydew and blossom types were found not significantly different. However, several physicochemical properties of honeydew honey including moisture content, free acidity, electrical conductivity, ash content, acetic acid, diastase, hydrogen peroxide, and mineral elements levels were significantly higher; while total soluble solid, proline, and hydroxymethylfurfural were significantly lower than blossom honey. Greater antioxidant capacity in honeydew honey was proven with higher total phenolic compounds, ABTS, DPPH, superoxide radical scavenging activities, peroxyl radical inhibition, iron chelation, and ferric reducing power. Using principal component analysis (PCA), two clusters of stingless bee honey from the honeydew and blossom origin were observed. PCA also revealed that the differentiation between honeydew and blossom origin of stingless bee honey is possible with certain physicochemical and antioxidant parameters. The combination of NMR spectroscopy and chemometrics are suggested to be useful to determine the authenticity and botanical origin of stingless bee honey.

Radioprotective Effects of Kelulut Honey in Zebrafish Model.

Large doses of ionizing radiation can damage human tissues. Therefore, there is a need to investigate the radiation effects as well as identify effective and non-toxic radioprotectors. This study evaluated the radioprotective effects of Kelulut honey (KH) from stingless bee (Trigona sp.) on zebrafish (Danio rerio) embryos. Viable zebrafish embryos at 24 hpf were dechorionated and divided into four groups, namely untreated and non-irradiated, untreated and irradiated, KH pre-treatment and amifostine pre-treatment. The embryos were first treated with KH (8 mg/mL) or amifostine (4 mM) before irradiation at doses of 11 Gy to 20 Gy using gamma ray source, caesium-137 (137Cs). Lethality and abnormality analysis were performed on all of the embryos in the study. Immunohistochemistry assay was also performed using selected proteins, namely γ-H2AX and caspase-3, to investigate DNA damages and incidences of apoptosis. KH was found to reduce coagulation effects at up to 20 Gy in the lethality analysis. The embryos developed combinations of abnormality, namely microphthalmia (M), body curvature and microphthalmia (BM), body curvature with microphthalmia and microcephaly (BMC), microphthalmia and pericardial oedema (MO), pericardial oedema (O), microphthalmia with microcephaly and pericardial oedema (MCO) and all of the abnormalities (AA). There were more abnormalities developed from 24 to 72 h (h) post-irradiation in all groups. At 96 h post-irradiation, KH was identified to reduce body curvature effect in the irradiated embryos (up to 16 Gy). γ-H2AX and caspase-3 intensities in the embryos pre-treated with KH were also found to be lower than the untreated group at gamma irradiation doses of 11 Gy to 20 Gy and 11 Gy to 19 Gy, respectively. KH was proven to increase the survival rate of zebrafish embryos and exhibited protection against organ-specific abnormality. KH was also found to possess cellular protective mechanism by reducing DNA damage and apoptosis proteins expression.

Physicochemical and Medicinal Properties of Tualang, Gelam and Kelulut Honeys: A Comprehensive Review.

Tualang, Gelam and Kelulut honeys are tropical rainforest honeys reported to have various medicinal properties. Studies related to the medicinal properties and physicochemical characteristics of these honeys are growing extensively and receiving increased attention. This review incorporated and analysed the findings on the biological and physicochemical properties of these honeys. Tualang, Gelam and Kelulut honeys were found to possess a wide variety of biological effects attributed to their physicochemical characteristics. Findings revealed that these honeys have anti-diabetic, anti-obesity, anti-cancer, anti-oxidative, anti-microbial, anti-inflammatory and wound-healing properties and effects on the cardiovascular system, nervous system and reproductive system. The physicochemical properties of these honeys were compared and discussed and results showed that they have high-quality contents and excellent antioxidant sources.

Stingless Bee Honey Reduces Anxiety and Improves Memory of the Metabolic Disease-induced Rats.

