[Study on changes of Styrax varieties].

Styrax is a commonly used imported traditional Chinese medicinal material in China. It was introduced to China in the Han Dynasty and was first described as a traditional Chinese medicine in Miscellaneous Records of Famous Physicians(Ming Yi Bie Lu). In this paper, by combing ancient and modern Chinese and foreign herbal medicine books and modern literature, combined with the results of field investigations on the origin of Styrax, the changes of Styrax involving the name, quality evaluation, origin, place of origin, and harvesting and processing were systematically verified. The results show that since ancient times, the origin and place of origin of Styrax have been unclear. The medical scientists of all dynasties in China have evaluated the quality of Styrax from four aspects: texture, viscosity, odor concentration, and color. The varieties of Styrax changed twice. The first change may have occurred during the Sui and Tang Dynasties, and the base changed from Styrax officinalis to Liquidambar orientalis. The second change was in modern times, and the base changed from L. orientalis to L. styraciflua. At the same time, the place of origin changed for the first time, from Turkey, Syria, and other countries in southern Asia Minor to Honduras, Guatemala, and other countries in Central America and southern North America. This paper studied the historical evolution of Styrax in terms of quality evaluation, origin, place of origin, character, and harvesting and processing. At the same time, it summarized the application of Styrax in the western countries, which can provide a historical basis for the further development and utilization of Styrax.

[Specific DNA barcodes, germplasm resources, and genetic diversity of Eleutherococcus senticosus].

Eleutherococcus senticosus is one of the Dao-di herbs in northeast China. In this study, the chloroplast genomes of three E. senticosus samples from different genuine producing areas were sequenced and then used for the screening of specific DNA barcodes. The germplasm resources and genetic diversity of E. senticosus were analyzed basing on the specific DNA barcodes. The chloroplast genomes of E. senticosus from different genuine producing areas showed the total length of 156 779-156 781 bp and a typical tetrad structure. Each of the chloroplast genomes carried 132 genes, including 87 protein-coding genes, 37 tRNAs, and 8 rRNAs. The chloroplast genomes were relatively conserved. Sequence analysis of the three chloroplast genomes indicated that atpI, ndhA, ycf1, atpB-rbcL, ndhF-rpl32, petA-psbJ, psbM-psbD, and rps16-psbK can be used as specific DNA barcodes of E. senticosus. In this study, we selected atpI and atpB-rbcL which were 700-800 bp and easy to be amplified for the identification of 184 E. senticosus samples from 13 genuine producing areas. The results demonstrated that 9 and 10 genotypes were identified based on atpI and atpB-rbcL sequences, respectively. Furthermore, the two barcodes identified 23 genotypes which were named H1-H23. The haplotype with the highest proportion and widest distribution was H10, followed by H2. The haplotype diversity and nucleotide diversity were 0.94 and 1.82×10~(-3), respectively, suggesting the high genetic diversity of E. senticosus. The results of the median-joining network analysis showed that the 23 genotypes could be classified into 4 categories. H2 was the oldest haplotype, and it served as the center of the network characterized by starlike radiation, which suggested that population expansion of E. senticosus occurred in the genuine producing areas. This study lays a foundation for the research on the genetic quality and chloroplast genetic engineering of E. senticosus and further research on the genetic mechanism of its population, providing new ideas for studying the genetic evolution of E. senticosus.

Oolong tea: A critical review of processing methods, chemical composition, health effects, and risk.

