ABSTRACT
Camptotheca acuminata produces camptothecin (CPT), a monoterpene indole alkaloid (MIA) that is widely used in the treatment of lung, colorectal, cervical, and ovarian cancers. Its biosynthesis pathway has attracted significant attention, but the regulation of CPT biosynthesis by the APETALA2/ethylene-responsive factor (AP2/ERF) transcription factors (TFs) remains unclear. In this study, a systematic analysis of the AP2/ERF TFs family in C. acuminata was performed, including phylogeny, gene structure, conserved motifs, and gene expression profiles in different tissues and organs (immature bark, cotyledons, young flower, immature fruit, mature fruit, mature leaf, roots, upper stem, and lower stem) of C. acuminata. A total of 198 AP2/ERF genes were identified and divided into five relatively conserved subfamilies, including AP2 (26 genes), DREB (61 genes), ERF (92 genes), RAV (18 genes), and Soloist (one gene). The combination of gene expression patterns in different C. acuminata tissues and organs, the phylogenetic tree, the co-expression analysis with biosynthetic genes, and the analysis of promoter sequences of key enzymes genes involved in CPT biosynthesis pathways revealed that eight AP2/ERF TFs in C. acuminata might be involved in CPT synthesis regulation, which exhibit relatively high expression levels in the upper stem or immature bark. Among these, four genes (CacAP2/ERF123, CacAP2/ERF125, CacAP2/ERF126, and CacAP2/ERF127) belong to the ERF-B2 subgroup; two genes (CacAP2/ERF149 and CacAP2/ERF152) belong to the ERF-B3 subgroup; and two more genes (CacAP2/ERF095 and CacAP2/ERF096) belong to the DREB-A6 subgroup. These results provide a foundation for future functional characterization of the AP2/ERF genes to enhance the biosynthesis of CPT compounds of C. acuminata.
ABSTRACT
To study the secondary metabolites and their cytotoxic activities of an endophytic fungus Diaporthe sp. XZ-07cultivated on Camptotheca acuminata. Colum chromatography by RP-18, Sephadex LH-20 and silica gel was used to isolate and purify the chemical constituent. Two new compounds were isolatedand identified as 5-((E)-1,4,5-trihydroxyhex-2-enyl)furan-2(5H)-one(1)and(5Z)-5-(2,3,4,5-tetrahydroxyhexylidene)furan-2(5H)-one(2)by spectroscopic analysis. Cytotoxic activities were evaluated by MTT method. Compound 1 showed strong inhibitory activity against Human cervical carcinoma cell line Hela, and compound 2 showed strong inhibitory activity against breast cancer cell line MCF-7, Human neuroblastoma SH-SY5Y and Lewis lung carcinoma cells 3LL.
ABSTRACT
Being a good anti-tumor drug, camptothecin (CPT) is a kind of modified monoterpene indole alkaloid firstly isolated from the deciduous Chinese happy tree with rapidly increasing clinical demand. Due to the great importance and low content of this compound, it is very important to improve CPT production by modern biotechnology. ORCA3 is a jasmonateresponsive APETALA2-domain transcript factor isolated from Catharanthus roseus, with strong ability to up-regulate expression of serveral key genes involved in TIA biosynthetic pathway. To investigate physiological function of ORCA3 gene in Camptotheca acuminata, the ORCA3 gene was transformed using Agrobacterium-mediated gene transfer technology. PCR analysis confirmed that the ORCA3 gene was integrated into the plant genome. HPLC showed that overexpression of ORCA3 in transgenic hairy root lines can effectively enhance the production of camptothecin with 1.5-fold compared with the control (1.12 mg/g dw). The results revealed that ORCA3 is an effective regulatory gene for improving metabolic flux in camptothecin biosynthetic pathway at the first time.
ABSTRACT
Object To develop a new process for the extraction of camptothecin from leaves of Camptotheca acuminata Decne Methods By uniform experimental design after proper choice of solvent Results The optimal conditions were extraction with 16 times of 0 3% NaOH for three hours each time Conclusion This is the first attempt to use dilute NaOH solution for the extraction of camptothecin from the previously seldom utilized leaves of C acuminata, which resulted in a yield well over 0 1% The process resulted in a lower production cost and require less fire protection measures as compaired with the conventional use of alcohol
ABSTRACT
Object To establish the process of purification for ?-linolenic acid from the fruit oil of Camptotheca acuminata Decne.. Methods Complexometry by AgNO 3 was applied. Results The optimal conditions: the AgNO 3 concentration was 4 mol/L, the complexometric temperature was lower than 15 ℃, and the complexometric time was 2 h. The purity of ?-linolenic acid was 91.25%. Conclusion The concentration of ?-linolenic acid from the fruit oil of C. acuminata can reach to 45.8%, therefore it is a new abundant resource for ?-linolenic acid. ?-linolenic acid can be well purified in the fruit oil by this process.
ABSTRACT
Objective To investigate the distribution of camptothecin(CPT),tryptophan synthase(TSB),and tryptophan decarboxylase(TDC) in Camptotheca acuminata seedlings.Methods The CPT content,TSB and TDC activities in different organs of C.acuminata seedlings subjected to different nitrogen forms treatments by sand culture in greenhouse were determined by HPLC.Results The CPT content in the young leaves of C.acuminata seedlings with different N-forms was significantly higher than that in other organs(P