Oxidative stress plays an important role in Parkinson’s disease and other neurodegenerative disorders. Lycium barbarum polysaccharides (LBP), the main active ingredients extracted from the fruits of Lycium barbarum L., have been shown to be a potent antioxidant. In the present study, we investigated the protective effects, and the possible mechanism of action of LBP against 6-hydroxydopamine (6-OHDA)-induced apoptosis in PC12 cells. Our data demonstrated that LBP significantly reversed the 6-OHDA-induced decrease in cell viability, prevented 6-OHDA-induced changes in condensed nuclei and decreased the percentage of apoptotic cells in a dose-dependent manner. Furthermore, LBP also slowed the accumulation of reactive oxygen species (ROS) and nitric oxide (NO), decreased the level of protein-bound 3-nitrotyrosine (3-NT) and intracellular free Ca²⁺, and inhibiting the overexpression of nuclear factor κB (NF-κB), neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS). These results demonstrate that LBP prevents 6-OHDA-induced apoptosis in PC12 cells, at least in part through the ROS-NO pathway.

Four new spirostanol saponins, named pavitnosides A–D (1–4), with six known steroidal saponins 5–10 were isolated from the rhizomes of Paris vietnamensis. Their chemical structures were determined based on extensive spectroscopic studies and chemical methods. The aglycones of pavitnoside B and pavitnoside C were not reported in previous work. The cytotoxicity of all saponins was evaluated against human glioblastoma U87MG and U251 cell lines. The new spirostanol saponin 1 displayed weak anti-proliferative activity against U87MG cell line and the known saponins 8 and 9 exhibited significant cytotoxicity against the two tumor cell lines, with IC₅₀ values of 2.16 to 3.14 μM, but did not affect the growth of primary cultures of human astrocytes.

Five new alkaloids, daphnicyclidins M and N (compounds 1 and 2) and calyciphyllines Q–S (compounds 3–5), along with four known ones, paxiphylline C (6), macropodumine B (7), macropodumine C (8) and daphnicyclidin A (9) were isolated from the stem bark of Daphniphyllum macropodum. Calyciphylline Q (3) is the first calyciphylline A derivative possessing a double bond between C-18 and C-19. Their structures and relative configurations were elucidated on the basis of spectroscopic methods, especially 2D NMR techniques. Compounds 1, 2, 8 and 9 exhibited cytotoxic activity against P-388 cells with IC₅₀ values of 5.7, 6.5, 10.3 and 13.8 µM, respectively. Compounds 1 and 2 also showed cytotoxic activity against SGC-7901 cells with IC₅₀ values of 22.4 and 25.6 µM.

Four new polyhydroxysteroidal glycosides—culcinosides A–D (1, 2, 4, and 7)—along with three known compounds—echinasteroside C (3), linckoside F (5), and linckoside L3 (6)—were isolated from the ethanol extract of starfish Culcita novaeguineae collected from the Xisha Islands of the South China Sea. The structures of new compounds were elucidated through extensive spectroscopic studies and chemical evidence, especially two-dimensional (2D) NMR techniques. The cytotoxicity of the new compounds against human glioblastoma cell lines U87, U251, and SHG44 were evaluated.