Abstract
We aimed to investigate whether 1-deoxynojirimycin (DNJ) modulates glycometabolism and has toxicity in Eri silkworm (Samia cynthia ricini, Saturniidae). In this paper, hemolymph metabolites were used to explore metabolic changes after oral administration of DNJ or mulberry latex and to characterize the biological function of DNJ at the metabolic and systemic levels. Hemolymph samples were collected from fourth-instar larvae of Eri silkworm and ex-vivo high-resolution 1H nuclear magnetic resonance (NMR) spectra were acquired from the collected hemolymph samples. Then the obtained spectra were analyzed by principal component analysis (PCA) and independent-samples t-test. Metabolic pattern recognition analysis of hemolymph samples indicated that the groups of 0.25% DNJ, latex, and the mixture of 0.5% DNJ and latex (1:1) were significantly different from the control group. Moreover, compared to the control group, the groups of 0.25% DNJ, latex, and the mixture of 0.5% DNJ and latex (1:1) showed the decreased levels of citrate, succinate, fumarate, malate, and glutamine in hemolymph, the groups of 0.25% DNJ and the mixture of 0.5% DNJ and latex (1:1) showed the increased levels of trehalose and lactate. In addition, mulberry leaves exude latex was highly toxic to Eri silkworm because rich unidentified high-molecular-weight factor (s) acted as toxic substances. In our results, latex caused 20 deaths among 50 fourth-instar larvae of Eri silkmoth, but DNJ or the mixture did not caused death. All these results suggest that DNJ has a positive impact on the reverse glycometabolism by modulating glycometabolism and inhibiting glucogenesis and energy metabolism. DNJ is a secure substance as a single-ingredient antidiabetic medicine due to its nontoxicity and bioactivity.
Highlights
Mulberry leaves have been widely cultivated for rearing the silkworm Bombyx mori (B. mori) in ancient times
Mulberry leaves will lose their toxicity to Samia cynthia ricini (S. cynthia ricini) when latex is eliminated from mulberry leaves through cutting leaves into slim pieces and subsequent rinsing, interpreting that the defensive ability of mulberry leaves is totally dependent upon toxic latex
After Eri silkworms were fed with 5 μL of latex containing 0.32% DNJ, among 50 larvae, 20 larvae died and the growth of other 30 larvae was significantly retarded with frequent vomiturition
Summary
Mulberry leaves have been widely cultivated for rearing the silkworm Bombyx mori (B. mori) in ancient times. Domesticated silkworms can grow adaptively on mulberry leaves, so the defense response and toxic properties of the leaves to the insect are generally ignored [1,2]. Metabolic Changes in Eri Silkworm by 1H-NMR Based Metabonomic Approach the defense response against silkworms, mulberry leaves exude latex containing rich 1-deoxynojirimycin (DNJ), 1,4-dideoxy-1,4-imino-D-ribitol, and 1,4-dideoxy-1,4-imino-D-arabinitol (D-AB1) (Fig 1A–1C). All the above three substances are glycosidase inhibitors These iminosugar inhibitors are lethal to Eri silkworms, a generalist herbivorous insect. They are safe to domesticated silkworms on mulberry leaves, B. mori [3]. In the when Eri silkworms were fed with 5 μL of 0.25% DNJ or the mixture of latex and 0.5% DNJ, no larva died (n = 50 in each group) and the morphology of larvae could not be distinguished from the controls by visual examination. Among the above three iminosugar inhibitors, only DNJ, was found in the latex from Morus alba (M. alba, a Chinese local species) [1]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
