Medicinal Plants: Therapeutic Potential, Safety, and Toxicity

According to the archaeological findings, humans used plants for their healing properties for over 60,000 years starting paleolithic. Due to the absence of powerful and effective conventional drugs, during many centuries, medicinal plants were harvested, and their leaves, bark, seeds, roots, stems, and fruits were applied to heal several illnesses. Contemporary science currently recognizes that their active compounds make an important contribution to modern drugs discovery and development of new efficient conventional medical drugs. Communities in developing countries sometimes totally rely on herbal products as a part of their culture, and these products are gaining popularity due to deficit of the conventional drugs that are often expensive and cannot be afforded by all. During the last decade, over 28,187 medicinal species were used by humans (MNPS, Medicinal plant names services (MNPS). Available at: https://mpns.science.kew.org/mpns-portal/ , 2020), and they are included in medical services provided in China (over 40%), as well as Canada, the USA, Belgium, Australia, and France. In 2008, the international market for widely used herbal remedies was about USD 83 billion, but in the year 2026, it is expected to reach USD 178.4 billion (Herbal Medicines – Global Market Trajectory and Analytics, Globe Newswire. ResearchAndMarkets.com , Sept 21, 2022). Herbal products are available for natural doctors and their patients as well as individual consumers without prescription, and often none of the potential health hazards are barely recognized. Sometimes medicinal plants can be cultivated on the contaminated soil with heavy metals or unknown chemicals, and via absorption and tissue accumulation, and herbal supplements made of these plants can cause unwanted side effects and toxic poisoning in healthy individuals. Unfortunately, in many countries, herbal medicine and diet supplements are entering the common market without any safety and toxicological evaluation, and manufacturing facilities often lack appropriate equipment and hygiene and cannot guarantee the quality and purity of the natural products. To increase bulk sales and lower the prices, some producers of the herbal diet supplements could adulterate the final products with plant material having similar and often fewer effective properties as well as specific commercial additives. A potential interaction between conventional drugs and herbal medicine or supplements can also be a cause for the serious health concern, and precise analytical studies and well-designed clinical evaluation must be done before their marketing and distribution.