|Year : 2017 | Volume
| Issue : 4 | Page : 182-186
A metallurgical study of Nāga Bhasma
Dev Nath Singh Gautam
Department of Rasa Shastra, Faculty of Ayurveda, IMS, BHU, Varanasi, Uttar Pradesh, India
|Date of Web Publication||28-Nov-2017|
Dev Nath Singh Gautam
Department of Rasa Shasrta, Faculty of Ayurveda, IMS, BHU, Varanasi, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Background: The metal Nāga (Lead) is being used by Indians since ancient times. Its external and internal uses have been described in Caraka, Suśruta and other Ayurvedic Saṃhitā. According to most of the Rasa texts, Nāga Bhasma and its formulations are used in many diseases such as Prameha, Jvara, Gulma, Śukrameha etc. Objectives: In the present study, Nāga Bhasma was prepared by the traditional Puṭa method (TPM) and by the electric muffle furnace Puṭa method (EMFPM) and standardized using Metallographic studies. Doing so helps in the study of the microstructure of Nāga Bhasma and also helps in the identification of the metal particles along with the nature of compound formed during the Māraṇa (Bhasmīkaraṇa) process. Setting and Design: Different samples from initial raw material to final product of Nāga Bhasma were collected during the pharmaceutical process (1st, 30th and 60th Puṭa) from both methods i.e. TPM and EMFPM. Samples from both methods were studied using metallographic examination. Materials and Methods: The processing of the Nāga Bhasma (ṣaṣṭipuṭa) was done according to Ānanda Kanda Samples from the raw material i.e. Aśodhita Nāga (raw Lead) and that processed after 1st, 30th and 60th Puṭa from both methods i.e. traditional Puṭa method (using heat from burning of cow dung cakes) and electric muffle furnace Puṭa method were taken. They were mounted on self hardening acrylic base. After careful polishing to obtain scratch free surface of product, they were used for metallurgical study. Conclusion: This study shows that traditional Puṭa method may be better than electric muffle furnace Puṭa method because of more homogeneous distribution of Lead sulphide in the Nāga Bhasma which is prepared by traditional method.
Keywords: Ayurvedic drug, Nāga Bhasma, Puṭa, traditional medicines
|How to cite this article:|
Gautam DN. A metallurgical study of Nāga Bhasma. Ancient Sci Life 2017;36:182-6
| Introduction|| |
The knowledge of different metals in the Indian tradition can be traced right from Vedic period. The descriptions are found in Veda, Yājñavalkya Smṛti  and Saṃhitā., There is a description of six metals viz. Gold, Silver, Copper, Iron, Tin and Lead in Śukla Yajurveda Nāga (Lead) is the most popular and useful metal known to Indians since the Vedic period. Nāga and its formulations is described in Caraka Saṃhitā and Suśruta Saṃhitā for the treatment of different diseases viz. Maṇḍala Kuṣṭha and Kaphaja Arbuda etc., According to Ayurvedic texts, calcined, non-toxic, organo-metallic, irreversible complexes or compound forms of metals and minerals formed under controlled heat is classified as Bhasma and the method of preparation thereof is called Bhasmīkaraṇa. The Bhasmīkaraṇa process (Māraṇa) changes the Śodhita Rasa drugs (metal and mineral) into desired medicine (chemical compound) which reduces the toxicity of the metal and potentiates the medicinal property., There are several tests described in Ayurvedic texts to check the quality of prepared Bhasma viz. Rekhāpūraṇa (small particle size), Niścandra (lack of metallic shine) and Niruttha (absence of alloy formation with silver), etc., However these tests do not provide any quantitative information about the standard composition and structure of the final drug. Standardization of such medicines as to their contents as well as concentration of their constituents is necessary before understanding of their mode of action.,Nāga Bhasma is recommended for the treatment of different diseases i.e. diarrhea, spleen enlargement and diabetes. Although several researches work has been done on different therapeutic effects of Nāga Bhasma, none have documented the proper standardization of Nāga Bhasma.
