Davidsonia Pruriens Research Articles

Exploring the potential of Davidson's plum (Davidsonia pruriens): A promising indigenous edible fruit as biopreservative in raw processed meat products.

This study evaluated the preserving effect of Davidson's plum (Davidsonia pruriens) fruit powder (DPP) in raw beef patties. Minced meat patties were treated with no additive (negative control), 45 mg/hg of Sodium metabisulphite (SMB), or DPP (0.2, 0.4, 0.6 and 0.8 g/hg) and stored for 20 days at 4 ± 1 °C. Lipid oxidation, microbial growth rate, pH, instrumental color were studied. Bioactive compounds of the DPP were analysed using UHPLC–HRAM-Orbitrap-MS/MS. The results showed that DPP contained high concentration of both anthocyanins and non-anthocyanins compounds. Furthermore, the beef patties treated with DPP exhibited reduced lipid oxidation (p<0.05) in comparison to beef patties with no added preservative. Moreover, the addition of DPP at concentration equal to or greater than 0.2 g/hg slowed down microbial growth (p<0.05) compared to raw beef patties with no preservative added. However, SMB-treated samples had the greatest antimicrobial activities in comparison to all other treatments. The inclusion of DPP led to reduced redness and pH of treated raw beef patties. This study provides evidence that Davidson's plum fruit can be used as natural preservative in raw processed meat.

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.

Biochemical, antioxidant and sensory evaluation of Davidsonia pruriens and Davidsoina jerseyana fruit infusion

Davidsonia pruriens (DP) and Davidsonia jerseyana (DJ) are a gourmet bushfood with a sweet and sour taste. This study investigated the biochemical content, antioxidant activities, and sensory attributes of DP and DJ fruit infusions in comparison with commercial forest fruits (FF) infusion. Total phenolic and anthocyanin content was higher in FF infusion compared to DP or DJ fruit infusions (P < 0.05). An abundant amount of gallic acid was found in DP and DJ fruit infusions (P < 0.05). Quercetin, kaempferol-3-O-rutinoside, and peonidin-3-sambubioside was detected only in DP and DJ fruit infusions (P < 0.05). However, a high level of oxalic acid, minerals and soluble sugars were observed in FF infusions (P < 0.05). The antioxidant capacities and overall likeness score of DP or DJ infusion were comparable with the commercial FF infusion. Therefore, bioactive compounds, antioxidant activities and sensory properties suggested that DP and DJ fruit infusion have the potential to become a commercial health promoting drink.

Davidsonia pruriens F. Muell. Fruit and Leaf Extracts Lack Antibacterial and Antifungal Activity

Davidsonia pruriens F. Muell. Fruit and Leaf Extracts Lack Antibacterial and Antifungal Activity

The edible native Australian fruit, Davidson’s plum (Davidsonia pruriens), reduces symptoms in rats with diet-induced metabolic syndrome

Abstract Davidson’s plum is a native Australian fruit used traditionally as food and medicine. The fruit contains anthocyanins as glucosides and sambubiosides of cyanidin and peonidin (691 mg/100 g of dried pulp) with rutin and quercetin glycosides (193 mg/100 g). Dietary supplementation of Davidson’s plum at approximately 8 mg anthocyanins/kg/day in rats attenuated the signs of metabolic syndrome induced by high-carbohydrate, high-fat diet. Davidson’s plum reduced visceral fat accumulation, total abdominal fat weight, size of retroperitoneal adipocytes, and plasma triglycerides and non-esterified fatty acids, normalised blood pressure, reduced left ventricular stiffness, decreased infiltration of inflammatory cells in both left ventricle and liver, decreased collagen deposition in heart, and reduced both fat vacuoles in liver and obesity-induced degeneration of knee cartilage. There were no changes in glucose tolerance with treatment. Davidson’s plum reduced colonic Clostridiaceae spp, and increased Turicibacter spp. and Akkermansia muciniphila. Our findings indicate that Davidson’s plum is a potential complementary treatment for metabolic syndrome.

