Abeotaxanes are a class of

taxoid Taxoids are a class of derivatives from taxol, that is, paclitaxel. They were developed for their anticancer chemotherapeutic properties. Taxoids are usually treated as synonymous with taxanes; for example, a major medical dictionary defines the ...

molecules with a core 5/7/6 type ring structure. This structure varies from the 6/8/6 or 6/10/6-membered core ring found in conventional taxoids such as

paclitaxel Paclitaxel (PTX), sold under the brand name Taxol among others, is a chemotherapy medication used to treat a number of types of cancer. This includes ovarian cancer, esophageal cancer, breast cancer, lung cancer, Kaposi's sarcoma, cervical canc ...

docetaxel Docetaxel (DTX or DXL), sold under the brand name Taxotere among others, is a chemotherapy medication used to treat a number of types of cancer. This includes breast cancer, head and neck cancer, stomach cancer, prostate cancer and non-small-cell ...

. The core carbon skeleton of a normal natural product taxane (e.g., paclitaxel, docetaxel) has a 6-membered A ring, 8-membered B ring and a 6-membered C ring, combined with conventional side chains. It is the side chains that provide most of the activity for regular taxanes. Abeotaxanes are compounds containing 3 altered ring structures, where ring A is 5 members, ring B is 7 members and ring C is 6 members, combined with conventional side chains. Like taxanes, abeotaxanes are diterpenes produced by the yew tree (genus ''

Taxus ''Taxus'' is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. They are relatively slow-growing and can be very long-lived, and reach heights of , with trunk girth averaging . They have reddish bark, lanceolate, flat ...

''). These agents inhibit the growth and replication of cancer cells by affecting

microtubules Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 a ...

. Taxanes are highly effective anti-cancer agents and are utilized as first and second-line therapy in the treatment of many solid-tumor cancers. Since the FDA approval of paclitaxel in 1998, subsequent research has focused on the synthesis of new and improved taxanes to address the issues of multi-drug resistance and central nervous system bioavailability, as well as on improvement of the side effect profile. Taxchinin A was the first naturally occurring rearranged taxoid identified as an 11(15→1)-abeotaxane. Taxchinin B was the first identified 11(15→1)-abeotaxoid with an oxetane ring. The first natural taxoid, identified to have an 11(15→1)-abeotaxane ring was brevifoliol. TPI 287 (formerly ARC-100), a 11(15→1)-abeotaxane that was in phase I clinical development in 2010, has demonstrated potent activity in multi-drug resistant tumor types, including taxane-resistant tumors, as well as efficacy in crossing the blood–brain barrier.

References

{{Reflist Taxanes