Australian native fruits: Potential uses as functional food ingredients

Bioassay-Guided Fractionation of Pittosporum angustifolium and Terminalia ferdinandiana with Liquid Chromatography Mass Spectroscopy and Gas Chromatography Mass Spectroscopy Exploratory Study

Bioprospecting native Australian plants offers the potential discovery of latent and novel bioactive compounds. The promising cytotoxic and antibacterial activity of methanolic extracts of Pittosporum angustifolium and Terminalia ferdinandiana led to further fractionation and isolation using our laboratory's bioassay-guided fractionation protocol. Hence, the aim of this study was to further evaluate the bioactivity of the fractions and subfractions and characterize bioactive compounds using liquid chromatography mass spectroscopy (LC-MS/MS) and gas chromatography MS (GC-MS). Compounds tentatively identified in P. angustifolium Fraction 1 using LC-ESI-QTOF-MS/MS were chlorogenic acid and/or neochlorogenic acid, bergapten, berberine, 8'-epitanegool and rosmarinic acid. GC-MS analysis data showed the presence of around 100 compounds, mainly comprising carboxylic acids, sugars, sugar alcohols, amino acids and monoalkylglycerols. Furthermore, the fractions obtained from T. ferdinandiana flesh extracts showed no cytotoxicity, except against HT29 cell lines, and only Fraction 2 exhibited some antibacterial activity. The reduced bioactivity observed in the T. ferdinandiana fractions could be attributed to the potential loss of synergy as compounds become separated within the fractions. As a result, the further fractionation and separation of compounds in these samples was not pursued. However, additional dose-dependent studies are warranted to validate the bioactivity of T. ferdinandiana flesh fractions, particularly since this is an understudied species. Moreover, LC-MS/GC-MS studies confirm the presence of bioactive compounds in P. angustifolium Fraction 1/subfractions, which helps to explain the significant acute anticancer activity of this plant. The screening process designed in this study has the potential to pave the way for developing scientifically validated phytochemical/bioactivity information on ethnomedicinal plants, thereby facilitating further bioprospecting efforts and supporting the discovery of novel drugs in modern medicine.

Tuning the mechanical properties of pectin films with polyphenol-rich plant extracts

The mechanical properties of pectin films enhanced with polyphenol-rich fruit extracts were investigated. The scavenging and reducing activity of plant extracts incorporated into the pectin films were determined using bench assays, and their antioxidant activity was correlated with a high presence of polyphenols, which were predominantly comprised of flavonoids and anthocyanins. The pectin films generated from the extracts exhibited a range of mechanical properties; tensile strength (4.99 MPa - 6.91 MPa), elongation at break (45.8 % - 52.3 %), and stiffness (1835 g mm-1 - 2765 g mm-1). To investigate the underlying relationships between plant extract composition and mechanical properties, Projection to Latent Structures (PLS) models were developed. The PLS models revealed that extracts containing high sugar and polyphenol content increase the tensile strength and moisture content of films. The elongation at break of the films was improved or diminished depending on the profile of sugar, acids, and polyphenols in the fruit extracts. Furthermore, the structures and concentration of anthocyanins and flavonoids were identified to strongly influenced the elongation at break differences. By modifying the concentration of sugars, organic acids, and polyphenols, the mechanical properties of pectin-based films can be tuned for tailored applications as food packaging materials.

A Review of Phytochemicals and Bioactive Properties in the Proteaceae Family: A Promising Source of Functional Food

In recent decades, natural plant-based foods have been increasingly used to improve human health due to unhealthy modern dietary patterns, such as the consumption of foods high in sugar and fat. Many indigenous species have been used by Aboriginal peoples for their food and therapeutic properties. Thus, it is important to understand the health-enhancing bioactive profile of Australian indigenous species. The Proteaceae family, such as the genera of Protea, Macadamia, and Grevillea, have been commercially used in the horticulture and food industries. Researchers have reported some findings about Persoonia species, one of the genera in the Proteaceae family. The aim of this review was to provide an overview of the family Proteaceae and the genus Persoonia, including distribution, traditional and commercial uses, phytochemicals, bioactive properties, potential opportunities, and challenges. In this review, bioactive compounds and their properties related to the health benefits of the Proteaceae family, particularly the Persoonia genus, were reviewed for potential applications in the food industry.