Oolong tea (OT) is a traditional Chinese tea (Camellia sinensis) and is especially popular in south China. This review is to comprehensively summarize the miscellaneous research that has been done towards to the processing, phytochemistry, health benefit, and risk of OT. These literatures were carried out not only from different electronic databases but also from text books written in English, Japanese, and Chinese, including those traditional records tracing back to the Tang Dynasty (A.D. 618-907). The full process OT producing is depicted below in this review. The phytochemistry of OT has been comprehensively investigated. More than 100 chemical compositions have been isolated and identified. In health benefit, OT performs outstandingly in reducing obesity and controlling diabetes explained by modern pharmacological studies. (-)-Epigallocatechin-3-gallate (6) in OT prevention of cancerous cells developing. OT can also improve and reduce on heart and vascular disease, protect teeth and bone, function as anti-oxidative and antibacterial agents. This review also mentioned the risk, summarized briefly on various forms of toxicity and harmful associated with OT. In short, this review can provided a natural product library of OT, gave inspirations for further new garden systems, designed idea on quality, bioactivity-oriented screening. In addition, it is suggested more scientists and education is necessary to guarantee the stability and safety of drinking OT.

Tissue-Specific Analysis of Secondary Metabolites Creates a Reliable Morphological Criterion for Quality Grading of Polygoni Multiflori Radix.

In commercial herbal markets, Polygoni Multiflori Radix (PMR, the tuberous roots of Polygonum multiflorum Thunb.), a commonly-used Chinese medicinal material, is divided into different grades based on morphological features of size and weight. While more weight and larger size command a higher price, there is no scientific data confirming that the more expensive roots are in fact of better quality. To assess the inherent quality of various grades and of various tissues in PMR and to find reliable morphological indicators of quality, a method combining laser microdissection (LMD) and ultra-performance liquid chromatography triple-quadrupole mass spectrometry (UPLC-QqQ-MS/MS) was applied. Twelve major chemical components were quantitatively determined in both whole material and different tissues of PMR. Determination of the whole material revealed that traditional commercial grades based on size and weight of PRM did not correspond to any significant differences in chemical content. Instead, tissue-specific analysis indicated that the morphological features could be linked with quality in a new way. That is, PMR with broader cork and phloem, as seen in a transverse section, were typically of better quality as these parts are where the bioactive components accumulate. The tissue-specific analysis of secondary metabolites creates a reliable morphological criterion for quality grading of PMR.

Correlation between Quality and Geographical Origins of Poria cocos Revealed by Qualitative Fingerprint Profiling and Quantitative Determination of Triterpenoid Acids.

Poria cocos (Schw.) Wolf (PC) is a well-known saprophytic fungus, and its sclerotium without the epidermis (PCS) is widely used in traditional Chinese medicine and as a functional food in many countries. PCS is normally collected from multiple geographical regions, but whether and how the quality of PCS correlates with where it grows have not been determined. This correlation could be significant both for quality control and optimum utilization of PCS as a natural resource. In this study, a qualitative fingerprint profiling method performed by ultra-performance liquid chromatography (UHPLC) with diode array detection (DAD) combining quadrupole time-of-flight-mass spectrometry (QTOF-MS/MS) and a quantitative UHPLC coupled with triple quadrupole mass spectrometry (QqQ-MS/MS) approach were established to investigate whether and how the quality of PCS correlates with its collection location. A standard fingerprint of PCS was generated by median simulation of 25 tested samples collected from four main producing areas of China, and similarity analysis was applied to evaluate the similarities between the fingerprints of samples and the standard fingerprint. Twenty three common peaks occurring in the fingerprint were unequivocally or tentatively identified by UHPLC-QTOF-MS/MS. Meanwhile, principal component analysis (PCA), supervised orthogonal partial least squares-discriminate analysis (OPLS-DA) and hierarchical cluster analysis (HCA) were employed to classify 25 batches of PCS samples into four groups, which were highly consistent with the four geographical regions. Ten compounds were screened out as potential markers to distinguish the quality of PCS. Nine triterpene acids, including five compounds that played important roles in the clusters between different samples collected from the four collection locations, were simultaneously quantified by using the multiple reaction monitoring (MRM) mode of UHPLC-QqQ-MS/MS. The current strategy not only clearly expounded the correlation between quality and geographical origins of PCS, but also provided a fast, accurate and comprehensive qualitative and quantitative method for assessing the quality of PCS.