Metallography is an advanced scientific tool which is used in the field of Ayurveda to confirm the Metallographic microscopy observation based tests in scientific manner. This helps to study the microstructure of the preparation and also helps in the identification of the parent metal particles along with the nature of compound formed during the Māraṇa. It also provides information regarding the quality of metal and mineral prepared by different methods as well as the effect of changes in the parameters. Hence metallographic studies help to confirm the effects of Māraṇa scientifically. In this study, different samples from initial raw material to final products of Nāga Bhasma were collected during pharmaceutical processing (1st, 30th and 60thPuṭa) from both methods i.e. traditional Puṭa method (using heat from burning of cow dung cakes) and electric muffle furnace Puṭa method. They were studied by metallographic examination. In this study, the samples of Nāga were mounted on self hardening acrylic base and then careful polishing was done to obtain scratch free surface of product.
Metallographic light microscope
Metallurgical light microscope differs from a biological microscope in the manner by which the specimen is illuminated. In a biological or medical microscope the specimen being transparent or translucent the study is generally done under transmitted light microscope. In this system generally the specimen is mounted on a glass slide and the light passes from the bottom through the slide to the optical system. In a metallurgical light microscope as the samples are opaque, generally the study is done under reflected light provided by the illuminating system on the side of the body of microscope, except in the case of TEM where very thin metallic foils or samples are studied under electron beam. During the preparation, Nāga Bhasma samples were taken out to analyze and understand physico-chemical changes taking place during different process of manufacturing using metallographic techniques.
| Aims and Objectives|| |
The present research work was conducted to use metallographic study as a tool (fingerprint) to distinguish between raw and processed Nāga Bhasma for their quality. This can also be used to generate standardization parameters of the finished material prepared by traditional and modern techniques.
| Materials and Methods|| |
Preparation of Nāga Bhasma
Nāga Bhasma was prepared by two methods viz., TPM and EMFPM. The processing of the Nāga Bhasma (Ṣaṣṭipuṭa) was done according to Ānanda Kanda. Raw material (600 g) was procured from the local market and identified.
Raw Nāga (crude Lead-600 g) was subjected to Śodhana by melting and pouring into a container of Cūrṇodaka (Lime water, strength 4.3 g/l) seven times. This Śodhita Nāga (590 g) was again subjected to Viśeṣa Śodhana (unique purification process specific to the metal) by following the above procedure and pouring into a mixture (decoction strength 250 g/l) of Nirguṇḍī (Vitex Negundo Linn.) svarasa and Haridrā (Curcuma Longa Linn) cūrṇa for seven times. The Śodhana of Manaḥśilā (chemical composition As2S2) was done by subjecting it to seven BhāvaNās (levigation) in Ārdraka (Zingiber officinale Linn.) svarasa.
The Nirguṇḍī svarasa śodhita Nāga (580 g) was subjected to Jāraṇa (6 hours) by melting śodhita Nāga and stirring it with a Neem (Azadirachta indica A Juss.) stick and adding the whole plant parts of Chichiri (Plectranthus coesta L.). The jarita Nāga (620 g) was obtained as a yellow–orange powder.