Antioxidant and anti-proliferative properties of Davidson’s plum (Davidsonia pruriens F. Muell) phenolic-enriched extracts as affected by different extraction solvents

The Davidson’s plum (DP; Davidsonia pruriens F. Muell) is a fruit native to Australia that is a rich source of phenolic compounds. This study investigated the effects of various extraction solvents (ethanol, methanol, acetone and water) on total phenolic content (TPC), antioxidant capacity (ABTS, DPPH, CUPRAC, FRAP assays) and anti-proliferative activity (MTT, CCK-8 assays) of DP. Our data revealed that extraction solvents significantly affected the physico-chemical, antioxidant and anti-proliferative properties of DP extracts. Within the tested solvents, ethanol was found to be the optimal solvent for extraction of bioactive compounds from DP as its extract had the greatest TPC (94.13 GAE/g), flavonoids (78.33mg RUE/g), proanthocyanidins (5.33mg CAE/g), anthocyanidins (2.81mg CGE/g), as well as possessed the highest antioxidant capacity and anti-proliferative activity against a panel of cancer cell lines. This included cancers of the pancreas, breast, lung, brain, skin, colon and ovary. Therefore, further investigations should be conducted to identify key bioactive compounds to determine the potential for utilization in the nutraceutical and phytopharmaceutical industries.

The prevention of fish spoilage by high antioxidant Australian culinary plants: Shewanella putrefaciens growth inhibition

SummaryShewanella putrefaciens is a marine bacterium and a major microbial cause of spoilage in low temperature stored seafood. A survey of fruits and culinary herbs was undertaken on Australian plants with high antioxidant capacities. Twenty‐eight extracts from thirteen plant species were investigated for the ability to inhibit S. putrefaciens growth. Of these, eight extracts (28.6%) substantially inhibited S. putrefaciens growth. The muntries (Kunzea pomifera), lemon aspen (Acronychia acidula) and desert lime (Citrus glauca) extracts were efficient anti‐S. putrefaciens agents, with MIC values ≤3000 μg mL−1. Of these, the muntries methanolic extract was the most potent growth inhibitor (MIC = 2240 μg mL−1). The aqueous desert lime extract was also an effective growth inhibitor (MIC of 3857 μg mL−1), whilst the methanolic bush tomato (Solanum aviculare), aqueous muntries and Davidson's plum (Davidsonia pruriens) extracts displayed moderate S. putrefaciens growth inhibition. All extracts were nontoxic in the Artemia fransiscana bioassay, with LC50 values (&gt;1000 μg mL−1). Nontargeted HPLC‐QTOF mass spectroscopy (with screening against three compound databases) putatively identified twenty compounds that were present in both inhibitory muntries extracts. The low toxicity of these extracts and their inhibitory bioactivity against S. putrefaciens indicates their potential as natural fish and seafood preservatives.

Optimum aqueous extraction conditions for preparation of a phenolic‐enriched Davidson's plum (Davidsonia pruriensF. Muell) extract

SummaryThis study aimed to optimise aqueous extraction conditions for total phenolic compounds (TPC) from Davidson's plum (Davidsonia pruriens F. Muell) and to assess the physicochemical and antioxidant properties of the phenolic‐enriched extract. The results showed that temperature, time and ratio significantly affected the extraction of TPC. Optimization of extraction conditions was performed using response surface methodology (RSM) utilising a Box–Behnken design. Optimal extraction conditions were determined to be temperature: 90 °C, extraction time: 30 min and solvent to mass ratio: 20:1 mL g−1. The extracted solid obtained under these conditions had low‐moisture content, high water solubility and contained 45 mg GAE g−1 of TPC, 22 mg RUE g−1 of flavonoids, 3.2 mg CAE g−1 of proanthocyanidins, 2 mg CGE g−1 of anthocyanidins and 56 mg ACE g−1 vitamin C. The extract possessed potent antioxidant capacity, but was comparatively lower than those of vitamin E and BHT. Thus, Davidson's plum should be further investigated for its potential health promoting benefits and utilisation in the nutraceutical and food industries.

