Chemical Constituents of Plants from the GenusBuxus

Structurally diverse triterpenoid alkaloids from Buxus rugulosa

Four new nortriterpenoid alkaloids, namely buxrugulines E-H (1-4), along with five known ones (5-9), were isolated from the twigs and leaves of Buxus rugulosa. Their structures were identified based on extensive NMR data and MS spectroscopic analyses. Our bioassays revealed that compounds 5, 6 and 8 exhibited potent cytotoxicity in vitro against MCF-7 cell lines, with IC50 values ranging from 6.70 to 11.00 μM, respectively.

The complete chloroplast genome sequence of Buxus megistophylla Levl. (Buxaceae Dumort.)

Buxus megistophylla Levl. is one of the most common green horticultural plants in the city presently. Here, we assembled and annotated the complete chloroplast (cp) genome of B. megistophylla. The whole length of the genome is 157,611 bp and encodes a total of 124 genes, which contains 89 protein-coding genes, 31 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. Phylogenetic tree analysis showed that B. megistophylla is separated from two other species of the same family, but these three species, clustered in one clade, are relatively closer to each other compared to the species in other families. This cp genome sequencing and phylogenetic analysis offer genetic background for conservation and may contribute to further evolutionary studies of this species.

Structurally diverse alkaloids from Buxus sempervirens with cardioprotective activity

Extensive phytochemical study of the methanol extract of twigs and leaves of Buxus sempervirens resulted in the identification of 17 Buxus alkaloids, including 12 new ones, namely buxusemines A-L (1-12). Their structures were delineated by detailed analysis of the HRESIMS and NMR data, as well as quantum chemical NMR calculations. Buxusemine A (1) represents the second Buxus alkaloid with a unique spiro[4.6]undecatriene moiety, buxusemines B-C (2-3) are a rarely occurring class of Buxus alkaloids featured with an additional five-membered ring through the ether or lactone linkage between C-10 and C-23, and buxusemines D-F (4-6) are another rare type of Buxus alkaloids with an epoxy motif. In the assessment of their bioactivities, buxusemine F (6) and buxanoldine (17) displayed more potent protective effects than the positive control cyclovirobuxinum D in the doxorubicin-induced cardiac injury model.

Buxaustroines A-N, a Series of 17(13→18)abeo-Cycloartenol Triterpenoidal Alkaloids from Buxus austro-yunnanensis and Their Cardioprotective Activities

Buxaustroines A-N (1-14), a series of triterpenoidal alkaloids featuring a novel 17(13→18)abeo motif, were obtained from the extract of Buxus austro-yunnanensis. Their structures were assigned based on NMR data analysis and X-ray diffraction crystallography. A putative biosynthetic pathway for one of the alkaloids from a co-isolate 15 is proposed. In the assessment of their bioactivities, some of the compounds displayed protective effects against doxorubicin-induced injury of myocardial cells. Preliminary structure-activity relationship studies of 1-14, which are based on the same skeleton, were conducted.

Cytotoxicity of Triterpenoid Alkaloids from Buxus microphylla against Human Tumor Cell Lines

Three new triterpenoid alkaloids, namely buxmicrophyllines P–R (1–3), were isolated from the twigs and leaves of Buxusmicrophylla. Their structures were elucidated on the basis of NMR and MS spectroscopic analyses. Structurally, compounds 1–3 belong to the 9,10-cycloartane type alkaloids. In addition, compound 3 exhibited moderate cytotoxic activities in vitro against HL-60, SMMC-7221, A-549, MCF-7, and SW480 cell lines (with IC₅₀ values ranging from 4.51 to 15.58 μM).