Name: source and route of pyrrolizidine alkaloid contamination in tea samples
Uploaded: 2022-09-28T14:00:00
Description: Watch this Scientific Journal Video about Source and Route of Pyrrolizidine Alkaloid Contamination in Tea Samples at JoVE.com

This work was supported by the National Natural Scientific Foundation of China (32102244), the National Agricultural Products Quality and Safety and Risk Assessment Project (GJFP2021001), the Natural Scientific Foundation of Anhui Province (19252002), and the USDA (HAW05020H).

For the present study, the following weed species were collected: Ludwigia prostrata Roxb., Murdannia triquetra (Wall. ex C. B. Clarke) Bruckn., Ageratum conyzoides L., Chenopodium ambrosioides, Trachelospermum jasminoide (L.) Lem., Ageratum conyzoides L., Emilia sonchifolia (L.) DC, Ageratum conyzoides L., and Crassocephalum crepidioides (Benth.) S. Moore. The fresh tea leaves were picked from the variety of Longjing 43# tea tree...

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The present work was designed to develop an effective, sensitive method to explore the contamination routes and sources of PAs in tea samples as well as the distribution of PAs in different parts of the tea plants. However, in this study, only 15 PAs were successfully separated on the chromatographic column, which is a very small number in comparison to the large number of alkaloids in plant species3,4. This was not only related to the packing properties of the c...

As secondary metabolites, pyrrolizidine alkaloids (PAs) protect plants against herbivores, insects, and pathogens1,2. Up to now, over 660 PAs and PA-N-oxides (PANOs) with different structures have been found in more than 6,000 plant species worldwide3,4. PA-producing plants are mainly found in the families Asteraceae, Boraginaceae, Fabaceae, and Apocynaceae5,6. PAs are easily oxidized to unstable dehydropyrrolizidine alkaloids, which have strong electrophilicity and can attack nucleophiles such as DNA and proteins, resulting in liver cell necrosis, venous occlusions, cirrhosis, ascites, and other symptoms7,8. The main target organ of PA toxicity is the liver. PAs can also cause lung, kidney, and other organ toxicity and mutagenic, carcinogenic, and developmental toxicity9,10.
Cases of human and animal poisoning have been reported in many countries from the ingestion of traditional herbs, supplements, or teas containing PAs or the indirect contamination of foods such as milk, honey, or meat (toxic from ingestion of pasturage containing PAs)11,12,13. The European Food Safety Authority (EFSA) findings indicate that substances such as (herbal) tea are an important source of human exposure to PAs/PANOs14. Tea samples do not produce PAs, whereas PA-producing plants are commonly found in tea gardens (e.g., Emilia sonchifolia, Senecio angulatus, and Ageratum conyzoides)15. It was previously suspected that the tea could be contaminated with PAs from their producing plants during picking and processing. However, PAs were also detected in some hand-picked tea leaves (i.e., no PA-producing plants), suggesting there must be other routes or sources of contamination16. A co-cultivation experiment of ragwort (Senecio jacobaea) with melissa (Melissa officinalis), peppermint (Mentha piperita), parsley (Petroselinum crispum), chamomile (Matricaria recutita), and nasturtium (Tropaeolum majus) plants was conducted, and the results showed that PAs were detected in all these plants17. It has been verified that PAs are indeed transferred and exchanged between living plants via soil18,19. Van Wyk et al.20 found that rooibos tea (Aspalathus linearis) was severely contaminated in weed-rich sites and contained PAs of the same type and proportion. However, no PAs were detected in rooibos tea in weed-free sites.
At present, ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) with high selectivity and sensitivity has been widely used in the qualitative and quantitative analysis of PAs in agricultural products and food21,22. The sample treatment method is usually comprised of either solid phase extraction (SPE) or the QuEChERS (Quick Easy Cheap Effective Rugged Safe) clean-up of complex food matrices extracts, which can obtain the highest possible sensitivity12,19. However, robust analytical methods allowing the detection and quantification of PAs in complex matrices like soil, weeds, and fresh tea leaves are still missing.
This study analyzed 15 PAs in dried tea samples, fresh tea leaves, weeds, and weed rhizospheric soil samples with UPLC-MS/MS combined with an adsorbent purification method. Furthermore, 15 paired weed and weed rhizospheric soil samples and 60 fresh tea leaf samples were collected from five sampling sites in Jinzhai tea garden in Anhui Province, China, and were analyzed for 15 PAs. These results can provide a survey method and some information on the source and route of PAs (contamination) in tea samples to ensure the quality and safety of tea.

