The world has a rich diversity of indigenous medicinal plants. The World Health Organization (WHO) gives high priority to eco-friendly, non-hazardous and cost effective healthcare such as the use of medicinal plants to treat various illnesses, including Human immunodeficiency virus (HIV) infection and Acquired immune deficiency syndrome (AIDS), tuberculosis (TB), diabetes mellitus (DM), malaria, and cancer. In developing countries, a high proportion of the population tends to use complementary and alternative medicines (CAM) together with conventional prescription drugs. Globally, CAM has been used in both developed and developing countries. In China, 30-50% of medicinal use is based on traditional alternative medicine. In Africa, it is estimated that 80% of primary health care is CAM, whilst in the USA, about 158 million people us CAM. This increase is due to three main influences: improve their eminence of life, relieve symptoms and preclude long-term complications. Despite the advances and advantages of conventional pharmaceutical medication, these are associated with long-term side effects and pose risks of inefficacy for treatment of chronic diseases such as cancer and DM. The biosynthesis of metal nanoparticles (NPs) using medicinal plants has received considerable attention as a proper alternative to using hazardous chemical and physical synthetic techniques. Plants are being exploited for their unique metal tolerance and effective production of gold metal NPs. A single medicinal plant contains an orchestra of chemical elements (e.g. proteins, vitamins, enzymes, amino acids, polysaccharides and organic compounds) that are "environmentally benign, yet chemically complex" and therefore serve as ideal tools for enhanced medicinal applications. It is reported that phytocompounds such as terpenoids, polysaccharides, polyols and flavones take part in the bio-reduction, stabilization and bio-capping mechanisms to form stable gold and silver NPs. Also the inhibitory potential of plant compounds against diabetic targets followed by a study of enzyme inhibitor kinetics, ligand binding dynamics supported by in silico docking studies that reveal the mode of bioactive compounds and their inhibitory activities. The present review focuses on the potential anticancer, antidiabetic and antimicrobial activity of phyto-synthesized gold and silver NPs. In phytonanotherapy, synergistic features of plant and metal NPs are unique as they offer healing properties that may be the clinical bioequivalent to many synthetic drugs, with minimal side effects. This could provide alternative treatment for chronic diseases that is efficient to overcome the disadvantages of synthetic monotherapy and allows medicinal plant therapy to co-exist with current synthetic treatments. This creates a much needed paradigm shift for further clinical studies in non-communicable and communicable diseases.
Keywords: Antimicrobials; Cancer; Diabetic; Docking; Gold nanoparticle; Green synthesis.
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