BACKGROUND: Scientific studies support the evidence of the involvement of Metabolic Syndrome (MetS) in the progression of neurodegenerative diseases through oxidative stress. Consumption of antioxidant compounds was found to be beneficial for brain-health as it reduced the brain oxidative stress level and improved cognitive performance in animals. Stingless bee honey or locally known as Kelulut Honey (KH) has high phenolic content and is widely used as a food supplement. OBJECTIVES: In this study, we aimed to investigate the effects of KH on the brain of MetS-induced rats. METHODS: Forty male Wistar rats were divided into 5 groups; 8 weeks (C8) and 16 weeks control groups (C16), groups that received High-Carbohydrate High Fructose (HCHF) diet for 8 weeks (MS8) and 16 weeks (MS16), and a group that received HCHF for 16 weeks with KH supplemented for the last 35 days (KH). RESULTS: Serum fasting blood glucose decreased in the KH group compared to the MS16 group. HDL levels were significantly decreased in MetS groups compared to control groups. Open field experiments showed that KH group exhibits less anxious behavior compared to the MetS group. Probe trial of Morris water maze demonstrated significant memory retention of KH group compared to the MS16 group. Nissl staining showed a significant decrease in the pyramidal hippocampal cells in the MS16 compared to the KH group. CONCLUSION: KH has the ability to normalise blood glucose and reduce serum triglyceride and LDL levels in MetS rats, while behavior studies complement its effect on anxiety and memory. This shows a promising role of KH in attenuating neurodegenerative diseases through the antioxidant activity of its polyphenolic content.

The Beneficial Effects of Stingless Bee Honey from Heterotrigona itama against Metabolic Changes in Rats Fed with High-Carbohydrate and High-Fat Diet.

Metabolic syndrome (MetS) is a group of conditions including central obesity, hyperglycemia, dyslipidemia, and hypertension that increases the risk for cardiometabolic diseases. Kelulut honey (KH) produced by stingless honey bees has stronger antioxidant properties compared to other honey types and may be a functional food against MetS. This study aimed to determine the efficacy of KH in preventing metabolic changes in rats with MetS induced by high-carbohydrate and high-fat (HCHF) diet. Male Wistar rats were randomly assigned to the control (C), HCHF diet-induced MetS (S), and MetS supplemented with KH (K) groups. The K group was given KH (1 g/kg/day) for eight weeks. Compared to the control, the S group had significant higher omental fat mass, serum triglyceride, systolic blood pressure, diastolic blood pressures, adipocyte area, and adipocyte perimeter (p < 0.05). KH supplementation significantly prevented these MetS-induced changes at week 16 (p < 0.05). Several compounds, including 4-hydroxyphenyl acetic acid, coumaric and caffeic acids, had been detected via liquid chromatography-mass spectrometry analysis that might contribute to the reversal of these changes. The beneficial effects of KH against MetS-induced rats provide the basis for future KH research to investigate its potential use in humans and its molecular mechanisms in alleviating the disease.

Kelulut honey ameliorates glucocorticoid induced osteoporosis via its antioxidant activity in rats

Objective: To explore the effects of kelulut honey on bone structure and histomorphometry against glucocorticoid-induced osteoporosis. Methods: Thirty-five male rats were used (n = 7). Twenty-eight adrenalectomized rats were divided into four groups; each group was given normal saline 0.9％ (negative control), calcium water (positive control), kelulut honey (200 mg/kg/day and 400 mg/kg/day, respectively) treatment, respectively. All of them were administered with intramuscular injection of dexamethasone (120 μg/kg/day) to induce osteoporosis. Seven sham operated rats were given vehicle palm olein 0.05 mL/100 g/day by intramuscular injection and 0.1 mL/kg/day orally. All the treatments were given daily for 2 month. Lipid peroxidation and oxidative stress enzymes were measured. In addition, bone structural and histomorphometry analyses were also conducted. Results: Two-month glucocorticoid treatment increased the level of malondialdehyde and decreased superoxide dismutase significantly. No significant changes were found in the activities of catalase and glutathion peroxidase. Bone volume/tissue volume and trabecular number were significantly reduced while trabecular separation of the femoral bones was increased which corresponded to the decreased number of osteoblast surface after two months of receiving glucocorticoid treatment. Kelulut honey treatment restored the level of superoxide dismutase and reduced malondialdehyde significantly (P<0.05). Moreover, kelulut honey increased bone volume/tissue volume, trabecular number and decreased trabecular separation significantly (P<0.05), which were further confirmed by increased osteoblast surface and decreased osteoclast surface number (P<0.05). Conclusions: Kelulut honey may have potential bone protective effect, and may be a prophylaxis against glucocorticoid-induced osteoporosis.

