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Manuka honey (MH) exhibits potential antitumor activity in preclinical models of a number of human cancers. Treatment in vitro with MH at concentrations ranging from 0.3 to 5.0% (w/v) led to significant dose-dependent inhibition of proliferation of human breast cancer MCF-7 cells, but anti-proliferative effects of MH were less pronounced in MDA-MB-231 breast cancer cells. Effects of MH were also tested on non-malignant human mammary epithelial cells (HMECs) at 2.5% w/v, and it was found that MH reduced the proliferation of MCF-7 cells but not that of HMECs. Notably, the antitumor activity of MH was in the range of that exerted by treatment of MCF-7 cells with the antiestrogen tamoxifen. Further, MH treatment stimulated apoptosis of MCF-7 cells in vitro, with most cells exhibiting acute and significant levels of apoptosis that correlated with PARP activation. Additionally, the effects of MH induced the activation of AMPK and inhibition of AKT/mTOR downstream signaling. Treatment of MCF7 cells with increased concentrations of MH induced AMPK phosphorylation in a dose-dependent manner that was accompanied by inhibition of phosphorylation of AKT and mTOR downstream effector protein S6. In addition, MH reduced phosphorylated STAT3 levels in vitro, which may correlate with MH and AMPK-mediated anti-inflammatory properties. Further, in vivo, MH administered alone significantly inhibited the growth of established MCF-7 tumors in nude mice by 84%, resulting in an observable reduction in tumor volume. Our findings highlight the need for further research into the use of natural compounds, such as MH, for antitumor efficacy and potential chemoprevention and investigation of molecular pathways underlying these actions.

Aim: Woody ecosystems provide critical ecosystem functions and services but are increasingly threatened as invasive pathogens spread globally. Myrtle rust, caused by Austropuccinia psidii, arrived in New Zealand in 2017 and infects at least 12 of 18 species in the susceptible Myrtaceae plant family. Among these are species of structural, successional and cultural importance. We aim to assess whether the functional consequences of Myrtaceae loss could be mitigated if co‐occurring species with shared functional attributes are able to replace them. Location: New Zealand (but with concepts and methodologies that apply globally). Methods: Using a nationwide forest and shrubland plot data set, we assessed community vulnerability to the loss of Myrtaceae species by analysing proportional changes in average trait values when they are absent and produced spatial predictions indicating where species loss might have the greatest impact on community functionality. We then assessed whether compensatory infilling by co‐occurring species would mediate community vulnerability. Results: Forests and shrublands containing Kunzea ericoides and Leptospermum scoparium are highly vulnerable to their loss. Areas most vulnerable overall are the central and south‐eastern North Island, north‐eastern South Island and Stewart Island. For all species, compensatory infilling moderated the impact of their loss. However, if co‐occurring Myrtaceae were unable to respond, possibly if they were also infected, community vulnerability almost always increased because infilling species had different functional attributes, compounding the functional impact. Main Conclusions: Early successional woody plant communities and Myrtaceae‐dominated old‐growth forests are at most risk. Our spatial assessment of species‐level functional impacts from myrtle rust will facilitate better‐informed landscape‐level responses. Management actions and monitoring can now be targeted to areas and communities at greatest risk of losing ecosystem‐level processes. [ABSTRACT FROM AUTHOR]

Summary: Floral nectar composition beyond common sugars shows great diversity but contributing genetic factors are generally unknown. Mānuka (Leptospermum scoparium) is renowned for the antimicrobial compound methylglyoxal in its derived honey, which originates from the precursor, dihydroxyacetone (DHA), accumulating in the nectar. Although this nectar trait is highly variable, genetic contribution to the trait is unclear. Therefore, we investigated key gene(s) and genomic regions underpinning this trait.We used RNAseq analysis to identify nectary‐associated genes differentially expressed between high and low nectar DHA genotypes. We also used a mānuka high‐density linkage map and quantitative trait loci (QTL) mapping population, supported by an improved genome assembly, to reveal genetic regions associated with nectar DHA content.Expression and QTL analyses both pointed to the involvement of a phosphatase gene, LsSgpp2. The expression pattern of LsSgpp2 correlated with nectar DHA accumulation, and it co‐located with a QTL on chromosome 4. The identification of three QTLs, some of the first reported for a plant nectar trait, indicates polygenic control of DHA content.We have established plant genetics as a key influence on DHA accumulation. The data suggest the hypothesis of LsSGPP2 releasing DHA from DHA‐phosphate and variability in LsSgpp2 gene expression contributing to the trait variability. [ABSTRACT FROM AUTHOR]

Leptospermum tairawhitiense G.J. Atkins, de Lange & M.A.M. Renner sp. nov. (Myrtaceae) is segregated from L. scoparium J.R. Forst. & G. Forst. (sensu lato). The new species is endemic to Tairāwhiti / East Cape, Te Ika a Māui / North Island of Aotearoa / New Zealand. The new species is genetically distinct from L. scoparium sensu lato, L. hoipolloi L.M.H. Schmid & de Lange, and L. repo de Lange & L.M.H. Schmid, and chemically it is distinguished by having unusually high levels of triketones. Morphologically, Leptospermum tairawhitiense differs from these species in vegetative characters by the shortly and densely branching growth habit; the often suckering growth habit; the patent leaves, arising at 70–90° from the stem; the lamina is narrow-lanceolate, elliptic lanceolate, or rarely narrowly ovate and (3.0–4.8–6.2(–9.0) mm long by (1.0–1.3(–2.1) mm wide and coloured dull green to dark green, red-tinged, ± glaucescent (new growth yellow-green, red-tinged, glaucescent); and in reproductive characters, the flowers are cupped and small in comparison to other species, being 8–14 mm in diameter, with 5(–8) white petals, 5.0–7.0 × 4.6–6.4 mm and 20–32 stamens with white or pink filaments. The capsules of Leptospermum tairawhitiense are up to 6.8 mm wide and 5.5 mm tall when unopened, with exserted valves that comprise half the capsule height in profile, and when opened the valves exceed the capsule rim. A conservation assessment using the New Zealand Threat Classification System is proposed and a revised key to Leptospermum of Aotearoa / New Zealand provided.