Antioxidant activities, phenolic compounds, and mineral composition of seed from Acacia retinodes, A. Provincialis and A. Tenuissima

Seeds of the species Acacia retinodes, A. provincialis, and A. tenuissima) from different growing locations were analysed for their mineral composition, free and bound polyphenols, and flavonoids. Previous research has studied these compounds in only a limited number of Acacia species, and only one study reports significant differences between three species. All species were rich in potassium (353 - 427 mg/100 g), sodium (14 - 240 mg/100 g) and iron (7 - 8 mg/100 g). The free polyphenol extracts of all species had higher total phenolic content, total flavonoid content and antioxidant activities than their bound counterparts, indicating the possibility of higher bioavailability than the bound polyphenol extracts. The predominant phenolic compounds found in the Acacia polyphenol seed extracts were 6-Hydroxy-2-methylindole and 2,2'-Methylenebis(6-tert-butyl-methylphenol), though no phenolic compounds were identified in the bound extracts of A. retinodes Grampians and A. provincialis Tarrington. Other compounds identified in the seed extracts include sucrose, d-fructofuranose and d-pinitol.

EBR and JA regulate aroma substance biosynthesis in 'Ruidu Hongyu' grapevine berries by transcriptome and metabolite combined analysis

Volatile compounds including terpenes, aldehyde, phenol, and alcohol are significantly contributed floral and fruity aromas to the Muscat variety. 'Ruidu Hongyu' grapevine is one of the newly developed grape varieties, and cultivation of this variety has been extended across China due to unique quality traits and taste. In this study, HS-SPME/GC-MS and transcriptome sequencing analysis were performed to evaluate the impact of exogenous 2,4-epibrassinolide (EBR), jasmonic acid (JA), and their signaling inhibitors brassinazole (Brz)/sodium diethyldithiocarbamate (DIECA) on the biosynthesis of aroma substances in 'Ruidu Hongyu' grapevine. According to the results, exogenous BR and JA promoted the accumulation of various aroma substances, including hexenal, 2-hexenal, nerol oxide, vanillin, hotrienol, terpineol, neral, nerol, geraniol, and geranic acid. After EBR and JA treatments, most of the genes responsible for terpene, aldehyde, and alcohol biosynthesis expressed at a higher level than the CK group. Relatively, EBR treatment could not only promote endogenous BR biosynthesis and metabolism but also elevate BR signaling transduction. JA treatment contributed to endogenous JA and MeJA accumulation, as well. Through transcriptome sequencing, a total of 3043, 903, 1470, and 607 DEGs were identified in JA vs. JD, JA vs. CK, BR vs. CK, and BR vs. Brz, respectively. There were more DEGs under both EBR and JA treatments at late fruit ripening stages. The findings of this study increase our understanding regarding aroma substances biosynthesis and endogenous BR/JA metabolism in response to exogenous EBR and JA signals.

Quality Assessment of Burdekin Plum (Pleiogynium timoriense) during Ambient Storage

Pleiogynium timoriense, commonly known as Burdekin plum (BP), is among many Australian native plants traditionally used by Indigenous people. However, only limited information is available on the nutritional and sensory quality of BP grown in Australia as well as its changes during storage. Therefore, this study evaluated the quality of BP during one week of ambient storage (temperature 21 °C, humidity 69%). Proximate analysis revealed a relatively high dietary fiber content in BP (7-10 g/100 g FW). A significant reduction in fruit weight and firmness (15-30% and 60-90%, respectively) with distinguishable changes in flesh color (ΔE > 3) and an increase in total soluble solids (from 11 to 21 °Brix) could be observed during storage. The vitamin C and folate contents in BP ranged from 29 to 59 mg/100g FW and 0.3 to 5.9 μg/100g FW, respectively, after harvesting. A total phenolic content of up to 20 mg GAE/g FW and ferric reducing antioxidant power of up to 400 μmol Fe²⁺/g FW in BP indicate a strong antioxidant capacity. In total, 34 individual phenolic compounds were tentatively identified in BP including cyanidin 3-galactoside, ellagic acid and gallotannins as the main phenolics. Principle component analysis (PCA) of the quantified phenolics indicated that tree to tree variation had a bigger impact on the phenolic composition of BP than ambient storage. Sensory evaluation also revealed the diversity in aroma, appearance, texture, flavor and aftertaste of BP. The results of this study provide crucial information for consumers, growers and food processors.

