Alkaloids
1-deoxynojirimycin is referred DNJ for short , it is an alkaloid extracted from the bark of mulberry leaves and roots, but it also exists in other plants and microorganisms. This product is an effective α-glucosidase inhibitor, it has significant hypoglycemic effect. After 1-deoxynojirimycin goes into the human body, it can inhibit sucrose, maltase, α-glucosidase enzyme, α-amylase decomposing starch, sugar in the human body , thereby it can block the body's absorption of sugar, inhibiting blood sugar rising to achieve the effect of prevention and treatment of diabetes, the use of it does not cause changes in diet . In addition, DNJ can inhibit glucose modification process of HIV tunica glycoprotein , at the same time, the accumulation of immature glycoproteins may inhibit cell fusion, viral and host cell receptor can combine,which causes syncytia formation to inhibit the replication of MoLV ,then the virus activity is inhibited.
Nojirimycin is first discovered from Streptomyces, and natural DNJ is first isolated from the bark of mulberry root. In plants, from mulberry, dayflower, hyacinth and Adenophora plants, DNJ has been isolated and identified , DNJ has the highest content in the mulberry and because of mulberry varieties, medicinal parts, seasonal climate, geography, soil, leaf position, different developmental stages and other factors , there is a big difference. In a microorganism, from a variety of Streptomyces and Bacillus,DNJ is isolated ,it is also found that two kinds of endophytes separated from Mulberry including Stenotrophomonas oligotrophic Pseudomonas and Micrococcus can produce DNJ,fermentation conditions of a variety of microbial production of DNJ are studied. In insects, in addition to silkworm rich in DNJ , single or oligophagous insects with eating mulberry leaves habit including wild silkworm, mulberry geometrid, Diaphania pyloalis Walker , mulberry white capterpillar are also rich in DNJ , DNJ in insects bodies are from the food , content of DNJ in Bombyx bodies is different due to the different varieties of silkworm, developmental stages, tissues and organs as well as feed and other factors, with the silkworm age of progress ,there is the existence of cyclical changes in absorption and accumulation and excretion of DNJ. Now DNJ biosynthetic pathways in Streptomyces, Bacillus and Commelina bodies are explored and it is found that synthesis of DNJ has different mechanisms in different species . In addition, three main synthesis methods of 1-deoxynojirimycin are proven , some of the synthetic derivatives of DNJ have been used clinically.
Recent studies show that the active ingredient of mulberry DNJ (l-deoxynojirimycin), only exists in mulberry leaves , by blocking the α-glucosidase enzymes to hinder sugar becoming to glucose, mulberry leaf extract can inhibit intestinal glucose absorption. This can suppress the blood sugar level and blood pressure rising , and it can have good inhibitory effect on variability of imidazopyridine, benzopyrene and other carcinogenic substances,it has anti-cancer effect, at the same time ,mulberry leaf extract can reduce cholesterol, and improve liver function and eliminate constipation and so on.
References
1) Fuhrmann et al. (1985), Inhibitors of oligosaccharide processing; Biochim. Biophys, Acta, 825 95
2) Hughs and Rudge (1994), Deoxynojirimycin: synthesis and biological activity; Nat. Prod. Rep., 11 135
3) Papandreou et al. (2002), The alpha-glucosidase inhibitor 1-deoxynojirimycin blocks human immunodeficiency virus envelope glycoprotein-mediated membrane fusion at the CXCR4 binding step; Mol. Pharmacol., 61 186
4) Hettkamp et al. (1984), Purification by affinity chromatography of glucosidase I, an endoplasmic reticulum hydrolase involved in the processing of asparagine-linked oligosaccharides; Eur. J. Biochem., 142 85
5) Suh et al. (1992), Identification of a novel mechanism for the removal of glucose residues from high mannose-type oligosaccharides; J. Biol. Chem., 267 21671