Bioprospecting Davidson's plum and quandong: Cytoprotective and proapoptotic activities

Polyphenolic-rich extracts of commercially grown Davidson's plum (Davidsonia pruriens, Cunoniaceae) and quandong (Santalum acuminatum, A.D.C., Santalaceae) were evaluated for their potential cytoprotective and proapoptotic activities. Quandong extract (0.2–0.6 mg/mL) exhibited superior cytoprotective activities and reduced the hydrogen peroxide (H2O2) induced death of hepatocellular carcinoma (HepG2) cells between 25 and 50%. Davidson's plum extract had comparable antiproliferative activity to blueberries against the colon adenocarcinoma (HT-29) and HepG2 cells but was not effective against the stomach adenocarcinoma cells (AGS; IC50 > 2.0 mg/mL). No significant cytotoxicity was observed towards non-transformed colon (CCD-18Co; IC50 > 2.0 mg/mL) and mixed stomach and intestine (Hs 738.St/Int; IC50 > 2.0 mg/mL) cells. The flow cytometry analysis conducted with promyelocytic leukaemia (HL-60) cells and the results of the cytokinesis blocked micronucleus cytome (CBMNCyt) assay conducted with HT-29 cells suggested an increase in apoptosis in the cellular population treated with the fruit extracts. The occurrence of apoptotic cells coincided with an increase in caspase-3 enzyme activity. The results of the CBMNCyt assay suggested DNA damage in HT-29 cells as a result of treatment with fruit extracts, applied at final concentrations of 0.5 and 1.0 mg/mL.

Composition and inhibitory activities towards digestive enzymes of polyphenolic-rich fractions of Davidson's plum and quandong

Davidson's plum (DP; Davidsonia pruriens, F. Muell, Cunoniaceae) and quandong (QD; Santalum acuminatum, A.D.C., Santalaceae) are two leading commercially grown native Australian fruits used in a variety of food products such as jam, chutney, sauces, wine or herbal teas. Within this study their inhibitory activities towards key enzymes relevant to metabolic syndrome: α-glucosidase, pancreatic lipase and angiotensin I-converting enzyme were evaluated and compared to these of reference samples: rabbit eye (REB, Vaccinium ashei J.M. Reade) and southern highbush (SHB, Vaccinium darrowii × Vaccinium corymbosum) blueberries. Polyphenolic-rich fraction obtained from DP comprised ellagic acid and ellagitannins accompanied by flavonoids: myricetin, quercetin, rutin, and anthocyanins. This fraction contained the highest level of total phenolics and exhibited superior antioxidant capacity (Ferric Reducing Antioxidant Power, FRAP and Oxygen Radical Absorbance Capacity, ORAC) to polyphenolic-rich fractions of QD, REB and SHB. DP closely followed REB and SHB in their inhibitory activities against isolated α-glucosidase (IC50 of 0.13; 0.097 and 0.091, respectively) and was the most efficient inhibitor of angiotensin converting-enzyme (ACE; 91.2% inhibition at extract concentration of 1 mg/mL). Polyphenolic-rich fraction of QD comprising hydroxycinnamic acids, quercetin and cyanidin 3-glucoside was the most effective inhibitor of pancreatic lipase (IC50: 0.60 mg/mL).

Influence of Copigment Derived from Tasmannia Pepper Leaf on Davidson's Plum Anthocyanins

Davidson's plum (Davidsonia pruriens, F. Muell.), a native to Australian rainforests, large, crimson-red fruit, which superficially resembles plum, has been commercially cultivated in Australia since 1990s. The current production volume exceeds market demands therefore this study was designed to evaluate the suitability of Davidson's plum extract as a source of anthocyanin-based food colorant. The stability of the Davidson's plum extract towards heat treatment at 95 °C was higher than that of commercial mulberry colorant, but inferior to colorants derived from red cabbage and purple sweetpotato. An addition of a variety of phenolic acids significantly increased color intensity indicating the formation of copigmentation complexes. Commercial chlorogenic acid as well as extract from a native Australian herb rich in chlorogenic acid, Tasmannia pepper leaf (Tasmannia lanceolata, R. Br.), were both tested in model soft drink solutions subjected to light irradiation and heat treatment. In both cases, the addition of the copigment resulted in a lasting increase in color intensity. In conclusion, Davidson's plum extract can successfully be utilized as a source of natural food color. Extract from Tasmania pepper leaf can be used as a co-pigment for Davidson's plum anthocyanins. The color properties of an anthocyanin colorant derived from the native Australian fruit Davidson's plum are comparable to those of mulberry, which is currently applied as a food colorant in Australian food products. Utilization of Davidson's plum fruit as a source of natural color will allow the industry to increase the range of natural pigments and will create new opportunities for the emerging native food industry.