Kelulut honey ameliorates glucocorticoid induced osteoporosis via its antioxidant activity in rats

Objective: To explore the effects of kelulut honey on bone structure and histomorphometry against glucocorticoid-induced osteoporosis. Methods: Thirty-five male rats were used (n = 7). Twenty-eight adrenalectomized rats were divided into four groups; each group was given normal saline 0.9% (negative control), calcium water (positive control), kelulut honey (200 mg/kg/day and 400 mg/kg/day, respectively) treatment, respectively. All of them were administered with intramuscular injection of dexamethasone (120 μg/kg/day) to induce osteoporosis. Seven sham operated rats were given vehicle palm olein 0.05 mL/100 g/day by intramuscular injection and 0.1 mL/kg/day orally. All the treatments were given daily for 2 month. Lipid peroxidation and oxidative stress enzymes were measured. In addition, bone structural and histomorphometry analyses were also conducted. Results: Two-month glucocorticoid treatment increased the level of malondialdehyde and decreased superoxide dismutase significantly. No significant changes were found in the activities of catalase and glutathion peroxidase. Bone volume/tissue volume and trabecular number were significantly reduced while trabecular separation of the femoral bones was increased which corresponded to the decreased number of osteoblast surface after two months of receiving glucocorticoid treatment. Kelulut honey treatment restored the level of superoxide dismutase and reduced malondialdehyde significantly (P<0.05). Moreover, kelulut honey increased bone volume/tissue volume, trabecular number and decreased trabecular separation significantly (P<0.05), which were further confirmed by increased osteoblast surface and decreased osteoclast surface number (P<0.05). Conclusions: Kelulut honey may have potential bone protective effect, and may be a prophylaxis against glucocorticoid-induced osteoporosis.

Antioxidant Properties of Stingless Bee Honey and Its Effect on the Viability of Lymphoblastoid Cell Line

@#Research on the medical benefit of stingless bee honey (kelulut honey) is rather new although it has been used as traditional food and additive for ages. The primary 92 Med & Health Jun 2019;14(1): 91-105 Hazirah H. et al. objective of our study was to evaluate the antioxidant properties of kelulut honey and its effect on lymphoblastoid cell line. We analysed the antioxidant properties of kelulut honey by ferric reducing antioxidant potential assay, total phenolic and flavonoid contents using UV spectrophotometry. The total phenolic content, total flavonoid content and ferric reducing antioxidant potential of Malaysian kelulut honey produced by Trigona spp. were found to be 844.45 mg RE/kg honey, 78.29 mg RE/kg honey and 1132.66 mM FE/kg honey, respectively. Our findings showed a strong correlation between total phenolics and flavanoids contents with its antioxidant potential at R2 = 0.920 and R2 = 0.951, respectively. The effect of honey on cell viability of lymphoblastoid cell line (LCL) was also investigated. The cells were cultured in RPMI-1640 medium supplemented with 0 - 500 μg/mL of kelulut honey for 24 hours. Cell viability was quantitated using 3-(4,5-dimethylthiazol2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, MTS assay showed that honey supplementation boosted the viability of LCL up to 164.64% (p< 0.01). The significant increase in cell viability might be modulated by the antioxidant properties of kelulut honey.