Licochalcone A (LicA) is a flavonoid isolated from the famous Chinese medicinal herb Glycyrrhiza uralensis Fisch and has a wide spectrum of pharmacological activities such as anti-oxidant, anti-bacterial, anti-viral, and anti-cancer. However, its pharmacological mechanism is not well defined. The anti-Inflammatory effects of LicA on IL-1β-Stimulated human osteoarthritis chondrocytes was reached by activating Nrf2 signaling pathway. LicA showed anti-proliferative and apoptotic effects in breast cancer cells through regulating Sp1 and apoptosis-related proteins in a dose- and a time-dependent manner. In addition, the chemotherapeutic potential of LicA for treatment of human cervical cancer was achieved by inhibition of PI3K/Akt/mTOR signaling.

Trichostatin A (TSA) was originally isolated as an antifungal antibiotic along with its fermentation congeners trichostatin B ((TSA)3-Fe) and the D-glucopyranosides trichostatin C and D. TSA inhibits HDAC in the low nanomolar range and is an inducer of histone hyperacetylation, both in vitro and in vivo. It inhibits all class I and II deacetylases to a similar extent in both tumor and non-tumor cells, although HDAC4 is slightly resistant when compared with HDAC1 and HDAC6. Class III HDAC is not affected by TSA. It has been shown that TSA dosedependently inhibits growth and induces apoptosis in a plethora of carcinoma cell lines in vitro. Recently, it was also found that TSA inhibits angiogenesis, which is important for the growth and metastasis of solid tumors, both in vivo and in vitro. In HT-29 colon carcinoma cells, a single dose of TSA induced transient hyperacetylation of histone H4 resulting in the induction of p21WAF1/Cip1 and inhibition of cellular proliferation at both the G1 and G2 phases of the cell cycle. Growth inhibition was associated with decreased cyclin D1 mRNA and cdk6 protein levels and increased cyclin D3 protein and p21WAF1/Cip1 mRNA levels. Cyclin D1 protein, cyclin D3 mRNA, cdk2 and cdk4 remained unaffected. In addition, TSA induced apoptosis by upregulating the expression of the pro-apoptotic genes ID1, ID2 and ID3, whereas the expression of the anti-apoptotic genes BclxL and Hsp27 was decreased In vivo, TSA induces differentiation and shows chemotherapeutic activity against N-methylnitrosureainduced rat mammary cancer without toxic side effects. TSA may also have therapeutic potential for the treatment of a variety of genetic and infectious diseases since silenced, transduced genes are reactivated probably due to structural changes of the chromatin on integrated viral sequences.

Bisphenol A is a small estrogenic monomer that is polymerized to produce polycarbonate plastic and resins used to line metal cans. It is also used to make some dental sealants. Bisphenol A had been considered to be a very weak environmental estrogen. It is able to interact with human estrogen receptors. In addition, it binds strongly to the estrogen-related receptor gamma. Bisphenol A inhibited androgen-induced androgen receptor transcriptional activity. Prenatal exposure to maternal Bisphenol A concentrations were related to higher levels of anxiety, depression, aggression, and hyperactivity in children. Bisphenol A exposure in childhood was associated with higher levels of anxiety, depression, hyperactivity, inattention, and conduct problems. It never found use as a drug.

Fosbretabulin (Combretastatin A4 phosphate, CA4P) is the lead compound of a relatively new class of agents termed vascular disrupting agents that target existing tumor blood vessels. Rapid tumor blood flow shutdown has been demonstrated in preclinical models and patients by various techniques such as dynamic contrast-enhanced MRI, perfusion computed tomography and PET scans following CA4P infusion. CA4P typically induces rapid tumor necrosis in the center of the tumor and leaves a rim of viable cells in the periphery. In oncology, CA4P does not appear to be that active by itself, but may be more efficacious when combined with chemotherapy, antiangiogenic therapy and radiation therapy. Combretastatin was initially isolated from the root bark of the South African Bush willow Combretum caffrum in 1982 by Pettit and colleagues at the Arizona State University (AZ, USA). Combretastatin A4 phosphate binds avidly to tubulin at the colchicine-binding site to inhibit microtubule assembly and destabilize the cytoskeleton. CA4P is a tubulin-binding agent that binds at or near the colchicine binding site of β-tubulin (Kd = 0.40 uM), inhibits tubulin assembly with IC50 of 2.4 uM. Fosbretabulin has orphan drug status in the EU and the US for the treatment of ATC (Anaplastic Thyroid Cancer). Later the development of this drug was discontinued.

2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH), a chlorin-based photosensitize, is used in photodynamic therapy. It has been shown the therapeutic potential of HPPH in phase II clinical trials for the treatment of esophageal cancer. Besides, HPPH participated in clinical trials in treating patients with advanced non-small cell lung cancer that blocks the air passages. However, these studies were terminated.

Marizomib is a natural beta-lactone produced by the marine bacterium Salinispora tropica. Marizomib has a broad inhibition profile for the 20S proteasome and has been shown to inhibit the CT-L (beta5) CT-T-laspase-like (C-L, beta1) and trypsin-like (T-L, beta2) activities of the 20S proteasome. The drug is being tested in phase II clinical trials for the treatment of Multiple Myeloma and Malignant Glioma and in phase I in patients with Non-small Cell Lung Cancer, Pancreatic Cancer, Melanoma or Lymphoma