Leptospermum hoipolloi de Lange & L.M.H. Schmid sp. nov. (Myrtaceae) is segregated from L. scoparium J.R. Forst. & G. Forst. (sensu lato). The new species is endemic to Te Ika a Maui / North Island and the northern part of Te Wai Pounamu / South Island of Aotearoa / New Zealand. The new species is morphologically distinguished from L. scoparium s. str. by the distinctly sericeous, narrower, and longer (up to 30 × 6 mm) lanceolate to elliptic lanceolate leaves, larger (up to 30 mm in diameter) flowers (these white, pink-tinged, pink-streaked or red); capsules up to 15.1 × 14.1 mm (unopened) and 16.6 × 18.0 mm (opened). Three formae are recognised, f. hoipolloi, for those plants with shorter, narrower, glabrescent leaves, mostly white (occasionally pink tinged or red) flowers, and smaller capsules; f. procumbens L.M.H. Schmid & de Lange f. nov., for those plants with a decumbent / prostrate growth habit, and silver-white to silvery grey hairy leaves, larger, white, pink-tinged or pink flowers, and larger capsules; and f. incanum (Cockayne) de Lange & L.M.H. Schmid f. comb. & stat. nov., for those plants previously recognised as L. scoparium var. incanum Cockayne, and which have an erect shrub growth habit, with longer, often broader leaves, whose young and maturing lamina is invested in silvery-grey or grey hairs; larger white, pink-tinged or streaked, pink or red flowers and capsules. Conservation assessments using the New Zealand Threat Classification System are proposed and a revised key to the Leptospermum of Aotearoa / New Zealand provided.

Leptospermum scoparium is the basis of a flourishing honey industry in Aotearoa New Zealand (NZ) and Australia. The genetic structure of L. scoparium across its range in NZ and Australia was previously assessed using pooled, whole genome sequencing; however, only one sampling site in Tasmania was included. Here, we used a single nucleotide polymorphism (SNP) array for genotyping samples of L. scoparium collected in natural stands around Tasmania and NZ, to determine the genetic relationship between L. scoparium individuals from the two regions. In total, 2069 high quality, polymorphic SNP markers were applied across the sample set of 504 individuals, revealing that Tasmanian L. scoparium are genetically distinct from NZ mānuka, confirming the observation from the pooled whole genome sequencing project. FST and discriminant analysis of principal components confirmed that the Tasmanian populations are well differentiated genetically from NZ populations, suggesting that they should be recognised as a separate, endemic Australian species. Within NZ, eight geographic groups are distinguished with genotypic variation exhibiting north to south landscape scale patterns with regional genetic clusters. We found support for isolation by distance, and this was reflected in the range of pairwise FST values estimated between NZ genetic clusters (0.056 to 0.356); however, each geographic genetic group exhibits geneflow and is only weakly differentiated from neighbouring clusters as evidenced by low population differentiation (low pairwise FST). These data provide little support for taxonomic revision and subdividing L. scoparium into segregate species within NZ. [ABSTRACT FROM AUTHOR]

Pleural mesothelioma (PM) is a highly aggressive, fast-growing asbestos-induced cancer with limited effective treatments. There has been interest in using naturally occurring anticancer agents derived from plant materials for the treatment of PM. However, it is unclear if an aqueous extract from Leptospermum polygalifolium (QV0) has activity against PM. Here we investigated the anti-cancer properties of QV0 and Defender® (QV0 dietary formula) in vitro and in vivo, respectively. QV0 suppressed the growth of eight PM cell lines in a dose-dependent manner, effective at concentrations as low as 0.02% w/v (equivalent to 0.2 mg/ml). This response was found to be associated with inhibited cell migration, proliferation, and colony formation but without evident cell cycle alteration. We observed mitochondrial dysfunction post-QV0 treatment, as evidenced by significantly decreased basal and maximal oxygen consumption rates. Ten SCID mice were treated with 0.25 mg/g Defender® daily and exhibited reduced tumor size over 30 days, which was associated with an average extension of seven days of mouse life. There was no evidence of liver toxicity or increased blood glucose post-treatment in animals treated with Defender®. Significantly enhanced tumor apoptosis was observed in the Defender®-treated animals, correlating to mitochondrial dysfunction. Lastly, the high levels of polyphenols and antioxidant properties of QV0 and Defender® were detected in HPLC analysis. To the best of our knowledge, this study constitutes the first demonstration of an improved host survival (without adverse effects) response in a QV0-treated PM mouse model, associated with evident inhibition of PM cell growth and mitochondrial dysfunction-related enhancement of tumor apoptosis. [ABSTRACT FROM AUTHOR]

