The Pharmacological Action of Common Herbal Remedies

Acceptance of the clinical efficacy and tolerance of herbal remedies by practitioners of conventional, Western medicine is strongly dependent on unambiguous and reproducible evidence, particularly their pharmacological action. A single conventional drug generally has one dominant pharmacological mode of action which accounts for its therapeutic efficacy, whereas a herbal remedy because of the various active agents it contains, generally influences several biochemical and/or physiological systems present in the body. Identifying this therefore poses several challenges. They are much more complex, and the active components of a herbal remedy may act synergistically or interact in other ways. Although the need to determine modes of action has not been a primary concern of complementary healthcare practitioners, there is increasing pressure to elaborate objectively on their pharmacological action. In response, there has been an encouraging, and escalating, release of scientific data documenting the mode of action of many herbal remedies. Some we know about in considerable detail; of others we have an inkling; but for the vast majority the’ modes of action remain to be elucidated. This brief review, based on a survey of the available scientific and clinical literature, examines the modes of action of several therapeutic herbs which are being increasingly used, whether informally or as part of complementary or integrative medical practice. It examines a major category of sub stances, the adaptogens, and the various chemical forms it embraces, such as the saponins and triterpenes. The herbs with modulate the immune system, for instance garlic, turmeric and St John’s Wort, are likewise surveyed, as are the alkaloids and botanical anti-inflammatory agents. Herbs which exert pharmacological action via their nitric oxide regulatory properties are listed, as are those which provide essential micro-nutrients, such as vitamins and certain minerals. The review concludes with comment on the importance of understanding herbal remedy modes of action as a positive step to their wider adoption in the modern-day therapeutic armamentarium.