Multiconstituent identification in root, branch, and leaf extracts of Juglans mandshurica using ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

As a traditional medicinal plant, Juglans mandshurica has been used for the treatment of cancer. Different organs of this plant showed anti-tumor activity in clinic and laboratory. Comparative identification of constituents in different plant organs is essential for investigation of the relationship between chemical constituents and pharmacological activities. For this aim, the roots, branches, and leaves of J. mandshurica were extracted with 50% v/v methanol and then subjected to ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry analysis conducted under low and high energy. As a result, we have to date identified 111 compounds consisting of 56 tannins, 29 flavonoids, 13 organic acids, 8 naphthalene derivatives, and 5 anthracenes. Five compounds, namely, diquercetin trihydroxy-truxinoyl-glucoside, two quercetin kaempferol dihydroxy-truxinoyl-glucosides, syringoyl-tri-galloyl-O-glucose, and dihydroxy-naphthalene syringoyl-glucoside, were tentatively identified as new compounds. Of the compounds identified, 76 were found in the root extract, 67 in the branch extract, and 37 in the leaf extract. Only six compounds including four organic acids and two tannins were found in all three extracts. We developed a rapid and sensitive ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry approach to identify multiple constituents of complex extracts without separation and ion selection. The results presented provide useful information on further research of the bioactive compounds of J. mandshurica.

Comparison of chemical profiles between the root and aerial parts from three Bupleurum species based on a UHPLC-QTOF-MS metabolomics approach.

BACKGROUND: Bupleuri Radix (Chaihu) represents one of the most successful and widely used herbal medicines in Asia for the treatment of many diseases such as inflammatory disorders and infectious diseases over the past 2000 years. In the Chinese Pharmacopoeia, Chaihu is recorded as the dried roots of Bupleurum chinense DC. and B. scorzonerifolium Willd. (Umbelliferae). However, the widespread demand for the herb has tended to far outstrip the supply. Whether the aerial parts, which account for 70 ~ 85% of the dry weights of Bupleurum species, could be used as an alternative for the root has become an important scientific issue for the sustainable utilization of Bupleurum species. On the other hand, in some areas including the southeast of China as well as in Spain, the aerial parts of Bupleurum species have already been used in the folk medications. Therefore, to clarify whether the root and aerial parts of Bupleurum species are "equivalent" in the types and quantities of chemical constituents which subsequently influence their biological activities and therapeutic effects is of great importance for both the rational and sustainable use of this herb. METHODS: In the present study, the chemical profiles between the root and aerial parts of Bupleurum species from different species and collected from various locations were analyzed and compared by the ultra-high performance liquid chromatography quadrupole/time of flight-mass spectrometry (UHPLC-QTOF-MS). RESULTS: A total of 56 peaks were identified in the root and/or aerial parts from different batches of Bupleurum species, by comparison of references standards or with those reported in the literature. Principal Component Analysis (PCA) was conducted for displaying the differentiating clustering between these two parts. CONCLUSION: The results disclosed the distinct variations between them, which indicated that the aerial parts could not be used as an alternative of root from a chemodiversity perspective. The differentiating markers resulted from the PCA analysis could also be utilized for the differentiation between them. Further validation of their biological differences is anticipated in the future study.

The Potential Impact of Radix Paeoniae Alba in Embryonic Development of Mice.