New insights into relationships in the tribe Leptospermeae (Myrtaceae) are presented based on phylogenetic analyses of a 6‐locus, 109‐taxon dataset comprising 98 taxa sampled from all nine genera currently recognised in tribe Leptospermeae, including 76 accessions of Leptospermum s.l., and 11 outgroups representing five related tribes. Maximum parsimony and Bayesian inference analyses of separate plastid and nuclear datasets resolved five major lineages within Leptospermum, which was found to be polyphyletic with respect to other genera in the tribe, including Homalospermum, Kunzea and Neofabricia. These results concur with relationships identified in the companion phylogenomic study of the tribe by Binks & al. We also tested congruence of ovule/seed characters with the clades and the possible synapomorphy of hemitropous ovules for Asteromyrtus + Agonis s.l. To better reflect the wide variation seen in Leptospermum s.l., the genus is here restricted to members of the clade of woody‐fruited taxa found in eastern Australia, New Zealand, the Cook Islands and Malesia. To accommodate the four distinct clades of non‐woody‐fruited taxa, Leptospermopsis is reinstated for one western Australian lineage, and three new genera Apectospermum, Aggreflorum, and Gaudium are created for the other western and two largely eastern lineages, respectively, and 45 new combinations made. A key to Leptospermum and the newly segregated genera is presented. Additionally, eight names are lectotypified. [ABSTRACT FROM AUTHOR]

As the source and main producing area of tea in the world, China has formed unique tea culture, and achieved remarkable economic benefits. However, frequent meteorological disasters, particularly low temperature frost damage in late spring has seriously threatened the growth status of tea trees and caused quality and yield reduction of tea industry. Thus, timely and accurate early warning of frost damage occurrence in specific tea garden is very important for tea plantation management and economic values. Aiming at the problems existing in current meteorological disaster forecasting methods, such as difficulty in obtaining massive meteorological data, large amount of calculation for predicted models and incomplete information on frost damage occurrence, this paper proposed a two-fold algorithm for short-term and real-time prediction of temperature using field environmental data, and temperature trend results from a nearest local weather station for accurate frost damage occurrence level determination, so as to achieve a specific tea garden frost damage occurrence prediction in a microclimate. Timeseries meteorological data collected from a small weather station was used for testing and parameterization of a two-fold method, and another dataset acquired from Tea Experimental Base of Zhejiang University was further used to validate the capability of a two-fold model for frost damage forecasting. Results showed that compared with the results of autoregressive integrated moving average (ARIMA) and multiple linear regression (MLR), the proposed two-fold method using a second order Furrier fitting model and a K-Nearest Neighbor model (K = 3) with three days historical temperature data exhibited excellent accuracy for frost damage occurrence prediction on consideration of both model accuracy and computation (98.46% forecasted duration of frost damage, and 95.38% for forecasted temperature at the onset time). For field test in a tea garden, the proposed method accurately predicted three times frost damage occurrences, including onset time, duration and occurrence level. These results suggested the newly-proposed two-fold method was suitable for tea plantation frost damage occurrence forecasting. [ABSTRACT FROM AUTHOR]

Leptospermum repo de Lange & L.M.H.Schmid sp. nov. (Myrtaceae) is segregated from L. scoparium J.R.Forst. & G.Forst. (sensu lato). The new species is endemic to the peat bogs of the Waikato, Bay of Plenty, and adjacent eastern ranges of the northern portion of Te Ika a Maui / North Island, Aotearoa / New Zealand. The new species belongs to the northern Te Ika a Maui / North Island clade of L. scoparium s. l., from whose other members it is morphologically distinguished by its gracile, spindly, open-branched growth habit; widely divergent, longer, linear, linear-lanceolate (rarely filiform), shortly cuspidate leaves; flowers with white petals, stamens mostly with white filaments (very rarely tinged pink near base), and by the style and stigma which are usually green (very rarely pink). Leptospermum repo now occupies ca. 10% of its former peat bog habitat, where aside from a few protected peat bogs the species is still in decline through loss of its habitat. A more recent potential threat to L. repo is myrtle rust disease, caused by Austropuccinia psidii, an exotic rust first detected in Aotearoa / New Zealand in May 2017. This rust poses a serious threat to the Myrtaceae of Aotearoa / New Zealand, for which there is at present no known effective treatment to prevent the death of infected hosts. Therefore, due to the historic loss of habitat, a threat which is still ongoing, causing the decline of many L. repo populations; and the potential threat of Austropuccinia psidii to this species, the listing proposed for the species (as Leptospermum aff. scoparium (c) (AK191319; "Waikato peat bog") by the New Zealand Indigenous Vascular Plant Threat Listing Panel of "Threatened / Nationally Critical DP, De" is here upheld.

Leptospermum sp. with dihydroxyacetone in their nectar are a source of high-value medicinal honey production and can provide income from agriculturally marginal lands. The current study was from two newly planted Leptospermum nitens sites, one with duplex soil and the other in deep sandy soil, in the low rainfall areas of the south-west of Western Australia, with the aim of identifying key soil parameters influencing the plantation’s survival and growth. Electromagnetic induction (EMI) at different depths was used to investigate the possible impact of soil variability on the Leptospermum nitens plantations. Two EMI surveys were conducted at each site, at different times of the year, to account for soil moisture variability (relatively dry and wet conditions). A least-square inversion algorithm was used to determine true electrical conductivities at three different soil depths (0–0.5, 0.5–0.8, and 0.8–1.6 m) to produce quasi-3D maps of soil inverted electrical conductivity. Corresponding soil samples from each depth were used for the physico-chemical analysis of soil parameters and to develop laboratory-based electrical resistivity to soil volumetric moisture calibrations with R2 values between 0.95 and 0.99. Shrub survival and growth (canopy diameter) were estimated using unmanned aerial vehicle (UAV) images and machine learning. Comparing EMI soil mapping with UAV imagery results showed significantly greater shrub survival and growth (p < 0.001) in areas with higher ECa ranges of 12–24 mS m−1 at the variable textured site and 6–9 mS m−1 at the uniformly sandy site. Overall, the variable textured site, with an 82% survival rate, had a significantly higher shrub count and larger plants than the uniformly sandy site, with a 75% survival rate. A principal component analysis (PCA) identified inverted EC to be strongly correlated with soil moisture > pH > soil texture. Such soil mapping may be a robust and effective method for risk assessment of new shrub plantations.

