Podocarpus Elatus Research Articles

Quality Assessment of Greek-Style Set Yoghurt Fortified with Extracted and Dried Australian Native Fruit, Illawarra Plum.

The Illawarra plum (IP) is native to Australia and has been used as a bush food for centuries. With rich phytochemicals and natural pigments, IP has the potential to be an added ingredient to improve the physicochemical properties of food, including yoghurt. This study prepared dried IP powders through vacuum drying (VD) and freeze drying (FD), produced extracts from these dried powders, and fortified them into Greek-style set yoghurt. The changes in colour, pH, titratable acidity (TA), syneresis, total soluble solids (TS), and phytochemicals were measured throughout a chilled storage period of 28 days. The results showed that FD and FD extract could provide a stable, distinct pink colour to yoghurt. IP powders and their extracts improved TS content and, thus, the consistency of yoghurt. Compared to the control, VD, FD, and FD extract of IP did not significantly affect the level of acidity or syneresis after 28 days of chilled storage. Yoghurt fortified with FD and FD extract had the greatest level of phenolics, anthocyanins, and radical scavenging antioxidant activities. This study revealed that IP powders and their extracts can positively improve the physicochemical properties of Greek-style set yoghurt. FD powder is recommended over its extract to fortify this yoghurt, as it can be cost-effectively prepared by freeze drying and then grinding the fresh fruit into powder. Future studies are needed to evaluate other variables in yoghurt preparation, including the concentration of IP and strains of yoghurt culture. Further, the consumer perception of sensory quality and acceptability of yoghurt fortified with FD IP powder should be investigated.

Podocarpus elatus R.Br. Leaf Extracts are IneffectiveInhibitors of the Growth of a Panel of Bacterial Pathogens

Podocarpus elatus R.Br. Leaf Extracts are IneffectiveInhibitors of the Growth of a Panel of Bacterial Pathogens

Antiproliferative effects of Australian native plums against the MCF7 breast adenocarcinoma cells and UPLC-qTOF-IM-MS-driven identification of key metabolites

The rich and unique phytochemical profiles of Australian native fruits are attributed to the intense climatic conditions of the island. Of these native fruits, the Kakadu plum (KP; Terminalia ferdinandiana), Illawarra plum (IP; Podocarpus elatus), and Davidson's plum (DP; Davidsonia pruriens) have been increasingly used in the food industry. However, their phytochemical profiles and bioactivity are not well explored. This study examined the antiproliferative activity of water and ethanol extracts of KP, IP and DP against the MCF7 breast adenocarcinoma cells using the Alamar blue assay. The potential induction of apoptosis and reactive oxygen species (ROS) generation in the MCF7 cells by the active extracts was examined. The most potent extracts were analysed using biochemometric and liquid chromatography-mass spectrometry (LC-MS) driven metabolomic identification. A dose-dependent antiproliferative activity of KP-water (IC50 = 239.9 μg/mL), KP-ethanol (IC50 = 254.7 μg/mL), and IP-ethanol (IC50 = 521.7 μg/mL) was observed. All other extracts (IP-water, DP-water, DP-ethanol) showed IC50 values > 3000 μg/mL. The three potent extracts at 3000 μg/mL induced apoptosis (P < 0.05) but did not increase the production of ROS in the MCF7 cells. The metabolomic identification revealed an abundance of tannin, flavonoids, and triterpenoid compounds as potential anticancer metabolites in the KP extracts. Further mechanistic investigations are warranted to formulate Australian plum-based dietary interventions.

