Despite significant advancements in allopathic medicine, over 80% of WHO member countries continue to utilize traditional medicinal practices in various forms to address a wide range of health issues 6. These practices are referred to as ‘non-conventional medicine’, or ‘complementary medicine’, or ‘alternative medicine’, depending on whether they rely solely on local and indigenous knowledge or are combined with modern medical practices, varying by region across the world 7. The World Health Organization defines traditional medicine as an indigenous practice used for maintaining health and for preventing, diagnosing, and treating physical and mental illness. It differs from allopathic medicine in its reliance on specific theories, beliefs, and experiences.” Many people worldwide rely heavily on traditional medicine for their health management, with Southeast Asian countries being particularly noted for their diverse traditional medicine systems 89. In East Asia, traditional medicine was the primary medical approach for treating various disorders before Western influences began in the 19^th century 10.

Traditional medicine encompasses a broad range of therapies and practices that vary from culture to culture and country to country. Each nation has developed its own system of traditional medicine, influenced by its unique culture, history, resources, social structures, economic conditions, and international interactions 11. Table 1 illustrates the various traditional medical systems practiced around the world and their primary approaches. Despite the different names and systems, traditional medicine can generally be categorized into three types: Scholarly medical systems, Folk medical systems, and Shamanistic medical systems 7.

A medical system that has a long-standing therapeutic history, established theories and principles, and a rigorous academic discourse is referred as a scholarly medical system. Ayurveda, believed to have originated during Vedic period (1500-900 BC), encompasses a vast body of scriptures detailing principles and practices in internal medicine and surgery, along with both informal and formal methods of education. Therefore, Ayurveda is considered one of the scholarly medical systems within the traditional medicine framework ^{7, 30}. Ayurveda, known as the ‘science of life’, extends beyond medical care to encompass the art of living a happy and prosperous life 31. It takes a holistic approach, offering a unique blend of science and philosophy that integrates physical, psychological, emotional and spiritual aspects of health 32. Although the exact origin and history of Ayurveda remain unclear and shrouded in the passage of time, it is mythologically believed that the original verses of Ayurveda originated from the consciousness of Lord Brahma (the creator) and were passed down to various disciples who compiled them into large texts called Samhitas (compendiums). Over time, these works were revised by numerous scholars, leading to the modern form of Ayurveda. A timeline of Ayurveda, as outlined in literature is depicted in Figure 1.

Ayurvedic formulations are medicines derived from plants, animals, and minerals, available as both single-ingredient and compound preparations. These formulations have been used to treat different disorders like acne, allergies, asthma, anxiety, arthritis, chronic fatigue syndrome, cold, colitis, constipation, depression, diabetes, flu, heart disease, hypertension, immune problem, inflammation, insomnia, nervous disorders, obesity, skin problems, and ulcers. They are administered in various ways within the body, and there are essentially two main types of Ayurvedic formulations: classical and proprietary 3435.

Classical Ayurvedic formulations are made using the exact methods outlined in ancient Ayurvedic texts such as the Charaka Samhita, and Sushruta Samhita. Examples of these formulations are mentioned in Table 2.

Proprietary or Patent formulations are those whose recipes are patented by the manufacturer and are not found in traditional Ayurvedic scriptures.

Panta et al. (2018) reported that certain Ayurvedic formulations with an amorphous texture and higher water solubility in water exhibit antibacterial properties, whereas formulations with a crystalline texture and lower solubility in water show no effect against bacterial strains 36.

Ayurveda is thus a scholarly traditional medicine system widely practiced in the Indian subcontinent, including Nepal. With a history spanning over 5,000 years, its precise origins remain unclear. Ayurveda focusses on achieving balance and harmony between the body, mind, and spirit to promote optimal health. It takes a holistic approach to wellness by addressing the underlying causes of imbalances rather than just alleviating symptoms. A significant portion of the population in India and Nepal continues to trust in Ayurvedic principles and uses various Ayurvedic formulations to treat various health disorders.

