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Oldest Pharmacological Cannabis Found in Chinese Tomb
ISSUE:
Page:
18-20

During a 2003 excavation, archaeologists discovered 789 grams of vegetative material in one of the 2,500 ancient Yanghai tombs in China’s Gobi Desert.1 Though the material was originally thought to be coriander (Coriandrum sativum, Apiaceae), researchers determined it to be cannabis (Cannabis sativa, C. indica, Cannabaceae) in 2006. Shortly afterward, a large and multidisciplinary team of international researchers came together to discover as much as possible about the ancient herb’s possible uses and chemical and genetic fingerprints (E. Russo, e-mail, February 20, 2009).

“This was a unique and rewarding project,” said Ethan Russo, MD, a lead researcher in the study.

After carrying out botanical, phytochemical, and DNA analyses in 2007 and field work in March 2008, the researchers concluded that the cannabis was psychoactive and cultivated for medicinal or divinatory purposes, a confirmation of their original hypothesis.2 Their research, published in the November 2008 issue of the Journal of Experimental Botany, also included radiocarbon dating to date the cannabis to 2,700 years BP (before present), making it the oldest discovered cannabis to have been used as a pharmacologically active agent.

Many findings led to their conclusion. A microscopic botanical analysis revealed the seeds to be light in color with some striations and rough, non-concave fruit attachment, all traits of domestication that show the cannabis was cultivated rather than wild-harvested. No obvious male cannabis plant parts were present, suggesting possible human removal of these psychoactive materials, which are less pharmacologically active. Also, phytochemical analysis showed the cannabis contained cannabinol (CBN), a degradation product of tetrahydrocannabinol (THC), as the predominant residual phytocannabinoid component, indicating that the original plants contained THC as the major constituent. This also suggests that humans selected the material from plants on the basis of their higher-than-average THC content.

Though some media reports have stated that the cannabis was potent, the relative potency cannot be determined with the available tools, said Dr. Russo, who is also a senior medical adviser for the Cannabinoid Research Institute at GW Pharmaceuticals (Salisbury, United Kingdom). The sample had very low concentration levels of THC and far greater amounts of THC oxidative breakdown products, all of which are consistent with very old cannabis samples.2

Genetic analysis also demonstrated the presence of THC’s biosynthetic enzyme, THCA synthase, and a unique variant with 2 single nucleotide polymorphisms (or mutations), never previously observed in cannabis.

After reading the detailed research article, Dennis McKenna, PhD, an ethnopharmacologist and senior lecturer at the University of Minnesota’s Center for Spirituality and Healing, agrees with the researchers’ conclusion that this ancient cannabis was used medicinally or for its psychoactive properties and said it is unlikely the cannabis was used for other purposes (D. McKenna, e-mail, February 16, 2009).

“The chief evidence here is the phytochemical data showing that the cannabis was a high THC variety. The major cannabinoid found was CBN, which is known to be a degradation product of THC. If it were a variety of cannabis not selected for medicinal or psychoactive properties, one would expect a more equal distribution of cannabinoids,” Dr. McKenna said.

The study’s findings were possible through a detailed examination of the cannabis, which was so well preserved that macroscopic and microscopic structures could be shown in great detail, including the nonglandular and glandular trichomes.2 Unlike all other discovered ancient cannabis specimens, which have carbonized or decayed, this cannabis was meticulously preserved by the tombs’ climatic and burial conditions; these included burial in deep graves of 2 or more meters, an extremely arid climate (< 16mm annual rainfall), and alkaline soil conditions.

The researchers’ original suspicion that the cannabis was used for its psychoactive effects by the ancient Gushi people, the culture to whom the tombs have been attributed, was partly based on the tomb’s absence of hemp textiles and a complete lack of evidence to suggest the Gushi used cannabis for food, oil, or fiber purposes. Also an important factor was the cannabis’s location near the skeletal remains of what is thought to be a shaman. The tomb containing the skeleton also held artifacts of high quality, denoting a person of high stature, a leader, healer, or sage, said Dr. Russo.

