Baccatin III is an isolate of the Pacific yew tree (Taxus brevifolia) and related species. Baccatin III is the precursor to paclitaxel/ taxol. Antileukaemic and antitumor agent, Baccatin III, binds to tubules when they are assembled in the cell and stabilizes the polymerized form of tubules so that they remain assembled even under conditions in which microtubules dissociate into tubulin subunits. Baccatin III is also an inducer of apoptosis and shows antitumor properties in vitro. Baccatin III exerts anti-tumor immunomodulatory activity in very low doses (0.05-0.5mg/kg), although it is regarded as an inactive derivative of paclitaxel. Oral administration of Baccatin III significantly reduced the growth of tumors induced by engrafting BALB/c mice with either 4 T1 mammary carcinoma or CT26 colon cancer cells. Baccatin III reduced tumor progression by inhibiting the accumulation and suppressive function of MDSCs. Baccatin III inhibited cell proliferation of a number of cancer cell lines. The cytotoxic activity exhibited by fungal taxol and Baccatin III involves the same mechanism, dependent on caspase-10 and membrane potential loss of mitochondria, with taxol having far greater cytotoxic potential.

27-Hydroxycholesterol (27-HC) is an endogenous oxysterol produced by the enzyme CYP27A1, with multiple biological functions, including acting as a selective estrogen receptor modulator (SERM) and as an agonist of the liver X receptor (LXR). Because of its estrogenic action, 27-HC stimulates the growth of ER-positive breast cancer cells and has been implicated in limiting the effectiveness of aromatase inhibitors in the treatment of breast cancer.

Coniine is a neurotoxic piperidine alkaloid found in poison hemlock (Conium maculatum L.). Coniine which is considered to be racemic mixture first described by Gieseke in 1827; von Hoffman confirmed the structure in 1881; Ladenburg perfermed synthesis in 1886. Coniine enantiomers are nicotinic acetylcholine receptor (nAChR) agonists. The relative potencies of these enantiomers on TE-671 cells expressing human fetal nicotinic neuromuscular receptors had the rank order of (-)-coniine > (+/-)-coniine > (+)-coniine. The rank order potency in SH-SY5Y cells which predominately express autonomic nAChRs was: (-)-coniine>(+)-coniine> (+/-)-coniine.

10-deactyltaxol (10-deacetylpaclitaxel) is a naturally occurring taxane related to taxol (paclitaxel). Taxol is an antitumor drug with cytotoxic properties that correlate with its microtubule-stabilizing activities. When compared to paclitaxel 10-deacetyltaxol is 100% as active as paclitaxel in promoting in vitro microtubule assembly, but is only 30% as cytotoxic as paclitaxel. 10-deactyltaxol is a semi-synthetic precursor of paclitaxel and considered to be paclitaxel impurity. 10-deactyltaxol, isolated from the bark of Taxus brevifolia, was converted into paclitaxel in one composite step (trimethylsilylation, acetylation, and desilylation) and in an overall yield of 80-85%.

Phenanthrene is one of a group of chemicals called polycyclic aromatic hydrocarbons, PAHs. Phenanthrene is one of the most abundant PAHs found in continental shelf sediment of the South China Sea and is on the EPA’s Priority Pollutant list. Phenanthrene can affect different organisms through some potential mechanism such as the aryl hydrocarbon receptor (AHR) agonists, reproductive endocrine disruptor and photosynthesis stimulation. Phenanthrene is used in manufacturing dyestuffs and explosives and in biological research. Sources of phenanthrene include diesel fuel exhaust, coal tar pitch and tobacco smoke. Phenanthrene has been found in particle emissions from natural gas combustion and municipal incinerator waste, and in the particulates present in ambient air pollution near high vehicular traffic and industrial or urban areas.

DL-5-hydroxytryptophan, 5-HTP is a serotonin precursor. It was discovered on the rats, that the pharmacological responses and changes in brain 5-hydroxytryptamine (5-HT) concentration elicited following the administration of 5-HTP did not reflect changes in the concentration of endogenous brain 5-HT. The biochemical and pharmacological properties of the 5-HTP-induced increases in brain 5-HT concentration were distinctly different from those of increases in the endogenous content of the amine. In normal rats, administered 5-HTP, observable pharmacological responses were not elicited, despite equal or even larger increases in brain 5-HT concentration.