Pharmacological activities of crocin in saffron

The induction of programmed cell death, or apoptosis, involves activation of a signalling system, many elements of which remain unknown. The sphingomyelin pathway, initiated by hydrolysis of the phospholipid sphingomyelin in the cell membrane to generate the second messenger ceramide, is thought to mediate apoptosis in response to tumour-necrosis factor (TNF)-alpha, to Fas ligand and to X-rays. It is not known whether it plays a role in the stimulation of other forms of stress-induced apoptosis. Given that environmental stresses also stimulate a stress-activated protein kinase (SAPK/JNK), the sphingomyelin and SAPK/JNK signalling systems may be coordinated in induction of apoptosis. Here we report that ceramide initiates apoptosis through the SAPK cascade and provide evidence for a signalling mechanism that integrates cytokine- and stress-activated apoptosis.

Crocin is a pharmacologically active component of Crocus sativus L. (saffron) used in traditional Chinese medicine. We report here the effects of crocin on neuronally differentiated pheochromocytoma (PC-12) cells deprived of serum/glucose. Depriving the PC-12 cells of serum/glucose caused peroxidation of their cell membrane lipids and decreased intercellular superoxide dismutase (SOD) activity. Treating the PC-12 cells with 10 microM crocin inhibited the formation of peroxidized lipids, partly restored the SOD activity, and maintained the neuron's morphology. These antioxidant effects of crocin were more effective than those of alpha-tocopherol at the same concentration. Crocin also suppressed the activation of caspase-8 caused by serum/glucose deprivation. These results together with our previous data suggest that crocin is a unique and potent antioxidant that combats oxidative stress in neurons.