LC-ESI-QTOF-MS/MS profiling of phenolic compounds in Australian native plums and their potential antioxidant activities

Australian native plums are rich in phenolic compounds, which have significant health-promoting effects. There are limited recordings and information on the number of species and phenolic content of Australian native plums. However, the number of species and phenolic content of Australian native plums are not well documented. This research was conducted to identify and quantify phenolic compounds in the peel, pulp, and seed of three common Australian native plums (Kakadu plum, Davidson plum, Illawarra plum) for applying and promoting the commercial worth of these fruits. Total phenolic content (TPC), total flavonoid content (TFC), and total tannins content (TTC) were used to determine the amount of phenolic compounds in these Australian native plums and in vitro experiments, including total antioxidant capacity (TAC), 2, 2′-Diphenyl-2-picrylhydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP), and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) were used to analyze the antioxidant activities of the samples. Phenolic compounds in the samples were thoroughly analyzed by liquid chromatography-mass spectrometry (LC-ESI-QTOF-MS/MS), and preliminarily identified as phenolic acids (10), flavonoids (23), and other phenolic substances (11). These results show the potent antioxidant properties of the Australian native plums and provide evidence for their potential use as culinary, medicinal, and nutraceutical components.

Bioassay Guided Fractionation Protocol for Determining Novel Active Compounds in Selected Australian Flora.

A large variety of unique and distinct flora of Australia have developed exceptional survival methods and phytochemicals and hence may provide a significant avenue for new drug discovery. This study proposes a bioassay guided fractionation protocol that maybe robust and efficient in screening plants with potential bioactive properties and isolating lead novel compounds. Hence, five native Australian plants were selected for this screening process, namely Pittosporum angustifolium (Gumbi gumbi), Terminalia ferdinandiana (Kakadu plum, seeds (KPS), and flesh (KPF)), Cupaniopsis anacardioides (Tuckeroo, seeds (TKS) and flesh (TKF)), Podocarpus elatus (Illawarra plum, seeds (IPS) and flesh (IPF)) and Pleiogynium timoriense (Burdekin plum, seeds (BPS) and flesh (BPF)). The methanolic extracts of the plants samples were analysed for Total phenolic content (TPC) and antioxidant capacity measure by FRAP. The highest values were found in the KPF which were 12,442 ± 1355 mg GAE/ 100 g TPC and 16,670 ± 2275 mg TXE/100 g antioxidant capacity. Extracts of GGL was deemed to be most potent with complete cell inhibition in HeLa and HT29, and about 95% inhibition in HuH7 cells. Comparative activity was also seen for KPS extract, where more than 80% cell inhibition occurred in all tested cell lines. Dose-dependent studies showed higher SI values (0.72-1.02) in KPS extracts than GGL (0.5-0.73). Microbial assays of the crude extracts were also performed against five bacterial strains commonly associated with causing food poisoning diseases were selected (Gram positive-Staphylococcus aureus and Gram negative-Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa bacteria). KPF extracts were effective in suppressing microbial growth of all tested bacterial strains except for P. aeruginosa, while TKS and TKF were only slightly effective against S. aureus. Due to the potential of the GGL crude extract to completely inhibit the cells compared to KPS, it was further fractionated and tested against the cell lines. HPLC phenolic profiling of the crude extracts were performed, and numerous peak overlaps were evident in the fruit extracts. The KPF extracts demonstrated the strongest peaks which was coherent with the fact that it had the highest TPC and antioxidant capacity values. A high occurrence of t-ferulic acid in the GGL extracts was found which may explain the cytotoxic activity of GGL extracts. Peaks in KPS and KPF extracts were tentatively identified as gallic acid, protocatechuic acid, 4-hydroxybenzoic acid and syringic acid and possibly ellagic acid. HPLC time-based fractionation of the GGL extract (F1-F5) was performed and Dose dependent cytotoxic effects were determined. It was construed that F1, having the highest SI value for HeLa, HT29 and HuH7 (1.60, 1.41 and 1.67, respectively) would be promising for further fractionation and isolation process.