ABSTRACT With rising antibiotic resistance, alternative treatments for communicable diseases are increasingly relevant. One possible alternative for some types of infections is honey, used in wound care since before 2000 BCE and more recently in licensed, medical‐grade products. However, it is unclear whether medical application of honey results in the evolution of bacterial honey resistance and whether this has collateral effects on other bacterial traits such as antibiotic resistance. Here, we used single‐step screening assays and serial transfer at increasing concentrations to isolate honey‐resistant mutants of Escherichia coli. We only detected bacteria with consistently increased resistance to the honey they evolved in for two of the four tested honey products, and the observed increases were small (maximum twofold increase in IC90). Genomic sequencing and experiments with single‐gene knockouts showed a key mechanism by which bacteria increased their honey resistance was by mutating genes involved in detoxifying methylglyoxal, which contributes to the antibacterial activity of Leptospermum honeys. Crucially, we found no evidence that honey adaptation conferred cross‐resistance or collateral sensitivity against nine antibiotics from six different classes. These results reveal constraints on bacterial adaptation to different types of honey, improving our ability to predict downstream consequences of wider honey application in medicine.

Leptospermum scoparium is emerging as an economically important plant for the commercial production of mānuka honey and essential oils, both exhibiting unique antibacterial attributes. To support its domestication this is the first quantitative genetic study of variation for L. scoparium traits. It utilised plants from 200 open-pollinated families derived from 40 native populations, from across the species range in Tasmania, grown in a common garden field trial. The traits studied were survival, growth, and the flowering traits precocity, the timing of seasonal peak flowering, flowering duration, and flowering intensity. Significant genetic variation was evident at the population level for all traits studied and at the family level for three traits—growth, flowering precocity, and time to peak flowering. These three traits had moderate to high narrow-sense heritability estimates ranging from 0.27 to 0.69. For six of the traits studied, population differences were associated with climate attributes at the locations where seed was collected, suggesting adaptation to the local climate may have contributed to the observed population differentiation. Population level geographical trends suggest that genotypes to focus on for domestication originate from the eastern half of Tasmania for precociousness and the western half of Tasmania for earlier time to peak flowering and extended flowering duration. [ABSTRACT FROM AUTHOR]

Aims: The Myrtaceae is a woody family that plays an important role in forest ecosystems globally. The recent spread of myrtle rust, caused by a fungal pathogen (Austropuccinia psidii), from its native South America into New Zealand (NZ), highlights the need to quantify the ecological importance of Myrtaceae in NZ woody ecosystems. Location: New Zealand. Methods: Using NZ nationwide forest and shrubland inventory data, collected from 2009 to 2014, we quantified the ecological importance of Myrtaceae based on its richness and abundance relative to co-occurring woody families. We then explored how climate and forest stand structure affect Myrtaceae importance in general and by tribe and growth form. Finally, we compared functional traits associated with plant growth and reproductive strategies with other dominant woody families and determined Myrtaceae's contributions to community-weighted mean (CWM) trait values. Results: Myrtaceae occurred in 74% of the study plots and its importance value was the second highest across the woody families. It was the only one in which climbers substantially contributed to the importance value (17%). Greater Myrtaceae importance values were associated with warmer and more mesic climates and early forest successional stages. Climate associations were similar within tribes and growth forms, whereas forest structure effects varied. Myrtaceae was functionally distinct from most co-occurring woody families. Contributions to CWM wood density, maximum height, and specific leaf area values were significantly greater than expected from its importance value. Conclusions: Myrtaceae is the second most ecologically important woody family in NZ woody ecosystems. The family has a distinctive functional trait spectrum associated with high wood density and tall stature, ensuring large and enduring carbon stocks. There will potentially be large and deleterious outcomes in forest ecosystems if taxon-specific pathogens, such as Austropuccinia psidii, spread and significantly reduce Myrtaceae importance. [ABSTRACT FROM AUTHOR]

To be considered an effective pollinator, a floral visitor must not only be able to remove pollen but also transfer this pollen to a receptive conspecific stigma. While studies of diurnal pollination are commonplace, our understanding of the effectiveness of nocturnal pollinators is limited largely because of the difficulties of doing these studies at night. As a result of this, the way in which moths transfer pollen between flowers has been understudied globally, despite many authors suggesting they could be significant contributors to pollination. Here, we tested whether moths are capable of transferring pollen between flowers under experimental conditions using a fluorescent pollen-tracker powder. A flower-feeding taxon (Noctuidae: Ichneutica plena) and non-feeding taxon (Hepialidae: Wiseana spp.) were contained overnight with flowering shoots of putatively moth-pollinated Leptospermum scoparium and Pimelea prostrata (I. plena only), and putatively bird-pollinated Crocosmia × crocosmiiflora. Moths were able to transfer pollen tracker between flowers for both of the putatively mothpollinated species, while no pollen tracker was removed from putatively bird-pollinated flowers. Both the feeding and non-feeding moth taxa were able to transfer pollen tracker between flowers; however, the feeding taxon could be considered a more effective pollinator because of the greater proportion of individuals both carrying and transferring pollen tracker compared with the non-feeding taxon. This study provides experimental evidence that moths may contribute to the pollination of L. scoparium and P. prostrata, and suggests a reassessment of the pollination ecology for these species is warranted. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the potency of Manuka honey UMF +15 against Carbapenem-resistant Enterobacterales (CRE). Bacterial resistance is a worldwide problem that is increasing year by year, especially Carbapenem resistance. Alternatives to antibiotics are needed to both reduce costs, and to reduce the spread of antibiotic resistance, with the ultimate goal of saving lives., Methods: The efficacy of Manuka honey UMF +15 was tested by 2 methods; Well diffusion assay and minimum bactericidal concentration (MBC) against twenty Carbapenem-resistant isolates which collected from Makkah city hospitals during three months of study from 1st of September 2023 up to 1st of December 2023., Results: The growth of all isolates of Carbapenem-resistant Enterobacterales (CRE) was severely inhibited by low concentrations of Manuka honey, affecting 25% of isolates at 15% and 75% of isolates at 18% of Manuka honey. In addition, using the honey at different concentrations in a well diffusion assay resulted, as expected, in a variable zone diameter, ranging from large zones(14mm) to small zones (2 mm) according to the concentration of the honey., Conclusion: This study shows the remarkable antibacterial activity of Manuka honey and suggests that this natural remedy might be used in the future as an alternative treatment option against Carbapenem-resistant Enterobacterales (CRE); however, further clinical trials should be performed to corroborate our initial findings., (Copyright: © Saudi Medical Journal.)