Antioxidant, Alpha-Glucosidase Inhibition Activities, In Silico Molecular Docking and Pharmacokinetics Study of Phenolic Compounds from Native Australian Fruits and Spices

Native Australian fruits and spices are enriched with beneficial phytochemicals, especially phenolic compounds, which are not fully elucidated. Therefore, this study aimed to analyze native Australian mountain-pepper berries (Tasmannia lanceolata), rosella (Hibiscus sabdariffa), lemon aspen (Acronychia acidula), and strawberry gum (Eucalyptus olida) for phenolic and non-phenolic metabolites and their antioxidant and alpha-glucosidase inhibition activities. Liquid chromatography-mass spectrometry-electrospray ionization coupled with quadrupole time of flight (LC-ESI-QTOF-MS/MS) was applied to elucidate the composition, identities, and quantities of bioactive phenolic metabolites in Australian native commercial fruits and spices. This study identified 143 phenolic compounds, including 31 phenolic acids, 70 flavonoids, 10 isoflavonoids, 7 tannins, 3 stilbenes, 7 lignans, 10 other compounds, and 5 limonoids. Strawberry gum was found to have the highest total phenolic content (TPC-36.57 ± 1.34 milligram gallic acid equivalent per gram (mg GAE/g), whereas lemon aspen contained the least TPC (4.40 ± 0.38 mg GAE/g). Moreover, strawberry gum and mountain pepper berries were found to have the highest antioxidant and anti-diabetic potential. In silico molecular docking and pharmacokinetics screening were also conducted to predict the potential of the most abundant phenolic compounds in these selected plants. A positive correlation was observed between phenolic contents and biological activities. This study will encourage further research to identify the nutraceutical and phytopharmaceutical potential of these native Australian fruits.

Rediscovering wild food to diversify production across Australia's agricultural landscapes

Conventional agriculture currently relies on the intensive and expansive growth of a small number of monocultures, this is both risky for food security and is causing substantial environmental degradation. Crops are typically grown far from their native origins, enduring climates, pests, and diseases that they have little evolutionary adaptation to. As a result, farming practices involve modifying the environment to suit the crop, often via practices including vegetation clearing, drainage, irrigation, tilling, and the application of fertilizers, pesticides, and herbicides. One avenue for improvement, however, is the diversification of monoculture agricultural systems with traditional foods native to the area. Native foods benefit from evolutionary history, enabling adaptation to local environmental conditions, reducing the need for environmental modifications and external inputs. Traditional use of native foods in Australia has a rich history, yet the commercial production of native foods remains small compared with conventional crops, such as wheat, barley and sugarcane. Identifying what native crops can grow where would be a first step in scoping potential native food industries and supporting farmers seeking to diversify their cropping. In this study, I modeled the potentially suitable distributions of 177 native food and forage species across Australia, given their climate and soil preferences. The coastal areas of Queensland's wet tropics, south-east Queensland, New South Wales, and Victoria were predicted to support the greatest diversity of native food and forage species (as high 80–120 species). These areas also correspond to the nation's most agriculturally intensive areas, including much of the Murray-Darling Basin, suggesting high potential for the diversification of existing intensive monocultures. Native crops with the most expansive potential distribution include Acacia trees, Maloga bean, bush plum, Emu apple, native millet, and bush tomatoes, with these crops largely being tolerant of vast areas of semi-arid conditions. In addition to greater food security, if diverse native cropping results in greater ecosystem service provisioning, through carbon storage, reduced water usage, reduced nutrient runoff, or greater habitat provision, then payment for ecosystem service schemes could also provide supplemental farm income.

