Pegaharmalines A (1) and B (2), two novel β-carboline alkaloids with unprecedented carbon skeletons, were isolated from the seeds of Peganum harmala. Their structures were determined by spectroscopic methods and the absolute configuration of 1 was elucidated by CD analysis. 1 and 2 exhibited significant cytotoxicities on HL-60 cells with IC₅₀ values of 9.4 and 13.6 μM, respectively.

Three new meroterpenoids, guajavadials A–C (1–3), were isolated from Psidium guajava cultivated in temperate zone. Their structures were established by extensive spectroscopic evidence and electronic circular dichroism (ECD) calculations. Guajavadial A (1) represents a novel skeleton of the 3,5-diformylbenzyl phloroglucinol-coupled monoterpenoid, while guajavadials B (2) and C (3) are new adducts of the 3,5-diformylbenzyl phloroglucinol and a sesquiterpene with different coupling models. The plausible biosynthetic pathways as well as antimicrobial and cytotoxic activities of these meroterpenoids are also discussed. All these isolates exhibited moderate cytotoxicities against five human cancer cell lines, with 3 being most effective with an IC₅₀ value of 3.54 μM toward SMMC-7721 cell lines.

Two new monoterpenoid coumarins: anisucumarin A (1) and B (2), a pair ofepimers, were isolated from Clausena anisum-olens. Their structures were establishedbased on extensive spectroscopic analyses.

Five new sesterterpenoids, compounds 1–5, have been isolated from the sponge Hippospongia lachne off Yongxing Island in the South China Sea. The structures of compounds 1–5 were elucidated through extensive spectroscopic analysis, including HRMS, 1D, and 2D NMR experiments. The stereochemistry, including absolute configurations of these compounds, was determined by spectroscopic, chemical, and computational methods. Compounds 1 and 5 showed moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activities with IC₅₀ values of 5.2 μM and 8.7 μM, respectively, more potent than previously reported hippolides.