Although Radix Paeoniae Alba (RPA) has been ranked as one of the top 6 herbs used frequently to prevent and treat miscarriages clinically, there is no clear evidence regarding its safety in embryonic development. This study aims to evaluate the potential impacts of RPA on embryonic stem cells (ESCs) and pregnant mice. Cytotoxicity assays of the extract were performed in ESCs and 3T3 cells. Pregnant ICR mice were orally treated with RPA extracts at dosages of 0 (G1 group as negative controls), 2, 8 and 32 g/kg/day (G2, G3 and G4 groups) respectively from the gestation day (Gd) 6-15. On Gd 18, there was no significant difference in the IC50 values between ESCs and 3T3 cells (p > 0.05). There was no significant difference in the maternal and fetal evaluations among four groups (p > 0.05). Fetal IL-2, IL-2r, TNF-α, TNF-αr, IL-4, IL-4r, IL-10r, IL-17 and IL-17r of G4 group were significantly lower than G1 group (p < 0.05). In conclusion, RPA at dosage of 32 g/kg/day (16-folds of human daily dosage) did not cause adverse impact in cultured ESCs and pregnant mice. RPA might down-regulate fetal Th1/Th2/Th17 cytokines and receptors maybe beneficial to embryonic survival and development. Copyright © 2017 John Wiley & Sons, Ltd.

[Investigation of genus Ardisia in Bencao literature].

Based on a systematic review of morphology and distribution of plants, alternate names, actions, and properties of herbs recorded in ancient and modern literatures, in combination of field investigation, 18 Chinese herbal medicines recorded in ancient bencao literature were regarded to be derived from 7 species in the Ardisia genus. Among them, the variety Ardisia crenata f. hortensis was identified as the source of Zhushagen and Zijinniu. A. hanceana is referenced as Tiesan in the illustrated atlas of Botanical Nomenclature (Zhiwu Mingshi Tukao). The name Pingdimu refers to a different substance in the illustrated atlas of Botanical Nomenclature and the Flower Mirror (Huajing). The medicinals named Yedihong, Aicha, and Duanjiao sanlangare all derived from A. japonica. The origin of the herb Xiaoqing referenced in the Illustrated Classic of the Materia Medica (Bencao Tujing) is A. pusilla. The medicinals Bailiangjin, Jiuguanxue and Zoumatai are derived from A. crispa, A. brevicaulis, and A. gigantifolia, respectively. This investigation clarifies the botanical sources and actions of related Chinese medicinal materials in the genus Ardisia, and provides clues and evidence for utilizing and developing their medicinal plant resources.

Neuroprotective effect of a novel Chinese herbal decoction on cultured neurons and cerebral ischemic rats.

BACKGROUND: Historically, traditional Chinese medicine has been widely used to treat stroke. Based on the theory of Chinese medicine and the modern pharmacological knowledge of herbal medicines, we have designed a neuroprotective formula called Post-Stroke Rehabilitation (PSR), comprising seven herbs - Astragalus membranaceus (Fisch.) Bunge, Salvia miltiorrhiza Bunge, Paeonia lactiflora Pall., Cassia obtusifolia L., Ligusticum chuanxiong Hort., Angelica sinensis (Oliv.) Diels, and Glycyrrhiza uralensis Fisch. We aim to examine the neuroprotective activity of PSR in vitro and in vivo, and to explore the underlying molecular mechanisms, to better understand its therapeutic effect and to further optimize its efficacy. METHODS: PSR extract or vehicle was applied to primary rat neurons to examine their survival effects against N-methyl-D-aspartate (NMDA)-elicited excitotoxicity. Whole-cell patch-clamp recording was conducted to examine the NMDA-induced current in the presence of PSR. ERK- and CREB-activation were revealed by western blot analysis. Furthermore, PSR was tested for CRE promoter activation in neurons transfected with a luciferase reporter. The protective effect of PSR was then studied in the rat middle cerebral artery occlusion (MCAO) model. MCAO rats were either treated with PSR extract or vehicle, and their neurobehavioral deficit and cerebral infarct were evaluated. Statistical differences were analyzed by ANOVA or t-test. RESULTS: PSR prominently reduced the death of cultured neurons caused by NMDA excitotoxicity in a dose-dependent manner, indicating its neuroprotective property. Furthermore, PSR significantly reduced NMDA-evoked current reversibly and activated phosphorylation of ERK and CREB with distinct time courses, with the latter's kinetics slower. PSR also triggered CRE-promoter activity as revealed by the increased expression of luciferase reporter in transfected neurons. PSR effectively reduced cerebral infarct and deficit in neurological behavior in MCAO rats when PSR decoction was administered starting either 6 days before or 6 h after onset of ischemia. CONCLUSIONS: PSR is neuroprotective both in vitro and in vivo - it protects cultured neurons against NMDA excitotoxicity, and effectively reduces ischemic injury and neurobehavioral deficit in MCAO rats in both the pre- and post-treatment regimens. The underlying neuroprotective mechanisms may involve inhibition of NMDA receptor current and activation of ERK and CREB. This study provides important preclinical data necessary for the further development of PSR for stroke treatment.

