Chinese Medicine, Succinum, Ameliorates Cognitive Impairment of Carotid Artery Ligation Rats and Inhibits Apoptosis of HT22 Hippocampal Cells via Regulation of the GSK3β/β-Catenin Pathway

Succipenoids A-C: A dimeric abietane and nor-abietane diterpenoids from fossil Chinese medicinal succinum and their anti-inflammatory potential

An unprecedented dimeric abietane, succipenoid A (1), and two previously undescribed nor-abietane diterpenoids featuring a rarely occurring naphthalene ring or with a large conjugated system, succipenoids B and C (2 and 3), along with seven known diterpenoids (4-10) were isolated from the CH2Cl2 extract of succinum. The structures of these compounds, including their absolute configurations, were elucidated using spectroscopic and computational techniques. Notably, compounds 1-4 and 6-10 were isolated from succinum for the first time. In order to evaluate their anti-inflammatory potential, in vitro tests were conducted. The results demonstrated that compounds 1, 2, 4, and 6-10 exhibite dose-dependent inhibition of iNOS expression in lipopolysaccharide-induced RAW 264.7 cells.

Succinum extracts inhibit microglial-derived neuroinflammation and depressive-like behaviors

Microglia are emerging as important targets for the treatment of neuropsychiatric disorders. The phagocytic microglial phenotype and the resulting neuroinflammation lead to synaptic loss and neuronal cell death. To explore potential candidates that inhibit microglial hyperactivation, we first investigated ten candidate extracts of traditional Chinese medicine (TCM) using lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Among the candidates, Pinus spp. succinum extract (PSE) was superior; thus, we further investigated its pharmacological activity and underlying mechanisms both in vitro and in vivo. Pretreatment with PSE (10, 20, and 40 μg/ml) attenuated the increases in inflammatory factors (nitric oxide and tumor necrosis factor-α), translocation of nuclear factor-kappa B (NF-κB), and phenotypic transformations (phagocytic and migratory) in a dose-dependent manner. These inhibitory effects of PSE on microglia were supported by its regulatory effects on the CX3C chemokine receptor 1 (CX3CR1)/nuclear factor erythroid-2-related factor 2 (Nrf2) pathway. In particular, intragastric administration of PSE (100 mg/kg) considerably improved sickness, anxiety, and depressive-like behaviors in mice subjected to chronic restraint stress (CRS). Our results suggest that PSE has strong antineuroinflammatory and antidepressant properties, and the underlying mechanisms may involve not only the regulation of NF-κB translocation but also the normalization of the CX3CR1/Nrf2 pathway.