Authentication of olive oil in commercial products using specific, sensitive, and rapid loop-mediated isothermal amplification.

Olive oil is an important and popularly used plant oil in the daily diet or chemical industry. Due to its biological benefits on human health and higher selling prices, adulteration of olive oil for commercial fraud by other plant oils is becoming a serious issue. In this study, a specific, sensitive and rapid loop-mediated isothermal amplification (LAMP) was first developed for the detection of Olea europaea DNA for olive oil authentication. The oleosin gene was used for the primer design of the LAMP assay. After primer validation, the results showed that the LAMP primers were specific and rapid to isothermally authenticate the oleosin gene of Olea europaea within 1 h at 62 °C and had no cross-reaction with other DNA of plant oils. The sensitivity of LAMP was 1 ng of genomic DNA in olive oil, and only 1% olive oil in the sample was requisite during DNA amplification. Additionally, positive detection by LAMP in all the collected commercial olive oil products was practically performed but not in PCR assays. In conclusion, herein, the established LAMP assay with specificity could not only be capable for rapid identification but also applicable for olive oil authentication for precluding adulteration in plant oil products. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05726-y.

Development of a specific isothermal nucleic acid amplification for the rapid and sensitive detection of shrimp allergens in processed food.

Food allergens that cause anaphylactic reactions have become an important health problem worldwide. Among them, shrimp is a popular seafood in many cuisines. The best way to avoid allergic reactions is to mitigate the intake of food allergens. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed for the detection of shrimp DNA. Using LAMP primers, the identification of shrimp DNA by the LAMP assay was specific and rapid (within 30 min). It exhibited no cross-reaction with the DNA of other Crustacea, including crabs and lobster, and at least 0.01% shrimp DNA existed in the test sample. Additionally, the sensitivity of LAMP for detecting shrimp DNA was 100-fold greater than that of conventional PCR. LAMP for the detection of shrimp DNA was reproducible regardless of whether the genomic DNA was extracted from boiled, steamed or roasted shrimp samples. In summary, the LAMP assay established herein not only could be potentially used for diagnosing shrimp DNA but could also be applicable for identifying shrimp allergens in commercial food products in marketplaces.

Specific, sensitive and rapid authentication of donkey-hide gelatine (Colla corii asini) in processed food using an isothermal nucleic acid amplification assay.

Donkey-hide gelatine (DHG) is a well-known, animal-derived traditional Chinese medicine material called Colla corii asini (known in Chinese as "E'jiao"). Because DHG is claimed to have properties that are beneficial to health, its consumption has increased, but its production has decreased. Thus, the incidence of DHG adulteration has become increasingly serious. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed for the authentication of DHG. Identification of donkey DNA from DHG was performed specifically and rapidly within one hour by LAMP primers. Moreover, the sensitivity of LAMP in authenticating DHG was 10-3 ng, which revealed a 105-fold higher sensitivity than that of conventional PCR. The relative detection limit was 0.1% DHG in the adulterants, including gelatines of horse, cow, pork, goat, sheep or chicken origins. When genomic DNAs extracted from heat-treated DHG samples, including boiling or autoclaving for 40 min, were used as templates, DHG detection by LAMP was unchanged and reproducible. In conclusion, the LAMP assay established herein could potentially be applied for the authentication of DHG and DHG-related products in herbal or food markets.

The rapid and sensitive detection of edible bird's nest (Aerodramus fuciphagus) in processed food by a loop-mediated isothermal amplification (LAMP) assay.

Edible bird's nest (EBN) is a well-known and precious traditional Chinese herbal material (CHM). Because of this, preventing the adulteration of EBN efficiently and precisely is crucial to protect consumers' interests and health. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed for the detection of EBN using specifically designed LAMP primers. The results demonstrated that the identification of EBN by LAMP assay was specific and rapid (within 1 h). It had no cross-reaction with EBN adulterants, including white fungus, egg white and pig skin, in different ratios. The relative detection limit was 0.01% EBN in the adulterants. Moreover, the sensitivity of LAMP in authenticating EBN was 10-8 µg, it showed higher sensitivity than that of conventional PCR with 105 fold. When genomic DNAs extracted from boiled or steamed EBN samples were used as templates, LAMP for EBN detection was not affected and was reproducible after heat processing. In conclusion, the LAMP assay established herein could be applicable for authenticating EBN and for identifying commercial EBN products in herbal markets.

High molecular weight of polysaccharides from Hericium erinaceus against amyloid beta-induced neurotoxicity.