Growth Inhibitory Properties of Kunzea pomifera F.Muell. and Podocarpus elatus R.Br. Fruit Extracts against Axillary and Foot Odour Producing Bacteria

Growth Inhibitory Properties of Kunzea pomifera F.Muell. and Podocarpus elatus R.Br. Fruit Extracts against Axillary and Foot Odour Producing Bacteria

Improving Osmia lignaria and O. cornifrons (Hymenoptera: Megachilidae) retention with preferred nest materials and attractant spray

AbstractMason bees (Megachilidae: Osmia) are alternative managed pollinators with the potential to supplement pollination by honey bees in many crops. However, challenges for their management in orchards still remain. If nesting conditions are not optimal, females can show high dispersion rates, which decrease their economic viability at commercial scales. One way to improve female retention is by offering attractive nesting substrates. We tested the effect of several combinations of substrate materials and shelter types, as well as an attractant compound, on the retention and performance of Osmia lignaria and O. cornifrons females. We compared nesting in three types of shelter (blue and white plastic totes and brown pine plywood), with cardboard tubes of four different diameters (5–8 mm), reeds, and wood blocks as substrates at an experimental farm orchard. In a separate experiment with plywood shelters and 7‐mm cardboard tubes, we tested an attractant spray based on decanoic acid (patent number US 9301521B2), a compound isolated from O. lignaria cocoons and expected to encourage females to nest in artificial cavities. In both experiments, O. cornifrons showed higher female retention than O. lignaria. The combination of plywood shelters with reeds had the highest nesting for both species, although O. cornifrons also readily used cardboard tubes of 5–6 mm diameter. The attractant spray increased nesting by O. cornifrons, but not by O. lignaria. We also found a significant interaction between the effect of the attractant and the year of the experiment, indicating that weather and other environmental variables could affect the efficacy of the attractant. Together, our results suggest that using the right combination of shelters and substrates, as well as the attractant spray, is an effective strategy to increase Osmia female retention for orchard pollination.

Mechanical Behaviour of Normal Concrete using Fibre of Pine Tree Needle Leaves

This research was carried out to study the behaviour of concrete, specifically flexural strength, by incorporating two types of pine needle leaves (green, and brown) recycled as fibre reinforcement in the concrete. The other goal of the study is to compare the two types of fibre and determine the maximum proportion of fibre to be added in the normal concrete. OPC concrete with 0%, 1% and 2% pine needle leaves fibre (green, and brown) was prepared based on the total weight of the mixture. At an ambient temperature of 28 ± 2°C, the specimens were checked for flexural strength (FS). Laboratory test results based on short term investigation reveals that the flexural strength of concrete containing brown pine fibre (BPF) is higher than that of Green pine fibre (GPF), and also higher than normal (OPC) concrete. The optimum proportion of pine needle leaf fibre is the brown fibre (fallen leaves) to be added in the concrete as fibre is 1% by the total weight of the mixture, which gave a positive reaction from the test that was performed.

The natural phytochemical trans‐communic acid inhibits cellular senescence and pigmentation through FoxO3a activation

Ageing is characterized by the accumulation of chronic and irreversible oxidative damage, chronic inflammation and organ dysfunction. To attenuate these ageing-related changes, various natural phytochemicals are often applied. Trans-communic acid (TCA), an active component of brown pine leaf extract, has antimicrobial and cancer chemopreventive activity and inhibits ultraviolet B (UVB)-induced MMP-1 expression. To determine whether the phytochemical TCA could affect the lifespan of an ageing model, Caenorhabditis elegans prevent ageing-related phenotypes of the skin. Caenorhabditis elegans (C.elegans) wild-type N2 and mutant strains were used in this study to explore the lifespan extension effect of TCA and its mechanism. We estimated lipofuscin accumulation and melanin levels, which are closely associated with skin senescence. Moreover, we explored the mechanism of action associated with ageing attenuation. We performed oxidative stress resistance and thermotolerance assays in C.elegans and surface plasmon resonance analysis of TCA binding with the forkhead box-O3a (FoxO3a) protein. TCA, which is the active component in Korean red pine (Pinus densiflora), attenuated ageing-related changes in skin cells. TCA lowered lipofuscin accumulation in fibroblasts and decreased melanin levels in melanocytes. These protective effects were mediated by activation of the representative longevity gene FoxO3a, which was induced by direct binding with TCA. Interestingly, TCA extended the lifespan of C.elegans, although it did not affect stress resistance, oxidative stress or thermotolerance. These results strongly suggest that TCA prevents the senescent phenotype of model organisms and exhibits beneficial effects on ageing-related skin phenotypes through direct FoxO3a activation.

