Three new polyketides 4,6,8-trihydroxy-5-methyl-3,4-dihydronaphthalen-1(2H)-one (1), 5,7-dihydroxy-3-(1-hydroxyethyl)-3,4-dimethylisobenzofuran-1(3H)-one (2) and 1-(4-hydroxy-6-methoxy-1,7-dimethyl-3-oxo-1,3-dihydroisobenzofuran-1-yl) ethyl acetate (3) together with seven known analogues (4-10) were isolated from desert endophytic fungus Paraphoma sp. The structures of these compounds were elucidated by analysis of NMR data. The absolute configuration of (1-3) was established on the basis of CD experiments. The possible biosynthetic pathway of compounds (1-10) was suggested, which implied that these secondary metabolites might be originated from polyketide biosynthesis with different post-modification reactions. Compounds 2, and 5-8 were evaluated for bioactivities against plant pathogen A. solani, whereas none of them displayed any biological effects. In addition, compounds 1, 2 and 5-10 were also tested for cytotoxic activities against three human cancer cell lines (HepG2 cells, MCF-7 cells and Hela cells) without biological effects.

The tree Croton laevigatus Vahl. (Euphorbiaceae) is distributed mainly in China in the provinces of Yunnan, Guangdong, and Hainan. Roots and leaves of the plant are usually used by the Dai people as a traditional drug for treating fractures, malaria, stomach ache, and wounds received from falling [1]. Phytochemical studies of C. laevigatus have not yet been reported with the exception of diterpenoids with interesting skeletons [2,3].Air-dried ground leaves (20 kg) were extracted with MeOH (3 u 80 L) in order to obtain the crude extract (2120 g) after evaporation in vacuo. The extract was suspended in H 2 O (8.0 L) and fractionated successively with petroleum ether, CHCl 3 , and n-BuOH (3 u 8.0 L). The petroleum-ether extract (673 g) was chromatographed over a column of silica gel with elution by petroleum ether:EtOAc mixtures (1:0, 9:1, 4:1, 3:2, 0:1) to afford compounds 1 (3 g) and 5 (10 g). The BuOH fraction was chromatographed over a column of silica gel with gradient elution by CHCl 3 :CH 3 OH mixtures (50:1o0:1) to afford 2 (50 mg), 3 (5 mg), 4 (20 mg), and 6 (20 mg).PMR and 13 C NMR spectra were used to identify 1-4. Compounds 5 and 6 were identified by direct comparison with authentic samples as E-sitosterol and daucosterol, respectively. 3c-(4cc-Hydroxy-3cc,5cc-dimethoxyphenyl)propylbenzoate (1), brown oil, C 18 H 20 O 5 . EI-MS (m/z, %): 316 (90) [M] + , 194 (100), 179 (23), 167 (52), 163 (53), 105 (75), 77 (92). The PMR and 13 C NMR spectra were published [4]. Dihydrodehydrodiconiferyl alcohol E-D-glucoside (2), yellow semi-solid compound, C 26 H 34 O 11 . ESI-MS (m/z, +-ions): 545.2 [M + Na] + , 383.1 [M + Na -glucose] + , 365.1 [M + Na -glucose -H 2 O] + . The PMR and 13 C NMR spectra were published [5]. Myrsinionoside C (3), yellow semi-solid compound, C 19 H 36 O 7 . ESI-MS (m/z, +-ions): 400.2 [M + Na] + . The PMR and 13 C NMR spectra were published [6]. Alangionoside J (4), yellow semi-solid compound, C 19 H 36 O 7 . ESI-MS (m/z, +-ions): 400.2 [M + Na] + . The PMR and 13 C NMR spectra were published [7].All compounds were isolated from C. laevigatus for the first time whereas 2-4 were isolated for the first time from a plant of the genus Croton. ACKNOWLEDGMENTS