In the first Puṭa, śodhita Manaḥśilā (620 g) was added in equal part to jarita Nāga (620 g) and triturated with the Citrus limon Linn. juice till it becomes a semisolid paste. This paste was made into small pellets and dried in shade. Dried pellets were in the range of approximately 5-6 grams per pellet. Pellets were kept in two separate earthen pots and packed by other earthen pots by cotton mud (sandhi bandhana). This is called śarāva sampuṭa. One pot was subjected to TPM (cow dung cakes – 18 kg.) and second pot was subjected to Puṭa in an electric muffle furnace at 600 deg. C. After leaving them to cool to room temperature, both the samples were taken out. This was the first Puṭa of the Nāga Bhasma samples. The samples of Nāga Bhasma obtained from first Puṭa (both TPM and EMFPM) were used in next (second) Puṭa. Śuddha Manaḥśilā was added in 1/20th part to the sample of Nāga Bhasma obtained from first Puṭa and triturated with Citrus limon Linn. juice till it became a semisolid paste. This paste was made into small pellets and dried in shade and pellets were kept in two separate earthen pots (śarāva sampuṭa). Both the pots were subjected to Puṭapāka (heat treatment i.e. traditional Puṭa with cow dung cakes – 15 kg and electric muffle furnace at 500 deg. C). This process was repeated fifty eight times to get the finally prepared (sixty Puṭa) Nāga Bhasma. Both the samples of the final product i.e. Ṣaṣṭipuṭa Nāga Bhasma (sixty Puṭa) in the form of pellets were powdered (280 g from TPM and 282 g from EMFPM) and kept in separate airtight containers. Total duration for the preparation of Nāga Bhasma was six months. In the present work metallurgical study has been used as parameter for the standardization of raw Nāga (Lead) and Ṣaṣṭipuṭa Nāga Bhasma. The starting material i.e. aśodhita Nāga (raw lead) and samples from 1st, 30th and 60thPuṭa from both methods were taken for metallurgical study. Following materials were used for making the block of the Nāga and Nāga Bhasma samples– acrylic hardener, metal ring, grease, glass slide, mounting material, emery paper (number 1/0, 2/0, 3/0, 4/0), sylvette cloth, kerosene oil, and wax.
Examination of metals and materials under metallurgical microscope require elaborate preparation of the sample surface such as mounting, grinding, polishing etching etc. For which it is essential that the sample size should be at least 1 cm in diameter and 1 cm in height. Since the samples in the present case are mostly in powder form, a special mounting technique using acrylic binder (powder and liquid) has been used. A metallic ring of 25 mm height and 20 mm inner diameter was internally coated with grease and kept on a smooth glass surface which was also coated by a thin layer of grease. 0.5 g of Nāga Bhasma sample was mixed with 1 g of acrylic powder and was spread evenly on the glass surface within the metallic ring. Afterwards acrylic powder was filled to half the capacity of the ring and liquid acrylic was also poured drop by drop. The liquid reacts with the powder and forms a plastic mass that binds the sample and gets converted into a pellet by self hardening. After about 15 minutes, the pellet was separated from the glass surface as well as from metallic ring by gently pushing it out. The presence of grease on the glass and ring surface prevents formation of bond between the acrylic material and the contact surfaces. It also helps in easy ejection of the sample from the ring. The surface of the acrylic plastic pellet containing the samples was prepared as described in the Khel metallographic technique. After grinding the sample surface of the mount it could not be polished finally to the desired scratch free levels by usual methods. Hence final polishing was done using clean solutions of paraffin (stearic acid wax) in kerosene oil on sylvette cloth. The polished sample was washed with methanol to remove the wax and oil. The microscopic study was done on unetched and as well as on etched surface with the following mixture till the etched structures were revealed at 40 deg. C. The etching reagent was prepared by mixing glacial acetic acid (3 parts), concentrated nitric acid (4 parts), and Distilled water (16 parts).
Polished mounts of samples were fixed on a glass slide with the help of plasticine and placed under the objective lens on the platform. Microscopic findings were studied at different magnifications.
The following samples were used for metallographic study:
- Raw material – Aśodhita Nāga (raw Lead)
- Śodhita Nāga
- Nāga Bhasma (by TPM)
- Product of 1stPuṭa
- Product of 30thPuṭa
- Product of 60thPuṭa
- Nāga Bhasma (by EMFPM)
- Product of 1stPuṭa
- Product of 30thPuṭa
- Product of 60thPuṭa
Raw material – Aśodhita Nāga (Raw Lead) [Figure 1] shows the microstructure of Lead metal with presence of some non- metallic inclusions.
