A new paclitaxel derivative and two new 2(3-->20)-abeo-taxoids were isolated from a methanol extract of the seeds of Taxus mairei, and their structures were established as 1-deoxypaclitaxel (1), 7beta,10beta-diacetoxy-2alpha,5alpha,13alpha-trihydroxy-2(3-->20)-abeo-taxa-4(20),11-dien-9-one (2), and 2alpha,13alpha-diacetoxy-10beta-hydroxy-2(3-->20)-abeo-taxa-4(20),6,11-triene-5,9-dione (3) on the basis of spectroscopic data analysis. Taxane 1 is the first example of a paclitaxel analogue with a C-1beta hydrogen substituent. Taxane 3 is an 2(3-->20)-abeo-taxane with a rare C-5 ketone and C-6 double bond.

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Two new taxoid metabolites, 2; 7; 10-triacetoxy-5,13-dihydroxy-2(3 ! 20)abeotaxa-4(20),11-dien-9-one (1) and 2-acetoxy-5-cinnamoyloxy-9,10-dihydroxy-3,11-cyclotax-4(20)-en-13-one (2), were isolated from the methanol extract of needles of the Japanese yew, Taxus cuspidata.Key words: Taxus cuspidata; Taxaceae; needles; 2(3 ! 20)abeotaxane; 3,11-cyclotaxane Yew trees are a rich source of biologically active taxane diterpenoids such as taxol Ò (paclitaxel), one of the most important drugs for ovarian and breast cancer currently on the market.1,2) Its unique mechanism of action, limited solubility and shortage have generated worldwide interest, and extensive chemical studies have been carried out.1-4) In a continuation of our studies on taxanes, 5,6) two new compounds were isolated from needles of the Japanese yew, Taxus cuspidata.Compound 1 was isolated from a methanolic extract of needles of Taxus cuspidata as white powder {½ D 22 ¼ À40 (c 0.06, CHCl 3 )} and its HR-FABMS analysis revealed the molecular formula as C 26 H 36 O 9 (m=z 531.1998 [MþK] þ , calcd. for C 26 H 36 O 9 K requires 531.1996). A combined analysis by 1-D and 2-D NMR (Table 1) revealed that 1 had a 2(3 ! 20)abeotaxane skeleton 3,5-10) with one keto, two hydroxy and three acetoxy groups. The positions of these functionalities was established by the HMBC spectrum. The relative configuration and proposed conformation of 1 were estimated from the results of an NOESY experiment (Table 1 and Fig. 1), enabling compound 1 to be unambiguously characterized as 2; 7; 10-triacetoxy-5,13-dihydroxy-2(3 ! 20)abeotaxa-4(20),11-dien-9-one. This was the 2-O-acetyl derivative of the compound previously isolated by us from the Chinese yew, Taxus mairei. 10)Compound 2 was isolated as a colorless gummy substance {½ D 22 ¼ þ19 (c 0.11, CHCl 3 )}. Its quasimolecular ion at m=z 561.2256 (MþK) þ generated by HR-FABMS revealed that the molecular formula of 2 was putatively C 31 H 38 O 7 (calcd. for C 31 H 38 O 7 K requires 561.2255). The 1 H-and 13 C-NMR, COSY and HMBC spectra tabulated in Table 2 indicated compound 2 to have a 3,11-cyclotaxane skeleton 3,6,11) with one acetoxy, one cinnamoyloxy, one keto and two hydroxy groups. The HMBC spectrum showed that the acetoxy and the cinnamoyloxy groups were respectively located at the 2-and 5-positions. The relative configuration was determined by an NOESY experiment, and the conformation is proposed to be that shown in Fig. 1. The structure of 2 was characterized as 2-acetoxy-5-cinnamoyloxy-9,10-dihydroxy-3,11-cyclotax-4(20)-en-13-one. This is the 10-O-deacetyl derivative of taxane isolated from seeds of the Chinese yew, Taxus yunnanensis. Biosci. Biotechnol. Biochem., 68 (7), [1584][1585][1586][1587] 2004 Note preparative column (22 Â 500 mm). Plant material. Needles of Taxus cuspidata, which were identified by Prof. Takashi Oritani of Toyama Prefectural University (Japan), were collected in the autumn of 2000 at Tsutsuzigaoka Park (Sendai, Japan).Extraction and isolation. Air-dried needles of Taxus cuspidata were ground...