Dihydroxyacetone in the Floral Nectar of (Turcz.) Rye (Myrtaceae) and Endl. (Myrtaceae) Demonstrates That This Precursor to Bioactive Honey Is Not Restricted to the Genus (Myrtaceae).

Ma̅nuka honey is known for its strong bioactivity, which arises from the autocatalytic conversion of 1,3-dihydroxyacetone (dihydroxyacetone, DHA) in the floral nectar of (Myrtaceae) to the non-peroxide antibacterial compound methylglyoxal during honey maturation. DHA is also a minor constituent of the nectar of several other species. This study used high-performance liquid chromatography to test whether DHA was present in the floral nectar of five species in other genera of the family Myrtaceae: (Turcz.

Anti-Fibrotic Potential of Tomentosenol A, a Constituent of Cerumen from the Australian Native Stingless Bee, .

Bioactivity-guided fractionation was used to isolate two compounds, tomentosenol A () and torellianone A (), from a cerumen extract from . The anti-fibrotic activity of these compounds was examined using human cultured neonatal foreskin fibroblasts (NFF) and immortalised keratinocytes (HaCaTs). Tomentosenol A (), inhibited NFF and HaCaT cell proliferation and prevented NFF and HaCaT scratch wound repopulation at 12.

Quality assessment and chemical diversity of Australian propolis from Apis mellifera bees.

The propolis industry is well established in European, South American and East Asian countries. Within Australia, this industry is beginning to emerge with a few small-scale producers. To contribute to the development of the Australian propolis industry, the present study aimed to examine the quality and chemical diversity of propolis collected from various regions across Australia.

Sugar and dihydroxyacetone ratios in floral nectar suggest continuous exudation and reabsorption in Leptospermum polygalifolium Salisb.

Leptospermum polygalifolium Salisb. can accumulate high concentrations of dihydroxyacetone (DHA), precursor of the antimicrobial compound methylglyoxal found in honey obtained from floral nectar of Leptospermum spp. Floral nectar dynamics over flower lifespan depends on internal and external factors that invariably impact nectar quality.

Chemical Characterization, α-Glucosidase, α-Amylase and Lipase Inhibitory Properties of the Australian Honey Bee Propolis.

The use of functional foods and nutraceuticals as a complementary therapy for the prevention and management of type 2 diabetes and obesity has steadily increased over the past few decades. With the aim of exploring the therapeutic potentials of Australian propolis, this study reports the chemical and biological investigation of a propolis sample collected in the Queensland state of Australia which exhibited a potent activity in an in vitro α-glucosidase inhibitory screening. The chemical investigation of the propolis resulted in the identification of six known prenylated flavonoids including propolins C, D, F, G, H, and solophenol D.

Floral attraction and flower visitors of a subcanopy, tropical rainforest tree, .

Flowering plants in tropical rainforests rely heavily on pollen vectors for successful reproduction. Research into pollination systems in tropical rainforests is dominated by canopy species, while subcanopy plant-pollinator interactions remain under-represented. The microclimate beneath the rainforest canopy is characterized by low light levels and is markedly different from the canopy environment that receives more light energy.

Use of kinetic data to model potential antioxidant activity: Radical scavenging capacity of Australian Eucalyptus honeys.

Antioxidant activity of honeys may be beneficial in wound healing processes by protecting cells against lipid oxidation. The DPPH assay assesses the efficacy of antioxidant molecules to reduce DPPH to DPPHH. Studies determining EC are limited by single time-point determinations of antioxidant effect and can miss vital information about the rate of antioxidant response.

Lessons from Exploring Chemical Space and Chemical Diversity of Propolis Components.

Propolis is a natural resinous material produced by bees and has been used in folk medicines since ancient times. Due to it possessing a broad spectrum of biological activities, it has gained significant scientific and commercial interest over the last two decades. As a result of searching 122 publications reported up to the end of 2019, we assembled a unique compound database consisting of 578 components isolated from both honey bee propolis and stingless bee propolis, and analyzed the chemical space and chemical diversity of these compounds.

