Lemon Myrtle Research Articles

Maximising extraction yields of gallic acid and hesperetin from lemon myrtle (Backhousia citriodora) leaf using microwave assisted extraction

Lemon myrtle (Backhousia citriodora) is native to Australia and is well-known for its lemon aroma and traditional uses in foods and as a medicine. The leaves are rich in phenolics, and gallic acid and hesperetin are the major phenolic compounds. Microwave-assisted extraction (MAE) is known as an effective extraction technique for phenolics from plant materials. This study aimed to investigate the individual and interaction effects of microwave on the isolation of gallic acid and hesperetin from lemon myrtle leaf and quantify the part in total phenolic compound. This study also optimized the MAE conditions. Extraction solvent was acetone (50%) in water and extraction time, microwave power and sample to solvent ratio were tested for their optimal conditions. The results showed that extraction time and microwave power had a positive significant effect on gallic acid, but not on hesperetin; whereas, the sample to solvent ratio had a negative significant impact on both gallic acid and hesperetin. The optimal MAE conditions were 6 min, 630 W, and 2 g/100 mL. Under these conditions, 43.32 mg gallic acid and 21.51 mg hesperetin could be obtained from a gram of dry sample. These account for approximately 42% and 21% of extracted total phenolic and flavonoid content, respectively. The optimized MAE conditions are recommended for recovery of gallic acid and hesperetin from lemon myrtle leaves for further applications.

Anti-inflammatory and anti-oxidative activities of lemon myrtle (Backhousia citriodora) leaf extract

In this present study, we examined the anti-inflammatory and anti-oxidative properties of alcoholic lemon myrtle extract (LME). The total polyphenol and flavonoid content of LME were determined as 118.77 and 14.53 mg/g extract, respectively. LME showed anti-oxidative properties, such as 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2′-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) radical scavenging activity. The anti-inflammatory activities of LME were investigated using the lipopolysaccharide-stimulated murine macrophage RAW 264.7 cells. Pretreatment with LME was performed at non-cytotoxic concentrations of 10–100 μg/mL. LME inhibited the production of inflammatory mediators such as nitric oxide (NO). Enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction (RT-PCR) revealed that pretreatment with LME suppressed the protein expression and mRNA levels of pro-inflammatory cytokines such as interleukin IL-6, and tumor necrosis factor (TNF)-α in a concentration-dependent manner, respectively. These results suggest that LME could be used as a potential therapeutic agent having potent anti-inflammatory effects that could be used to treat inflammatory bowel disease.

Effects of different drying methods on extractable phenolic compounds and antioxidant properties from lemon myrtle dried leaves

Lemon myrtle (Backhousia citriodora) is one of the most commercially grown native herbs in Australia. This study aimed to evaluate the effects of different drying methods on phenolic compounds and antioxidant properties of lemon myrtle leaves to identify the most suitable drying conditions. The drying methods include hot air drying, vacuum drying, microwave drying, sun drying, shade drying and freeze drying. The results showed that drying conditions significantly (p < 0.05) affected the retention of total phenolic content (TPC), total flavonoids (TFC), proanthocyanidins, gallic acid, hesperetin, and antioxidant properties of lemon myrtle leaves. The optimal conditions for hot air drying and vacuum drying are 90 °C for 75 min and 90 °C for 120 min, respectively; whereas optimal drying conditions for microwave drying are 960 W for 7 min, and the time required for sun drying and shade drying are 2 days and 12 days, respectively. The freeze dried leaves contained the highest level of TPC, TFC, proanthocyanidins, gallic acid and hesperetin (74.11 ± 2.87 mg GAE/g dw, 87.15 ± 2.70 mg CE/g dw, 123.49 ± 6.12 mg CE/g dw, 53.77 ± 0.22 mg/g dw and 38.99 ± 0.26 mg/g dw, respectively). The freeze dried leaves also contained higher antioxidant capacity as compared to other samples. No significant difference in phenolic compounds and antioxidant capacity was observed between tested other drying methods. Therefore, any of these methods can be selected for dehydration of lemon myrtle leaves for industrial purposes. However, microwave drying can be selected for drying of lemon myrtle leaves for an industrial scale as it was the most time and/or energy efficient technique.

