Comparative Chemical Study of Three Different Market Samples of an Important Clay Mineral Drug “Gil-E-Makhtum” with A Brief Ancient Description of Earth's Natural Resources

Akhlaq Mustafa¹*, Anas Iqbal Alvi², Zaki Ahmad Siddiqui³, Mahesh Chandra⁴, Ghazala Javed⁵

^1,2Research Officer (Chemistry): Drug Standardization Research Unit,

Central Council for Research in Unani Medicine), 61-65, Institutional Area, Janakpuri, New Delhi.

³Research Officer Incharge (Unani): Safdarjung Hospital (RRIUM, New Delhi),

Central Council for Research in Unani Medicine, 61-65, Institutional Area, Janakpuri, New Delhi.

⁴Lab Technician (Chemistry): Drug Standardization Research Unit,

Central Council for Research in Unani Medicine, 61-65, Institutional Area, Janakpuri, New Delhi.

⁵Assistant Director Incharge (Unani): Drug Standardization Research Unit, Central Council for

Research in Unani Medicine, 61-65, Institutional Area, 61-65, Institutional Area, Janakpuri, New Delhi.

*Corresponding Author E-mail: amh786786@gmail.com

ABSTRACT:

The medical use of earth's natural resources or mineral drugs is probably as old as the history of man kinds and has been used widely for the ailments of many diseases despite knowing the presence of chemical constituents or pharmacological activities of that particular substance but in the present era, with the modern techniques much more research work has been done to know the active components and their pharmacological properties which could have now been used in the modern medicine. Among the various earth natural resources or mineral drugs Gil-e-Makhtum (Sealed earth or the type of clay) also known by the name Lemnian earth, is a medicine in the shape of a stamped clay tablet (Sphragis) from Lemons, northeastern Greece, was much valued in antiquity and is utilized as such as well as an ingredient in the number of compound formulations in the Unani system of medicine for the treatment of various diseases. In this paper with the description of the brief history of Earth’s Natural Resources, the comparative chemical study of three different market samples of Gil-e-Makhtum was carried out by following some parameters of qualitative analysis and quantitative estimations. The analysis included Loss of weight on drying at 105oC, solubility in 1 normal hydrochloric acid and water, total ash, acid insoluble ash, bulk density, and tapped density. Besides, some major estimations e. g. Hematite (Fe2O3), Alum (Al2O3), Quartz (SiO2), and Calcium oxide (CaO) were also carried out.

KEYWORDS: Clay, Clay Mineral, Earth’s Natural resources, Terra Sigillata/Lemnian Earth.

INTRODUCTION:

The historical materia medica incorporates minerals that have been made use of in both medical folklore and academic analysis. The most rudimentary use of mineral materials was in a magico-medicinal way as amulets worn for protection against harmful influences which might be expressed in the body as loss of health and as prophylactics against specific diseases and poisons¹. In the composition of clay minerals, particles are very small in size, and flaky in shape, and crystalline substances have considerable surface area. They can only be viewed with an electronic microscope. Research on clay minerals started in the 1930s. Chemically, these minerals are hydrous alumina-silicate (e.g. kaolin, Al₂Si₂O₅(OH)₄), and maybe the mixture of iron, magnesium, alkali metals, alkaline earth, etc, which form in the presence of water² and play a very significant role in life. These metallic ions present in the soils have been beneficial in various fields like agriculture and manufacturing. On heating or drying they become hard, brittle, and non–plastic and show plasticity when wet.^3-5. It is a very common material known by the name of ceramic. Some useful properties of clay e.g. making pottery, and the presence of nutrient cations in it such as potassium and ammonium, are important to soil fertility^6-8. Due to varied chemical compositions and structures, it is very difficult to quantify the clay minerals, and the possibility of analytical errors always remains⁹. As far as the use of clay material for cosmetic and medical purposes is concerned, in Egypt, metal-sulfide minerals like galena, pyrolusite, magnetite, and stibnite were pulverized and used to create "kohl" or "kajal," a black color used as makeup for the eyes and green makeup was made from minerals like malachite and chrysocolla. Malachite was also a popular ingredient for medicine, believed to cure diseases of the abdomen and dental problems. The powder "molochotis" is reported to have been used to clean wounds in Natural History with the descriptions of the magic-medical powers of minerals in Assyrian and Babylonian texts like lapis-lazuli, hematite, and native copper were used as talismans to protect from evil spirits, along with many other minerals caused by ghosts and spirits. In the 13th century diamonds were used as pulverized medicine against impotence and to increase longevity as per Indian sources. Some of the supposed powers of minerals still play a role in modern Ayurveda medicine. According to traditional Chinese medicine, diseases are caused by an imbalance of energy in the body. Islamic medical texts show a great influence on Roman and especially Greek medicine. Fossils and precious gemstones were used for tonics to cure or strengthen the inner organs.^10-11.