Australian native fruits and vegetables: Chemical composition, nutritional profile, bioactivity and potential valorization by industries

Australian native plants have adapted themselves to harsh climatic conditions enabling them to produce unique and high levels of secondary metabolites. Native fruits and vegetables have been an integral part of the Indigenous Australian diet and Bush medicine for centuries. They have recently gained popularity owing to their rich dietary fiber, minerals, polyphenolic and antioxidant contents. This review presents a comprehensive summary and critical assessment of the studies performed in the last few decades to understand the phytochemical and nutritional profiles and therapeutic properties of Australian native fruits and vegetables. Furthermore, the potential of these fruits and vegetables as functional food ingredients and in the prevention and treatment of different diseases is discussed. Research on the nutritional and phytochemical profiles and therapeutic activity of Australian vegetables is limited with most studies focused on native fruits. These fruits have demonstrated promising antioxidant, anticancer, anti-inflammatory and antimicrobial activities mostly in in vitro models. More research to a) identify novel bioactive compounds, b) define optimal post-harvest and extraction methods, and c) understand molecular mechanisms of pharmacological activity through preclinical and clinical studies is prudent for the prospective and wider use of Australian native fruits and vegetables by the food, pharmaceutical, and nutraceutical industries.

Myrtaceae in Australia: Use of Cryobiotechnologies for the Conservation of a Significant Plant Family under Threat

The Myrtaceae is a very large and diverse family containing a number of economically and ecologically valuable species. In Australia, the family contains approximately 1700 species from 70 genera and is structurally and floristically dominant in many diverse ecosystems. In addition to threats from habitat fragmentation and increasing rates of natural disasters, infection by myrtle rust caused by Austropuccinia psidii is of significant concern to Australian Myrtaceae species. Repeated infections of new growth have caused host death and suppressed host populations by preventing seed set. Although most Myrtaceae species demonstrate orthodox seed storage behavior, exceptional species such as those with desiccation sensitive seed or from myrtle rust-suppressed populations require alternate conservation strategies such as those offered by cryobiotechnology. Targeting seven key Australian genera, we reviewed the available literature for examples of cryobiotechnology utilized for conservation of Myrtaceae. While there were only limited examples of successful cryopreservation for a few genera in this family, successful cryopreservation of both shoot tips and embryonic axes suggest that cryobiotechnology provides a viable alternative for the conservation of exceptional species and a potential safe storage method for the many Myrtaceae species under threat from A. psidii.

Tropical fruits from Australia as potential treatments for metabolic syndrome

Australia has a unique and diverse flora, including indigenous fruits, used by Australian Aboriginals for food and medicines for up to 45,000 years as well as recently introduced fruits for commercial production. However, this range of fruits has not led to the development of functional foods, for example for chronic inflammatory diseases such as metabolic syndrome including obesity, hypertension, fatty liver and diabetes. This review examines the potential of tropical and subtropical fruits from Australia to be used as functional foods for metabolic syndrome, including Davidson's plum, Queen Garnet plum, durian, litchi, breadfruit, jackfruit, mangosteen, papaya, jabuticaba, coffee and seaweed. Preclinical studies have defined potential responses of these functional foods in metabolic syndrome but the usefulness in humans with metabolic syndrome requires clinical studies which are scarce in the relevant literature. Overall, these Australian examples show that tropical fruits can provide functional foods to decrease chronic inflammatory diseases.

Health benefits and biological activities of spiny monkey orange (Strychnos spinosa Lam.): An African indigenous fruit tree

ETHNOPHARMACOLOGICAL RELEVANCE

Spiny monkey orange (Strychnos spinosa Lam.) is an African endemic fruit tree that is widely consumed by humans and animals for its nutritional value. In folk medicine, different parts of S. spinosa are widely used for the management of the health and well-being of humans and livestock.

AIM

We provide a critical appraisal on the ethnobotanical uses, nutritional and pytochemical as well as the biological activities of S. spinosa.

METHODS

Articles were mined from online databases such as Google Scholar, PubMed, Science Direct, SciELO and SpringerLink. We captured research outputs that aligned with the scope of the review.