In the ‘Kupipakwa’ method, illustrated in Figure 3, metals or minerals are first purified through the ‘Sodhan’ process and then amalgamated with mercury. The amalgam is triturated with sulphur in a mortar until it becomes black, lustreless, fine and smooth mass is obtained. This process is called ‘Kajjali’ preparation. Once the ‘Kajjali’ is ready, it is shade-dried and placed in a glass bottle known as ‘Kachkupi’. The glass bottle is then sealed and wrapped with seven layers of mud smeared cloth. This assembly is placed in a sand bath and heated repeatedly for a specific period until the bhasma is formed 38.

Ayurvedicbhasmas are herbo-mineral or metallic formulations used as potent medicines in Ayurvedic treatments. These drugs are prepared by repeated grinding of minerals or metals with extracts from Ayurvedic herbs, followed by calcination at temperature above 650 ^°C. This preparation process closely resembles the top-down approach used in nanoparticle synthesis, and bhasma is regarded as a form of biologically produced nanomedicine.

Traditional methods for assessing the quality of bhasmas are straightforward and primarily rely on physical characteristics. Several of these traditional characterization techniques for Ayurvedic bhasmas are detailed in Table 3.

Modern analytical methods, including XRD, EDX, FTIR, DLS, SEM, and TEM, are used to analyze the chemical composition and properties of bhasma particles. X-ray diffraction (XRD) is a non-destructive technique that characterizes crystalline materials. It provides detailed information on structures, phases, preferred crystal orientations, and several other structural parameters such as average grain size, degree of crystallinity, strain, and crystal defects in the particles 40. Energy Dispersive X-ray (EDX) microanalysis is a technique specifically used to determine the quantitative elemental composition of particles. It allows for the identification of major, minor and trace elements within a sample 41. This method detects the X-rays emitted as a result of the interaction between an electron beam and the sample. Fourier-Transform Infrared (FTIR) spectroscopy is a rapid, non-destructive optical technique that measures the vibrations of excited molecules using IR radiation within a specific wavelength range. It is used to identify various types of organic and some inorganic materials, molecular species, and molecular orientations 42. FTIR spectroscopy can be employed to detect organic moieties in bhasma particles that may have been introduced during its preparation. Dynamic Light Scattering (DLS), also referred to as Photon Correlation Spectroscopy (PCS) is a rapid spectroscopic technique used to determine the size distribution of particles in solution or suspension 43. This technique provides information on the effective diameter and polydispersity of bhasma particles. Scanning Electron Microscopy (SEM) produces detailed three dimensional images of particles at very high magnifications, offering insights into their topography, morphology, composition, and crystallographic nature 44. SEM can be used to examine the size, shape and structure of bhasma particles.

For the purpose of illustrating structure and properties in the following sections, three metal based bhasmas – Tamra (Copper based), Vanga (Tin based), and Yashad (Zinc based) – as well as three mineral-based bhasmas – Abhrak (mica based), Mandura (Haematite based), and Godanti (Gypsum based) – are selected as representative examples. These bhasmas are chosen because their raw materials are relatively inexpensive and readily available, and they have broad applications beyond medicinal use, making them commonly recommended by practitioners.

XRD analysis of Mandura bhasma shows major peaks corresponding to ferric oxide (Fe₂O₃) with a rhombohedral structure and minor peaks of potassium sulphate (K₂SO₄) (Figure 8). EDX results indicate the presence of elements such as carbon (C), oxygen (O), aluminium (Al), silicon (Si), chlorine (Cl), potassium (K), calcium (Ca), and iron (Fe). SEM images reveal an irregular distribution of particles, mostly with a rhombohedral shape (Figure 9). FTIR analysis confirms the presence of organic groups with O-H, N-H, C-H, C-C and C-X bonds. The average particle size is 3.2 nm, with a zeta potential of – 32.7 mV, indicating high colloidal stability. The UV spectrum shows maximum absorbance at 300 nm in UV region 5556.