Ultrasound-Assisted Extraction May Not Be a Better Alternative Approach than Conventional Boiling for Extracting Polysaccharides from Herbal Medicines.

In clinical practice polysaccharides from herbal medicines are conventionally prepared by boiling water extraction (BWE), while ultrasound-assisted extraction (UAE) has often been used instead employed in laboratory research due to its strong extraction ability and efficiency. However, if and how the polysaccharides obtained by UAE and BWE are comparable, and hence whether the UAE-based research is instructive for the actual usage of herbal polysaccharides still requires further evaluation. To address this issue, here we chemically analyzed and compared the UAE- and BWE-obtained polysaccharides from three herbal medicines, i.e., Ginseng Radix, Astragali Radix and Dendrobii Officinalis Caulis. Then, the spike recovery of two series of standard dextran and pullulan by UAE and BWE was tested. The results showed that the polysaccharides from the herbal medicines by UAE were quantitatively and qualitatively different with those by BWE. The powerful extraction ability and polysaccharide degradation caused by ultrasound collectively contributed to these differences. It was then revealed that not only the UAE conditions but also the polysaccharide structures could affect the extraction ability and polysaccharide degradation. Given these, we highly recommended that the effects of UAE on polysaccharides from herbal medicines should be first carefully considered before employing it in relevant chemical and pharmacological analysis.

[Transmission and development of foreign medicinal materials in the Tang and Song Dynasties].

Many foreign medicinal materials that were imported to China via the Silk Road and maritime trade have enriched Chinese medicine. Imported foreign medicines reached a high point by the Tang and Song Dynasties, particularly in the case of aromatic medicines, which supplemented domestic Chinese aromatics and were widely employed in official dispensaries in the Song Dynasty. This study investigated historical records related to imported Chinese medicines in the Tang and Song periods, focusing on their varieties, quantity, use, and localization trends. Foreign medicines were assimilated as Chinese medical theory was applied to interpret their effects, and aromatics such as frankincense that were extremely expensive in the Tang Dynasty became accessible to common people by the Song Dynasty. By the Song Dynasty, some foreign medicines began to be domestically cultivated and the boundary between foreign and traditional Chinese medicines became blurred; foreign medicines gradually transformed into Chinese medicines. The importation of foreign medicines during the Tang and Song Dynasties was a historical turning point that contributed greatly to the development of traditional Chinese medicine.

[Bencao literature investigation of Polygonum multiflorum (Heshouwu)].

Heshouwu, derived from the root of Polygonum multiflorum (=Fallopia multiflora), is widely used in the Chinese medicine market as a traditional tonic. The emergence of heshouwu material with a human shape reflects a pursuit of its supplementing effects. However, reports of Heshouwu toxicity have repeatedly surfaced in recent years, attracting widespread concern. To clarify the situation surrounding the safety and efficacy of Heshouwu, this research utilizes a systematic review of the text and illustrations in historical bencao (materia medica) literature to investigate the origin, botanical characteristics, actions and processing of Heshouwu, as well as the origin and historical evolution of Baishouwu ("white Heshouwu").