Śodhita Nāga [Figure 2] shows the changes after Śodhana, as compared to the [Figure 1], it is clearly seen that liquid metal when poured in lime water and decoction breaks it into smaller particles whose surface reacts to form a black coating; the chemical nature of the coating has not been identified.
Ṣaṣṭipuṭa Nāga Bhasma [Figure 3], [Figure 4], [Figure 5] (by TPM) - Nāga Bhasma after 1stPuṭa, 30thPuṭa and 60thPuṭa shows the presence of lead sulfide but other compounds have not been identified.
|Figure 3: Distributed particles of Lead Sulfide after 1st Puṭa of Nāga Bhasma (Mag × 200) using the traditional Puṭa method|
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|Figure 4: Distributed particles of Lead Sulfide after 30th Puṭa of Nāga Bhasma (Mag × 200) using the traditional Puṭa method|
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|Figure 5: Distributed particles of Lead Sulfide after 60th Puṭa of Ṣaṣṭipuṭa Nāga Bhasma (Mag × 200) using the traditional Puṭa method|
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Ṣaṣṭipuṭa Nāga Bhasma [Figure 6], [Figure 7], [Figure 8] (by EMFPM) - Nāga Bhasma after 1stPuṭa, 30thPuṭa and 60thPuṭa shows the same nature of compound as above.
|Figure 6: Distributed particles of Lead Sulfide after 1st Puṭa of Ṣaṣṭipuṭa Nāga Bhasma (Mag × 200) using electric muffle furnace Puṭa method|
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|Figure 7: Distributed particles of Lead Sulfide after 30th Puṭa of Ṣaṣṭipuṭa Nāga Bhasma (Mag × 200) using electric muffle furnace Puṭa method|
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|Figure 8: Distributed particles of Lead Sulfide after 60th Puṭa of Ṣaṣṭipuṭa Nāga Bhasma (Mag × 200) electric muffle furnace Puṭa method|
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| Discussion|| |
In metallographic study, while preparing the samples, every metal responds differently specially during polishing and etching. Lead, being a soft metal, it has been observed that even polishing by using Silvo with sylvette cloth, it was not possible to get rid of the scratches on the surface. Another alternative for polishing a solution of kerosene and paraffin wax mixed together was beneficial in polishing in getting rid of the scratches. A specific etching solution is prepared by mixing nitric acid, acetic acid and water. Metallographic microscopy observation suggests that the dark shade appearance show on etching, the metallic phase appears dark in shade (lead) while other materials shine (free sulfur, plastic). This has been observed clearly in the crude lead (raw drug). While in Ṣaṣṭipuṭa Nāga Bhasma of both samples i.e. TPM and EMFPM, the aggregated metallic material in the initial stages and distributed sulfide phases in the later stages serves as identifying features of different stages of Ṣaṣṭipuṭa Nāga Bhasma. Thus this study shows that lead is present in the form of lead sulfide in both samples of Nāga Bhasma and lead is least toxic in this form (lead sulfide). Careful comparison of [Figure 5] and [Figure 8] showed that lead sulfide form is more homogeneous in TPM than in EMFPM. This indicates that TPM may be more appropriate than EMFPM in the preparation of Nāga Bhasma.
| Conclusion|| |
Metallographic study showed that the metallic phase appears dark in shade in Aśodhita and Śodhita Nāga (Lead metal). However, the distribution pattern of Ṣaṣṭipuṭa Nāga Bhasma (TPM and EMFPM) was similar to lead sulfide, while free lead is not present in both samples of Nāga Bhasma. This study also shows that traditional Puṭa method may be better than electric muffle furnace Puṭa method because the distribution of lead sulphide is more homogeneous in TPM sample. Thus we can say that metallographic study can be used as a tool to standardize metal based preparations (Dhātu Bhasma) in the field of Rasa śāstra.
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Conflicts of interest
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]