Australian native fruits: Potential uses as functional food ingredients

Abstract As an island continent, Australia experiences diversified climatic conditions, giving a unique botanical diversity with many plants native to Australia. Australian flora including native fruits have been used for many years as food and medicine. Many native fruits have unique qualities and potential uses as functional ingredients. Among the native fruits, eleven prominent native species have been commercially produced in Australia including bush tomato, Davidson’s plum, desert lime, finger lime, Kakadu plum, lemon aspen, muntries, quandong, Tasmanian pepper berry, and Illawarra plum. As the global demand for high quality and functional natural products is steadily growing, native fruits have great opportunities to be used as a rich source of nutrients, flavouring and colouring agents, natural preservatives and functional ingredients. This review outlines production, highlights the nutritive and bioactive components, reviews traditional and current uses, and discusses potential applications of the eleven commercialised Australian native fruits for future utilisation and research.

Pine pest aphids of the genus Eulachnus (Hemiptera: Aphididae: Lachninae): how far can their range extend?

Abstract Species of the aphid genus Eulachnus (Hemiptera, Aphididae), associated with pine trees, are an example of insects reported as rare over their native geographical range in Europe and serious pine pests far from their natural distribution. To predict the risk of invasion of spotted pine aphid Eulachnus agilis (Kaltenbach, 1843), green pine aphid Eulachnus brevipilosus Börner, 1940 and narrow brown pine aphid Eulachnus rileyi (Williams, 1911) on a global scale, ecological niche modelling was applied. We used the maximum entropy model, based on associations between unique occurrence localities and a set of environmental variables. We obtained models of potentially suitable habitats, based on climatic variables and distribution of host plants, suggesting that favourable conditions for each species may be present on every continent. However, E. agilis and E. rileyi appear to be potentially the most widespread species. In Europe, models showed that the potential distribution of the representatives of the genus Eulachnus overlapped with that of the host plants. In places where they have been introduced, these aphid species have readily adapted to indigenous or introduced pines, including trees grown commercially for timber. A jackknife test indicated that annual mean temperature and mean temperature of the coldest quarter were the most important environmental variables restricting the expansion of the species under investigation. Moreover, the most important factor in the decrease in population density of the feeding aphids is the rainy season and, on a smaller scale, the presence of their natural enemies.

Growth inhibition of the zoonotic bacteria Bacillus anthracis by high antioxidant Australian plants: New leads for the prevention and treatment of anthrax

Introduction: Anthrax is severe acute disease caused by Bacillus anthracis infections. If untreated, it often results in mortality. High antioxidant plant extracts have documented therapeutic properties as general antiseptics, inhibiting the growth of a wide variety of bacterial species. This study examines the ability of selected high antioxidant Australian plant extracts to inhibit B. anthracis growth. Methods: Solvent extracts were prepared using various high antioxidant Australian fruits and herbs and investigated by disc diffusion assay for the ability to inhibit the growth of an environmental strain of B. anthracis. Their MIC values were determined to quantify and compare their efficacies. Toxicity was determined using the Artemia franciscana nauplii bioassay. The most potent extracts were analysed by non-targeted HPLC-QTOF mass spectroscopy (with screening against 3 compound databases) for the identification and characterisation of individual components in crude plant extracts. Results: Methanolic and aqueous extracts of several high antioxidant plant extract sdisplayed potent antibacterial activity in the disc diffusion assay against B. anthracis. The aqueous and methanolic extracts of lemon aspen, as well as the methanolic extracts of muntries, Illawarra plum and native tamarind were particularly potent growth inhibitors with MIC values 1000 µg/mL. Non-biased phytochemical analysis of the lemon aspen aqueous and methanolic extracts putatively identified 85 compounds and highlighted several that may contribute to the ability of these extracts to inhibit the growth of B. anthracis. Conclusion: The low toxicity of several high antioxidant plant extracts and their potent inhibitory bioactivity against B. anthracis indicates their potential as medicinal agents in the treatment and prevention of anthrax. Lemon aspen is particularly worthy of further study.

Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K.

Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression.

Inhibitory activity of high antioxidant Australian native fruits against the bacterial triggers of selected autoimmune diseases

Introduction: High antioxidant capacities have been linked to the treatment of rheumatic diseases and in the inhibition of microbial growth. Recent reports have identified several native Australian fruits with high antioxidant capacities. Despite this, several of these species are yet to be tested for the ability to inhibit the growth of the bacterial triggers of autoimmune inflammatory diseases. Methods: Solvent extracts prepared from selectedAustralian native fruits were analysed for antioxidant capacity by the DPPH free radical scavenging assay.Growth inhibitory activities against bacterial species associated with initiating rheumatoid arthritis and ankylosing spondylitiswere determined bydisc diffusion assay and quantified by MIC determination. Toxicity was determined by Artemia franciscana bioassay. Results: Methanolic extracts of all plant species displayed high antioxidant contents (equivalent to approximately 7-16 mg of vitamin C per gram of fruit extracted). Most aqueous extracts also contained relatively high antioxidant capacities. In contrast, the ethyl acetate, chloroform and hexane extracts for most species (except lemon aspen and bush tomato) had lower antioxidant contents (below 1.5 mg of vitamin C equivalents per gram of plant material extracted). Interestingly, the bacterial growth inhibitory activity of the extracts did not correlate with their antioxidant capacities. The fruit extracts with the highest antioxidant capacities (lemon aspen and desert lime methanolic extracts) had only low antibacterial activity, with MIC values generally >10,000 µg/ml against all bacterial species. In contrast, the Illawarra plum and desert lime ethyl acetate extracts, which had mid-range antioxidant capacities (1-6.5 mg ascorbic acid equivalents/g extracted), had potent bacterial growth inhibitory activity (200-400 µg/ml). The native tamarind ethyl acetate extract displayed low-moderate toxicity in the Artemia franciscana bioassay (LC50valuesbelow 1000 µg/mL).All other extracts were nontoxic. Conclusion: The lack of toxicity and inhibitory activity against microbial triggers of rheumatoid arthritis and ankylosing spondylitis by the fruit extracts indicates their potential in the treatment and prevention of these diseases.

The Australian fruit Illawarra plum (Podocarpus elatusEndl., Podocarpaceae) inhibits telomerase, increases histone deacetylase activity and decreases proliferation of colon cancer cells

Fruit antioxidants have many health benefits including prevention of cancer development. The native Australian bush fruit Illawarra plum (Podocarpus elatus Endl., Podocarpaceae) has a high content of anthocyanin-rich phenolics, with an antioxidant capacity at levels higher than most fruits. In the present study the molecular mechanisms of the anti-proliferative activity of Illawarra plum on colorectal cancer cells were investigated. Non-tumorigenic young adult mouse colonic (YAMC) cells and tumorigenic human colonic (HT-29) cells were treated with a polyphenolic-rich Illawarra plum extract (0-1000 microg/ml). Illawarra plum had anti-proliferative properties in only the cancer cells, with growth suppressed in a dose- and time-dependent manner. Treatment of HT-29 cells with Illawarra plum extract (500 mg/ml; 24 h) was also associated with a 2-fold increase in apoptosis, and a cell cycle delay in the S phase (P < 0.01). Assessment of biomarkers for DNA damage revealed that plum treatment caused a 93% down-regulation of telomerase activity (P < 0.001) and a decrease in telomere length (up to 75%; P < 0.01). Treatment with Illawarra plum extract also induced morphological alterations to HT-29 cells that were suggestive of induction of autophagy, as the formation of cytoplasmic vacuoles was observed in many cells. This could be induced by the increased (6-fold) histone deacetylase (HDAC) activity (P < 0.001) and the trend for increased expression of the class III HDAC sirtuin 1. The present study has shown that Illawarra plum extract is able to reduce the proliferation of colon cancer cells by altering the cell cycle, increasing apoptosis and possibly inducing autophagy. The active ingredients in Illawarra plum may provide an alternative chemoprevention strategy to conventional chemotherapy.

