Novel Arsenic Markers for Discriminating Wild and Cultivated Cordyceps

Arsenic transfer along the soil-sclerotium-stroma chain in Chinese cordyceps and the related health risk assessment

Background

Chinese cordyceps (Lepidoptera: Ophiocordyceps sinensis)is a larval-fungus complex. The concentration and distribution of arsenic (As) may vary during the stroma (ST) germination process and between the sclerotium (SC) and the ST. The soil-to-Chinese cordyceps system is an environmental arsenic exposure pathway for humans. We studied the As concentration in the soil, the SC, and the ST of Chinese cordyceps, and performed a risk assessment.

Methods

Soil and Chinese cordyceps samples were collected from the Tibetan Plateau in China. The samples were analyzed for the total As concentration and As species determination, which were conducted by inductively coupled plasma mass spectrometry (ICP-MS) and HPLC-ICP-MS, respectively.

Results

The concentration of total As in the soil was much higher than in SC and ST. The major As species in the soil was inorganic As^V. In SC and ST, organic As was predominant, and the majority of As was an unknown organic form. There are significant differences in the As distribution and composition in soil, SC, and ST. Our risk assessment indicated that chronic daily ingestion was higher than inhalation and dermal exposure in children and adults. The hazard index (HI) of the non-carcinogenic and cancer risks (CR) for human health were HI ≤ 1 and CR < 1 × 10^-4, respectively.

Conclusion

The Chinese cordyceps possesses highly-efficient detoxifying characteristics and has a significant role in As transformation during its life cycle. We found that the levels of As in soils from the habitat of Chinese cordyceps were higher than the soil background values in China, but the probability for incurring health risks remained within the acceptable levels for humans.

Arsenocholine-O-sulfate: A novel compound as major arsenic species in the parasitic mushroom Tolypocladium ophioglossoides

The As concentrations, along with 34 other elements, and the As speciation were investigated in wild-grown samples of the parasitic mushroom Tolypocladium ophioglossoides with inductively coupled plasma mass spectrometry (ICPMS) and high performance liquid chromatography coupled to ICPMS. The As concentrations were 0.070-3.44 mg kg^-1 dry mass. More remarkable was the As speciation, where up to 56% of the extracted As were found to be an unknown As species, which was marginally retained under anion- and also cation-exchange conditions. After testing several different chromatographic settings, the compound was finally isolated and identified as 2-(sulfoxyethyl) trimethylarsonium ion (in short: arsenocholine-O-sulfate) with high resolution mass spectrometry. The compound was synthesized and further quantified in all investigated samples via ion-pair chromatography coupled to ICPMS. In addition to the high abundance of arsenocholine-O-sulfate in T. ophioglossoides, small amounts of this As species were also detected in one sample of the host mushroom, Elaphomyces asperulus. In a sample of another parasitic mushroom, Ophiocordyceps sinensis, arsenocholine-O-sulfate could not be detected, but the main species was another unknown compound that was oxidized to inorganic As(V) with hydrogen peroxide. This is the first discovery of arsenocholine-O-sulfate in nature. It is possible that it is present in many other organisms, at least in low concentrations, and just has not been detected there yet because of its unusual chromatographic behavior. The existence of arsenocholine-O-sulfate brings up questions again about the biotransformation pathways of As in the environment and the specific behavior of fungi.

Comparative study of the composition of cultivated, naturally grown Cordyceps sinensis, and stiff worms across different sampling years

Natural Cordyceps sinensis, which is a valuable anti-tumor, immunomodulatory, and antiviral agent in Asia, has been overexploited in recent years. Therefore, it is important for cultivated C. sinensis to be recognized in the market. In this research, the main components of entirely cultivated, naturally grown C. sinensis, and stiff worms across different sampling years were detected and compared by HPLC-MS and UV spectrometry. The results indicated that the mean levels of adenosine and cordycepin were significantly higher, whereas the mean levels of mannitol and polysaccharides were remarkably lower in the cultivated type than in the natural type. No distinct difference in the average soluble protein content was observed. The composition of the stiff worms was similar to that of the natural herb, except that the total soluble protein content was higher, and that of mannitol was lower. In addition, the ultraviolet absorption spectroscopy of the three types showed high similarity at 260 nm. This research indicates that the main nutritional composition of cultivated and natural C. sinensis is identical and that cultivated type can be used as an effective substitute.