Combinational Treatment of Curcumin and Quercetin against Gastric Cancer MGC-803 Cells in Vitro.

Gastric cancer remains a major health problem worldwide. Natural products, with stronger antitumor activity and fewer side effects, are potential candidates for pharmaceutical development as anticancer agents. In this study, quercetin and curcumin were chosen for testing and were applied separately and in combination to human gastric cancer MGC-803 cells. The MTT assay was used to evaluate cell growth inhibition. Annexin V-FITC/PI was carried out to measure apoptosis rate. Flow cytometry was performed to analyze mitochondrial membrane potential levels. Western blots were applied to detect expression of cytochrome c, total and phosphorylated ERK and AKT. Combined treatment with curcumin and quercetin resulted in significant inhibition of cell proliferation, accompanied by loss of mitochondrial membrane potential (ΔΨm), release of cytochrome c and decreased phosphorylation of AKT and ERK. These results indicate that the combination of curcumin and quercetin induces apoptosis through the mitochondrial pathway. Notably, effect of combined treatment with curcumin and quercetin on gastric cancer MGC-803 cells is stronger than that of individual treatment, indicating that curcumin and quercetin combinations have potential as anti-gastric cancer drugs for further development.

[Identification of ancient Chinese medicinal specimens preserved at Natural History Museum in London].

On-site field investigation was conducted to authenticate a batch of ancient Chinese medicinal decoction pieces that have been preserved in a rare collection at the Natural History Museum in London. These treasured artifacts comprise a portion of the Sloane Collection, and the nearly one hundred Chinese medicinal specimens examined within provide an objective record of the real situation regarding the Chinese medicinal materials in commercial circulation three hundred years ago. The precious data from this collection pro-vides an extremely valuable reference for the research into the history of medicinal exchange between China and the West during the Age of Exploration, shedding light on the evolution and historical changes in the species used in Chinese medicine, as well as the history of medicinal processing and decoction pieces.

[Metabolites Identification for Alkaloids from Nelumbinis Plumula in Caco-2 Cells by LC/MS/MS].

OBJECTIVE: To identify the metabolites of norcoclaurine,liensinine, isoliensinine and neferine in Caco-2 cells by LC/ MS/MS. METHODS: After Caco-2 cells were treated with norcoclaurine, liensinine, isoliensinine or neferine for 3, 6 and 12 h, samples were collected, purified and then analyzed by LC/MS/MS. The structures of the metabolites were elucidated by molecular masses, retention times, MS and MS/MS spectra comparing with those of the parent drug. RESULTS: The procedure identified that the major metabolites of norcoclaurine were methylnorcoclaurine and norcoclaurine-glucuronide, the major metabolite of liensinine was demethyl-liensinine, the major metabolite of isoliensinine was demethyl-isoliensinine, the major metabolites of neferine were liensinine, isoliensinine and their further demethylation products. CONCLUSION: LC/MS/MS is simple, rapid and sensitive for the metabolites identification. Methylation, demethylation and glucuronidation are main metabolic pathways of alkaloids from Nelumbinis Plumula in Caco-2 cells.

[Inheritance and innovation of traditional Chinese medicinal authentication].

Chinese medicinal authentication is fundamental for the standardization and globalization of Chinese medicine. The discipline of authentication addresses difficult issues that have remained unresolved for thousands of years, and is essential for preserving safety. Chinese medicinal authentication has both scientific and traditional cultural connotations; the use of scientific methods to elucidate traditional experience-based differentiation carries the legacy of Chinese medicine forward, and offers immediate practical significance and long-term scientific value. In this paper, a path of inheritance and innovation is explored through the scientific exposition of Chinese medicinal authentication, featuring a review of specialized publications, the establishment of a Chinese medicine specimen center and Chinese medicinal image databases, the expansion of authentication technologies, and the formation of a cultural project dedicated to the Compedium of Materia Medica.

