Biological Evaluation of Plants of Laos Used in the Treatment of Tuberculosis in Lao Traditional Medicine

Due to many circumstances, Laos has remained relatively secluded from the outside world. It is surrounded by China and Myanmar (Burma) to the North, Vietnam to the East, Cambodia to the South, and Thailand to the West, and has been referred to as “the land in between” due to its position. The country covers 236,800 square kilometers (CIA World Factbook, 2007), an area slightly larger than the size of Utah. Undeveloped forest covers more than forty per cent of the country, and eighty percent of the population lives in rural areas as subsistence farmers. This situation puts most of the population into close contact with medicinal plants from forested areas. Therefore, in the event of health problems, it is less expensive and easier to turn to traditional herbal remedies than to visit a government clinic for medicine. The magnitude of traditional medicine use in Laos makes it an ideal place to study ethnopharmacology.
    The government recognizes the importance of traditional medicine in Laos, and has established the Traditional Medicine Research Center (TMRC) under the Ministry of Public Health. An important focus of their research is to gather and catalogue indigenous traditional medicine treatments, the greater part of which consists of herbal remedies, and to publish the results of their research to serve as a reference for use by contemporary healers and the wider public. As part of its function and mandate, the TMRC has established smaller traditional medicine units called Provincial Traditional Medicine Stations (TMS’s) (Soejarto et al., 1999).     Initially, a TMS was established in each of 10 provinces. Each TM Station is also affiliated with a Traditional Medicine Hospital. Today, three more TM Stations have been added, for a total of 13 TM Stations in operation.  The staff of a TMS works in direct contact with rural traditional healers that both give and receive information on treatment methods currently being used around the country. 
    Lao Traditional Medicine, or “Ya Phurn Meuang Lao” dates back to 4500 years (the first group of Lao nation in southern part of present China), while the well documented practices started as early as the 14th century, after the establishment of the First Kingdom (Lane Xang Kingdom) (Viravong, 1973). While the earliest practices of traditional medicine in Lao PDR are still unclear, it is evident that Buddhist and Sino-Indian influences helped shape the traditional pharmacopoeia and practices used in traditional medicine.  In addition, in many of the Buddhist temple-compounds, or wats found in every village in Lao PDR, young monks are trained in traditional medicine by older monks .  Information about the uses of medicinal plants also appears in palm-leaf manuscripts located in the libraries of the larger wats, written several generations ago in old Lao and Pali, the language of the sacred Buddhist texts (Abhakorn, 2000).  
Lao palm leaf manuscripts date back to the 1400s CE. They are typically written on leaves of the palmyra palm (Borassus flabellifer L., Arecaceae), which are very thick and durable. The leaves are pressed, dried, and cut into uniform shapes, usually around 10 cm in width and range anywhere from 15 to 60 cm in length. The leaves are cleaned and sanded to get a uniform writing surface, then transcribed onto using a stylus of wood or metal. It has actually been hypothesized that the characters used in the manuscripts developed their rounded shapes because too many straight lines has a tendency to tear the leaves. As this scratching does not give any color, a mixture of soot and oil are then rubbed onto the leaves to make the characters stand out. The leaves are attached together with string, and are often bound between two flat pieces of wood. The length often indicates the type/subject of palm leaf manuscript, with medicinal manuscripts being around the length of a forearm while religious manuscripts are typically the length of an entire arm. 
Many Buddhist monks in Laos have been regarded as healers for many centuries, and have kept records of their treatments in palm leaf manuscripts. Many of these manuscripts are recorded in scripts that are known only by monks or lay-people who have studied them for many years. The TMRC and the National Library of Laos have hundreds of these medical manuscripts that have yet to be translated into a modern language. There is a vast amount of information waiting to be uncovered. 
In the recent past, the use of palm leaf manuscripts has declined and many are becoming subject to mould and insects before being recopied. In recognition of the amount of information at risk of being lost, Dara Kanlaya headed up the Palm Leaf Manuscript Preservation (PLMP) Project in 1989 (Abhakorn, 1996). This project allowed researchers to travel to rural areas of the country with microfilm equipment to capture images of important manuscripts without removing them from their respective community wats (temples). The microfilm is kept at the National Library of Laos, which currently holds around six thousand actual bundles of palm leaves dating back to 1465 along with more than 1030 rolls of microfilm containing more than 54,000 palm leaf manuscript fascicles from more than 830 wats. 

The TMRC holds an ample library about traditional medicines, including a collection of medical palm leaf manuscripts. Many of these manuscripts have been translated from their original scripts into the modern Lao language, and some have been translated into English. It has been one of the goals of the International Cooperative Biodiversity Group (ICBG) project, a collaborative research between the University of Illinois at Chicago (UIC), government institutions in Vietnam, and the TMRC in Laos, to explore past and contemporary traditional medicinal plant treatments as a potential source of biologically active compounds for pharmaceutical development (Soejarto et al., 1999, 2006). In this search, the information contained in the palm leaf manuscripts represents therapeutic practices of the past. 
One of the disease targets in the ICBG project is tuberculosis (TB). Although TB is conventionally treated using modern antibiotics such as isoniazid, rifampin, pyrazinamide and ethambutol, the causative agent, Mycobacterium tuberculosis, has developed strains resistant to conventional antibiotics. Additionally, in countries such as Vietnam and Laos, modern drugs are often expensive and difficult to obtain for much of the population. There is an urgent need for alternative treatments. The aim of this research is to identify some of the herbal remedies used in contemporary and past traditional medical practices  for the treatment of tuberculosis in Laos, and to investigate their effectiveness.