Relationships between Nut Size, Kernel Quality, Nutritional Composition and Levels of Outcrossing in Three Macadamia Cultivars.

Tree nuts play an important role in healthy diets, but their economic value and nutritional quality may be affected by their size and paternity. We assessed relationships between nut size and kernel recovery, the incidence of whole kernels, fatty acid composition and mineral nutrient concentrations in three macadamia cultivars, "Daddow", "816" and "A4". We determined to what extent differences in nut size and quality were the result of different levels of cross- or self-paternity.

Dihydroxyacetone Production in the Nectar of Australian Leptospermum Is Species Dependent.

This study is the first large-scale survey of the presence of dihydroxyacetone (DHA) in the nectar of the Australian Leptospermum tree species. The work undertaken supports the growing global demand for bioactive Leptospermum honey. Leptospermum honey derived from L.

Streptophage-mediated control of off-flavour taint producing streptomycetes isolated from barramundi ponds.

Off-flavour taint of aquaculture products is a global issue reducing consumer confidence in the farmed produce as they are taken up via the gills of fish, and deposited in the lipids of the animal. If the fish are not purged, resulting undesirable muddy earthy flavour taint can be tasted by consumers. These undesirable flavour and odour is caused by the terpenoid compounds namely geosmin and 2-methylisoborneol, produced as secondary metabolites by certain bacteria including the cyanobacteria and actinomycetes.

Antibacterial Properties of Flavonoids from Kino of the Eucalypt Tree, Corymbia torelliana.

Traditional medicine and ecological cues can both help to reveal bioactive natural compounds. Indigenous Australians have long used kino from trunks of the eucalypt tree, , in traditional medicine. A closely related eucalypt, , produces a fruit resin with antimicrobial properties that is highly attractive to stingless bees.

Natural products isolated from Tetragonula carbonaria cerumen modulate free radical-scavenging and 5-lipoxygenase activities in vitro.

Background: Propolis and cerumen are plant-derived products found in honeybees and stingless bees, respectively. Although propolis is an ancient folk medicine, the bioactivities of cerumen obtained from Australian native stingless bees (Tetragonula carbonaria) have not been widely studied. Therefore, we investigated selected anti-oxidant and anti-inflammatory properties of T.

Investigation of long chain omega-3 PUFAs on arterial blood pressure, vascular reactivity and survival in angiotensin II-infused Apolipoprotein E-knockout mice.

Abdominal aortic aneurysm (AAA) is an inflammatory vascular disease. Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) decrease inflammation and oxidative stress in an angiotensin II-infused apolipoprotein E-knockout (ApoE(-/-)) mouse model of AAA. This study investigated the effects of LC n-3 PUFAs on blood pressure and vascular reactivity in fourteen angiotensin II-infused ApoE(-/-) male mice.

Moderate Dietary Supplementation with Omega-3 Fatty Acids Does Not Impact Plasma Von Willebrand Factor Profile in Mildly Hypertensive Subjects.

Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) have blood pressure lowering and antithrombotic effects, which may benefit hypertensive patients. Increased plasma concentration of von Willebrand factor (vWF), a procoagulant glycoprotein, has been identified in patients with severe hypertension, with some, but not all studies showing an increase with mild hypertension. In this study, we determined the plasma concentration, multimer distribution, and collagen binding activity of vWF in subjects with mild hypertension and determined whether these parameters might improve after dietary supplementation with moderate amounts of LC n-3 PUFAs.

Quantitation of Dihydroxyacetone in Australian Leptospermum Nectar via High-Performance Liquid Chromatography.

The nonperoxide antibacterial activity of New Zealand ma̅nuka honey originates from dihydroxyacetone (DHA) within Leptospermum scoparium nectar. This study determined if DHA was present within the nectar of four Australian Leptospermum species: L. laevigatum, L.