RESULTS

Strychnos spinosa remains a commonly consumed fruit due to its high nutritional (e.g. carbohydrates, crude protein and fats) content and energy. In folk medicine, different parts of S. spinosa are prescribed as remedy for diverse medical conditions especially for treating malaria, diabetes, snakebites, skin-related conditions and sexually transmitted infections in humans as well as sleeping sickness in livestock. Together with essential oils, more than 25 compounds have been profiled using Gas chromatography-mass spectrometry (GC-MS), and approximately 45 compounds have been isolated and structurally elucidated using diverse spectroscopic techniques such as UV-visible, Infrared (IR), Nuclear Magnetic Resonance (NMR) and mass spectroscopy (MS). Strychnos spinosa exerts varying degrees of biological activities against different microorganisms (bacteria and fungi) and parasites (plasmodia, trypanosomes and ticks) responsible for many diseases in humans and livestock. Furthermore, low to moderate enzyme-inhibitory effects of S. spinosa extracts suggest its ability to mitigate pains, inflammations and diabetics as well as snakebite venom. Increasing evidence from the in vivo studies support the use of the plant as a popular remedy for managing diabetics in folk medicine. The low cytotoxic effect of the plant extracts against different cell lines could be an indication of its relative safety.

CONCLUSION

Strychnos spinosa exhibits various health-promoting benefits due to its diverse nutritional and phytochemical constituents. Given that the majority of the existing evidence on these aforementioned therapeutic properties and safety are in vitro-based, the clinical significance of these results remain limited.

Protective Effect and Potential Antioxidant Role of Kakadu Plum Extracts on Alcohol-Induced Oxidative Damage in HepG2 Cells

Serial alcohol consumption causes alcoholic liver disease (ALD), which can lead to fatty liver, hepatitis, and cirrhosis. Terminalia ferdinandiana (Kakadu plum) is an indigenous fruit of Australia, which is utilized as a functional food. It is a commercially important antioxidant as it contains a more eloquent level of ascorbic acid than other oranges. In this study, we analyzed the chemical constituents of vitamin C, gallic acid, ellagic acid, and daidzin via High-performance liquid chromatography (HPLC) in the Kakadu plum from two different regions including the Northern Territory (NT) and Western Australia (WA), and compared their biochemical properties. The vitamin C content was much higher (almost 70%) in Kakadu plum (KKD) from the NT than WA. Moreover, ROS generation was inhibited significantly in HepG2 (human hepatoma) cells with the KKD-NT extract treatment when compared to the KKD-WA extract treatment. The cytotoxicity produced by ethanol was significantly suppressed in response to the treatment with both of the samples. In addition, our samples (KKD-NT and KKD-WA) increased the activity of two key enzymes involving alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) that metabolize ethanol. These results show the biochemical confirmation of the mechanism by which KKD exhibits its biological functions including relief from alcohol hangovers as well as protection of the liver cells by the suppression of ROS production and toxic insults.

Undervalued Spiny Monkey Orange (Strychnos spinosa Lam.): An Indigenous Fruit for Sustainable Food-Nutrition and Economic Prosperity

Strychnos spinosa Lam. is among the top nutrient-dense indigenous fruit species that are predominant in Southern Africa. It is a highly ranked indigenous fruit based on the nutrition and sensorial properties, which make it an important food source for the marginalized rural people. On the basis of the high vitamin C, iron, and zinc content, it has the capacity to improve the food- nutrition and the socioeconomic status of individuals, especially those in the rural areas of the developing nations. The nutritional composition of Strychnos spinosa compare favorably with many of the popular fruits, such as strawberries and orange. Additionally, Strychnos spinosa has antioxidant activity similar to well-known antioxidant fruits, which keeps it in the class of the popular fruits, giving it added nutrition-health-promoting benefits. In order to improve the availability of Strychnos spinosa, more research on the domestication, processing, preservation, value chain, and economic potential need to be further explored. Therefore, we recommend more concerted efforts from relevant stakeholders with interest in Strychnos spinosa fruit production as a possible sustainable solution to food shortage, food-nutrition insecurity, malnutrition, and austerity, mainly in the rural communities of the developing countries.