HPTLC based approach for bioassay-guided evaluation of antidiabetic and neuroprotective effects of eight essential oils of the Lamiaceae family plants

A high-performance thin-layer chromatography (HPTLC) method combined with effect-directed-analysis (EDA) was developed to screen the antioxidant, neuroprotective and antidiabetic effects in essential oils derived from lavender flower, lemon myrtle, oregano, peppermint, sage, and rosemary leaves (Lamiaceae family). HPTLC hyphenated with microchemical (DPPH•, p-anisaldehyde, and ferric chloride) derivatizations, was used to evaluate antioxidant activity, presence of phytosterols and terpenoids, and polyphenolic content, while the combination with biochemical (α-amylase and acetylcholine esterase (AChE) enzymatic) derivatizations was used to asses α-amylase and AChE inhibitory activities. The superior antioxidant activity of oregano leaf extract is attributed to the presence of high levels of aromatic compounds, like polyphenolic acids. The strongest α-amylase inhibition was observed in lemon myrtle and rosemary plus extracts due to the presence of monoterpenes. Rosemary and sage extracts exhibit the highest AChE inhibition activity, with 1 μL essential oils being more potent than the recommended daily dose of donepezil. This superior neuroprotection was attributed to the presences of di- and triterpenes that displayed strong AChE inhibition and antioxidant potential in DPPH• free radical assay. Antioxidant activity was related to phenolic content (R = 0.49), while α-amylase inhibitory activity was positively related to antioxidant activity (R = 0.20) and terpenoid/sterol content (R = 0.31). AChE inhibitory activity was correlated (R = 0.80) to the combined effect of phenolics and terpenoids. Thus, the superior AChE inhibitory and neuroprotection potential of rosemary and sage essential oils could be attributed to joint effects of main phenolic and terpene constituents. The hyphenated HPTLC method provided rapid bioanalytical profiling of highly complex essential oil samples.

Multispectral, Aerial Disease Detection for Myrtle Rust (Austropuccinia psidii) on a Lemon Myrtle Plantation

Disease management in agriculture often assumes that pathogens are spread homogeneously across crops. In practice, pathogens can manifest in patches. Currently, disease detection is predominantly carried out by human assessors, which can be slow and expensive. A remote sensing approach holds promise. Current satellite sensors are not suitable to spatially resolve individual plants or lack temporal resolution to monitor pathogenesis. Here, we used multispectral imaging and unmanned aerial systems (UAS) to explore whether myrtle rust (Austropuccinia psidii) could be detected on a lemon myrtle (Backhousia citriodora) plantation. Multispectral aerial imagery was collected from fungicide treated and untreated tree canopies, the fungicide being used to control myrtle rust. Spectral vegetation indices and single spectral bands were used to train a random forest classifier. Treated and untreated trees could be classified with high accuracy (95%). Important predictors for the classifier were the near-infrared (NIR) and red edge (RE) spectral band. Taking some limitations into account, that are discussedherein, our work suggests potential for mapping myrtle rust-related symptoms from aerial multispectral images. Similar studies could focus on pinpointing disease hotspots to adjust management strategies and to feed epidemiological models.

Developing a spectral disease index for myrtle rust (Austropuccinia psidii)

Since 2010 Australian ecosystems and managed landscapes have been severely threatened by the invasive fungal pathogen Austropuccinia psidii. Detecting and monitoring disease outbreaks is currently only possible by human assessors, which is slow and labour intensive. Over the last 25 years, spectral vegetation indices (SVIs) have been designed to assess variation in biochemical or biophysical traits of vegetation. However, diagnosis of individual diseases based on classical SVIs is currently not possible because they lack disease specificity. Here, a novel spectral disease index (SDI), the lemon myrtle–myrtle rust index (LMMR), has been developed. The index was designed from hyperspectral leaf‐clip data collected at a lemon myrtle plantation in New South Wales, Australia. A total of 236 fungicide‐treated (disease free) and 228 untreated (diseased) lemon myrtle leaves were sampled and a random forest classifier was used to show that the LMMR discriminates those classes with an overall accuracy of 90%. Compared to three classical SVIs (PRI, MCARI, NBNDVI), commonly applied for stress detection, the LMMR clearly improved classification accuracies (58%, 67%, 60%, respectively). If the LMMR can be validated on independent datasets from similar and different host species, it could enable land managers to reduce disease impact by earlier control. There might also be potential to collect useful data for epidemiology models. Calculating the LMMR based on hyperspectral data collected from aerial platforms (e.g. drones) would allow for rapid and high‐capacity screening for disease outbreaks.

