RESEARCH COMMUNICATIONS Cannabis sativa (Cannabaceae) in medicine contain a number of references about Cannabis. The medicinal use of Cannabis was first recorded in ancient clay plaster of Ellora Caves, India in the medical work ‘Sushrita’ compiled around India 1000 BC (refs 8, 9) and finds mention in the ancient Per- sian literature Zend Avesta8. Cannabis has also been 1 2, listed in Indian texts such as Tajnighuntu and Rajbu- M. Singh and M. M. Sardesai * 8,9 1Archaeological Survey of India, Science Branch, Western Zone, lubha . According to these texts, Cannabis is used in the Aurangabad 431 004, India treatment for clearing phlegm, expelling flatulence, in- 2Department of Botany, Dr Babasaheb Ambedkar Marathwada ducing costiveness, sharpening memory, increasing elo- University, Aurangabad 431 004, India quence, as an appetite stimulant, for gonorrhea, and also as a general tonic. Moreover, the Hindus consider Can- The present research trend is to explore sustainable nabis as a holy plant, and it is used in Hindu festivals like construction materials having least environmental im- Shivratri even today. pact that also encapsulate in terms of our natural re- The stalk of hemp plant consists of fibres (soft and sources. The present communication discusses the use of raw hemp as an organic additive in the clay plaster flexible) and hurds (rigid and hard). Processing of C. sa- of the 6th century AD Buddhist Caves of Ellora, a tiva results in three basic constituents, namely shives or World Heritage Site. Cannabis sativa L. admixed in hurds (~62%) by weight plant fibres (~35%), and seed the clay plaster has been identified using scanning and dust with particle size less than 0.5 m (~4%). Hemp electron microscope, Fourier transform infrared spec- is an environment-friendly plant that does not require troscopy and stereomicroscopic studies and the results pesticides or herbicides to grow. Hemp hurds are acid- are compared with fresh specimens. The study indi- free and unlikely to deteriorate over time. Hemp is also cates that many valuable properties of hemp were resistant to rodents, fungus and many weeds. It is also a known to the ancient Indians in the 6th century AD. heterogeneous plant, its microstructure is extremely com- plicated and therefore Cannabis itself can be regarded as Keywords: Ancient caves, Cannabis sativa, clay plas- composite system10,11. ter, World Heritage Site. The basic unit of Cannabis consists of cellulose poly- meric chain aligned in micro fibrils. They are linked to CANNABIS is one of the oldest domestic plants in the his- each other by lignin, pectin and hemi cellulose. The tory of mankind, probably being utilized for more than strength and stiffness of the fibres are provided mostly by 10,000 years1,2. Hemp grows in most climates and en- 3 hydrogen bonds between the different chemical compo- riches poor soils after every crop . Owing to its fast nents. The hemp composition and properties of each growth in both temperate and tropical climates, hemp has component are responsible for its thermal stability, resis- been used for centuries to make a variety of items such as tance to UV rays and biodegradation of Cannabis. Hemps rope, paper, clothing, sails, etc. The fibrous strands of are low-density light-weight materials which can exhibit hemp are ideal for fabric owing to its better durability mechanical strength parameters12,13. Hemp hurds can be over cotton. combined with lime to form concrete-like substance Hemp originated from Central Asia and has been called hempcrete. A combination of hemp hurd, lime, grown there for thousands of years. It is mentioned in clay, cement and water in various proportions has been Roman literature from around 100 BC, claiming that the 4 used for centuries in the construction of building. Hemp- plant was grown in southern Europe . The remains of crete has been discovered in a bridge abutment in France hemp (C. sativa L.) unearthed mainly in Eurasia have built in the 6th century AD. C. sativa was chosen for either carbonized or decayed due to climatic change and 2,5 industrial use due to its long, soft, durable fibrous proper- storage conditions . The oldest example of hemp re- ties that provide immense amount of strength. mains with macroscopic/microscopic structure has been The significant advantage of hempcrete is that it is reported from Yanghai Tombs located in Turpan Basin of 6 greenhouse negative, as it absorbs more carbon dioxide China . This material has provided significant informa- from the atmosphere than it produces in its life cycle, tion on ancient civilization of the Turpan area and about thereby reversing the effect of global warming. Hemp- utilization of hemp. crete produces no toxic by-products. It has a high thermal In India, hemp domestication dates back to 5000–4000 mass and insulating properties, and therefore lowers the BCE (ref. 7), cultivated for multiple purposes, including heating and cooling emission to maintain a healthy and use of its