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			<td>Lvming, Qingshan, Luyuchun, Changling, Huixing, Wuyunjian, Heshengchun</td>
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			<td>cence</td>
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			<td>Max:16000 r/min, 330 &#215; 390 &#215; 300 mm (L &#215; W &#215; H), Capacity: 6 &#215; 50 mL</td>
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			<td>HSS T3 column</td>
			<td>Waters</td>
			<td>186004976</td>
			<td>ACQUITY UPLC HSS T3 (2.1 &#215; 100 mm 1.8 &#956;m)</td>
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			<td>40-60 &#956;m, 60 &#197; 100g.per box</td>
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			<td>Cation Mixed Mode, 6 mL</td>
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			<td>Inner slot size: 500 &#215; 300 &#215; 150 mm; Capacity: 22.5 L</td>
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			<td>UPLC-xevoTQMS</td>
			<td>Waters</td>
			<td>ZPLYY-003</td>
			<td>Triple four-stage rod mass analyzer, Waters Alliance 2695/Waters ACQUITY UPLC Liquid Phase System</td>
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			<td>Guoyu instrument</td>
			<td>SHY-2AHS</td>
			<td>Oscillation times:&#160; 60-300 times/min, Constant temperature range: room temperature to 100 &#176;C</td>
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source and route of pyrrolizidine alkaloid contamination in tea samples

Toxic pyrrolizidine alkaloids (PAs) are found in tea samples, which pose a threat to human health. However, the source and route of PA contamination in tea samples have remained unclear. In this work, an adsorbent method combined with UPLC-MS/MS was developed to determine 15 PAs in the weed Ageratum conyzoides L., A. conyzoides rhizospheric soil, fresh tea leaves, and dried tea samples. The average recoveries ranged from 78%-111%, with relative standard deviations of 0.33%-14.8%. Fifteen pairs of A. conyzoides and A. conyzoides rhizospheric soil&#160;samples and 60 fresh tea leaf samples were collected from the Jinzhai tea garden in Anhui Province, China, and analyzed for the 15 PAs. Not all 15 PAs were detected in fresh tea leaves, except for intermedine-N-oxide (ImNO) and senecionine (Sn). The content of ImNO (34.7 &#181;g/kg) was greater than that of Sn (9.69 &#181;g/kg). In addition, both ImNO and Sn were concentrated in the young leaves of the tea plant, while their content was lower in the old leaves. The results indicated that the PAs in tea were transferred through the path of PA-producing weeds-soil-fresh tea leaves in tea gardens.

The optimized adsorbent purification and analysis method of 15 PAs in dried tea samples, fresh tea leaves, weeds, and soil was established and compared with the commonly used purification method using the SPE cartridge. The results showed that the recoveries of the 15 PAs in dried tea samples, weed, and fresh tea leaves using the SPE cartridge were 72%-120%, while that using adsorbent purification was 78%-98% (Figure 1). The recoveries of the 15 PAs in soil using adsorbent purification were ...

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Source and Route of Pyrrolizidine Alkaloid Contamination in Tea Samples

The present protocol describes the contamination of pyrrolizidine alkaloids (PAs) in tea samples from PA-producing weeds in tea gardens.

Toxic pyrrolizidine alkaloids (PAs) are found in tea samples, which pose a threat to human health. However, the source and route of PA contamination in ...

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