Determination of edible bird's nest and its products by gas chromatography

Effects of house-cultivated edible bird's nest on immunoglobulin and cytokine release in vitro

Background and Aim

Edible bird's nest (EBN) is known as the "Caviar of the East" because of its high nutritional and medicinal values. Nevertheless, its effect on human immunity is yet to be explored. This study examined the effects of EBN's aqueous extract (EBNE) on human immunity through the modular immune in vitro construct (MIMIC) model consisting of peripheral tissue equivalent (PTE) and lymphoid tissue equivalent (LTE) modules.

Materials and Methods

One hundred twenty mL of full blood was obtained from four healthy human volunteers. The human immune system was simulated using an in vitro model, called MIMIC. Under EBNE treatment, monocyte transendothelial migration through reversed endothelial layers was observed. Using PTE and LTE modules, monocytes were differentiated into dendritic cells with lipopolysaccharide, then co-cultured with T- and B-cells for cytokine and immunoglobulin (Ig) production. The human cytokine array G2000 and quantitative human Ig isotyping array were used to identify the cytokine profile and Ig isotypes, respectively.

Results

IgE, IgA, and IgG3 levels were significantly raised by EBNE. These cytokines, including brain-derived neurotrophic factor, ciliary neurotrophic factor, glial cell line-derivative neurotrophic factor, insulin-like growth factor 1, and insulin-like growth factor binding protein 4, were generated.

Conclusion

For the first time, this work uses a MIMIC model to illustrate the impact of EBNE on human immune response. This new understanding of EBN's immunoregulatory effect allows for further exploration of how EBN interacts with the human immune system.

Adulteration Detection of Edible Bird’s Nests Using Rapid Spectroscopic Techniques Coupled with Multi-Class Discriminant Analysis

Edible bird’s nests (EBNs) are vulnerable to adulteration due to their huge demand for traditional medicine and high market price. Presently, there are pressing needs to explore field-deployable rapid screening techniques to detect adulteration of EBNs. The objective of this study is to explore the feasibility of using a handheld near-infrared (VIS/SW-NIR) spectroscopic device for the determination of EBN authenticity against the benchmark performance of a benchtop mid-infrared (MIR) spectrometer. Forty-nine authentic EBNs from the different states in Malaysia and 13 different adulterants (five types) were obtained and used to simulate the adulteration of EBNs at 1, 5 and 10% adulteration by mass (a total of 15 adulterated samples). The VIS/SW-NIR and MIR spectra collated were subsequently processed, modelled and classified using multi-class discriminant analysis. The VIS/SW-NIR results showed 100% correct classification for the collagen and nutrient agar classes in authenticity classification, while for the other classes, the lowest correct classification rate was 96.3%. For MIR analysis, only the karaya gum class had 100% correct classification whilst for the other four classes, the lowest rate of correct classification was at 94.4%. In conclusion, the combination of spectroscopic analysis with chemometrics can be a powerful screening tool to detect EBN adulteration.

Why the importance of geo-origin tracing of edible bird nests is arising?

Edible bird's nest (EBN) swiftlet existed naturally 48,000 years ago in caves as their natural dwellings. Nowadays, edible bird's nest has become a very important industry due to its high nutritional, medicinal and economic value. Additionally, edible bird's nest has a long quality guarantee period. Obviously, the nutritional components and medicinal functions vary depending on geographical origins. Recently, the global demand for edible bird's nest has markedly increased, accompanied by the increasing attention of all key players of the global food trade system, i.e., producers, consumers, traders and the authorities to obtain safe and high-quality edible bird's nest. Hence, this target can be accomplished via the enforcement of an efficient and universal geo-tracing technique. Current methods of the geo-tracking of edible bird's nest, i.e., automation, physical and analytical techniques have several limitations and all of them fail to discriminate different quality grades of edible bird's nest. Meanwhile, in many studies and applications, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) has proven to be a "cutting edge" technique for greatly enhance food traceability from field to fork through its ability in distinguishing the food products in terms of their quality and safety. This article provides an overview of (1) edible bird's nest as a multiuse strategic food product, (2) quality issues associated with edible bird's nest including implications that the site of acquisition of the edible bird's nest has food safety implications, (3) current regulations and geo-tracking approaches to ensure the safety and quality of edible bird's nest with the special focus on polymerase chain reaction-denaturing gradient gel electrophoresis technique as a vigorous and universal geo-tracing tool to be suggested for edible bird's nest geo-traceability.

A comprehensive review of edible bird's nest

Edible bird's nest (EBN) is built by seven species of Aerodramus and Collocalia (Apodidae), using salivary gland secretion mixed with feathers or grass during the breeding. Its rich nutritional values such as anti-aging activity, immunomodulatory and antioxidant activity make consumers flock to it. Consumers' pursuit, on the one hand, aroused the arrogance of counterfeiters, which eventually leads to food safety problems. On the other hand, it promotes the in-depth studies of EBN in all aspects, such as compositions, biological activities, authenticity identification, quality control, and so on. This paper presented the origins and classifications of EBN and the current situation of EBN industry in detail; reviewed the nutritional compositions, pharmacological actions, identification, inspection and content determination of EBN comprehensively; and prospected the future research directions to provide suggestions for the further study.