“Given the medicinal nature and abundance of the cannabis, and the presence of one other seeming shaman’s tomb with cannabis, the archeologists involved feel his shamanic status is certain,” he said.

A second cannabis specimen, found in a different tomb along with seed clumps of caper (Capparis spinosa, Capparaceae), an important culinary and medicinal herb with numerous uses,3 has not yet been analyzed to the detailed extent as the first sample.

Though the tombs are full of numerous well-preserved artifacts, no evidence has been found to suggest any possible conditions or diseases that the Gushi people used cannabis to treat, said Dr. Russo. There is very little information known about this culture, whose people have been described as nomadic, light-haired, blue-eyed Caucasians who spoke an Indo-European language.2

“This study was one of the first times that there has been any degree of discussion of the Gushi in an English language publication,” said Dr. Russo.

Limited information does show that the Gushi people had worn teeth from a fiber-rich diet or mechanical wear, as well as wear-and-tear arthritic effects, a result of the extremely harsh conditions of the local terrain, he added.

Also unanswered is the question of how the Gushi people ingested or administered the cannabis. No evidence has come to light that suggests its mode of administration, though this information might surface with more excavations and research.

Dr. McKenna suspects the cannabis was administered orally or by fumigation (e-mail, February 17, 2009).

“There is no evidence that it was smoked, and in fact smoking was not a practice in the Old World prior to its introduction from the New World, post Columbus. Still, [the Yanghai tomb cannabis] was probably used for medicinal or therapeutic purposes by oral administration,” Dr. McKenna said.

In addition to documenting the oldest pharmacological use of cannabis, this study could potentially lead to further research, including shedding light on the historical migration routes of cannabis. Researchers said the cannabis studied is probably indigenous to Central Asia, but point out that the plant’s long history of cultivation makes it difficult to know the specimen’s original distribution point.1

“If, for example, we were able to find the same SNPs (single nucleotide polymorphisms) from the ancient cannabis in the shaman’s tomb in other regional samples, this would be an important clue that might help to map the peregrinations of this extraordinarily useful plant,” said Dr. Russo (e-mail, February 13, 2009).

The research team has plans for more investigation into the Yanghai tomb cannabis and may have additional results to announce in the coming months, said Dr. Russo. He added that he is interested in doing field research in the Tian Shan Mountains, where researchers assume the shaman died, to try to trace cannabis migration routes, find evidence of Gushi settlements (none have been found to date), and to look for feral cannabis, the genetics of which could be compared to the ancient sample.

With the vast Yanghai tombs, many possibilities exist for future studies of migration routes and ancient uses of cannabis.

“Only 500 of the 2,500 Yanghai tombs have been excavated to date, with only 2 harboring cannabis. Potential remains for additional discoveries if funding can be secured,” said Dr. Russo.

Although the Yanghai tomb cannabis adds to the historical knowledge of cannabis as a drug, both Dr. McKenna and Mahmoud A. ElSohly, PhD, of the Marijuana Project at the University of Mississippi, said this discovery does not have much significance on modern medicinal cannabis research and legality.

“We’re not going to start approving a drug today because we just found out it was used 3,000 years ago,” said Dr. ElSohly (oral communication, February 26, 2009). “We’re going to approve drugs today based on the studies that need to be done.”

—Lindsay Stafford

References

  1. Jiang HE, Xiao L, Zhao YX, Ferguson DK, et al. A new insight into Cannabis sativa (Cannabaceae) utilization from 2500-year-old Yanghai Tombs, Xinjiang, China. J Ethnopharmacol. 2006;55(4):481-485.

  2. Russo EB, Jiang HE, Xiao L, et al. Phytochemical and genetic analyses of ancient cannabis from Central Asia. J Exp Bot. 2008;59(15)4171-4182.

  3. Jiang HE, Xiao L, Ferguson DK, et al. The discovery of Capparis spinosa L. (Capparidaceae) in the Yanghai Tombs (2800 years b.p.), NW China, and its medicinal implications. J Ethnopharmacol. 2007; 113;409–420.