The influence of varietal characteristics on the quality indicators of candied fruits from plum fruits

The influence of varietal characteristics of plum fruits on the physicochemical parameters of the drying process has been investigated. Revealed significant differences in the content of biologically active compounds on the example of varieties: Stanley, Big Stanley, Grossa di Felisio, President, Blue moon, August Delish, Kabardinskaya early. The consumption rates of raw materials for the production of candied fruits have been determined. The results of laboratory studies on the variation of the content of vitamins (C, P), anthocyanins in plum fruits, taking into account varietal characteristics, are presented. The drying process on a dryer with infrared rays led to a slight decrease in polyphenolic and mineral substances, and higher losses of vitamins in the finished candied fruit. The mathematical processing of the experimental data was carried out by the method of analysis of variance and descriptive statistics using the Microsoft Excel software package. In the production of candied plum fruits, optimal technological modes have been selected that contribute to a high yield of high-quality finished products, taking into account the varietal characteristics of the feedstock. According to biochemical and organoleptic indicators of the quality of candied fruits, Stanley and President varieties were distinguished, the energy value of which is 147.0 kcal with an organoleptic assessment of 4.9 points. The results of experimental biochemical and technological analyzes of fruits at individual technological stages of production made it possible to assess the intensity of complex processes that cause a qualitative transformation of raw materials.

Unlocking the Secrets of Terminalia Kernels Using Near-Infrared Spectroscopy

In recent years, the native food industry in Australia has increased in both value and volume due to the discovery of a wide range of phytochemicals (e.g., vitamin C, polyphenols) that have potential health benefits. Thus, plant organs and tissues of these native plants are used in a wide range of applications. In particular, the kernel of a native plum, the Kakadu plum (Terminalia ferdinandiana, Combretaceae) is considered to be rich in lipids and other phytochemical compounds. The aim of this study was to evaluate the use of NIR spectroscopy to analyze and characterize kernel samples and tissues of wild harvest fruit samples. The Fourier transform near-infrared reflectance spectra of cracked kernels, seeds cover tissues, and dry powder Kakadu plum kernels were acquired. Both principal component analysis and partial least squares discriminant analysis were used to analyze and interpret the spectral data. A correct classification rate of 93%, 86%, and 80% was achieved for the identification of kernel provenance using all tissues, seed coats, and the whole nuts, respectively. The results of this study reported for the first time the analysis of Kakadu plum kernels and their tissues using NIR spectroscopy.

Hydrolysable tannins in Terminalia ferdinandiana Exell fruit powder and comparison of their functional properties from different solvent extracts

This study identified and quantified hydrolysable tannins (HTs) in Terminalia ferdinandiana Exell (Kakadu plum) fruit, freeze dried powder extracted with 80% aqueous acetone (AA) and 80% aqueous acidified ethanol (AAE), using UHPLC-Q/Orbitrap/MS/MS. The vitamin C and ellagic acid were quantified by UHPLC-PDA. A total of seven HTs were identified: corilagin, 3,4,6-tri-O-galloyl-β-d-glucose, elaeocarpusin, chebulinic acid, chebulagic acid, helioscopin B, and punicalagin, with five classified as ellagitannins. The two extracts AA and AAE, comprised of gallic acid (2.5 and 2.2 mg/g DW), punicalagins α and β (2.8 and 1.3 mg/g DW), respectively, and both contained ellagic acid (~4 g/100 g DW). These extracts showed high antioxidant properties and strong antimicrobial effects against methicillin-resistant Staphylococcus aureus clinical isolate, Staphylococcus aureus, and Shewanella putrefaciens. These results suggest that Kakadu plum fruit is a rich, edible source of ellagitannins, ellagic acid and vitamin C with potential applications in food, cosmetic and nutraceutical industries.

Antioxidative and therapeutic potential of selected Australian plants: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Numerous common pharmaceuticals, including anti-cancer, antiviral and antidiabetic drugs, are derived from traditional plant-derived medicines. With approximately 25,000 species of flora occurring in Australia that are adapted to the harsh environment, there is a plethora of novel compounds awaiting research in the context of their medicinal properties. Anecdotal accounts of plant-based medicines used by the Australian Aboriginal and Torres Strait Islander peoples clearly illustrates high therapeutic activity.

AIM

This review aims to demonstrate the medicinal potentials of selected native Australian plants based on scientific data. Furthermore, it is anticipated that work presented here will contribute towards enhancing our knowledge of native plants from Australia, particularly in the prevention and potential treatment of disease types such as cancer, microbial and viral infections, and diabetes. This is not meant to be a comprehensive study, rather it is meant as an overview to stimulate future research in this field.

