The sigma-1 receptor is a transmembrane protein first identified in the 1980s as a binding site for the hallucinogenic drug phencyclidine (PCP). Since then, numerous studies have revealed the sigma-1 receptor's involvement in various physiological processes, including pain perception, mood regulation, and drug addiction.

The sigma-1 receptor is widely distributed throughout the body, including the central nervous system (CNS), where it is expressed in multiple brain regions. This suggests that the receptor plays a crucial role in CNS function. Research has shown that the sigma-1 receptor can modulate neurotransmitter release, ion channel activity, and intracellular signalling pathways.

More recently, the sigma-1 receptor has been implicated in developing and progressing various types of cancer. In particular, the receptor has been found to be overexpressed in several cancer types, including breast, lung, prostate, and colon cancer. Research has also demonstrated that sigma-1 receptor antagonists can inhibit cancer cell proliferation, migration, and invasion in vitro and in vivo.

The potential of the sigma-1 receptor as a therapeutic target has garnered considerable attention in recent years. In particular, the receptor's role in cancer and CNS function has led to developing sigma-1 receptor modulators as potential treatments for cancer, neurodegenerative diseases, and psychiatric disorders.

Drug repurposing is a hot topic for several reasons. Firstly, developing new drugs from scratch is time-consuming, expensive, and fraught with challenges. It can take over a decade and cost billions of dollars to bring a new drug to market, and the failure rate for new drug development is high. In contrast, drug repurposing involves investigating existing drugs that have already undergone safety testing and clinical trials, which can reduce the time and cost of drug development.

Secondly, drug repurposing has the potential to identify new therapeutic uses for existing drugs that were not initially intended for those purposes. This can lead to the development of new treatments for diseases with few or no effective therapies and can also help address drug shortages in certain regions or countries.

Thirdly, drug repurposing can potentially accelerate the translation of research findings into clinical practice. In many cases, drugs that have been found to be effective in preclinical studies have failed to translate into clinical practice due to safety concerns, lack of efficacy, or other issues. Repurposing existing drugs that have already been approved for use in humans can help to bypass some of these barriers and accelerate the translation of research findings into clinical practice.

Natural products have been used for centuries by various cultures as medicines, indicating that they possess biological activity and therapeutic potential. Studying natural products can help to identify the active compounds responsible for their therapeutic effects and elucidate the mechanisms underlying their activity.

Natural products offer a rich source of chemical diversity. Living organisms produce natural products and have evolved over millions of years to serve various biological functions, including defence against predators, communication, and reproduction. This has led to developing a vast array of structurally diverse natural products with potential therapeutic applications. Many drugs currently on the market or in clinical development are derived from natural products or inspired by natural product structures.

Studying natural products can help to identify new leads for drug discovery. Natural products often serve as starting points for developing synthetic analogues or derivatives that exhibit improved pharmacological properties, such as increased potency or reduced toxicity. This can lead to the development of novel drugs that have the potential to treat diseases more effectively and with fewer side effects than existing therapies.

Lastly, studying natural products can help to address the issue of drug resistance. Drug resistance is a growing concern in many disease areas, and there is an urgent need for new therapies that can overcome resistance mechanisms. Natural products have been shown to possess a wide range of biological activities and can act on multiple targets, making them attractive candidates for the development of new therapies that can overcome resistance mechanisms.

In conclusion, studying natural products for disease treatment is important because it can lead to the identification of new therapeutic leads, address the issue of drug resistance, and provide a rich source of chemical diversity for drug discovery