title: Effect of drying methods on the free and conjugated bufadienolide content in toad venom determined by ultra-performance liquid chromatography-triple quadrupole mass spectrometry coupled with a pattern recognition approach.
abstract: Drying is a useful technique for extending the shelf-life of biological products and enabling long-term storage; however, improper drying can reduce the chemical quality of the products. In this study, we used ultra-performance liquid chromatography-triple quadrupole/mass spectrometry (LC-MS/MS) and multivariate statistical analysis to investigate the effects of four drying methods (V: vacuum-drying at 60°C, F: freeze-drying, H: air-drying at 60°C and R: air-drying at room temperature) on the levels of 36 bufadienolides in toad venom. Vacuum-drying at 60°C produced the highest quality dried toad venom in terms of total bufadienolide content, whereas traditional air-drying at room temperature (RT) to dehydrate the toad venom led to a dramatic loss in free and conjugated bufadienolides, reaching up to 60% and 70%, respectively. Assaying for free bufadienolides ranked the drying methods as V≈F>H>R, whereas assaying for conjugated bufadienolides slightly changed the order to V>F≈H>R. Furthermore, we identified 21 bufadienolides as biomarkers responsible for the decline in the quality of dried toad venom, whose loss varied from 1.5-fold to 100-fold. Of these biomarkers, group I bufadienolides that contain 16-OAc (e.g., cinobufagin and its hydroxyl or arginine ester derivatives) were characteristic components and were reduced to trace levels (loss of more than 10-fold) following traditional air-drying at RT. This might be attributed to the fact that most enzyme-sensitive bufadienolides were biotransformed or degraded at room temperature but were retained using other drying methods.
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China. Electronic address: hongyuema@126.com.
authors.forename: Hongyue
authors.initials: H
authors.lastname: Ma
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Honglan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Qian
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wen
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Liu
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Jinao
authors.initials: J
authors.lastname: Duan
authors.affiliation: Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal, Resources Industrialization and Formulae Innovative Medicine, and Jiangsu Key Laboratory for High Technology Research of TCM Formulae, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China. Electronic address: qnwyjs@163.com.
authors.forename: Qinan
authors.initials: Q
authors.lastname: Wu
mesh_terms: D000664:Amphibian Venoms / Q000737:chemistry*; D000818:Animals; D015415:Biomarkers / Q000737:chemistry; D002018:Bufanolides / Q000032:analysis* / Q000737:chemistry; D002025:Bufonidae; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003890:Desiccation; D004365:Drugs, Chinese Herbal / Q000032:analysis*; D005612:Freeze Drying; D008516:Medicine, Chinese Traditional; D015999:Multivariate Analysis; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013696:Temperature
chemical_list: D000664:Amphibian Venoms; D015415:Biomarkers; D002018:Bufanolides; D004365:Drugs, Chinese Herbal; C087925:bufadienolide; C002471:cinobufagin
keywords: Bufadienolides; Drying methods; LC–MS/MS; Multivariate statistical analysis