Mechanism of Action against Food Spoilage Yeasts and Bioactivity of Tasmannia lanceolata, Backhousia citriodora and Syzygium anisatum Plant Solvent Extracts.

Bioactive properties of solvent extracts of Tasmannia lanceolata, Backhousia citriodora and Syzygium anisatum investigated. The antimicrobial activities evaluated using agar disc diffusion method against two bacteria (Escherichia coli and Staphylococcus aureus) and six weak-acid resistant yeasts (Candida albicans, Candida krusei, Dekkera anomala, Rhodotorula mucilaginosa, Saccharomyces cerevisiae and Schizosaccharomyces pombe). The antioxidant activities determined using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging and reducing power assays. Quantification of major active compounds using ultra-high performance liquid chromatography. Extracts showed broad-spectrum antifungal activity against weak-acid resistant yeasts in comparison to the standard antifungal agents, fluconazole and amphotericin B. Dekkera anomala being the most sensitive and strongly inhibited by all extracts, while Escherichia coli the least sensitive. Polygodial, citral and anethole are the major bioactive compounds identified in Tasmannia lanceolata, Backhousia citriodora and Syzygium anisatum, respectively. Hexane extracts contain the highest amount of bioactive compounds and demonstrate the strongest antimicrobial activities. Methanol and ethanol extracts reveal the highest phenolic content and antioxidant properties. Fluorescence microscopic results indicate the mechanism of action of Backhousia citriodora against yeast is due to damage of the yeast cell membrane through penetration causing swelling and lysis leading to cell death.

Biochemical and functional properties of indigenous Australian herbal infusions

The phytochemical profile, organic acid content, minerals, various antioxidant assays and consumers acceptability of indigenous Australian herbal infusions namely gulban (Melaleuca citrolens), anise myrtle (Syzygium anisatum), and lemon myrtle (Backhousia citriodora) were compared with a commercial green tea (Camellia sinensis). Total phenolic content and catechin derivatives were higher in green tea as compared to indigenous herbal infusions (P < 0.05). Phytochemical profiles showed high levels of caffeine in green tea, but, it was not found in herbal infusions (P < 0.05). Australian indigenous herbal infusions were a good source of calcium and magnesium compared to green tea (P < 0.05). Oxalic acid was higher in green tea, whereas gulban and anise myrtle infusions were rich in citric acid (P < 0.05). Antioxidant activities of green tea and gulban herbal infusions were comparable (P ≥ 0.05). Overall liking scores were higher for herbal infusions compared to green tea (P < 0.05). Indigenous Australian herbal infusions particularly gulban has a potential to become a successful commercial herbal beverage.

A lemon myrtle extract inhibits glucosyltransferases activity ofStreptococcus mutans

Streptococcus mutans is a bacterium found in human oral biofilms (dental plaques) that is associated with the development of dental caries. Glucosyltransferases (GTFs) are key enzymes involved in dental plaque formation, and compounds that inhibit their activities may prevent dental caries. We developed a screening system for GTF-inhibitory activities, and used it to profile 44 types of herbal tea extracts. Lemon myrtle (Backhousia citriodora) extract exhibited the highest GTF-inhibitory activity, with an IC50 for GTF in solution of 0.14mg mL-1. Furthermore, lemon myrtle extracts had the third-highest polyphenol content of all tested extracts, and strongly inhibited S. mutans biofilm. Interestingly, lemon myrtle extracts did not inhibit cell growth.

Wrażliwość bakterii beztlenowych na australijski olejek mirtowy (Backhousia citriodora F. Muell.)

