ABSTRACT Background: Dragon′s blood is a well-known traditional Chinese medicine, isolated mainly from the trunks of Dracaena trees. Overexploitation of the Dracaena resource has resulted in this plant becoming endangered. This work aimed to assess the potential to use various tissues of the Dracaena cochinchinensis tree, such as leaves and roots, to produce dragon′s blood. Results: We found that many dragon′s blood components accumulated in the bark of trunk and roots of D. cochinchinensis under natural conditions. In addition, small amounts of loureirin A were detected in leaves, suggesting that the leaves could be a potential source of dragon′s blood. Real-time quantitative PCR analysis showed that most of the genes tested in this study, which encoded enzymes involved in the biosynthesis of dragon′s blood flavonoids, were highly expressed in the bark of roots and trunk. Conclusion: We confirmed that the bark of roots and trunk of D. cochinchinensis tree were the main tissues for the synthesis and storage of dragon′s blood under natural conditions. This study demonstrated the potential to extract dragon′s blood from the roots that have been abandoned due to mining difficulties without destroying the tree, a process which would be beneficial to the protection of the endangered wild D. cochinchinensis tree populations.

Background: Berkleasmium sp. Dzf12, an endophytic fungus from Dioscorea zingiberensis, was a high producer of palmarumycin C13 with various bioactivities. In the present study, the experimental designs based on statistics were employed to evaluate and optimize the medium for palmarumycin C13 production in mycelia liquid culture of Berkleasmium sp. Dzf12. Results: Among various carbon and nitrogen sources, glucose, peptone and yeast extract were found to be the most favourable for palmarumycin C13 production based on the one-factor-at-a-time experiments. After Plackett-Burman test on the medium, glucose, peptone and yeast extract were further verified to be the most significant factors to stimulate palmarumycin C13 accumulation. These three factors (i.e., glucose, peptone and yeast extract) were then optimized through the experiments of central composite design (CCD) and analysis of response surface methodology (RSM). The optimized medium compositions for palmarumycin C13 production were determined as 42.5 g/l of glucose, 6.5 g/l of peptone, 11.0 g/l of yeast extract, 1.0 g/l of KH2PO4, 0.5 g/l of MgSO4 x 7H2O, 0.05 g/l of FeSO4 x 7H2O, and pH 6.5. Under the optimal culture conditions, the maximum palmarumycin C13 yield of Berkleasmium sp. Dzf12 was increased to 318.63 mg/l, which was about 2.5-fold in comparison with that (130.44 mg/l) in the basal medium. Conclusions: The results indicate that the optimum production of palmarumycin C13 in Berkleasmium sp. Dzf12 liquid culture can be achieved by addition of glucose, peptone and yeast extract with their appropriate concentrations in the modified Sabouraud medium.