B-052 Establishment of New Antibodies and ELISA System to Detect the Potato Alkaloids α-Solanine and α-Chaconine

Abstract

Abstract Background Food poisoning by potato alkaloids, α-solanine (SO) and α-chaconine (CHA), currently occurs worldwide, however laboratory methods have not yet been established to detect these toxins in biological samples. In this study, we established new antibodies to detect SO and CHA and evaluated the practicality of enzyme-linked immunosorbent assays (ELISAs) using these antibodies in laboratory medicine. Methods Solanidine, a chemical compound found in both SO and CHA, was conjugated with bovine albumin, and this complex was repeatedly injected into two rabbits for two months. Two types of polyclonal solanidine antibodies were then purified from rabbit serum using affinity column chromatography. Using these antibodies, two forms of direct ELISAs (Sold ELISA-1, 2) were constructed. The basic detection performance of the ELISAs was confirmed by measuring the levels of SO and CHA diluted in phosphate-buffered saline (PBS). To simulate biological samples from patients with potato food poisoning, SO and CHA powders were mixed with commercially available human serum and urine, and SO and CHA levels were then measured using ELISA. Lastly, SO and CHA levels were detected in extracts from rotten potato (Irish Cobbler) sprouts, peels, and tubers. Results In samples of SO diluted in PBS, the limit of quantification (LoQ) was determined as 2.56 ng/mL and 9.55 ng/mL for Sold ELISA-1 and -2, respectively. In CHA diluted in PBS, the LoQs of Sold ELISA-1 and -2 were 1.36 ng/mL and 4.8 ng/mL, respectively. The LoQs of SO in the serum were calculated as 14.25 ng/mL and 19.41 ng/mL using Sold ELISA-1 and -2, respectively. In contrast, the LoQs of CHA in the serum were 12.48 ng/mL and 16.92 ng/mL using Sold ELISA-1 and -2, respectively. The LoQs of SO in the urine were determined as 30.28 ng/mL and 45.16 ng/mL using Sold ELISA-1 and -2, respectively. Conversely, the LoQs of CHA in the urine were 22.92 ng/mL and 38.15 ng/mL using Sold ELISA-1 and -2, respectively. Using Sold ELISA-1, both SO and CHA in the extracts from rotten potato tubers and peels were detected as approximately 1.7- and 2.3-fold higher, respectively, in each part than those in the extracts from fresh potatoes. When both SO and CHA were measured in the same samples using Sold ELISA-2, the levels were approximately 1.6- and 2.4-fold higher, respectively, in the tubers and peels than those in fresh potato samples. Furthermore, the potato sprout extract contained approximately 80-fold more SO and CHA than the tuber and 8-fold more than the peel. Discussion and Conclusion Based on our results, Sold ELISA-1 presented greater performance in detecting SO and CHA than Sold ELISA-2. The non-specific reactions in the serum samples and influence of urea in the urine samples may underlie the reduced detection performance of SO and CHA in ELISA, respectively. Although the sensitivity depends on the sample type, these ELISAs may be effective as future clinical and food testing methods.