Introduction. Herbs have been known and utilize since ancient Times in China, Europe and America. The ancient Egiptians used the myrtle to treat fever and infections. The plant have been mentioned in the Bible six times. Dioscorides recommended myrtle oil on patients with blader and lung infections. The herb and essential oil were used in Ayuveric treating infections respiratory tract and neuralgic. Backhousia citriodora F. Muell. belonging to the genus Backhousia and family Myrtaceae. It grown to 20-30 m high, on plantations in Australia, in subtropical rainforests of central and south-eastern Queensland. The leaves of the tree Backhousia citriodora produces an essential oil. It is obtained via hydro distillation. Lemon myrtle oil is known for its characteristic lemon flavor, related with presence of citral. Research indicated, that constituents of oil showed antibacterial activity against aerobic bacteria. There are no information about its activity towards anaerobic bacteria. Aim. The aim of the study was to determine activity of myrtle oil against anaerobic bacteria isolated from patients. Material and methods. The anaerobic bacteria were isolated from various infections of oral cavity. A total 135 strains isolated from patients and 7 reference strains were tested. The suscibility anaerobes to myrtle oil was carried out using plate dilution technique in Brucella agar supplemented with 5% defibrynated sheep blood, menadione and hemin. Inoculum containing 106 in CFU per spot was seeded with Steers replicator upon the surface of agar with myrtle oil and without oil (strains growth control). Incubation the plates was performed in anaerobic jars (10% C02 , 10% H2 , 80% N2 , palladic catalyst and anaerobic indicator) at 37°C for 48 hrs. The MIC was defined as the lowest concentrations of the myrtle oil that completely inhibited growth the tested anaerobic bacteria. Results. The results indicated that the myrtle oil was active against the 44 (50%) from all the tested strains of anaerobes to the concentrations from ranges &lt; 0.12-1.0 mg/ml. The rods from genus of Prevotella oralis and Prevotella oris were sensitive on concentrations &lt; 0.12 mg/ml. The oil was less active against the Gram-negative anaerobes from genus of Prevotella buccalis, Prevotella levii, Prevotella loescheii, Bacteroides uniformis and Parabacteroides distasonis (MIC &gt; 4.0 mg/ml). The Clostridial strains were very sensitive. The growth of this strains was inhibited by concentrations of &lt; 0.12 mg/ml. The volatile oil did appeared to be equally effective against both Gram-negative and Gram-positive anaerobic rods. The growth of 50 and 47% of this bacteria was inhibited in ranges from &lt; 0.12 to 1.0 mg/ml. The tested Gram-negative cocci from genus Veillonella parvula were less sensitive (MIC 1.0-&gt; 4.0 mg/ml). The strains of Gram-positive cocci were the least sensitive. Its growth was inhibited by concentrations 2.0-&gt; 4.0 mg/ml. Conclusions. The myrtle oil was more active against anaerobic bacteria from genus Prevotella oralis, Prevotella oris and strains from genera of Clostridium. The strains from genus Prevotella buccalis, Prevotella levii, Prevotella loescheii, Bacteroides uniformis and Parabacteroides distasonis were the lowest sensitive. The oil was equally effective against Gram-negative and Gram-positive anaerobic bacteria.

Vitamin D Content of Australian Native Food Plants and Australian-Grown Edible Seaweed.

Vitamin D has previously been quantified in some plants and algae, particularly in leaves of the Solanaceae family. We measured the vitamin D content of Australian native food plants and Australian-grown edible seaweed. Using liquid chromatography with triple quadrupole mass spectrometry, 13 samples (including leaf, fruit, and seed) were analyzed in duplicate for vitamin D2, vitamin D3, 25-hydroxyvitamin D2, and 25-hydroxyvitamin D3. Five samples contained vitamin D2: raw wattleseed (Acacia victoriae) (0.03 µg/100 g dry weight (DW)); fresh and dried lemon myrtle (Backhousia citriodora) leaves (0.03 and 0.24 µg/100 g DW, respectively); and dried leaves and berries of Tasmanian mountain pepper (Tasmannia lanceolata) (0.67 and 0.05 µg/100 g DW, respectively). Fresh kombu (Lessonia corrugata) contained vitamin D3 (0.01 µg/100 g DW). Detected amounts were low; however, it is possible that exposure to ultraviolet radiation may increase the vitamin D content of plants and algae if vitamin D precursors are present.

Detecting myrtle rust (Austropuccinia psidii) on lemon myrtle trees using spectral signatures and machine learning

Hundreds of species in one of Australia's dominant plant families, the Myrtaceae, are at risk from the invasive pathogenic fungusAustropuccinia psidii. Since its arrival in Australia in 2010, native plant communities have been severely affected, with highly susceptible species likely to become extinct from recurring infections. While severe impact on Australian native and plantation forestry has been predicted, the lemon myrtle industry is already under threat. Commercial cultivars of lemon myrtle (Backhousia citriodora) are highly susceptible toA. psidii. Detecting and monitoring disease outbreaks is currently only possible by eye, which is costly and subject to human bias. This study aims at developing a proof‐of‐concept for automated, non‐biased classification of healthy (naïve), fungicide‐treated and diseased lemon myrtle trees by means of their spectral reflectance signatures. From a lemon myrtle plantation, spectral signatures of fungicide‐treated and untreated leaves were collected using a portable field spectrometer. A third class of spectra, from naïve lemon myrtle leaves that had not been exposed toA. psidii, was collected from a botanical garden. Reflectance spectra in their primary form and their first‐order derivatives were used to train a random forest classifier resulting in an overall accuracy of 78% (kappa = 0.68) for primary spectra and 95% (kappa = 0.92) for first‐order derivative‐transformed spectra. Thus, an optical sensor‐based discrimination, using spectral reflectance signatures of this as yet uninvestigated pathosystem, seems technically feasible. This study provides a foundation for the development of automated, sensor‐based detection and monitoring systems for myrtle rust.

