Medicinal plants. 'jamu' real or myth?

Bambang Kiranadi, Contributor, Bkiranadi@centrin.net.id

Experts have estimated that over 25 percent of the prescriptions in the U.S. contain active ingredients from plants. In Indonesia, medicinal plants have been widely used to remedy some diseases.

Unfortunately, the efficacy of some plants and herbs have not been documented. Pharmaceutical or biological tests on the drugs have not been conducted, and details on the properties of medicinal plants or herbs have yet to be understood.

Many plants have the potential to be made into drugs after careful and sophisticated investigation. Digitalis is one such example. It has been on the market since 1785 when William Withering, a British physician, reported that taking dried leaves from foxglove plants eased dropsy, an accumulation of fluid now known to be caused by the heart's failure to function adequately.

The drug is known as digoxin or digitoxin, and is still widely prescribed by doctors. The drug works by causing a blockage in a sodium-potassium pump, which makes biologists Jens Skou and T.D. Boyer earn the Nobel prize.

Similarly aspirin, made from the bark of the Filinpendula ulmaria tree and then later synthesized by Hoffman has been widely used since World War I for reducing pain and inflammation. The drug's properties inhibit the formation of prostaglandin, the culprit that causes pain and inflammation. Inhibiting prostaglandin also has an effect on stopping blood from clotting, thus preventing stroke.

By opening Pandora's box on how aspirin works also earned John R. Vane Nobel prize. Another example is the shrub of the Rauvolvia serpentina or Indian snakeroots, a traditional treatment used by the people of India. It was discovered to be reserpine, and it is still occasionally prescribed by doctors for lowering blood pressure.

We can add more discoveries to the list of drugs that come from plants, such as opiates for painkillers, quinine for malaria, theopylline for opening bronchial passages and taxol for cancer.

Basically, plants produce a chemical compound to be used for an anti-predator or disease, which is also used for medicine. Thanks to the development of analytical chemistry and organic synthesis, scientists are capable of analyzing the compounds and synthesizing some of them.

With the advent of modern biology some of the mechanisms of how these components work in the body have been elucidated.

In tropical forests, such as in Indonesia, many plants with potentially potent compounds for drugs are widespread but with limited financial resources, it is impossible to screen their biological activities extensively.

Since we understand the efficacy of medicinal plants from tribes who have used them for generations, we have to start the investigation of a potential drug through studying the belief of what it can cure and interviewing the local healers, who can choose the plants for pharmacological studies. The local healer will be able to give clues to the biological activity of the compound in the plants.

One notable result in using an ethnobotanical approach was the hunt for a cancer drug compound from the plant Taxus brevifolia, which produces taxol, and is used for the treatment of ovarian cancer. It was approved by the U.S. Food and Drug Administration (FDA) in 1994 for treating the metastasis of breast cancer.

Taxol worked in a different way than any other drug known at that time. It bound the microtubules that played a crucial role in cell division thereby curbing the process of cancer by inhibiting uncontrollable cell division.

However, the plant that produces taxol grows very slowly and scientists are hunting for a synthesis of the compound. The ethnobotanical approach is also being used to search for a drug to treat HIV. Special attention has been given to a plant called Homalanthus mutants from Samoa, which contains a compound called prostratin.

We can also approach the investigation through an ecological survey, when plants survive in a very severe habitat or produce molecules capable of affecting animals, then the toxic compound might be capable of achieving a therapeutic effect.

What about Indonesian medicinal plants? Many have been widely used by people in herbal remedies, such as jamu (herbal medicine). Experts claim that plants such as bratawali (Tinaspora crispa) could be a drug used to treat type two diabetes. Unfortunately, we have not done enough to investigate the medicinal properties of this compound to reduce the blood glucose level.

The drug's properties that lower the blood glucose level do so by either blocking the potassium channel or increasing the sensitivity of the insulin receptor.

The belief that a mixture of kunyit (turmeric) and asam (tamarind) aids in weight loss has attracted the attention of many people. Based on the belief that losing weight is related to a reduction in fat, this mixture is actually a potential drug that can stop the absorption of lipids if we understand how it works.

We understand that there is a drug that is isolated from fungus called strepmyce toxytrini capable of reducing fat absorption by up to 30 percent. It works by inhibiting the enzyme lipase in the intestine.

Fat, which has a structure as a triglyceride, will not be broken down into free fatty acids in the intestine, thereby inhibiting the absorption of it. This drug is being used for treating people with a high level of lipids and cholesterol in the blood.

The arteries narrow as fatty acids and cholesterol accumulate on the walls inside, and this is a major cause of stroke. To be confident in using herbal medicine, we have to have information on how this drug works in the body.

Traditional medicines are based on beliefs and healers, so to utilize herbal remedies by using them in modern medicine and synthesizing new drugs based on medicinal plants, there has to be a good relationship between the healer and the scientist.

To locate the plants, healers should be treated as colleagues and partners and not only as a source of information. The partnership will have a greater impact on discovering the medicinal plants needed for modern medicine.

Unfortunately, the traditional healer as a profession is not attracting younger people. Healers do not have apprentices, and when the healer dies, their knowledge is lost as well.

In the era of globalization, when the philosophy is to maximize profit, the extraction of medicinal plants and their extinction will be inevitable. Some western universities with a good infrastructure, pharmaceutical companies and stockbrokers could earn a lot of money from the knowledge given by traditional healers.

Communities that have a history of using plants in traditional medicine are a very good source of information as well as a source for further studies on the effects of those medicinal plants.

-- The writer is a senior lecturer at the Bogor Institute of Agriculture (IPB) and a researcher at Unisosdem Jakarta.