Palaeodistribution modelling and genetic evidence highlight differential post‐glacial range shifts of a rain forest conifer distributed across a latitudinal gradient

AbstractAim We examine the range expansion/contraction dynamics during the last glacial cycle of the late‐successional tropical rain forest conifer Podocarpus elatus using a combination of modelling and molecular marker analyses. Specifically, we test whether distributional changes predicted by environmental niche modelling are in agreement with (1) the glacial maximum contractions inferred from the southern fossil record, and (2) population genetic‐based estimates of range disjunctions and demographic dynamics. In addition, we test whether northern and southern ranges are likely to have experienced similar expansion/contraction dynamics.Location Eastern Australian tropical and subtropical rain forests.Methods Environmental niche modelling was completed for three time periods during the last glacial cycle and was interpreted in light of the known palynology. We collected 109 samples from 32 populations across the entire range of P. elatus. Six microsatellite loci and Bayesian coalescence analysis were used to infer population expansion/contraction dynamics, and five sequenced loci (one plastid and four nuclear) were used to quantify genetic structure/diversity.Results Environmental niche modelling suggested that the northern and southern ranges of P. elatus experienced different expansion/contraction dynamics. In the northern range, the habitat suitable for P. elatus persisted in a small refugial area during the Last Glacial Maximum (LGM, 21 ka) and then expanded during the post‐glacial period. Conversely, in the south suitable habitat was widespread during the LGM but subsequently contracted. These differential dynamics were supported by Bayesian analyses of the population genetic data (northern dispersal) and are consistent with the greater genetic diversity in the south compared with the north. A contact zone between the two genetically divergent groups (corresponding to the Macleay Overlap Zone) was supported by environmental niche modelling and molecular analyses.Main conclusions The climatic fluctuations of the Quaternary have differentially impacted the northern and southern ranges of a broadly distributed rain forest tree in Australia. Recurrent contraction/expansion cycles contributed to the genetic distinction between northern and southern distributions of P. elatus. By combining molecular and environmental niche modelling evidence, this unique study undermines the general assumption that broadly distributed species respond in a uniform way to climate change.

Potential Antioxidant, Antiinflammatory, and Proapoptotic Anticancer Activities of Kakadu Plum and Illawarra Plum Polyphenolic Fractions

Kakadu plum (Terminalia ferdinandiana Exell, Combretaceae) and Illawarra plum (Podocarpus elatus Endl., Podocarpaceae) extracts were fractionated, using a bioassay-guided approach and screened for antioxidant activity [oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) assays] and antiinflammatory activity (nitrite concentration and prostaglandin E2 release in lipopolysaccharide (LPS)-activated murine macrophages). Among 8 fractions obtained from KP and 5 fractions obtained from IP, fraction KPF5 from KP exhibited superior activity in all assays, with an ORAC value of 3,776 ± 603 μmol Trolox/g DW and a CAA value of 52.2 ± 8.6 μmol quercetin equivalents/g DW. In addition, KPF5 further demonstrated an upregulation of the Nrf2/Keap1 ratio in Hep G2 cells. KPF5 also inhibited the expression of COX-2 and iNOS in LPS-activated murine macrophages, potentially through the NF-κB, p44/42 mitogen activated protein kinase and Akt pathways. KPF5 also induced apoptosis and DNA damage in HT-29 cells, as determined by the cytokinesis block micronucleus cytome assay.

