The integration of herbal medicine into modern medical practises, including treat-ments for infections and cancer, must take into account the interrelated issues of quality, safety, and efficacy [64]. Quality is the paramount issue because it can af-fect the efficacy and/or safety of the herbal products being used. Current product quality ranges from very high to very low due to intrinsic, extrinsic, and regulatory factors. Intrinsically, species differences, organ specificity, diurnal and seasonal variations can affect the qualitative and quantitative accumulation of active chemical constituents in the source medicinal plants. Extrinsically, environmental fac-tors, field collection methods such as cultivation, harvest, post-harvest transport,and storage, manufacturing practises, inadvertent contamination and substitution,and intentional adulteration are contributing factors to the quality of herbal medicinal products. Source plant materials that are contaminated with microbes, microbial toxins, environmental pollutants, or heavy metals; or finished products that are adulterated with foreign toxic plants or synthetic pharmaceutical agents can lead to adverse events. Substandard source materials or finished products will yield therapeutically less effective agents. Herbal medicine quality can also be attributed to regulatory practises. In a number of countries, herbal medicines are unregulated, which has led to product quality differences.
Product quality improvement may be achieved by implementing control measures from the point of medicinal plant procurement under Good Agricultural Practises (GAPs) and the manufacture of the finished botanical products under Good Manufacturing Practises (GMPs), plus postmarketing quality assurance surveillance. The lack of pharmacological and clinical data on the majority of herbal medicinal products is a major impediment to the integration of herbal medicines into conventional medical practise. For valid integration, pharmacological and especially, clinical studies, must be conducted on those plants lacking such data. Adverse events, including drug–herb interactions, must also be monitored to promote a safe integration of efficacious herbal medicine into conventional medical practises.
For the developing countries, the approval as drugs of standardized and formu-
lated plant extracts might be the starting point of an innovative and successful local pharmaceutical industry, which can compete with the large pharmaceutical companies, not only for the treatment of minor diseases, but also for the treatment of severe and life-threatening diseases. It can be stated that the major activities of natural products research of the past decades have clearly demonstrated that natural products represent an unparalleled reservoir of molecular diversity to drug discovery and development, and are complementary to combinatorial libraries.The major disadvantage is the time taken to isolate and to characterize the activecomponents from the extracts. By improving the diversity and quality of sample source and screen suitability, by accelerating dereplication and by automating and standardizing early isolation steps, the effectiveness of natural products research can be enhanced. The efforts to establish collaboration between universities and local pharmaceutical companies to produce new medicines with scientific proof of safety, quality and efficacy are relevant to progress in this area. This interaction
between the pharmaceutical industry and the universities has in turn stimulated the appearance of preclinical pharmacological studies and of well-controlled and randomized clinical trials to prove their worth. Furthermore, emphasis on domestication, production, and biotechnological studies, followed by genetic improvements to medicinal plants, are other fields of science that emerge from such progress in the use of medicinal plants in the world. Scientists have dedicated significant efforts to the publishing of both basic and clinical studies on herbal medicines, and thus certainly will create the scientific basis for the physician’s prescription of herbal drugs. In spite of this, so far insufficient data exist to provide an accurate assessment of the quality, efficacy, and safety of most of the herbal medicines currently available on the market. For all these reasons, a great effort in training more scientists in the relevant areas is still necessary in order to establish rational and sustainable exploitation of the world’s biodiversity.
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