Cucurbituril

“Cucurbituril” may sound as a name of a natural product derived from some plant of Cucurbita genus. Wrong. There is a connection, though. According to this review,

In 1981, the macrocyclic methylene-bridged glycoluril hexamer (CB[6]) was dubbed cucurbituril by Mock and co-workers because of its resemblance to the most prominent member of the cucurbitaceae family of plants — the pumpkin.

My best 2-D representation for cucurbit[5]uril (a) does not look particularly pumpkiney. It is more like a sea urchin skeleton. Granted, its 3-D model (b) may look a bit like cleaned pumpkin devoid of top and bottom, but it still looks like a sea urchin skeleton (c) to me.

(a) cucurbit[5]uril in 2-D

(b) cucurbit[5]uril in 3-D

(c) sea urchin skeleton

Cucurbiturils, pumpkin-like or not, can be as useful as hunny pot that Pooh the Bear presented Eeyore: you can put things in them. For example, the platinum-containing anticancer drug oxaliplatin (d) can be put inside of cucurbit[7]uril to form a stable 1:1 complex (e). Jeon et al. suggest that this can increase the stability of the drug as well as to reduce unwanted side effects of oxaliplatin.

(d) oxaliplatin

(e) cucurbit[7]uril-oxaliplatin