Demand for therapeutic honey is driving establishment of Leptospermum plantations. This study developed micropropagation methods for two species – Leptospermum polygalifolium Salisb. and L. scoparium J.R.Forst. & G. Forst. The study determined how shoot proliferation and adventitious rooting were influenced by the original explant position on the seedling and the concentration of benzyladenine (BA) in the proliferation medium. Hormone-free node culture was highly effective for both species. Nodal explants often formed roots in the absence of BA and developed elongated axillary shoots. Median shoot numbers of 584 and 659 were formed in 31–32 weeks from a single L. polygalifolium or L. scoparium seed, respectively. A low BA dose was effective for callogenesis and shoot proliferation of L. polygalifolium, but not L. scoparium. The median number of shoots produced from a single L. polygalifolium seed was 630 using 2.22-mM BA. This dose induced extremely high shoot numbers in some clones because explants often produced extensive callus and multiple short shoots. Shoots formed adventitious roots without indole-3-butyric acid and plantlets were acclimatised to nursery conditions. The original explant position did not influence shoot proliferation or adventitious rooting. Leptospermum polygalifolium and L. scoparium proved amenable to micropropagation, facilitating rapid establishment of nectar plantations. [ABSTRACT FROM AUTHOR]

With rising antibiotic resistance, alternative treatments for communicable diseases are increasingly relevant. One possible alternative for some types of infections is honey, used in wound care since before 2000 BCE and more recently in licensed, medical‐grade products. However, it is unclear whether medical application of honey results in the evolution of bacterial honey resistance and whether this has collateral effects on other bacterial traits such as antibiotic resistance. Here, we used single‐step screening assays and serial transfer at increasing concentrations to isolate honey‐resistant mutants of Escherichia coli. We only detected bacteria with consistently increased resistance to the honey they evolved in for two of the four tested honey products, and the observed increases were small (maximum twofold increase in IC90). Genomic sequencing and experiments with single‐gene knockouts showed a key mechanism by which bacteria increased their honey resistance was by mutating genes involved in detoxifying methylglyoxal, which contributes to the antibacterial activity of Leptospermum honeys. Crucially, we found no evidence that honey adaptation conferred cross‐resistance or collateral sensitivity against nine antibiotics from six different classes. These results reveal constraints on bacterial adaptation to different types of honey, improving our ability to predict downstream consequences of wider honey application in medicine. [ABSTRACT FROM AUTHOR]

Leptospermum scoparium is emerging as an economically important plant for the commercial production of mānuka honey and essential oils, both exhibiting unique antibacterial attributes. To support its domestication this is the first quantitative genetic study of variation for L. scoparium traits. It utilised plants from 200 open-pollinated families derived from 40 native populations, from across the species range in Tasmania, grown in a common garden field trial. The traits studied were survival, growth, and the flowering traits precocity, the timing of seasonal peak flowering, flowering duration, and flowering intensity. Significant genetic variation was evident at the population level for all traits studied and at the family level for three traits—growth, flowering precocity, and time to peak flowering. These three traits had moderate to high narrow-sense heritability estimates ranging from 0.27 to 0.69. For six of the traits studied, population differences were associated with climate attributes at the locations where seed was collected, suggesting adaptation to the local climate may have contributed to the observed population differentiation. Population level geographical trends suggest that genotypes to focus on for domestication originate from the eastern half of Tasmania for precociousness and the western half of Tasmania for earlier time to peak flowering and extended flowering duration.

This special issue of New Zealand Journal of Crop & Horticultural Science includes papers describing some current research activities in mānuka. The research projects were planned and undertaken with various degree of Māori involvement. Here we give a perspective as three of the senior authors, and discuss science at the intersection of Māori and Pākehā cultures, focusing on mānuka. The underlying conclusion is that the processes for accessing plant material, engaging with Māori on the use of this material in science, and the ownership and dissemination of resulting data, have not often been appropriate and there should be a greater degree of inclusion of Māori in research involving taonga species. There is increasing recognition amongst non-Māori scientists within the Aotearoa New Zealand science community that research involving taonga species must follow the country's founding document, the Treaty of Waitangi, and be led by Māori cultural values, concepts and practices. On this basis future research involving taonga species should include co-design and co-management of research projects, analysis of the risks and benefits, and prior discussion and agreement on the use and implications of any new knowledge generated. [ABSTRACT FROM AUTHOR]