The literal meaning of Terra sigillata is sealed or stamped earth. The archaeologist defined it as a type of fine, red earth used in pottery or the type of earth or clay used medicinally and originated from the Greek islands. Roman pottery was made from the 1-3 AD in Gaul (France, Luxembourg, and Belgium, most of Switzerland, and parts of Northern Italy (Lombardy), the Netherlands, and Germany west of the Rhine) by using terra sigillata¹². In 1580, a miner named Adreas Berthold traveled around Germany selling Silesian terra sigillata made from special clay dug from the hills outside the town of Striga, now Strzegom, Poland, and processed into small tablets. He promoted it as a panacea effective against every type of poison and several diseases, including plague. Berthold invited authorities to test it themselves. The trial was conducted by taking two dogs as a tested animal. In two cases, these animals were either given poison followed by this terra sigillata as an antidote or poison alone; the dogs that got the antidote lived and the dogs that got the poison alone died. Afterward in 1581, a prince tested the trial of antidote was conducted on a condemned criminal, who survived ¹³.

With the inclusion of Terra sigillata in the first edition of the Pharmacopoeia of the Royal College of Physicians of London, in 1618, it was also included in the Pharmacopoeia Universalis of Jourdan as Terra Sigillata, Terra Lemnia, or Lemnian Bole in 1833. The last investigator to visit the site of Terra sigillata in 1909 was Hasluck who could not obtain the specimens of it in the capital of the island, however, he bought bowls of clay bearing the old inscription tin Maktum¹⁴. Terra sigillata obtained from Silesia (modern-day Poland) known as Terra Silesia (or Silesiaca) was the best alternative for antidotes to 'poison' and preventives 'against the plague'. Italian medicine chest analyzed the chemical composition of 'Terra Sigillata' medicinal tablet in the late 17th century and was found that it contained three major components; kaolinite (67%), muscovite (16%), and Chlorite Group of silicate minerals (probably clinochlore) (10%)¹⁵. The six samples of Terra sigillata available in the Pharmacy Museum of the University of Basel were analyzed for their chemical composition. Out of six, the red sample was found to contain 37.6% kaolinite, 41% illite, 17.7% quartz, and 3.8% hematite. The yellow grey contained 66% montmorillonite, 18.1% illite, 6.9% quartz, 9% albite¹⁶. Analysis of Lemnian Earth carried out during the 19th century showed it to consist of siliceous mineral material; they were reported by Klaproth¹⁷. The analysis of Thompson (1914) also indicated its siliceous mineral nature and he suggested that its virtues, like those of many other ancient remedies, were chiefly due to the mystery surrounding its origin and the superstitions connected with the source ¹⁴. It appears to have been first recognized as a pigment, but not as a medicine, by Theophrastus in the fourth century BC. He called it Lemnian miltos instead of Lemnian Earth¹⁸. Miltos is the name given to a red pigment, and the famous variety from Kea was almost certainly red because of the presence of hematite¹⁹.