Comparative analysis of diosgenin in Dioscorea species and related medicinal plants by UPLC-DAD-MS.

BACKGROUND: Dioscorea is a genus of flowering plants, and some Dioscorea species are known and used as a source for the steroidal sapogenin diosgenin. To screen potential resource from Dioscorea species and related medicinal plants for diosgenin extraction, a rapid method to compare the contents of diosgenin in various plants is crucial. RESULTS: An ultra-performance liquid chromatography (UPLC) coupled with diode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS) method was developed for identification and determination of diosgenin in various plants. A comprehensive validation of the developed method was conducted. Twenty-four batches of plant samples from four Dioscorea species, one Smilax species and two Heterosmilax species were analyzed by using the developed method.The present method presented good sensitivity, precision and accuracy. Diosgenin was found in three Dioscorea species and one Heterosmilax species, namely D. zingiberensis, D. septemloba, D. collettii and H. yunnanensis. CONCLUSION: The method is suitable for the screening of diosgenin resources from plants. D. zingiberensis is an important resource for diosgenin harvesting.

A novel and rapid HPGPC-based strategy for quality control of saccharide-dominant herbal materials: Dendrobium officinale, a case study.

Qualitative and quantitative characterization of natural saccharides, especially polysaccharides, in herb materials remains a challenge due to their complicated structures and high macromolecular masses. Currently available methods involve time-consuming and complicated operations, and present poor specificity. Here, a novel and rapid high-performance gel permeation chromatography (HPGPC)-based approach is described for quality assessment of saccharide-dominant herbal materials by simultaneous qualitative and quantitative analysis of saccharide components. Dendrobium officinale, one of the rarest tonic herbs worldwide, was employed as the model herb in this study. First, a HPGPC fingerprint based on the molecular weight distribution of its carbohydrate components was established for qualitative identification of D. officinale. Then, HPGPC-guided dominant holistic polysaccharide marker was separated using ultra-filtration followed by HPGPC determination for quantitative evaluation of D. officinale. The experimental results suggest that this method is more efficient, stable, and convenient compared with the currently available methods for authentication and quality evaluation of D. officinale, and we expect the method will have similar advantages when used for quality control of other saccharide-dominant herbal materials and products.

Comparative analysis of EPA and DHA in fish oil nutritional capsules by GC-MS.

BACKGROUND: Fish oil is a popular nutritional product consumed in Hong Kong. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the two main bioactive components responsible for the health benefits of fish oil. Market survey in Hong Kong demonstrated that various fish oil capsules with different origins and prices are sold simultaneously. However, these capsules are labelled with same ingredient levels, namely EPA 180 mg/g and DHA 120 mg/g. This situation makes the consumers very confused. To evaluate the quality of various fish oil capsules, a comparative analysis of the contents of EPA and DHA in fish oil is crucial. METHODS: A gas chromatography-mass spectrometry (GC-MS) method was developed for identification and determination of EPA and DHA in fish oil capsules. A comprehensive validation of the developed method was conducted. Ten batches of fish oil capsules samples purchased from drugstores of Hong Kong were analyzed by using the developed method. RESULTS: The present method presented good sensitivity, precision and accuracy. The limits of detection (LOD) for EPA and DHA were 0.08 ng and 0.21 ng, respectively. The relative standard deviation (RSD) values of EPA and DHA for repeatability tests were both less than 1.05%; and the recovery for accuracy test of EPA and DHA were 100.50% and 103.83%, respectively. In ten fish oil samples, the contents of EPA ranged from 39.52 mg/g to 509.16 mg/g, and the contents of DHA ranged from 35.14 mg/g to 645.70 mg/g. CONCLUSION: The present method is suitable for the quantitative analysis of EPA and DHA in fish oil capsules. There is a significant variation in the contents of the quantified components in fish oil samples, and there is not a linear relationship between price and contents of EPA and DHA. Strict supervision of the labelling of the fish oil capsules is urgently needed.