The jungles of Linyun and Longlin Autonomous Prefecture, located in the heart of the southwestern Guangxi Zhuang Autonomous Region of China, are home to the oldest tea trees (Camellia sinensis) in the world. In the absence of regular annual rings, radiocarbon (14C) dating is one of the most powerful tools that can assist in the determination of the ages and growth rates of these plants. In this work, cores were extracted from large ancient tea trees in a central Longlin rain forest; extraction of carbon was performed with an automated sample preparation system. The 14C levels in the tree cores were measured using accelerator mass spectrometry (AMS) at the University of Tsukuba. These measurements indicated that contrary to conventional views, the ages of trees in these forests range up to ~700 years, and the growth rate of this species is notably slow, exhibiting a long-term radial growth rate of 0.039±0.006 cm/yr. It was demonstrated that 14C analyses provide accurate determination of ages and growth rates for subtropical wild tea trees. [ABSTRACT FROM AUTHOR]

There is an urgent need for new effective antimicrobial agents since acquired resistance of bacteria to currently available agents is increasing. The antimicrobial activity of Mono-floral Agastache honey produced from Australian grown Agastache rugosa was compared with the activity of commercially available honeys derived from Leptospermum species and with Jarrah honey for activity against clinical and non-clinical strains of Staphylococcus aureus (methicillin-susceptible and methicillin-resistant strains), Pseudomonas aeruginosa, and Escherichia coli. The minimum inhibitory concentration (MIC) for Agastache honey was in the range of 6–25% (w/v) for all species examined. The MICs for Leptospermum honeys were generally similar to those of Agastache honey, but MICs were higher for Super manuka and Jarrah honeys and lower for Tea tree honey. Staphylococci were more susceptible to all honeys than Pseudomonas aeruginosa and Escherichia coli. Pretreatment of honey with catalase increased the bacterial growth at MIC of Tea tree honey (35%), Super Manuka (15%), Jarrah honeys (12%), and Agastache honey (10%), indicating variable contributions of hydrogen peroxide to antimicrobial activity. Manuka and Jelly bush honeys retained their antimicrobial activity in the presence of catalase, indicating the presence of other antimicrobial compounds in the honey. An LC-MS/MS method was developed and used to identify possible antimicrobial phenolic compounds in Agastache honey and flowers, and five commercial honeys. The chemical markers characteristic of Agastache honey and honeys of Leptospermum origin were phenyllactic acid and methyl syringate. Overall, the bioactive compounds with antimicrobial and antioxidant activity in Agastache honey suggested a possible use for topical application and in wound care.

There is an urgent need for new effective antimicrobial agents since acquired resistance of bacteria to currently available agents is increasing. The antimicrobial activity of Mono-floral Agastache honey produced from Australian grown Agastache rugosa was compared with the activity of commercially available honeys derived from Leptospermum species and with Jarrah honey for activity against clinical and non-clinical strains of Staphylococcus aureus (methicillin-susceptible and methicillin-resistant strains), Pseudomonas aeruginosa , and Escherichia coli. The minimum inhibitory concentration (MIC) for Agastache honey was in the range of 6–25% (w/v) for all species examined. The MICs for Leptospermum honeys were generally similar to those of Agastache honey, but MICs were higher for Super manuka and Jarrah honeys and lower for Tea tree honey. Staphylococci were more susceptible to all honeys than Pseudomonas aeruginosa and Escherichia coli. Pretreatment of honey with catalase increased the bacterial growth at MIC of Tea tree honey (35%), Super Manuka (15%), Jarrah honeys (12%), and Agastache honey (10%), indicating variable contributions of hydrogen peroxide to antimicrobial activity. Manuka and Jelly bush honeys retained their antimicrobial activity in the presence of catalase, indicating the presence of other antimicrobial compounds in the honey. An LC-MS/MS method was developed and used to identify possible antimicrobial phenolic compounds in Agastache honey and flowers, and five commercial honeys. The chemical markers characteristic of Agastache honey and honeys of Leptospermum origin were phenyllactic acid and methyl syringate. Overall, the bioactive compounds with antimicrobial and antioxidant activity in Agastache honey suggested a possible use for topical application and in wound care. [ABSTRACT FROM AUTHOR]

The use of High-Performance Thin-Layer Chromatography (HPTLC) coupled with the use of DPPH* (2,2-diphenyl-1-picrylhydrazyl) as a derivatisation reagent is a novel approach to the analysis of antioxidant activity of honeys. The method facilitates the visualisation of individual constituents that contribute to the overall antioxidant activity of the honey, even if they are not yet chemically identified, and allows for the quantification of their antioxidant activity as gallic acid equivalents. The method supports a more in-depth study of the antioxidant activity of honey as it allows for a comparative analysis of the antioxidant fingerprints of honeys of different floral origin and is able to capture differences in their individual bioactive constituents. Further, it supports the tracking of changes in antioxidant activity of individual honey constituents over time upon exposure to different temperature conditions, which demonstrates the potential value of the method for in-process quality control.

The chemical profiles of Tasmanian Leatherwood and Manuka honeys from Tasmania and New Zealand have been compared by a combination of GC-MS analysis of volatiles and semi-volatiles, RP-HPLC-DAD analysis of phenolics and flavonoids and HPLC-DAD analysis of derivatised dihydroxyacetone, hydroxymethylfurfural and methylglyoxal. This study found that Tasmanian and New Zealand Manuka honeys have high concentrations of methylglyoxal. However, syringic acid was only detected in Manuka honeys grown in New Zealand. The Tasmanian honeys can be distinguished by the higher concentration of 3-phenyllactic acid in Manuka compared to Leatherwood floral sources.