From the earlier analysis, it was clear that Lemnian Earth was a clay-based material. However, in the Sloane collection in the Natural History Museum, there are indeed museum samples²⁰ but there is no way of knowing about whether which samples are genuine. With all that several fakes circulated about the Lemnian Earth in the markets both in the East and in Western Europe from the 16th to the 19th centuries which increased to a lucrative trade in other earths from numerous localities in Central Europe and the Middle East²¹.

It is clear that, for Pliny also, Lemnian Earth was red (it resembles cinnabar) and, as well as naming it Terra Lemnia or Terra Sigillata, he refers to it as Terra Rubricata by using ‘rubrica’in relation to Lemnian Earth, Lemnian sphragis (20). Belon mentions that the Turks differentiated between two types of earth, the thin-i Maktoum-i ahmer—that is, the red earth—and the thin-i Maktoum-i ebiez, the white earth, the latter considered of lower quality²².

The drug selected for work here “Gil-e-Makhtum” is also a type of clay mineral drug known by the name of sealed earth or Lemnian earth/terra lemnia/lemnia GI. Makhtum is an Arabic word that means stamped or sealed. The scientific name of Gil-e-Makhtum is Terra Sigillata which is a Latin word. Pliny described it as Lemnia rubrica (Lemnian reddle) and also said it Lemnia sphragis. Sphragis is a Greek word that means sealed^23-24. It is also used as an ingredient in some compound classical formulations like Majoon-e-Muqaww-e-Reham, Sufoof-e-Kishneez, Sufoof-e-Ziyabetus²⁵Habb-e-Teewaj, Mufarreh Azam²⁶ Jawarish-e-Teewaj, and Tirya al Tin^27-28.

Chemical composition:

The bulk composition of Lemnian Earth is approximately 40% Montmorillonite, 30% Kaolin, 20% Alum, and 5% Hematite. Montmorillonite is an absorbing or expanding clay mineral²⁹. Natural Montmorillonite is usually either a calcium or sodium-rich aluminum silicate hydrate. Kaolin is a common clay mineral known commercially as China clay (a hydrated alumina silicate clay mineral) with a chemical composition Al₂Si₂O₅(OH)₄. Alum is a mineral usually aluminum sulfate e.g., Al₂(SO₄)₃.17H₂O and Potssium alum (K-alum) KAl (SO₄)₃.12H₂O having astringency or styptic property. Hematite Fe₂O₃, is a common iron oxide mineral that is distinctly red and its presence is the usual reason for the red color of sediments and soils. It is used commercially as a red pigment. Fine red hematite is common worldwide. It can also form on hydrothermal alteration of rocks. It is anhydrous. The more common amorphous to semi-crystalline iron oxyhydroxides (limonite, FeOOH·nH2O) are yellowish brown and contain both structural and molecular water. It is well known that yellowish-brown iron oxyhydroxides turn red on heating as they are converted to ferric oxide³⁰

Several researchers have reported the chemical composition of terra sigillata in different periods which may be seen below; The chemical composition of Gil-e-Makhtum (Lemnian Earth) as reported by Thompson as; Silicates-37.23%, Ferric oxide-4.08%, Aluminum oxide-13.51%, Calcium oxide-22.90%, Magnesia and alkali oxides-1.50%, Water and carbon dioxide-17.72%, Moisture as determined by heating at 1300^oC is 3.06% in 100parts¹⁴.

Material and methods: Three samples of Gil-e-Makhtum were procured from different shops of the local market NCR region Delhi and were coded their names as GM(DR), GM(LR), and GM(LY) and studied for physical characteristics, qualitative and quantitative analysis.