XRD analysis of Godantibhasma shows that calcium sulphate (CaSO₄) with orthorhombic structure is the major phase, while calcium sulphide (CaS) with a cubic structure is present as a minor phase. EDX analysis confirms the presence of calcium (Ca), sulphur (S), oxygen (O), and carbon (C). The FTIR spectrum shows bands corresponding to O-H bending and SO₄ stretching vibrations. SEM images depict a mixture of rod-shaped and rhombohedral particles with sizes ranging from 14 to 33 nm 57.

Instrumental analysis of various bhasmas using different techniques has shown that the particles are crystalline and fall within the nanoscale size range. These particles primarily consist of metal oxides or metal sulphides, along with other elements and organic compounds derived from Ayurvedic herbs used during preparation. The size, shape, and distribution of the particles are influenced by factors such as the preparation steps, heating methods, equipment used, temperature, and duration of heating. Bhasmas prepared using modern muffle furnace heating tend to have a higher percentage of smaller particles with uniform distribution compared to those produced with traditional cow dung cake heating. In the traditional method, the particle fineness increases with the number of puta cycles (processing rounds). The particles exhibit various shapes, including spherical, irregular flakes, rhombohedra, and rod-like forms. Their high colloidal stability suggests they disperse easily and are quickly absorbed into body fluids.

Bhasmas are metal- or mineral-based preparations that undergo specific purification and calcination processes to enhance their therapeutic properties. The reduction of particle size to the nanometer scale, along with the incorporation of various herbal ingredients during synthesis, enriches these particles with medicinal value. For centuries, they have been used to treat various human ailments58. Practitioners of bhasma believe that these preparations promote healing, balance the body’s doshas (energy principles), and improve overall well-being 3132. Recent studies have shown that bhasmas possess antioxidant, anti-inflammatory, antibacterial, antiviral and antitumor properties and may serve as potential carriers for drug delivery 375960. The therapeutic uses of some Ayurvedicbhasmas are listed in the Table 4.

Recent studies have highlighted the therapeutic potential of various bhasma particles. Swarna Bhasma has been shown to be effective in treating malignant tumors in the lungs, liver, pancreas, gall bladder, colon, and rectum. Yashad Bhasma has demonstrated effectiveness as a cytostatic drug in human pancreatic ductal adenocarcinoma. Abhrak Bhasma has exhibited anti-cancer activity, particularly in cases of breast cancer and leukemia. Tamra Bhasma, synthesized using Acalypha indica extract, has shown cytotoxic potential against human breast cancer cells. Heerak Bhasma has been found to possess immunostimulatory and tumoricidal properties, particularly against highly metastatic and aggressive murine lymphoma 6268697071.

Ayurvedic bhasmas have been an integral part of traditional Ayurvedic medicine, used for therapeutic purposes over centuries. According to Ayurvedic principles, bhasmas are believed to enhance the medicinal properties of the substances from which they are made. They are thought to have unique healing abilities and are used to treat various ailments. Advocates of Ayurvedic medicine suggest that bhasmas can help restore balance, support overall health, provide nourishment, improve digestion and metabolism, and stimulate the body’s natural healing processes. However, due to a lack of sufficient scientific evidence, research, and rigorous clinical trials, it is important to use bhasmas with caution and under the guidance of a qualified practitioner.

A nanometer one billionth of a meter. The concept of nanotechnology was first introduced by Richard Feynman in his 1959 lecture titled “There is Plenty of Room at the Bottom” given at an American Physical Society meeting. The term ‘nanotechnology’ was coined by Norio Taniguchi in 1974. Nanotechnology involves the innovative application of science and technology to design, synthesize, characterize, and apply materials at the molecular level, specifically within the range of a few to several hundred nanometers 72. This field has opened up new possibilities in various domains, including medicine, electronics and communication, energy and environment, transportation, food and agriculture, and space exploration 7374.

