In this study, we synthesized a series of amide and mitochondria-targeted derivatives with 3- O -acetyl-11-keto-β-boswellic acid (AKBA) as the parent structure and an ethylenediamine moiety as the link chain. Compound 5e , a mitochondrial-targeting potential derivative, showed significantly stronger antitumor activity than that of AKBA, and it could induce vacuolization of A549 cells and stimulate the production of reactive oxygen species (ROS) in a time- and concentration-dependent manner. The antioxidant N -acetylcysteine (NAC) could inhibit the ROS level but could not suppress vacuolization and cell death induced by 5e . Further studies demonstrated that 5e caused abnormal opening of mitochondrial permeability transition pore (MPTP) and a decrease of mitochondrial membrane potential; additionally, it caused cell cycle arrest in G 0 /G 1 but did not induce apoptosis. 5e represented a compound with improved antiproliferative effects for cancer therapy working through new mechanisms.

Two pairs of diastereoisomeric isoindoline alkaloids, xylarins A–D (1–4), were isolated from the endolichenic fungus Xylaria sp. Xylarins A and B (1 and 2) possess a previously undescribed 5/6/5–5/6 polycyclic scaffold, featuring a combination of a novel dihydrobenzofurone unit and an isoindoline unit, while xylarins C and D (3 and 4) contain an additional N,N-dimethylaniline at the C-3′ position. Their structures were elucidated by comprehensive spectroscopic analyses combined with single-crystal X-ray diffraction and electronic circular dichroism calculations. The plausible biosynthetic pathways and gene clusters for 1–4 were proposed. Compound 1 exhibited significant antithrombotic activity.

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