BACKGROUND: Hericium erinaceus (HE) is a well-known mushroom in traditional Chinese food and medicine. HE extracts from the fruiting body and mycelia not only exhibit immunomodulatory, antimutagenic and antitumor activity but also have neuroprotective properties. Here, we purified HE polysaccharides (HEPS), composed of two high molecular weight polysaccharides (1.7 × 10(5) Da and 1.1 × 10(5) Da), and evaluated their protective effects on amyloid beta (Aß)-induced neurotoxicity in rat pheochromocytoma PC12 cells. METHODS: HEPS were prepared and purified using a 95 % ethanol extraction method. The components of HEPS were analyzed and the molecular weights of the polysaccharides were determined using high-pressure liquid chromatography (HPLC). The neuroprotective effects of the polysaccharides were evaluated through a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and an MTT assay and by quantifying reactive oxygen species (ROS) and mitochondrial membrane potentials (MMP) of Aß-induced neurotoxicity in cells. RESULT: Our results showed that 250 µg/ml HEPS was harmless and promoted cell viability with 1.2 µM Aß treatment. We observed that the free radical scavenging rate exceeded 90 % when the concentration of HEPS was higher than 1 mg/mL in cells. The HEPS decreased the production of ROS from 80 to 58 % in a dose-dependent manner. Cell pretreatment with 250 µg/mL HEPS significantly reduced Aß-induced high MMPs from 74 to 51 % and 94 to 62 % at 24 and 48 h, respectively. Finally, 250 µg/mL of HEPS prevented Aß-induced cell shrinkage and nuclear degradation of PC12 cells. CONCLUSION: Our results demonstrate that HEPS exhibit antioxidant and neuroprotective effects on Aß-induced neurotoxicity in neurons.

Immunomodulating activity of Nymphaea rubra Roxb. extracts: activation of rat dendritic cells and improvement of the T(H)1 immune response.

Polysaccharides play a key role in enhancing immune function and facilitating cellular communication. Here, we purified Nymphaea rubra Roxb. polysaccharides (NR-PS) by treating them with pullulanase. They were then cultured with immature dendritic cells (DCs) derived from rat bone marrow hematopoietic cells (BMHCs). After treatment with bioactive NR-PS with a degree of polymerization (DP) value of 359.8, we found that the DCs underwent morphological changes indicative of activation. CD80/86 (87.16% ± 8.49%) and MHC class II (52.01% ± 10.11%) expression levels were significantly up-regulated by this treatment compared to the controls (65.45% ± 0.97% and 34.87% ± 1.96%). In parallel, endocytosis was also reduced (167.94% ± 60.59%) after treatment with 25 µg/mL of NR-PS as measured by the medium fluorescence intensity compared to the control (261.67% ± 47.26%). Furthermore, the DCs after treatment with 25 µg/mL NR-PS showed increased IL-12 (102.09 ± 10.16 to 258.78 ± 25.26 pg/mL) and IFN-γ (11.76 ± 0.11 to 15.51 ± 1.66 pg/mL) secretion together with reduced IL-10 secretion (30.75 ± 3.35 to 15.37 ± 2.35 pg/mL), which indicates a T(H)1 immune response. In conclusion, NR-PS exhibits stimulatory effects on rat DCs and promotes the secretion of T(H)1 cytokines. Taken together, our studies are the first to show that NR-PS is an immunomodulator affecting the maturation and functioning of DCs.

Composition analysis and immuno-modulatory effect of okra (Abelmoschus esculentus L.) extract.

The aim of this study was to analyse the composition of okra (Abelmoschus esculentus L.) extract and investigate the effect of A. esculentus L. polysaccharides (AE-PS) on the maturation and function of dendritic cells (DCs) derived from rat bone marrow hematopoietic cells (BMHCs) in vitro. BMHC-derived immature DCs (BMHC-imDCs) were extracted from rats and treated with AE-PS. The hydrolysed okra extract contained 0.6% ß-1, 3-D-glucan. AE-PS induced the presence of polymorphic nuclei and elongated protrusion in the BHMC-imDCs, indicating DC activation. Treatment with 100 µg/mL of AE-PS increased the MHC class II and CD80/86 expression levels by 41% and 42%, respectively. Treated cells had reduced endocytosis activity. The secretion of IL-12 and IFN-γ increased significantly by 120% and 75%, respectively, when treated with 100 µg/mL of AE-PS. Moreover, IL-10 production was reduced by 66%. In conclusion, AE-PS exhibits stimulatory effects on rat dendritic cells and promotes the secretion of T(H)1 cytokines.