Diastase is used internationally as a quality monitor for excessive heat treatment and prolonged storage of honey; honey must contain an activity of at least 8 diastase numbers (DN) for it to be considered export quality. Freshly harvested mānuka honey can have diastase activity close to the export threshold of 8 DN without excess heating, increasing susceptibility for export failure. This research investigated the effect of compounds unique to or high in concentration in mānuka honey on diastase activity. Investigation of the effect of methylglyoxal, dihydroxyacetone, 2-methoxybenzoic acid, 3-phenyllatic acid, 4-hydroxyphenyllactic acid and 2'-methoxyacetophenone on diastase activity was carried out. Mānuka honey was stored at 20 and 27 °C and clover honey spiked with compounds of interest were stored at 20, 27 and 34 °C and monitored overtime. Methylglyoxal and 3-phenyllactic acid were found to accelerate the loss of diastase above the loss normally observed with time and elevated temperature., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Abstract A pair of epimer brachyanins A (1) and B (2), along with a new phloroglucinol brachyanin C (3), were isolated from the leaves of Leptospermum brachyandrum. Brachyanins A (1) and B (2) were the first example of novel meroterpenoid with a unique skeleton that combined a synacrpic acid and a pinene units via a benzyl moiety. Their structures were elucidated through the application of extensive spectroscopic measurements and single-crystal X-ray diffraction analysis and with the absolute configurations of 1 and 2 were confirmed by the quantum chemical CD calculation. The hetero Diels-Alder as the key biotransformation was proposed to account for the biosynthesis of brachyanins A and B sheding light by the potential procursor brachyanin C. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract: Aims: To investigate the effect of natural products on the spore cycle of Clostridium difficile in vitro. Methods and Results: Twenty‐two natural products were investigated using four C. difficile strains. Effects on sporulation, determined using microscopy and a conventional spore recovery assay, showed that fresh onion bulb extract (6·3% v v−1) and coconut oil (8% v v−1) inhibited sporulation in all four isolates by 66–86% and 51–88%, respectively, compared to untreated controls. Fresh ginger rhizome extract (25% v v−1) was also inhibitory, although to a lesser extent. Using a standard spore germination and outgrowth assay, germination was unaffected by the 22 products, whereas outgrowth was significantly reduced by artichoke extract (18·8 mg ml−1), fresh onion bulb extract (25% v v−1), Leptospermum honeys (8% w v−1) and allicin (75 mg ml−1; P < 0·01). Sporicidal activity, investigated using a standard plate recovery assay, was minimal. Conclusions: Three of the 22 natural products (13%) showed inhibitory effects on sporulation of C. difficile and six products (27%) reduced vegetative outgrowth of C. difficile. Significance and Impact of the Study: This study shows the potential of natural products to inhibit different stages of C. difficile sporulation and encourages further investigation in this field. [ABSTRACT FROM AUTHOR]

The nomenclature of a number of taxa that occur in Southeast Asia in Baeckea, Decaspermum, Leptospermum, Melaleuca, Psidium, Rhodamnia, Rhodomyrtus and Tristaniopsis is discussed: eight lectotypes are designated, six taxa are shown to have been previously lectotypified under Article 9.9 with second-stage lectotypification being deemed unnecessary for two of them, and comments are made on two species that we cannot yet typify. [ABSTRACT FROM AUTHOR]

Manuka honey from New Zealand is derived from the nectar of Leptospermum scoparium and contains high amounts of methylglyoxal (MGO), which is responsible for its extraordinary antibacterial properties and its high market value. It was shown recently, that honeys from Australian Leptospermum species, often referred to as “jellybush honey”, also contain MGO. Recently, an official method has been published by the Ministry of Primary Industries (MPI) New Zealand to characterize monofloral and multifloral manuka honey from New Zealand, based on the concentration of the phytochemical compounds 2′-methoxyacetophenone (2-MAP), 2-methoxybenzoic acid (2-MB), 3-phenyllactic acid (3-PLA) and 4-hydroxyphenyllactic acid (4-HPLA). Here we show that these phytochemical markers are suitable to differentiate honeys originating from Leptospermum species from New Zealand or Australia, respectively. Three non-manuka honeys and eight manuka honeys from New Zealand as well as four non-Leptospermum honeys and 15 Leptospermum honeys from Australia were analysed for their MGO content via RP-HPLC-UV and their 2-MAP, 2-MB, 4-HPLA and 3-PLA concentration via RP-HPLC-MS/MS. All non-manuka honeys contained only negligible amounts of MGO, whereas honeys from Leptospermum species contained up to 1100 mg/kg, independent of the geographical origin. No significant amounts of 3-PLA, 4-HPLA, 2-MB and 2-MAP were found in the non-manuka honeys. In contrast, all marker compounds were abundantly present in manuka honeys from New Zealand, thus enabling a characterization of monofloral or multifloral quality. All honey samples from Australian Leptospermum species contained 2-MAP in concentrations below the limit of detection. The concentrations of the other marker compounds ranged from 58 to 357 mg/kg for 3-PLA, from 1 to 3 mg/kg for 4-HPLA and from 26 to 175 mg/kg for 2-MB and were significantly different when compared to New Zealand manuka honeys. Based on the results of this study, the marker compounds suggested by the MPI might be useful to distinguish honeys derived from Leptospermum species of different geographical origins. [ABSTRACT FROM AUTHOR]