Sources of Antioxidant Activity in Australian Native Fruits. Identification and Quantification of Anthocyanins

Selected native Australian fruits, muntries (Kunzea pomifera F. Muell., Myrtaceae), Tasmanian pepper berry (Tasmanian lanceolata R. Br., Winteraceae), Illawarra plum (Podocarpus elatus R. Br. ex Endl., Podocarpaceae), Burdekin plum (Pleiogynium timorense DC. Leenh, Anacardiaceae), Cedar Bay cherry (Eugenia carissoides F. Muell., Myrtaceae), Davidson's plum (Davidsonia pruriens F. Muell. var. pruriens, Davidsoniaceae), and Molucca raspberry (Rubus moluccanus var. austropacificus van Royen, Rosaceae), were evaluated as sources of antioxidants by 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays and compared with blueberry (Vaccinum spp. cv. Biloxi). The total reducing capacity of five fruits was 3.5-5.4-fold higher than that of blueberry, and the radical scavenging activities of muntries and Burdekin plum were 1.5- and 2.6-fold higher, respectively. The total phenolic level by Folin-Ciocalteu assay highly correlated with the antioxidant activity. Therefore, systematic research was undertaken to identify and characterize phenolic complexes. In the present study we report on the levels and composition of anthocyanins. The HPLC-DAD and HPLC/ESI-MS-MS (ESI = electrospray ionization) analyses revealed simple anthocyanin profiles of one to four individual pigments, with cyanidin as the dominating type. This is the first evaluation of selected native Australian fruits aiming at their utilization for the development of novel functional food products.

Micropropagation of Two Australian Native Fruit Species, Davidsonia pruriens and Davidsonia jerseyana G. Harden &amp; J.B. Williams

Nodal explants from in vitro grown seedlings of Davidsonia pruriens and D. jerseyana, established on MS media were treated with various concentrations of three cytokinins. D. pruriens developed optimum shoot growth in terms of shoot height and number of leaves per shoot when 1.0 µM BA was added to basal MS medium while optimum shoot growth for D. jerseyana was obtained when 0.01 µM 2iP was added to the medium. Optimum root initiation and development was obtained when actively growing axillary shoots were cultured on 1/2MS medium plus 32.2 µM IBA for 3–5 days for D. pruriens and 2–3 days for D. jerseyana before transfer to PGR-free medium containing 10 µM riboflavin. Root initiation of more than 80% was achieved with multiple genotypes of D. pruriens and three genotypes of D. jerseyana using juvenile material. The plantlets were transferred to pots and grown in the greenhouse with a success rate of 60% for D. pruriens and 75% for D. jerseyana. Adult D. jerseyana stem explants produced 2–5 shoots per nodal explant upon treatment with 0.1 µM BA. Side shoots from adult D. jerseyana produced similar results for shoot multiplication as for juvenile material. Protocol for multiplication of adult D. pruriens was achieved with much greater difficulty by using material from the green house. Axillary shoots were initiated when 100 µM TDZ was applied to the stem of an adult pot plant and the resultant side shoots were cultured on MS medium containing 1.0 µM BA and 1.0 µM GA3.

The carpology and taxonomic relationships of Davidsonia (Davidsoniaceae)

The fruit of Davidsonia pruriens F. v. Muell. drying and splitting at maturity into two indehiscent mericarps is re-defined as a schizocarpic didrupe. The sclerified mesendocarpic construction of the whole pericarp supports its classification as a drupe. The peculiar fimbriate surface of the mericarp is caused by the destruction of parenchymatous exocarpic and mesocarpic tissues exposing radially elongated mesendocarpic osteosclereids. The seed coat is described as diffusive exotegmic with expanding pachychalaza substituting the two integuments in the chalazal half of the seed. The diffusive exotegmy of the spermoderm supports a close relationship with Cunoniaceae, but refutes any relationships with Saxifragales or with Staphyleaceae or any Hamamelidae. The seed-coat structure indicates advancement and specialization of Davidsonia among Cunoniales; its origin could trace back possibly to Rosales, but never to hamamelidalean stock.