Nanomedicine is a field of medicine that makes advanced nanotechnology techniques for the prevention, diagnosis and treatment of diseases. It has had a transformative effect on health care in the twenty-first century. Nanomedicine employs nanoparticles, including polymeric micelles, liposomes, and lipid nanoparticles, to improve disease prevention and treatment within living organisms. It provides opportunities for earlier disease detection, more effective and personalized therapies with minimal side effects, and reduced health care costs. Additionally, nanomedicine proves valuable in drug delivery systems, cancer therapy, tissue engineering, and holds potential for future applications in molecular nanotechnology 75767778798081.

The principles of nanomedicine revolve around integrating nanotechnology into medicine. This field focusses on developing and applying nanoscale tools, devices and materials for various medical purposes. The core principle of nanomedicine is the manipulation and control of materials at the nanoscale to achieve specific therapeutic or research outcome. The basic principles of nanomedicine include 7580818283

Targeted delivery: Nanoparticles can be engineered to specifically target diseased cells or tissues. By attaching ligands or antibodies that bind to particular cell surface markers, these particles can deliver drugs or therapeutic agents directly to the intended location, minimizing side effects and enhancing treatment effectiveness.

Enhanced drug delivery: Nanoparticles can improve drug delivery and release by being chemically modified to protect against corrosion, enhanced solubility, and sustain their effects over time. This allows better drug bioavailability and longer therapeutic periods.

Imaging and diagnosis: Nanoparticles can be designed with unique imaging properties, making them valuable for various diagnostic techniques. They can serve as high- resolution contrast agents in imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT), or fluorescence imaging.

Regenerative medicine: Nanotechnology contributes to tissue engineering and regenerative medicine by providing nanoscale scaffolds and materials that mimic the extracellular matrix, supporting cell growth and tissue regeneration.

Studies have demonstrated that the methods used in the preparation of bhasmas closely align with the top down approach in nanoparticle synthesis77. In Ayurveda, various pharmaceutical techniques such as Sodhana (Purification), Bhavana (Trituration), and Marana (Intense heating) are used in the manufacture of bhasmas. These processes are aimed at reducing particle size and transforming minerals and metals into non-toxic forms with therapeutic properties 32. During the Sodhana process, the metal or mineral is subjected to increasing tension during heating and decreasing tension during cooling, making the material more brittle and easier to process further. In the Bhavana process, the metal or mineral particles endure high stress when ground between a pestle and mortar, which helps to reduce their size. Additionally, levigation with appropriate herbal extracts or decoctions during this process integrates herbal metabolites into the preparation. The Marana process involves exposing the particles to high temperatures, which reduces their size to the nanometer range and endows them with various beneficial qualities 84.

It is worth mentioning that various modern analytical techniques have been employed to investigate and characterize the physicochemical properties of Ayurvedic bhasmas. These analyses have examined particle size, elemental composition, and surface characteristics. Research has identified the presence of nanoparticles or nanocrystals, as well as therapeutically significant herbal ingredients in certain bhasmas, indicating their potential for nanoscale properties 38. Ayurvedicbhasmas are used in the treatment of various diseases, including chronic diseases such as cancer, asthma, and gastritis. Recent studies have highlighted that bhasmas possess antioxidant, anti-inflammatory, immunomodulatory, antibacterial, antiviral and antitumor properties, along with the capability to target drug delivery to specific sites in the body with fewer side effects. Thus, Ayurvedicbhasmas are nanoparticles with considerable medicinal value 85.

Nanomedicine generally refers to the deliberate design and use of nanoscale materials for specific therapeutic applications in modern medicine. It involves meticulous control over the size, shape, surface properties, and targeting abilities of nanoparticles to improve drug delivery, imaging, and diagnostics 81. Ayurvedicbhasmas are prepared by following Ayurvedic principles with the aim of reducing particle size, extending shelf life, transforming toxic nature of metals or minerals into non-toxic forms, and enriching them with medically important herbal metabolites. In this regard, Ayurvedicbhasmas can be considered a form of nanomedicine 59. However, the precise control of particle size, shape, and properties, as well as the mechanisms and specific features related to nanoscale interactions or effects, have not been thoroughly documented or scientifically explored in the context of Ayurvedicbhasmas.