Abstract: Background: The increase in resistance of head lice to neurotoxic pediculicides and public concern over their safety has led to an increase in alternative treatments, many of which are poorly researched or even untested. Methods: A multicentre, randomised, assessor‐blind, parallel‐group trial (Trial 1) was conducted to compare the safety and efficacy of a head lice treatment containing Australian eucalyptus oil and Leptospermum petersonii (EO/LP solution; applied thrice with 7‐day intervals between applications) with a neurotoxic treatment containing pyrethrins and piperonyl butoxide (P/PB mousse; applied twice with a 7‐day interval) in children. A single‐blind, open trial (Trial 2) was conducted to assess the efficacy of EO/LP solution following a single application. In addition, skin irritancy and sensitisation tests using EO/LP solution were performed in adults and children. In vitro tests were performed to further assess the ovicidal and pediculicidal efficacy of EO/LP solution. Results: EO/LP solution was found to be more than twice as effective in curing head lice infestation as P/PB mousse in per‐protocol participants (Trial 1; 83% vs 36%, P < 0.0001), and was also found to be 100% pediculicidal following a single application (Trial 2). Adverse events were limited to transient itching, burning or stinging. Further skin testing with the EO/LP solution reported no irritation or sensitisation in adults, or irritation in children. In vitro exposure of lice and eggs to the EO/LP solution resulted in 100% mortality. Conclusion: The efficacy, safety and relative ease of use of the EO/LP solution make it a viable alternative in treating head lice. [ABSTRACT FROM AUTHOR]

Background: The aim was to evaluate the efficacy of standardised Manuka (Leptospermum species) antibacterial honey as adjunctive twice daily treatment to conventional therapy (warm compresses, lid massage and preservative-free lubricant), in participants with evaporative dry eye due to moderate to advanced meibomian gland dysfunction.Methods: This prospective, open-label study involved 114 participants. After two weeks of conventional therapy participants were randomised to one of three treatment groups: Optimel Antibacterial Manuka Eye Gel (98 per cent Leptospermum species honey) plus conventional therapy (n = 37), Optimel Manuka plus Lubricant Eye Drops (16 per cent Leptospermum species honey) plus conventional therapy (n = 37) and a control (conventional therapy) (n = 40). Clinical evaluations performed at baseline and Week 8 included: symptom scores (Ocular Surface Disease Index, Ocular Comfort Index), daily lubricant use, tear assessments (break-up time, secretion, osmolarity and InflammaDry), corneal sensation, ocular surface staining, meibomian gland secretion quality and expressibility, bulbar conjunctival, limbal and lid marginal redness and eyelid marginal bacterial cultures and colony counts.Results: Significant improvements (p ≤ 0.05) occurred at Week 8 in symptoms, tear break-up time, staining, tear osmolarity, meibum quality and bulbar, limbal and lid margin redness for all treatments. Improvement in staining was significantly greater with Optimel 16 per cent drops (p = 0.035). Significant improvements (p < 0.05) in meibomian gland expressibility and InflammaDry occurred for both Optimel treatments. Optimel 98 per cent gel was significantly more effective in improving meibum quality (p = 0.005) and gland expressibility (p = 0.042). Total eyelid marginal bacterial colony counts reduced significantly with Optimel 16 per cent drops (p = 0.03) but not the other treatments. Staphylococcus epidermidis counts reduced significantly with Optimel 16 per cent drops (p = 0.041) and Optimel 98 per cent gel (p = 0.027). Both Optimel treatments significantly reduced the need for lubricants, with Optimel 16 per cent drops decreasing lubricant use most (p = 0.001). Temporary redness and stinging were the only adverse effects of Optimel use.Conclusions: Optimel antibacterial honey treatments are effective as adjunctive therapies for meibomian gland dysfunction. [ABSTRACT FROM AUTHOR]

Reliable exposure data are essential to evaluate the safety of ingredients in cosmetics. The study reported here was carried out on behalf of the Australian Tea Tree Industry Association in order to support safety assessment of TTO in consumer cosmetic products. Data regarding the use of TTO-containing cosmetic products were collected through a web-survey among 2535 qualified users of validated TTO-containing cosmetics in 5 European countries. Data regarding the percentage of TTO present in the individual products (TTO-inclusion) were collected from the suppliers of those products. Beyond TTO exposure-measures there were several significant findings: One is a special “TTO-effect” for several categories of TTO-containing cosmetic products showing a positive correlation between consumers' strength of TTO-orientation and frequency of product use, combined with a negative correlation between frequency of product use and amount of product used per application. Another is significant differences regarding the intensity of product use between TTO-containing cosmetics and respective types of products in general. Thus it seems not to be appropriate to evaluate the toxicological safety of certain ingredients of cosmetic products from exposure data on “generic” types of cosmetic products. [ABSTRACT FROM AUTHOR]

The leaves of harvested tea [ Camellia sinensis (L.) O. Kuntze] can be processed into different products such as black tea, green tea and oolong tea. Black tea is the mostly consumed worldwide among these products. Black tea production is achieved by a series of processing steps namely withering, rolling, fermentation, drying, sieving and packaging. Rolling is one of the most important steps in the production as it ensures uniform maceration of tea leaves and promotes oxidation reactions catalysed by phenol oxidase enzymes during the fermentation process. The rolling of tea leaves is generally performed by either Crushing-Tearing-Curling (CTC), rotorvane or Orthodox methods. However, in Turkey, rolling is also performed using a combination of rotorvane and orthodox which is called the 'ÇAYKUR' method. The rolling method provides a unique taste and flavours. Thus, this study was conducted to compare volatile constituents of the black teas produced by the above rolling methods and to determine the volatiles during the 6-month storage period. Some specific compounds such as 2,6-nonadienal, 3-hexen-2-one and dodecanal for ÇAYKUR, 2,5-octanedione for Orthodox and methylpyrazine for CTC were identified to differentiate the rolling system. This study also showed that a few compounds can be used as markers of storage. The number and amounts of volatiles, especially compounds with a high molecular weight, increased by storage. In addition, the flavour quality of the teas was evaluated by the Wickremasinghe-Yamanishi ratio (WYR), Mahanta ratio (MR) and Owuor Flavour Index. [ABSTRACT FROM AUTHOR]