Kuguacin Explained

A kuguacin is one of several chemical compounds isolated from the bitter melon vine (Momordica charantia, kǔguā in Chinese) by J.-C. Chen and others.^[1]

Kuguacins are cucurbitacins, formally derived from the triterpene hydrocarbon cucurbitane. They include:

• Kuguacin A
• Kuguacin B
• Kuguacin C
• Kuguacin D
• Kuguacin E^[2]
• Kuguacin F: ; 47 mg/kg, needles, melts at 275–276 °C ^[1]
• Kuguacin G: ; 23 mg/kg, needles, melts at 250–252 °C ^[1]
• Kuguacin H: ; 27 mg/kg, needles, melts at 226–228 °C ^[1]
• Kuguacin I: ; 20 mg/kg, needles, melts at 235–237 °C ^[1]
• Kuguacin J: ; 243 mg/kg, powder, melts at 166–169 °C ^[1]
• Kuguacin K: ; 130 mg/kg, powder, melts at 275–277 °C ^[1]
• Kuguacin L: ; 30 mg/kg, needles, melts at 320–321 °C ^[1]
• Kuguacin M: ; 7 mg/kg, needles, melts at 332–333 °C ^[1]
• Kuguacin N: ; 247 mg/kg, powder, melts at 140–143 °C ^[1]
• Kuguacin O: ; 20 mg/kg, needles, melts at 267–269 °C ^[1]
• Kuguacin P: ; 293 mg/kg, prisms, melts at 229–231 °C ^[1]
• Kuguacin Q: ; 11 mg/kg, needles, melts at 219–221 °C ^[1]
• Kuguacin R: ; 1357 mg/kg ^[1]
• Kuguacin S: ; 17 mg/kg, powder, melts at 174–177 °C ^[1]

Kuguacins F-S can be extracted with ethanol from the stems and leaves of M. charantia. Kuguacins I, J, and Q are artifacts of the extraction process. Kuguacin R is obtained as mixture of two epimers. In this process one also obtains momordicine I,^[3] kuguacin E, 5β,19-epoxycucurbita-6,23-diene-3β,19,25-triol,^[4] karavilagenin D,^[5] 3β,7β,25-trihydroxycucurbita-5,(23E)-dien-19-al,^[6] and 3β,7β-dihydroxy-25-methoxycucurbita-5,(23E)-dien-19-al^[6] In vitro tests showed weak anti-HIV activity for kuguacins F-S, especially kuguacin Q and kuguacin S.^[1]

Notes and References

1. Jian-Chao Chen, Wu-Qing Liu, Lu Lu, Ming-Hua Qiu, Yong-Tang Zheng, Liu-Meng Yang, Xian-Min Zhang, Lin Zhou and Zhong-Rong Li (2009), "Kuguacins F–S, cucurbitane triterpenoids from Momordica charantia". Phytochemistry, volume 70, issue 1, pages 133-140
2. J. C. Chen, R. R. Tian, M. H. Qiu, L. Lu, Y. T. Zheng, Z. Q. Zhang (2008), "Trinorcucurbitane and cucurbitane triterpenoids from the roots of Momordica charantia." Phytochemistry, volume 69, pages 1043–1048
3. M. Yasuda, M. Iwamoto, H. Okabe, T. Yamauchi (1984), "Structures of momordicines I, II and III, the bitter principles in the leaves and vines of Momordica charantia L. Chem. Pharm. Bull., volume 32, pages 2044–2047.
4. Dulcie A. Mulholland, Vikash Sewram, Roy Osborne, Karl H. Pegel and Joseph D. Connolly (1997), "Cucurbitane triterpenoids from the leaves of Momordica foetida." Phytochemistry, volume 45, issue 2, pages 391-395.
5. H. Matsuda, S. Nakamura, T. Murakami, M. Yoshikawa (2007). "Structures of new cucurbitane-type triterpenes and glycosides, karavilagenins D and E, and karavilosides VI, VII, VIII, IX, X, and XI, from the fruit of Momordica charantia." Heterocycles,volume 71, pages 331–341.
6. Majekodunmi Fatope, Yoshio Takeda, Hiroyasu Yamashita, Hikaru Okabe, and Tatsuo Yamauchi (1990), "New cucurbitane triterpenoids from Momordica charantia." Journal of Natural Products, volume 53, issue 6, pages 1491-1497.