A kuguacin is one of several chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

s isolated from the bitter melon

Bitter melon

Momordica charantia, called bitter melon or bitter gourd in English, is a tropical and subtropical vine of the family Cucurbitaceae, widely grown in Asia, Africa, and the Caribbean for its edible fruit, which is among the most bitter of all fruits...

 vine (Momordica charantia, kǔguā in Chinese) by J.-C. Chen and others.

Kuguacins are cucurbitacin

Cucurbitacin

Cucurbitacin is any of a class of biochemical compounds that some plants — notably members of the family Cucurbitaceae, that includes the common pumpkins and gourds — developed in order to defend themselves from herbivores...

s, formally derived from the triterpene

Triterpene

Triterpenes are terpenes consisting of six isoprene units and have the molecular formula C30H48.The pentacyclic triterpenes can be classified into lupane, oleanane or ursane groups.Animal- and plant-derived triterpenes exist, such as:*squalene...

 hydrocarbon

Hydrocarbon

In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

 cucurbitane

Cucurbitane

Cucurbitane is a chemical compound with formula . It is a polycyclic hydrocarbon, specifically a triterpene. It is an isomer of lanostane , from which it differs by the formal shift of a methyl group from the 10 to the 9β position in the standard steroid numbering scheme.The name is applied to...

. They include:

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

Kuguacins F-S can be extracted with ethanol

Ethanol

Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...

 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

Momordicine

A momordicine is any of several compounds found the bitter melon vine, Momordica charantia. They are glycosides of cucurbitane derivatives. They include* Momordicine II...

, kuguacin E, 5β,19-epoxycucurbita-6,23-diene-3β,19,25-triol , karavilagenin D, 3β,7β,25-trihydroxycucurbita-5,(23E)-dien-19-al, and 3β,7β-dihydroxy-25-methoxycucurbita-5,(23E)-dien-19-al In vitro tests showed weak anti-HIV activity for kuguacins F-S, especially kuguacin Q and kuguacin S.