Rameli MA, Jaoi Edward M, Mohd Hanafi N, Abdul Aziz S, Abu Hassim H, Mohd Noor MH, Ahmad H. The effects of dietary edible bird nest supplementation on learning and memory functions of multigenerational mice

INTRODUCTION

Edible bird nest (EBN) is a natural food product produced from edible nest swiftlet's saliva which consists of glycoproteins as one of its main components; these glycoproteins contain an abundant of sialic acid. The dietary EBN supplementation has been reported to enhance brain functions in mammals and that the bioactivities and nutritional value of EBN are important during periods of rapid brain growth particularly for preterm infant. However, the effects of EBN in maternal on multigeneration learning and memory function still remain unclear. Thus, the present study aimed to determine the effects of maternal EBN supplementation on learning and memory function of their first (F1)- and second (F2)-generation mice.

METHODS

CJ57BL/6 breeder F0 mice were fed with EBN (10 mg/kg) from different sources. After 6 weeks of diet supplementations, the F0 animals were bred to produce F1 and F2 animals. At 6 weeks of age, the F1 and F2 animals were tested for spatial recognition memory using a Y-maze test. The sialic acid content from EBN and brain gene expression were analyzed using HPLC and PCR, respectively.

RESULTS

All EBN samples contained glycoprotein with high level of sialic acid. Dietary EBN supplementation also showed an upregulation of GNE, ST8SiaIV, SLC17A5, and BDNF mRNA associated with an improvement in Y-maze cognitive performance in both generations of animal. Qualitatively, the densities of synaptic vesicles in the presynaptic terminal were higher in the F1 and F2 animals which might derive from maternal EBN supplementation.

CONCLUSION

This study provided a solid foundation toward the growing research on nutritional intervention from dietary EBN supplementation on cognitive and neurological development in the generation of mammals.

Physicochemical Characteristics of Edible Bird’s Nest Proteins and Their Cooking Processing Properties

Edible bird’s nest (EBN) has a high nutritional and medicinal value. In this study, physicochemical and processing properties of EBN proteins were investigated for better application of EBN. EBN proteins were extracted by combination of several methods. Electrophoresis showed that EBN contained proteins with molecular weight of 128, 106, 80, 55, 43, and 34 kDa. The denaturation temperature of EBN proteins was 62.5°C and heating promoted hydrophobicity as well as dramatically affecting the gel microstructure of EBN proteins. EBN proteins also showed excellent emulsifying activity and stability while their foaming properties were not good enough.

Effect of Maternal Administration of Edible Bird's Nest on the Learning and Memory Abilities of Suckling Offspring in Mice

Although human brains continue developing throughout the underage developmental stages, the infancy period is considered the most important one for the whole life. It has been reported that sialic acid from edible bird's nest (EBN) can facilitate the development of brain and intelligence. In this study, by oral administration of EBN to female mice during the pregnancy or lactation period, the effects of EBN on the levels of sialic acid in mouse milk were determined using high-performance liquid chromatography (HPLC). Furthermore, the spatial learning performances of their offspring were assessed using the Morris water maze test. Additionally, cerebral malondialdehyde (MDA), superoxide dismutase (SOD), choline acetyltransferase (ChAT), and acetylcholinesterase (AChE) in cubs nursed by the female mice given the EBN homogenate were examined, while BDNF immunohistochemical staining and neuron count in hippocampi were investigated as well. These results showed that administration with EBN in maternal mice during pregnancy or lactation period can improve the learning and memory functions in their offspring, possibly by increasing the activities of SOD and ChAT and, at the meantime, decreasing the levels of MDA and activities of AChE. Moreover, BDNF levels for CA1, CA2, and CA3 regions in hippocampi and the numbers of dyed neurons in CA1, CA2, CA3, and DG regions among the offspring were significantly enhanced due to the intake of EBN by the maternal mice. We concluded that maternal administration of EBN during the pregnancy and lactation periods can improve the spatial learning performances in the offspring.

Lactoferrin and ovotransferrin contribute toward antioxidative effects of Edible Bird's Nest against hydrogen peroxide-induced oxidative stress in human SH-SY5Y cells

There are reports of improved redox outcomes due to consumption of Edible Bird's Nest (EBN). Many of the functional effects of EBN can be linked to its high amounts of antioxidants. Interestingly, dietary components with high antioxidants have shown promise in the prevention of aging and its related diseases like Alzheimer's disease. In this study, the antioxidative potentials of EBN and its constituents, lactoferrin (LF) and ovotransferrin (OVF), were determined and protective effects against hydrogen peroxide (H2O2)- induced toxicity on SH-SY5Y cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and acridine orange and propidium iodide (AO/PI) staining with microscopy were examined. Results showed that EBN and its constituents attenuated H2O2-induced cytotoxicity, and decreased radical oxygen species (ROS) through increased scavenging activity. Furthermore, LF, OVF, and EBN produced transcriptional changes in antioxidant related genes that tended towards neuroprotection as compared to H2O2-treated group. Overall, the results suggest that LF and OVF may produce synergistic or all-or-none antioxidative effects in EBN.