N-3 PUFAs protect against aortic inflammation and oxidative stress in angiotensin II-infused apolipoprotein E-/- mice.

Abdominal aortic aneurysm is associated with infiltration of inflammatory cells into the aortic wall. The inflammatory response is also evident in animal models, such as apolipoprotein E-deficient (ApoE-/-) mice that have been infused with angiotensin II, prior to development of aortic aneurysm. Since omega-3 polyunsaturated fatty acids (n-3 PUFAs) and their metabolites have anti-inflammatory and pro-resolving activity, we hypothesised that dietary supplementation with n-3 PUFAs would protect against inflammatory processes in this mouse model.

Chemical constituents of kino extract from Corymbia torelliana.

Seven flavanones were identified from kino exudate of Corymbia torelliana by spectroscopic and spectrometric methods including UV, 1D and 2D NMR and UPLC-HR-MS. The study identified seven molecules, namely 3,4',5,7-tetrahydroxyflavanone (1), 3',4',5,7-tetrahydroxyflavanone (2), 4',5,7-trihydroxyflavanone (3), 3,4',5-trihydroxy-7-methoxyflavanone (4), (+)-(2S)-4',5,7-trihydroxy-6-methylflavanone (5), 4',5,7-trihydroxy-6,8-dimethylflavanone (6) and 4',5-dihydroxy-7-methoxyflavanone (7) from this eucalypt species. This is the first report of these natural products from C.

Cardiovascular responsiveness to sympathoexcitatory stress in subjects with and without mild hypertension.

Purpose: This study compared blood pressure, heart rate variability (HRV) and forearm blood flow, at rest and in response to sympathoexcitatory stressors between normotensive and mildly hypertensive participants.

Methods: Participants aged 30-79 years with normal blood pressure (n = 49) or mild hypertension (n = 17), with no history of taking antihypertensive medication, were recruited. Participants completed a cold pressor test (CPT) followed by an ischaemic handgrip test (IHGT).

Effect of Australian propolis from stingless bees (Tetragonula carbonaria) on pre-contracted human and porcine isolated arteries.

Bee propolis is a mixture of plant resins and bee secretions. While bioactivity of honeybee propolis has been reported previously, information is limited on propolis from Australian stingless bees (Tetragonula carbonaria). The aim of this study was to investigate possible vasomodulatory effects of propolis in KCl-precontracted porcine coronary arteries using an ex vivo tissue bath assay.

Omega-3 fatty acids modulate Weibel-Palade body degranulation and actin cytoskeleton rearrangement in PMA-stimulated human umbilical vein endothelial cells.

Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) produce cardiovascular benefits by improving endothelial function. Endothelial cells store von Willebrand factor (vWF) in cytoplasmic Weibel-Palade bodies (WPBs). We examined whether LC n-3 PUFAs regulate WPB degranulation using cultured human umbilical vein endothelial cells (HUVECs).

Cerumen of Australian stingless bees (Tetragonula carbonaria): gas chromatography-mass spectrometry fingerprints and potential anti-inflammatory properties.

Cerumen, or propolis, is a mixture of plant resins enriched with bee secretions. In Australia, stingless bees are important pollinators that use cerumen for nest construction and possibly for colony's health. While extensive research attests to the therapeutic properties of honeybee (Apis mellifera) propolis, the biological and medicinal properties of Australian stingless bee cerumen are largely unknown.

The occurrence of bioactive micromonosporae in aquatic habitats of the Sunshine Coast in Australia.

Screening strategies based on the ecological knowledge of antibiotic producing microorganisms and their roles in the natural environment are being increasingly employed in the search for novel antibiotic agents. Micromonosporae are common inhabitants of aquatic habitats and have proved to be a continuing source of novel bioactive compounds including antibacterial and antitumor agents. The ecological distribution and frequency of bioactive micromonosporae in Sunshine Coast region aquatic habitats were studied through a range of selective isolation procedures designed to negatively select against the isolation of unwanted microbial taxa commonly associated with marine environments.