Formulation, characterisation and antibacterial activity of lemon myrtle and anise myrtle essential oil in water nanoemulsion

This study focussed on the formulation, characterisation of lemon myrtle (LM) and anise myrtle (AM) essential oil (EO) in water nanoemulsion and their antibacterial activity. The required hydrophilic lipophilic balance (rHLB) value of LM EO and AM EO was 14 and 12, respectively. The Central Composite Rotatable Design (CCRD) model produces the smallest droplet size and polydispersity index (PDI) for LMEO (d ≈ 16.07 nm; PDI ≈ 0.209) and AMEO (d ≈ 30.23 nm; PDI ≈ 0.216) at 1% EO and 10% surfactant mixture (Smix) ratio using ultrasonication for 5 min. Whereas, increased in EO, decrease in Smix concentrations and ultrasonication time produces higher droplet size of nanoemulsions. LMEO (LM-15, LM-17) nanoemulsions was clear and transparent compared to AMEO (AM-15, AM-17). All the selected nanoemulsions showed good stability at 4, 25 and 40 °C during storage, except LM-15 at 40 °C. LMEO nanoemulsion showed enhanced antibacterial activity compared to LMEO alone (P < 0.05).

Extraction and Isolation of Natural Organic Compounds from Plant Leaves Using Ionic Liquids.

Plants contain many kinds of natural organic compounds, and their compounds possess many useful properties. Natural organic compounds are important for the development of medicines, pesticides, fragrances, cosmetics, and synthetic chemicals. In this chapter, we introduce efficient methods for extraction and isolation of valuable natural organic compounds from various plant leaves by using cellulose-dissolving ionic liquids. High-polarity ionic liquids, which can dissolve cellulose, contribute to the extraction of natural organic compounds from plant leaves probably by breaking down plant cell walls, which are composed of cellulose, hemicellulose, and lignin. Extraction and isolation of shikimic acid from ginkgo leaves, caffeoylquinic acids from sweet potato leaves, and neral and geranial (which combine to form citral) from lemon myrtle leaves were performed. Ionic liquids can achieve extraction rates greater than those achieved with water and other organic solvents. Graphical Abstract.