GM (DR) GM (LR) GM (LY)

RESULTS:

S. No.	parameters	GM(DR)	GM(LR)	GM(LY)
1.	Physical characteristics Appearance Color Smell	Powder form Dark red Not specific	Powder form Light red Not specific	Powder form Light yellow Not specific
2	Total ash	94.83	93.80	84.50
3.	Acid insoluble ash	92.90	87.06	70.00
4.	Water soluble content	8.00	10.00	20.00
5.	1N Hydrochloric acid solubility	6.00	14.50	20.00
6.	Bulk density	1.6352	1.3034	0.744
7.	Tapped density	1.822	1.533	0.815
8.	Alum (Al2O3)	20.50	14.50	6.50
9.	Hematite (Fe2O3)	8.50	5.80	3.50
10.	Quartz SiO2	48.00	41.00	35.00
11.	Calcium Oxide (CaO)	5.50	1.90	3.50
12.	Loss on drying at 105o C	1.00	3.6	5.80

DISCUSSION:

Three coded samples GM (DR), GM (LR), and GM (LY) were dark red, light red, and light yellow respectively. Sample GM (LY) turns red after heating as it contains both structural and molecular water and has more moisture content as compared to other samples. They are converted to ferric oxide¹⁹. The results of the major parameters analyzed here neither show any similarity to each other nor with the studies reported in the literature or previously carried out. Range of the result of our parameters e. g. water soluble contents (8.00 – 20.00%), 1 normal hydrochloric acid solubility (6.00 – 20.00%), moisture contents (1.00 - 5.80%), ash values (84.50 - 94.83%), acid insoluble ash (70.00-92.90%), bulk density (0.7440 -1.6352 gm/ml), and tapped density (0.8150 – 1.822 gm/ml) were found to be present. Here it is also important to note the reference of literature that the composition of the original Lemnian earth could not be determined on account of the lack of a genuine sample. Although there is a museum sample in the Sloane collection in the Natural History Museum³¹, there is no way to detect its authenticity because, in East and West Europe, several fakes were circulated between the 16th and 19th centuries²¹ and raised to a lucrative trade in central Europe and the middle east³².

The range of reported results of yellow and red samples in the literature for hematite, quartz, alum, and calcium oxide are 4.60- 9.62%, 56.81-55.70%, 22.4-23.70%, and 1.97-1.24% respectively³³ while in all three market samples of Gil-e-Makhtum GM (DR), GM (LR), and GM(LY) which we analyzed here found the considerable percentage variation in the results of the respective components as 3.50-8.50%, 35.00-48.00%, 6.50- 20.50%, and 1.90-5.50%. This variation was not only among the market samples itself but also deviated from the values reported in literature except the values of hematite and alum in our one sample.

CONCLUSION:

It is quite clear that that Gil-e-Makhtum (Lemnian earth) is a clay-based material but ascertaining its authenticity is not an easy task because in the name of Gil-e-Makhtum which is available in the market, has different textures or looks and also the color of it varies to a great extent. However, the clue from the literature regarding Galen's statement that Lemnian Earth is an astringent and he also insisted in his advice not to wash it more than once, which shows a piece of powerful evidence that alum is the significant component present in Gil-e-Makhtum because it is soluble in water, means it is the main ingredient of its efficacy³⁴. However, there is a remarkable difference in our findings as compared to the reported results of different samples in most of the parameters but if we focus on the values of our estimation of alum (20.5%) and hematite (8.50%) of market sample GM(DR) which are near up to some extent to the literature reported results 22.40 and 9.62% respectively but despite only resemblance of these results, it doesn’t allow us to accept that it is a genuine sample. Therefore, to know the authenticity of a genuine sample, it is suggested that along with the data presented here, we should go through Spectroscopy which is mainly complementary to X-ray diffraction (XRD) and other methods used to study clays for the identification tests that can discriminate between the mineral compounds in mixtures.

ACKNOWLEDGMENT:

The authors are grateful to the Director General, Central Council for Research in Unani Medicine for encouraging and providing the necessary facilities to carry out the work.

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Received on 26.03.2024 Modified on 09.05.2024

Asian J. Res. Pharm. Sci. 2024; 14(3):231-235.

DOI: 10.52711/2231-5659.2024.00038