METHODS

The EBSCOhost platform which included PubMed, SciFinder, Web of Knowledge, Scopus, and ScienceDirect databases were searched for papers using the keywords: medicinal plants, antioxidative, antimicrobial, antibacterial, anticancer, anti-tumor, antiviral or antidiabetic, as well as Australian, native, traditional and plants. The selection criteria for including studies were restricted to articles on plants used in traditional remedies which showed antioxidative potential and therapeutic properties such as anticancer, antimicrobial, antiviral and antidiabetic activity.

RESULTS

Some plants identified in this review which showed high Total Phenolic Content (TPC) and antioxidative capacity, and hence prominent bioactivity, included Tasmannia lanceolata (Poir.) A.C. Sm., Terminalia ferdinandiana Exell, Eucalyptus species, Syzygium species, Backhousia citriodora F.Muell., Petalostigma species, Acacia species, Melaleuca alternifolia (Maiden & Betche) Cheel, Eremophila species, Prostanthera rotundifolia R.Br., Scaevola spinescens R. Br. and Pittosporum angustifolium Lodd. The majority of studies found polar compounds such as caffeic acid, coumaric acid, chlorogenic acid, quercetin, anthocyanins, hesperidin, kaempferol, catechin, ellagic acid and saponins to be the active components responsible for the therapeutic effects. Additionally, mid to non-polar volatile organic compounds such as meroterpenes (serrulatanes and nerol cinnamates), monoterpenes (1,8-cineole and myodesert-1-ene), sesquiterpenes, diterpenes and triterpenes, that are known only in Australian plants, have also shown therapeutic properties related to traditional medicine.

CONCLUSION

Australian plants express a diverse range of previously undescribed metabolites that have not been given full in vitro assessment for human health potential. This review has included a limited number of plant species of ethnomedicinal significance; hundreds of plants remain in need of exploration and detailed study. Future more elaborate studies are therefore required to screen out and purify lead bioactive compounds against numerous other disease types. This will not only improve our knowledge on the phytochemistry of Australian native flora, but also provide a platform to understand their health-promoting and bioactive effects for pharmaceutical interventions, nutraceuticals, cosmetics, and as functional foods. Finally, plant-derived natural compounds (phytochemicals), as well as plant-based traditional remedies, are significant sources for latent and novel drugs against diseases. Extensive investigation of native medicinal plants may well hold the key to novel drug discoveries.

Untargeted and Targeted Metabolomic Profiling of Australian Indigenous Fruits

Selected Australian native fruits such as Davidson's plum, finger lime and native pepperberry have been reported to demonstrate potent antioxidant activity. However, comprehensive metabolite profiling of these fruits is limited, therefore the compounds responsible are unknown, and further, the compounds of nutritional value in these native fruits are yet to be described. In this study, untargeted and targeted metabolomics were conducted using the three fruits, together with assays to determine their antioxidant activities. The results demonstrate that targeted free and hydrolysed protein amino acids exhibited high amounts of essential amino acids. Similarly, important minerals like potassium were detected in the fruit samples. In antioxidant activity, Davidson's plum reported the highest activity in ferric reducing power (FRAP), finger lime in antioxidant capacity (ABTS), and native pepperberry in free radical scavenging (DPPH) and phosphomolybdenum assay. The compounds responsible for the antioxidant activity were tentatively identified using untargeted GC×GC-TOFMS and UHPLC-QqQ-TOF-MS/MS metabolomics. A clear discrimination into three clusters of fruits was observed using principal component analysis (PCA) and partial least squares (PLS) analysis. The correlation study identified a number of compounds that provide the antioxidant activities. GC×GC-TOFMS detected potent aroma compounds of limonene, furfural, and 1-R-α-pinene. Based on the untargeted and targeted metabolomics, and antioxidant assays, the nutritional potential of these Australian bush fruits is considerable and supports these indigenous fruits in the nutraceutical industry as well as functional ingredients for the food industry, with such outcomes benefiting Indigenous Australian communities.