레몬머틀의 항산화 활성 및 인위적으로 갱년기를 유도한 흰쥐의 골 형성에 미치는 영향

본 연구에서는 레몬머틀 추출물의 항산화 활성 및 갱년기장애를 유발한 흰쥐의 골 형성에 미치는 영향을 검토하고자 하였다. 레몬머틀 추출물의 항산화 활성을 검토하기 위하여 in vitro에서 DPPH 라디칼 소거능, SOD 유사 활성 및 총폴리페놀 함량을 측정하여 항산화 활성을 분석하였다. 레몬머틀 추출물의 DPPH 라디칼 소거능은 레몬머틀 에탄올 추출물, 열수 추출물 및 ascorbic acid(AsA) 모두 50 μg/mL 이상의 농도에서 100%에 가까운 활성을 나타내었다. SOD유사 활성을 측정한 결과 농도 1, 50 및 100 μg/mL에서 AsA와 유사한 활성을 나타내었다. 농도 500과 1,000 μg/mL에서는 열수 추출물보다 에탄올 추출물이 유의적으로 높은 활성을 나타내었다. 총 폴리페놀 함량의 경우 열수 추출물보다 에탄올 추출물이 상대적으로 높은 폴리페놀 함량을 나타냈다. 이상의 결과 레몬머틀 추출물은 같은 식물종에서도 비교적 높은 항산화 활성을 가지고 있으며, 폴리페놀 함량의 경우 열수 추출물보다 에탄올 추출물에서 그 함량이 높은 것으로 나타났다. 따라서 레몬머틀 에탄올 추출물을 이용하여 인위적으로 갱년기를 유도한 실험동물의 혈중 ALP 활성 및 골 조직 중 콜라겐 함량 변화에 미치는 레몬머틀의 영향을 검토하고자 하였다. 실험동물은 9주령 흰쥐를 비 난소절제 대조군(SHAM), 난소절제 대조군(OVX-CON), 난소절제 후 레몬머틀 에탄올 추출물 50 mg/kg bw 투여군(OVX-BCE50), 난소절제 후 레몬머틀 에탄올 추출물 200 mg/kg bw 투여군(OVX-BCE200)으로 각 6마리씩 4군으로 나누어 난소절제 시술 후 6주간 추출물을 투여하며 사육하였다. 혈청 중 ALP 활성은 난소절제를 하지 않은 SHAM군에 비해 난소 절제군인 OVX-CON군의 활성이 1.8배 증가하였으나, 레몬머틀 에탄올 추출물 50 mg/kg 및 200 mg/kg 투여한 군에서는 OVX-CON군에 비하여 유의적으로 감소하여 난소절제로 인해 골 흡수가 상대적으로 증가한 상태에서 레몬머틀 에탄올 추출물이 골 형성에 영향을 주어 혈청 중 ALP 활성을 개선시킨 결과로 생각된다. 연골 조직 중의 콜라겐 함량은 비 난소절제군인 SHAM군에 비해 난소절제를 한 OVX-CON군에서 유의적으로 감소하였으나, 레몬머틀 에탄올 추출물을 투여한 OVX-BCE50군에서는 OVXCON군 대비 유의적으로 증가하는 결과를 나타내었다. 또한, 골 조직에서 있어서도 레몬머틀 에탄올 추출물 투여로 콜라겐 함량이 유의적으로 증가하는 경향을 나타내었다. 한편 피부 조직의 경우 난소절제로 인해 콜라겐 함량이 감소하였으나, 레몬머틀 에탄올 추출물 50 mg/kg/d 투여로 인해 유의적으로 증가하는 결과가 나타났다. 이상과 같이 연골, 골 및 피부와 같은 결합조직 중의 콜라겐 함량은 난소절제로 인해 감소하였으나, 레몬머틀 에탄올 추출물의 투여로 인해 개선되는 경향을 나타내었다. 이는 레몬머틀의 높은 항산화활성 및 미지의 활성 성분 등의 상호작용에 의해 폐경 이후의 골다공증 예방 및 완화에 긍정적인 영향을 준 것으로 생각되며, 갱년기 장애 개선 식품 소재로서의 이용 가능성을 시사하고 있어 이를 활용한 기능성 소재 개발도 가능할 것으로 기대된다.

Effect of the essential oils from Melaleuca alternifolia, Melaleuca quinquenervia and Backhousia citriodora on the synthesis of ochratoxin A by Aspergillus niger and Aspergillus carbonarius isolated from tropical wine grapes.

The influence of essential oils (EOs) extracted from the leaves of Melaleuca alternifolia, Melaleuca quinquenervia and Backhousia citriodora on ochratoxin A (OTA) synthesis by fungi was studied. The extraction of EOs was performed by hydrodistillation (Clevenger apparatus) over a 2-h period and subsequently analyzed by GC-MS and GC-FID. The toxigenic activity of the essential oils (31.25; 15.62 and 7.81µgmL-1) was evaluated by inhibiting the production of OTA by Aspergillus niger and Aspergillus carbonarius in Czapek agar medium culture. The quantification of the toxin was performed by HPLC. The production of OTA was dependent on the fungal species, incubation temperature (15 and 25°C) and the presence of the essential oils. In tests carried out at 15°C, the oils caused a reduction in OTA synthesis that ranged from 57.60 to 76.93% and from 54.78 to 98.68% for the fungal species A. carbonarius and A. niger, respectively. At 25°C, reductions ranged from the 38.66 to 75.93% and from 17.94 to 71.79% for the respective fungi. The study concluded that natural products could be potential biocontrol agents against OTA contamination in food.

