Triterpenes (Triterpenoids)
Solvents: water, good; alcohol, excellent; glycerin, fair to good; vinegar, poor; oil, excellent
The largest subgroup of the terpenoids, have 30 carbons in their skeleta, which are usually arranged in a series of five fused rings (i.e., they arepentacyclic). Triterpenes often occur as water-soluble saponins in the plants, but the aglycones are oil-soluble. About 4,000 different structures are known. Pentacyclic triterpene skeleton types include lupane, oleanane, and ursane. Biosynthetically, they are derived from squalene via cycloartenol; in turn, they are the precursors of steroidal compounds in plants. (-Ganora)
Triterpenoids are ubiquitous in the plant kingdom. Recent evidences support the beneficial effects of naturally occurring triterpenoids against several types of human diseases, including various cancers. Here, we have summarized the potential of triterpenoids belonging to the lupane, oleanane, ursane, and cucurbitacin groups, and their beneficial effects based on both laboratory and clinical investigations. Anticancer potential of triterpenoids and their anti-inflammatory, anti-proliferative, and pro-apoptotic effects have been discussed both in in vitro and in vivo models. Importantly, a large number of preclinical efficacy studies using chemically-induced, as well as tumor xenograft models provided evidence that both naturally occurring and synthetic derivatives had chemopreventive and therapeutic effects. In this review, we have highlighted several studies on chemopreventive and anticancer potential of triterpenoids based on various preclinical animal models of colon, breast, prostate, and melanoma cancers. Also, we made an attempt in discussing various mechanisms by which triterpenoids regulate various transcription and growth factors, inflammatory cytokines, and intracellular signaling pathways involved in cancer cell proliferation, apoptosis and tumor angiogenesis.