Calophyllum inophyllum is a medicinal plant that is rich in bioactive natural products. Calophinone¡]29¡^¡Bcaloxanthone I¡]30¡^¡Bbrasilixanthone B¡]31¡^¡Bpyranojacareubin¡]32¡^ and osajaxanthone¡]33¡^are five compounds which were isolated from the bark in this experiment. It is the first time to isolate calophinone¡]29¡^ from a matural source. In order to identify calophinone¡]29¡^, 6-acetylcalophinone¡]34¡^ was prepared via acylation. All structures were determined primarily on the basis of 1D, 2D NMR¡BUV¡BIR and Mass spectral analyses. Besides, biological studies don¡¦t reveal that Calophinone¡]29¡^¡Bcaloxanthone I¡]30¡^¡Bbrasilixanthone B¡]31¡^¡Bpyranojacareubin¡]32¡^¡Bosajaxanthone¡]33¡^and 6-acetylcalophinone¡]34¡^, exhibited in vitro cytotoxicity against human liver carcunoma¡BHuman oral epidermoid carcunoma and Human cervical epidermoid carcunoma. In addition, four new Taxoid derivatives that were 13-O-camphanyl-7-O -nicotinoylbaccatin III¡]34¡^¡B13-O-camphanyl-1-deoxybaccatin VI¡]35¡^¡B13-O-¡]4-chlorobenzoyl¡^-7-O-nicotinoylbaccatin III¡]36¡^and 13-O-benzoyl-7-O -nicotinoylbaccatin III¡]37¡^have been prepared via esterification under sonication starting from 13-deacetyl-7-O-nicotinoylbaccatin III¡]32¡^ and 13-deacetyl-1-deoxybaccatin VI¡]31¡^. All the structures were established primarily on the basis of 1D and 2D NMR techniques including DEPT, COSY, HMBC experiments, as well as comparison with known related compounds. It was deemed quite promising to investigate the structure-activity relationship ( SAR ) for the C - 13 side chain analogues of Taxol with some modification of the baccatin III¡]30¡^ moiety in order to discover more effective anticancer agents with better pharmacological properties. Compounds 34 and 35 showed significant cytotoxicity against prostate cancer cell line¡]PC-3¡^. Under concentration of 10£gM, the cell survival percent was 76% and 65% in case of compounds 34 and 35 compared to 60 % in case of Taxol. According to the structure-activity relationship, nicotinoyl and camphanic acyl group should be the source of activity in compounds 30 and 31. Consequently, it is necessary to introduce nicotinoyl chloride and camphanic acyl chloride groups via chemical reaction to improve the bioactivity.