Structural elucidation of anti-metastatic rhamnogalacturonan II from the pectinase digest of citrus peels (Citrus unshiu).
The aim of this study was to characterize a polysaccharide found in citrus peels with an anti-metastatic property. CPE-II was purified by the pectinase digestion of citrus peels. During in vivo lung metastasis of Colon26-M3.1, administration of 10μg of CPE-II per mouse showed 81.3% inhibition of metastasis. CPE-II consists of 15 different monosaccharides and 22 different glycosyl linkages, characteristic of rhamnogalacturonan II (RG-II). The primary structure was elucidated based on sugar composition, methylation analysis, oligosaccharide analysis, and sequencing using GC, GC-MS, LC-MS, and ESI-MS/MS analyses. Sequential degradation using partial acid hydrolysis indicated that CPE-II contained Rhap-(1→5)-Kdo, Araf-(1→5)-Dha, an AceA-containing nonasaccharide, and an uronic acid-rich oligosaccharide in addition to an α-(1→4)-galacturono-oligosaccharide main chain. The molecular weight of CPE-II was observed to decrease from 9 to 5kDa at a pH value of <2.0, as observed by HPSEC. Thus, we propose that the anti-metastatic CPE-II is primarily present as an RG-II dimer.
Department of Food Science and Biotechnology, Kyonggi University, Gyeonggi, South Korea; Department of Integrated Biomedical and Life Science, Korea University, Seoul, South Korea. Electronic address: pooh-lup@hanmail.net.
Hye-Ryung
HR
Park
Department of Food Science and Biotechnology, Kyonggi University, Gyeonggi, South Korea; Chong Kun Dang Healthcare, Seoul, South Korea. Electronic address: sbpark@ckdhc.com.
Su Beom
SB
Park
Korea Food Research Institute, Sungnam, South Korea. Electronic address: honghd@kfri.re.kr.
Hee-Do
HD
Hong
Department of Integrated Biomedical and Life Science, Korea University, Seoul, South Korea. Electronic address: suh1960@korea.ac.kr.
Hyung Joo
HJ
Suh
Department of Food Science and Biotechnology, Kyonggi University, Gyeonggi, South Korea. Electronic address: ksshin@kyonggi.ac.kr.
Kwang-Soon
KS
Shin
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002236:Carbohydrate Conformation; D045744:Cell Line, Tumor; D002957:Citrus / Q000737:chemistry; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D005638:Fruit / Q000737:chemistry; D008175:Lung Neoplasms / Q000517:prevention & control* / Q000556:secondary; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D010368:Pectins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011096:Polygalacturonase / Q000737:chemistry
D000972:Antineoplastic Agents, Phytogenic; C042492:rhamnogalacturonan II; D010368:Pectins; D011096:Polygalacturonase
Anti-metastatic activity; Citrus peels; Pectin; Polysaccharide; Rhamnogalacturonan II