Synthesis and characterization of gold-conjugated Backhousia citriodora nanoparticles and their anticancer activity against MCF-7 breast and HepG2 liver cancer cell lines

Environmentally benign-synthesized gold nanoparticles (Au-NPs) have received substantial attention owing to their biomedical applications, particularly in cancer therapy. In the current study, Backhousia citriodora (B. citriodora) leaf extract was applied as a reducing agent for one-pot synthesis of controlled size Au-NPs. The effect of various parameters such as reaction time, pH, and B. citriodora leaf boiling time on the synthesis of Au-NPs was studied. The characterization of the Au-NPs synthesized at 15.0-min incubation time showed colour change because of the surface plasma resonance band around 530.0 nm. TEM photographs showed spherical morphologies with an average size of 8.40 ± 0.084 nm and zeta potential value was − 29.74 mV, indicating stability of the nanoparticles. The biomedical properties of Au-NPs and B. citriodora leaf extract showed strong DPPH radical scavenging. The in vitro anticancer activity determined using MTT assay exhibited that Au-NPs showed a significant dose-dependent reduction in the viability of the MCF-7 breast cancer cell line and the HepG2 liver cancer cell line with IC50 values of 116.65 and 108.21 µg, respectively.

284 Backhousia citriodora leaf extract: A new active solution to control hyper-seborrhea for multi-ethnic skins

284 Backhousia citriodora leaf extract: A new active solution to control hyper-seborrhea for multi-ethnic skins

Social enterprise to social value chain: Indigenous entrepreneurship transforming the native food industry in Australia

AbstractSharon Winsor was not intent on becoming one of Australia’s leading female Indigenous entrepreneurs, it was rather unexpected. In seeking to escape from an abusive relationship and provide for her family, she turned to her knowledge of native foods and love of ‘wild harvesting’ from her childhood, to develop a thriving business. Her traditional knowledge of harvesting native foods has now led to the creation of products such as lemon myrtle sweet chilli sauce, Davidson plum syrup and cosmetics using ingredients such as Kakadu plum, emu oil, lemon myrtle and wild berry. Sharon now finds herself in a position where increased opportunities for international expansion are demanding increased volume and scale from her rural operations, where she works with Indigenous communities. She faces three key challenges about the future of Indigiearth:1.How can Indigiearth achieve scale while maintaining profitability and social mission?2.How can Indigiearth protect its competitive advantage in the face of increased local agricultural competition, as Indigenous crops increase in value?3.How can traditional knowledge be both shared and protected for community development (jobs and wealth creation) and for future generations?The New Year is close and Sharon already has received large orders coming in from Europe and there is much interest from China and Japan. These decisions will determine how Indigiearth is structured, with whom it needs to partner to develop the Indigenous food industry, and how it will need to work with stakeholders on the issue of traditional knowledge while meeting the growing needs of the company. Sharon has a passion for her native products and wants to preserve the knowledge and respect that goes into her products – the dilemmas she is facing are putting her under immense pressure. She may choose to expand while maintaining the integrity of her business – but how can this be done?

Cytogenotoxic effect of essential oil from Backhousia citriodora L. (Myrtaceae) on meristematic cells of Lactuca sativa L.

The objective of this study was to evaluate the cytogenotoxic effects of essential oil (EO) extracted from Backhousia citriodora L. (Myrtaceae) on the plant model Lactuca sativa L. EO was obtained through hydrodistillation, using a modified Clevenger apparatus (2h), and subsequently analyzed by GC/MS and GC-FID. Germinated seeds of L. sativa with root length of 1–2mm were exposed to different concentrations of EO (5, 25, 50, 100, 200 and 500μgmL−1) for 48h. Distilled water was used as negative control. Cytogenetic analyses, cell cycle evaluation, TUNEL test, agarose gel electrophoresis and flow cytometry were performed. The main constituent found in the EO was citral (91.19%). Overall, EO interferes with the normal dynamics of the cell cycle (mitotic index or frequency of each dividing stage). Here, both clastogenic chromosomal abnormalities (e.g. chromosome bridges, fragments and stickiness) and aneugenic alterations (e.g. delayed segregation and c-metaphases) were observed in meristematic cells exposed to EO. TUNEL-positive nuclei revealed the occurrence of DNA fragmentation. In agarose gel, DNA laddering pattern was not observed. EO genotoxicity was reinforced by flow cytometry analysis, which revealed loss of DNA content, decrease in the frequency of dividing cells, increase of nuclear complexity and reduction of nuclear diameter in cells exposed to the EO of B. citriodora. We conclude that B. citriodora EO presents cytogenotoxic effects besides inducing cell death and therefore constitutes a promising source of biologically active compounds.