Pseudolaric acid B: Natural sources, preparation, structural modification, bioactivities, and translational challenges.

Cortex pseudolaricis, commonly known as Tu-jin-pi, is a traditional Chinese herbal medicine derived from the dried root bark or bark near the root of Pseudolarix amabilis. In traditional Chinese medicine, this herb is characterized by a pungent taste, warm nature, and affinity for the lung and spleen meridians. Historically, it has been used to treat skin diseases such as tinea. To date, more than 200 constituents have been reported in Cortex pseudolaricis, including diterpenes, triterpenes, sesquiterpenes, phenylpropanes, flavonoids, sterols, and other chemical compounds. Among these, pseudolaric acid B (PAB) serves as a key chemical marker and has been investigated for antifungal, anticancer, antibacterial, and anti-inflammatory effects in preclinical models. More importantly, PAB has also been extensively studied and applied in areas such as antibacterial and anti-inflammatory effects. This review systematically summarizes research progress on PAB, covering its natural sources, extraction and isolation techniques, synthesis strategies, structural modifications, and biological activities. It also identifies critical knowledge gaps concerning its mechanisms of action, pharmacokinetic-pharmacodynamic relationships, and toxicological profile, thereby underscoring the need for a thorough risk-benefit assessment. Future studies should focus on elucidating the molecular mechanisms underlying PAB's therapeutic effects to better define its bioactivity-toxicity profiles. This review provides a comprehensive overview of the natural sources, preparation, structural modifications, bioactivities, and translational challenges of PAB, with the aim of consolidating current knowledge and facilitating its development into viable therapeutic candidate.