A review on protease inhibitors of herbal origin to combat malignancy

Protease is the enzyme responsible for the breakdown of proteins. Proteases are involved in events of growth, development, progression and metastasis of cancers. If any agent could inhibit the protease i.e., protease inhibitor, it would arrest the cancer; thus indicating the search of protease inhibitors for newer anti-cancer drug discovery. Higher plants are the rich sources of different protease inhibitors that are effective against several types of cancers both at pre-clinical and clinical stages. Plant-derived natural protease inhibitors have both cancer chemopreventive and chemotherapeutic properties together with inhibitory activity against different types of pertinent proteases. Clinically, these are found to be safe unlike the synthetic drugs. Further studies in this direction are necessary in casting about for newer generation drugs without adverse effects for the prevention and treatment of malignancies.