fibre from stem, edible food/oil from its achene, comfortable living environment. Hempcrete buildings medicine and psychoactive substances from its resin 1 have long life due to material properties of the durable glands . Cannabis is popularly known as ganja or bhang fibre. Hempcrete also exhibits higher vapour permeability in India. The Ayurvedic and Siddha systems of Indian that regulates moisture content and internal humidity, and also improves indoor air quality and health of the build- *For correspondence. (e-mail: [email protected]) ing occupants. A hemp home also maintains the acoustic 884 CURRENT SCIENCE, VOL. 110, NO. 5, 10 MARCH 2016 RESEARCH COMMUNICATIONS Figure 1. General view of Ellora caves, a World Heritage Site in Aurangabad, India. requirement of buildings. Incorporation of hemp will also with vegetal plant remains were extracted from cave no. result in aggregate reduction to save our natural re- 12 for laboratory study (Figure 3). sources14–16. Specimens of C. sativa were isolated from the clay The production of building materials for construction is plaster. The isolated specimens include pounded pieces of responsible for consumption of energy from fossil fuel shoots, fragmented leaves and single (male?) flower. The resources and depletion of non-renewable materials17. sample of Cannabis was examined using scanning elec- Nowadays the trend is shifting towards finding produc- tron microscope (SEM), light microscope, stereomicro- tion technologies that encapsulate saving of our natural scope and Fourier transform infrared spectroscopy resources. Because of their positive environmental (FTIR) techniques. impact, the sustainable construction materials are now For SEM examination, the dried specimens were gaining more ground worldwide. New bio-composites directly placed on the stubs and sputter-coated with gold containing natural fibres and/or particles, lignocelluloses using a SPI-MODUEL Sputter coater. The C. sativa sam- wastes are the subject of current research worldwide. ples were examined and photographed under EDAX The Ellora Caves, dating back from 6th to 11th century model JEOI–SEM360. The fresh specimen of Cannabis AD are located near a village locally known as Verul at a was also similarly examined. distance of 29.8 km to the northwest of Aurangabad city, For FTIR examination, the pounded pieces of shoots Maharashtra, India (Figure 1). This is a group of 34 rock- were examined using Agilent Technologies Cary 600 cut caves dedicated to the three main religions of India – Series FTIR spectroscopy along with fresh specimens of Buddhism, Hinduism and Jainism. In 1983, the caves C. sativa for comparative study. were declared a World Heritage Site (WHS) by For light microscopic examination, the pounded pieces UNESCO. The caves of Ellora are breathtaking examples of shoots were examined and measured with a calibrated of rock-cut architecture that stands testimony to the ocular micrometer and photographed under a LABOMED imagination and artistry of its creators. Unlike the Ajanta vision 2000 and lab vision Madstar light microscope. Caves, a nearby WHS site, the caves of Ellora lie on an For stereomicroscopic examination, the flowers and ancient trade route and have almost remained in public leaves of C. sativa were examined and photographed eye. The caves run approximately in north–south direc- under a Olympus Magnus MSZ and LABOMED CSM 2 tion for about 2 km. At the southern end are 12 Buddhist stereo microscope. caves, while in the north there are 6 Jain caves and in be- For comparative studies, fresh specimen (Pardeshi tween lie 17 Brahmanical caves. The Buddhist caves of 3723) was collected from Jalna, Aurangabad district, Ellora are the earliest (AD 550–700) among the group. Maharashtra and also from the roadside on the outskirts The Buddhist cave no. 12, from where clay plaster of Delhi city (Sardesai 1500). The specimens are stored samples were examined, is a remarkable three-storeyed in the Herbarium of Dr Babasaheb Ambedkar Marath- building with indistinguishable traces of paintings on the wada University, Aurangabad. ceilings and walls of the inner shrine (Figure 2). The de- The temperature and relative humidity were monitored signs painted on the wall and ceilings represent floral and both inside and outside the caves during the period No- creeper patterns and other geometric shapes, jeweller vember to December 2014. For measurement of tempera- designs and wood work. It is obvious that the colour of ture and humidity inside cave no. 12, an Oakton RH/T these paintings is dull and insipid owing to deposition of data logger was temporarily fixed near the Buddha cham- soot and weather conditions as the caves are exposed to ber in the inner part of the cave. The temperature and sunshine and rainfall. The clay plaster samples admixed Humidity data outside the cave were derived from CURRENT SCIENCE, VOL. 110, NO. 5, 10 MARCH 2016 885 RESEARCH COMMUNICATIONS Figure 2. Paintings on the walls of cave no.