Pharma Voice

The truth behind herbal drugs

Herbal products have a special place in the world of pharmaceuticals. Gandhali Mulay and Ashwin Deshpande make an attempt at looking at the benefits and harms of herbal treatments

Side effects of conventional medicine, efficiency of plant-derived drugs and growing interest in natural products has increased scientific interest in medicinal plants. A look at the research and investments that are going into medicinal plants looks like, they will continue to play an important role in human health.

Today, there are at least 120 distinct chemical substances derived from plants that are considered important herbal drugs. Statistical data available in USA shows that 41 percent of pharmaceutical development has originated from herbal drugs. As per WHO estimates, 80 percent of about 4000 million inhabitants one this planet rely on plant products. In addition, herbal medicines have a good potential in the emerging nutraceutical industry as these materials are often considered food, as well as, medicines.

They are used in preventive and curative treatments throughout the world. Though there is anecdotal evidence supporting the use of herbal medicines, scientific studies in this field is in its infancy.

For instance, Garlic is wellknown for assisting immune system to fight cancer. This claim is backed by epidemiological evidence, which suggests that garlic helps reduce the risk of gastrointestinal tract cancer. A research published in the Japanese Journal of Cancer, indicates that garlic offers protection against esophageal and stomach cancers. Research is on to investigate garlic's potential to prevent breast, prostate and uterine cancers. Another promising natural drug candidate is green tea. It has also demonstrated its effect against several forms of cancer, including skin, stomach, duodenum, colon, liver, lung, prostate and pancreas.

Herbal medicines have been used since the dawn of civilisation to maintain health and to treat diseases. The WHO estimates that about three-quarters of the world's population currently use herbs and other forms of traditional medicines to treat their diseases. Even as we commence the new century with its exciting prospect of gene therapy, herbal medicines remain one of the common forms of therapy available to the world population.

Adaptogenic Herbs

Adaptogens comprise of safe natural substances that have a balancing, homeostatic effect on various body functions and increase resistance to stress. Herbal adaptogens should produce calmness and relaxation. Unlike drugs prescribed for stress, herbal adaptogens can also deliver the "side benefit" of strengthening the immune system. Adaptogens are best taken daily. Ashwaganda is the primary strengthening tonic and adaptogen of ayurvedic medicine. It is used for physical weakness, nerve weakness and the effects of old age. Ginseng, it appears, is a mildly stimulating adaptogen that improves memory, decreases fatigue and increases one's ability to handle stress. Reishi mushrooms too, can have a dramatically relaxing and strengthening effect on the nervous system. It also relieves insomnia. Schizandra berries also have a tonic and sedative effect, making them helpful both for insomnia and low energy, especially low mental energy. Siberian ginseng is widely used to relieve stress, to help people adapt to life changes and jet lag and to enhance athletic or work performance.

Herbs are not an anachronistic throwback to a bygone era. Rather, herbs are a much-needed tool to strengthen our "nerve power" so we can more readily relax and manage the stress in our lives. Taken internally or in a therapeutic herbal bath, and with key nutrients on the side, herbs are a valuable component in any relaxation program.

In addition to medicines, herbal products also have a say in the healthcare systems as de-stress nutrient supplements. 5-hydroxy-L-tryptophan (5-HTP) is a metabolite of the amino acid L-tryptophan and the precursor to serotonin and melatonin, two brain chemicals necessary for preventing anxiety, facilitating sleep, regulating mood and controlling appetite. 5-HTP can be obtained in synthetic form or as an extract from the Griffonia simplicifolicia plant.

Herbal myths

Society's growing interest in herbal products and other dietary supplements stems from a disappointment in allopathic medicine. Because herbal products are thought to be "natural", many people believe that they are safe. However, herbal products can be as toxic as or even more toxic than prescription medicine. They can also have unwanted side effects, cause drug interactions and possibly create surgical problems. Another problem is that people tend to rely more on testimonials on the benefits of herbal products than solid, scientific evidence. According to a study in the Journal of the American Medical Association (JAMA), roughly 15 million adults are at risk of possible adverse interactions between prescription medicines and herbs or high dose vitamins.

All the research on herbal products has triggered companies and research organisations lend an ear to the vast untapped potential source of drugs. Over the decades, there have been several instances of drugs sourced from herbal medicines like reseroine, vincristine and vinblatine. Neem and turmeric have been patented abroad recently. In India, companies like Ajanta Pharmaceuticals, Dabur and The Himalaya Drug Company have launched several herbal remedies in the market.

Kava in a cloud

Kava, the popular herbal relaxant, is making people nervous these days. In the last few years, more than 24 cases of severe liver damage have been reported in German and Swiss users. In Britain and France, Kava has voluntarily been pulled from the shelves or suspended. Health Canada is advising consumers to avoid the best-selling herb. The exact cause of the problem is still unclear. In 18 of the 24 cases, Kava users were also taking drugs with known or potential liver toxicity. Strangely, there have been no reports of liver damage among the millions of Canadian and US users.

Safety and efficacy

Herbal formulations are popular among the rural and urban community in India. The reason for the popularity and acceptability being the belief that all natural products are safe. In the literature, therapeutic efficacy or toxicity is some times attributed to the herb without describing the brand or its content of bio-active or quantitatively significant components. Pharmaceutical products used as medicines are usually single chemical entities with specific actions at receptors, enzymes and other cellular sites. These drugs or preparations are marketed after vigorous clinical trials to support rational pharmacotherapy. The most important question regarding any drug to be used is how safe it is for clinical use. Unfortunately this aspect is not addressed or transparent to the consumers who want to use the herbal formulation.

The herbal formulations which are sold as over the counter (OTC) have a different protocol regarding preparation, acquiring license and marketing. The active principles of herbal preparations are not often well defined. Regulations regarding safety and efficacy are not known to scientists or consumers.

The herbal medicines are poorly regulated. Assurance of safety, quality and efficacy of medicinal plants and herbal products is a key issue which needs to be addressed.

It is clear that the herbal industry can make great strides in India, with the co-operation between drug regulatory authorities, scientists and industries. However, standardisation of methods and quality control data on safety and efficacy are required for proper understanding of the use of herbal medicines.