Taxanes isolated from

Seasonal Changes in the Concentration of Major Taxanes in the Biomass of Wild Canada Yew (Taxus canadensis. Marsh.)

“…The most abundant taxane was 9-DHAB III, found in the same range as has been previously observed (reported as 0.014% 7,9-deacetylbaccatin VI by Zamir et al, 1992). The 9-DHAB III content was highest in the fall and reached peak levels of 1600-1800 µg g dwt −1 in the youngest needles (C, C→C+1), decreasing to 1200-1400 µg g dwt −1 in 3-year-old needles.…”

“…The commercially valuable taxanes 10-deacetylbaccatin III (10-DAB III) and paclitaxel (PAC) generally both occur in shoot biomass at autumn values of 300-400 µg/g and cephalomannine (CEPH) in smaller amounts (50-100 µg/g) (Cameron & Smith, unpublished data). The unique taxane 9-dihydro-13-acetylbaccatin III (9-DHAB), also known as 7,9-deacetylbaccatin VI (Zamir et al, 1992), is also present in large amounts (1000-1500 µg/g). 9-DHAB has potential commercial value because it is abundant, and several different synthetic routes already have been patented to convert it to semisynthetic precursors of paclitaxel (Zamir & Caron, 2001;Findlay et al, 2004).…”

Isolation and characterization of impurities in docetaxel

“…Docetaxel (N-debenzoyl-N-tert-butoxycarbonyl-10-deacetyl taxol) was synthesized in 1985. Docetaxel is obtained by semisynthesis from 10-deacetylbaccatin III, non-cytotoxic precursor extracted from the needles of the European yew, Taxus baccata [1]. Taxotere is approximately twice as potent as taxol in inhibiting cold and calcium-induced depolymerization of microtubules [2].…”

Novel Taxa-4(20),12-diene and 2(3→20)Abeotaxane from Needles ofTaxus canadensis

“…[3][4][5][6] T. canadensis, an evergreen shrub distributed in North America, especially in the Quebec region of Canada, is one of the most extensively studied yews and more than 100 new taxanes have been reported. [7][8][9] As a continuation of our phytochemical study on T. canadensis, [10][11][12][13] we investigated the needles and isolated a new 6/8/6-membered taxane with a rare C-12(13)-double bond (1) and a new rearranged 2(3!20)abeotaxane (2) (Fig. 1).…”