Phytochemical profile of Paulownia tomentosa (Thunb). Steud.

Paulownia tomentosa, a member of the plant family Paulowniaceae and a rich source of biologically active secondary metabolites, is traditionally used in Chinese herbal medicine. Flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and miscellaneous other compounds have been isolated from different parts of P. tomentosa plant. Recent interest in this species has focused on isolating and identifying of prenylated flavonoids, that exhibit potent antioxidant, antibacterial, and antiphlogistic activities and inhibit severe acute respiratory syndrome coronavirus papain-like protease. They show cytotoxic activity against various human cancer cell lines and inhibit the effects of human cholinesterase, butyrylcholinesterase, and bacterial neuraminidases. Most of the compounds considered here have never been isolated from any other species of plant. This review summarizes the information about the isolated compounds that are active, their bioactivities, and the structure-activity relationships that have been worked out for them.

Undescribed C-geranylflavonoids isolated from the fruit peel of Paulownia catalpifolia T. Gong ex D.Y. Hong with their protection on human umbilical vein endothelial cells injury induced by hydrogen peroxide.

Six undescribed C-geranylated flavonoids, including five C-geranylflavanones named as paucatalinones F - J, one C-geranylflavonol named as paucatalinone K, along with seven known geranylated flavanones, were isolated from the fruit peel of Paulownia catalpifolia T. Gong ex D.Y. Hong. Their structures were elucidated distinctly according to their UV, IR, MS, NMR, and CD data. Among them, two compounds were substituted with unusual modified geranyl groups, namely paucatalinone F with an oxygenated cyclogeranyl substituent and paucatalinone H with a terminal pyranoid geranyl substituent. Furthermore, the protective effects on human umbilical vein endothelial cells (HUVECs) injury induced by H2O2 were evaluated, and paucatalinone F showed the most potential activity. The bioactive results suggested that the geranyl substituent may be an important factor for restraining oxidative HUVECs damage and Paulownia C-geranylated flavonoids might have the potential for preventing cardiovascular complications.

Two complete chloroplast genome sequences of genus Paulownia (Paulowniaceae): Paulownia coreana and P. tomentosa.

The nucleotide sequence of the two chloroplast (cp) genomes from Paulownia coreana and P. tomentosa are the first to be completed in genus Paulownia of family Paulowniaceae. The structure of two Paulownia cp genomes shows similar characteristic with general cp genome of angiosperms. The lengths of two cp genomes are 154,545 bp and 154,540 bp, respectively. The cp genomes are divided into LSC region (85,241 bp and 85,236 bp) and SSC region (17,736 bp and 17,736 bp) by two IR regions (25,784 bp and 25,784 bp). Both of two cp genomes contain 113 genes (79 protein coding genes, 30 tRNA genes and 4 rRNA genes), eight protein-coding genes, seven tRNA genes and four rRNA genes duplicated in the IR regions. Similar to the general cp genome of angiosperms, 18 of the genes in the two cp genomes have one or two introns. The overall A-T contents of two genomes are 62.0% which is similar with general angiosperms. The A-T content in the non-coding (64.6%) is higher than in the coding (60.1%) regions. Seventy-one and seventy simple sequence repeat (SSR) loci were identified in the P. coreana and P. tomentosa cp genomes, respectively. In phylogenetic analysis, genus Paulownia shows closed relationship with Lindenbergia philippensis of Orobanchaceae.