Native Australian Fruit Polyphenols Inhibit Cell Viability and Induce Apoptosis in Human Cancer Cell Lines

Apoptosis is one of the most critical forms of defense against cancer, and the induction of apoptosis by dietary polyphenols represents significant potential for cancer preventive activity. The present study examined polyphenols extracted from selected native Australian fruits—Illawarra plum (Podocarpus elatus Endl., Podocarpaceae), Kakadu plum (Terminalia ferdinandiana Exell, Combretaceae), muntries (Kunzea pomifera F. Muell., Myrtaceae), and native currant (Acrotriche depressa R.Br., Epacridaceae)—for antiproliferative activity against a panel of cancer and normal cell lines. Each fruit selectively inhibited the growth of cancer cell lines in a dose-dependent manner. The mechanism of growth inhibition of the human promyelocytic leukaemia cells (HL-60) was determined to be apoptosis by morphological assessment, DNA fragmentation, flow cytometry, and caspase-3 induction. Furthermore, Kakadu plum was found to activate caspase-7, -9, and poly (ADP-ribose) polymerase (PARP), suggesting it acts via the intrinsic apoptosis pathway. The same fruit also caused direct DNA damage in colon adenocarcinoma cells (HT-29) as detected using the cytokinesis-block micronucleus cytome (CBMN Cyt) assay.

Consequences of long- and short-term fragmentation on the genetic diversity and differentiation of a late successional rainforest conifer

The east Australian rainforests provide a unique system with which to study historic climate-driven habitat fragmentation. The long life span of rainforest conifers and consequent lag effects on genetic variation, offer insights into demographic stochasticity in small populations and persistence in increasingly fragmented systems. Microsatellite markers were used to investigate the genetic diversity and structure of Podocarpus elatus (Podocarpaceae), a long-lived rainforest conifer endemic to Australia. Twenty-seven populations throughout the east Australian rainforests were screened and two divergent regions separated by the dry Clarence River valley (New South Wales) were discovered. This biogeographic barrier may be referred to as the Clarence River Corridor. Niche modelling techniques were employed to verify the incidence of habitat divergence between the two regions. Significantly high inbreeding was detected throughout the species range with no evidence of recent bottlenecks. Most of the diversity in the species resides between individuals within populations, which suggest the species would be sensitive to the adverse effects of inbreeding, yet evidence suggests that these populations have been small for several generations. Slightly higher diversity estimates were found in the southern region, but it is likely that the species survived historic population contraction in dispersed refugia within each of these genetically differentiated regions.

Native Australian fruit polyphenols inhibit COX-2 and iNOS expression in LPS-activated murine macrophages

Purified polyphenolic-rich extracts from four native Australian fruits, Illawarra Plum (Podocarpus elatus Endl., Podocarpaceae), Kakadu Plum (Terminalia ferdinandiana Exell, Combretaceae), Muntries (Kunzea pomifera F. Muell., Myrtaceae) and Native Currant (Acrotriche depressa R.Br., Epacridaceae), were screened for their ability to modulate anti-inflammatory activity in LPS-activated murine macrophages (RAW 264.7). The Kakadu Plum extract inhibited the expression of inducible nitric oxide synthase (iNOS), and importantly was the only fruit in this study that displayed differential inhibition of the expression of cyclooxygenase (COX)-2 but not COX-1. Illawarra Plum (COX-2 and iNOS) and Native Currant (iNOS only) also inhibited inflammatory enzymes, while Muntries exhibited none of these activities under the same conditions. All evaluated extracts inhibited the production of prostaglandin E2 and nitric oxide, suggesting the involvement of alternative pathways in their regulation for the Muntries extract. Further molecular investigations, showed that Kakadu Plum inhibited the NF-кB pathway, but not the p44/42 mitogen activated protein kinase (MAPK) pathway. Collectively, these results demonstrate potential anti-inflammatory activities of native Australian fruits, in particular Kakadu Plum, in LPS-activated murine macrophages, thus confirming the potential biological activities of these fruits.