Limonoid glucosides

A. M. Couvillon, et al. Inhibition of oral carcinogenesis by green coffee beans and limonoid glucosides. ACS Symp Ser 1994 546 220-229. CA186... 

In further research on the limonoid glucosides, we found that they appear to be present only in fruit tissues and seeds. Radioactive tracer work showed that the fruit tissue itself is... 

Biochemical studies carried out at the Pasadena laboratory have shown how, where and when limonoids are biosynthesized and accumulate in citrus. The recent discovery of limonoid glucosides has cleared an unanswered question of how limonoid aglycones disappear at late stages of fruit growth and maturation. 

Limonoid UDP-D>glucose transferase Limonin bitterness is a problem in juices extracted from early-season to mid-season winter fruit, but not a problem in juice extracted from the late season fruit. As the fruit ripens, the concentration of limonoate A-ring lactone (2) decreases (23,24). This natural limonin debittering process has been known for over a century, but the mechanism of this metabolism was not understood until the recent discovery that limonoid glucosides are present in mature fruit tissues and seeds. We observed that in navel orange the initial... 

Two limonoid glucosides, obacunone and nomilin glucoside, were extracted from Citrus tangeria and analyzed on a Cig column (A = 215nm) using a 15/85... 

In comparison to values obtained from HPLC, the RIA limonin values from commercial grapefruit juices were found to be higher (Rouseff and Mansell 1982). It is possible that the limonoid glucosides in the juice cross-react with the limonin antibody, which results in artificially higher limonin determinations. 

Limonoid glucosides and deoxylimonin were found to cross-react with the antibodies. The relatively low levels of deoxylimonin in citrus juices should not contribute to the limonin values significantly. However, the high concentration of limonoid glucosides, which can be over 400 ppm, can give artificially high limonin values. 

Kimball (1991) pointed out that besides the interference from limonoid glucosides, the failure to properly calibrate EIA test systems and the irreproducibility of results in juice samples analyzed at different Brix levels are the primary reasons for the less reliable result of EIA. 

Limonin has recently become commercially available from several chemical companies including Aldrich and Sigma. Nomilin is also available from Takasago (Toyko, Japan). Other limonoid aglycones and limonoid glucosides are currently only obtained by isolation from citrus seeds. See Herman et al. (1992) for extraction and isolation methods. 

Hasegawa S, Bennett RD, Herman Z, Fong CH, Ou P (1989) Limonoid glucosides in citrus. Phytochemistry 28 1717-1720... 

Raman, G., Cho, M., Brodbelt, J.S., and Patil, B.S. 2005. Isolation and purification of closely related Citrus limonoid glucosides by flash chromatography. Phytochemical Analysis, 16, (3), 155-160. 

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