Edible bird's nest: food or medicine?

Edible bird's nest (EBN) is derived from the saliva of certain types of swiftlets. It is consumed in many parts of the world for its nutritional and medicinal values. Although many claims have been made on the therapeutic and health-promoting effects of EBN, scientific documentations regarding these effects are very limited in published literature. It is not until recently that the biological effects of EBN are being investigated and evidence-based studies are being conducted. Several studies have found that EBN may enhance cell proliferation and differentiation and various beneficial effects have been reported in vitro as well as in vivo. While these studies point towards the potential use of EBN in the treatment or even prevention of several diseases, the mechanisms of action of EBN remain largely unknown and more explorations are needed. This review is one of the very few scientific reviews on EBN which focuses on recent evidence-based discoveries.

Evaluation of Taurine by HPTLC Reveals the Mask of Adulterated Edible Bird’s Nest

Detection of amino acid is an effective and common method to determine adulteration in edible bird’s nest. Therefore, a simple and sensitive method was developed to detect taurine for determining adulteration in edible bird’s nest in the future. Sample was separated on precoated silica gel GF254 high-performance thin layer chromatographic plates. Separation of taurine was performed by n-propyl alcohol : ethanol : water : glacial acetic acid (5.2 : 0.8 : 2 : 2, v : v : v : v). Densitometric analysis of taurine was carried out in the absorbance mode at 485 nm. The method was validated for precision, intra- and interday variation, and recovery. This study proved that high-performance thin layer chromatography is a simple, rapid, precise, and selective method for qualitative and quantitative analysis of taurine in edible bird’s nest.

Competitive enzyme-linked immunoassay for sialoglycoprotein of edible bird's nest in food and cosmetics

The proliferation of fake and inferior edible bird's nest (EBN) products has recently become an increasingly serious concern. To identify and classify EBN products, a competitive enzyme-linked immunoassay (ELISA) was developed to quantitate sialoglycoprotein in EBN used in food and cosmetic applications. The characteristic sialoglycoprotein in EBN was found, extracted, purified, and analyzed. Sialoglycoprotein, considered the main carrier of sialic acid in EBN, consisted of 106 and 128 kDa proteins. A monoclonal antibody that could recognize both proteins was prepared. The heat-treated process did not change the affinity of sialoglycoprotein with the antibody. An optimized ELISA method was established with a cross-reactivity of less than 0.1% and an IC(50) of 3.3 μg/mL. On the basis of different food and cosmetic samples, the limits of detection (LOD) were 10-18 μg/g. Recoveries of fortified samples at levels of 20 and 80 μg/g ranged from 81.5 to 96.5%, respectively. The coefficients of variation were less than 8.0%.

Edible bird's nest extract inhibits influenza virus infection

Edible bird's nest (EBN) is the nest of the swift that is made from its saliva. Although EBN has been widely used for enhancing immunocompetence, its antiviral efficacy has not been studied in detail. We found that EBN extract could strongly inhibit infection with influenza viruses in a host range-independent manner when it was hydrolyzed with Pancreatin F. Western blotting assay showed that the EBN extract bound to influenza virus. Furthermore, EBN extract could neutralize the infection of MDCK cells with influenza viruses and inhibit hemagglutination of influenza viruses to erythrocytes, but it could not inhibit the activity of influenza virus sialidase. Fluorometric HPLC indicated that the major molecular species of sialic acid in EBN is N-acetylneuraminic acid. The results suggest that EBN is a safe and valid natural source for the prevention of influenza viruses.

Identification of a serine protease inhibitor homologue in Bird's Nest by an integrated proteomics approach

For centuries, the edible nests of Collocalia spp. ("Bird's Nests") have been used as a Chinese delicacy that had been claimed to be an effective health-giving tonic. However, clinical studies indicated that in Singapore, Bird's Nest is the most common cause of food-induced anaphylaxis in children, which could lead to potentially life-threatening allergenic reactions. The purpose of this study was to characterize the major allergens in Bird's Nest by using the combined technologies of two-dimensional gel electrophoresis (2-DE), immunochemistry, N-terminal protein sequencing, and mass spectrometry. Results from the immunostaining of the Western blots of the Bird's Nest 2-DE separated proteins with the sera from allergic patients indicated the presence of a major allergen of 66 kDa. Initial searches of the matrix assisted laser desorption/ionization--time of flight--mass spectrometry (MALDI-TOF-MS) tryptic peptide masses of the allergen in the SWISS-PROT and NCBI nonredundant databases revealed that this protein was novel. Based on the partial protein sequence information obtained from N-terminal microsequencing and nanoelectrospray-tandem MS, the 66 kDa immunoreactive allergen was found to be homologous to ovoinhibitor, a Kazal-type serine protease inhibitor, which is one of the dominant allergens found in chicken egg white.