The role of plant-derived drugs and herbal medicines in healthcare

The acetone soluble fraction from bark extract of Stryphnodendron adstringens (Mart.) coville inhibits gastric acid secretion and experimental gastric ulceration in rats

The acetone soluble fraction from a crude methanol extract of Stryphnodendron adstringens stem bark (AFSAB) was evaluated in acute (ethanol, indomethacin and hypothermic restraint-stress) and chronic (acetic acid) models of gastric ulceration and on basal and bethanechol-stimulated gastric acid secretion in rats. Rats pretreated orally with AFSAB at doses of 400 and 800 mg/kg showed significant decreases of gastric lesion scores in ethanol (62% and 98%) and hypothermic restraint-stress (89% and 88%) models but exerted no significant influence on indomethacin-induced acute or acetic acid-induced chronic ulceration. In pylorus-ligated rats, AFSAB significantly decreased the basal as well as bethanechol-stimulated gastric secretory volume and the total acidity with an elevated pH value. AFSAB failed to modify the gastric mucus and the gastric wall nonprotein-sulphydryl content. These results point to a possible antisecretory effect of AFSAB which account for the observed antiulcer activity in ethanol and hypothermic restraint-stress induced models of acute gastric ulceration.

Antimicrobial studies on three species of Hypericum from the Canary Islands

The antimicrobial activity of several extracts and fractions of the aerial parts of Hypericum canariense, Hypericum glandulosum and Hypericum grandifolium was investigated using the disc diffusion and broth microdilution methods against twelve reference microorganisms (eight bacterial and four fungal strains). The methanol extract and chloroform fraction of H. canariense, as well as the methanol extracts, butanol and chloroform fractions of both H. glandulosum and H. grandifolium exhibited a good antibacterial activity against four Gram-positive bacteria (Bacillus cereus var. mycoides, Micrococcus luteus, Staphylococcus aureus and Staphylococcus epidermidis) and the Gram-negative bacterium Bordetella bronchiseptica with the diameters of growth inhibition area in the range 10-25 mm and MICs values between 0.03 and 0.29 mg/ml. Neither the infusions and aqueous fractions of the species studied nor the butanol fraction of H. canariense showed any antibacterial activity against the tested microorganisms. Amongst the active extracts, the minimum inhibitory concentration (MIC) determination showed that the H. canariense chloroform fraction was the most active against M. luteus, S. aureus and S. epidermidis. No antifungal activity was seen with any of the extracts or fractions tested. The results of this study support the use of these species in Canarian traditional medicine to treat skin infections.

Medicinals for the millennia: the historical record

Nature has been a source of medicinal agents for thousands of years, and an impressive number of modern drugs have been isolated from natural sources, many based on their use in traditional medicine. The use of herbal drugs is once more escalating in the form of complementary and alternative medicine. The past century, however, has seen an increasing role played by microorganisms in the production of the antibiotics and other drugs for the treatment of some serious diseases. With less than 1% of the microbial world currently known, advances in procedures for microbial cultivation and the extraction of nucleic acids from environmental samples from soil and marine habitats, and from symbiotic and endophytic microbes associated with terrestrial and marine macro-organisms, will provide access to a vast untapped reservoir of genetic and metabolic diversity. By use of combinatorial chemical and biosynthetic technology, novel natural product leads will be optimized on the basis of their biological activities to yield effective chemotherapeutic and other bioactive agents.

Lepidium meyenii Walp. improves sexual behaviour in male rats independently from its action on spontaneous locomotor activity

Lepidium meyenii Walpers (Maca) is traditionally employed in the Andean region for its supposed properties to improve energy and fertility. The aim of this study was to evaluate the effect of acute and chronic Maca pulverised root oral administration on rat sexual behaviour. Sixty male sexually experienced rats (20 group) were daily treated for 15 days with Maca 15 mg kg(-1), Maca 75 mg kg(-1) or saline 0.5 ml kg(-1). The following sexual performance parameters were evaluated at first and last day of treatment: 1st mount (ML), 1st intromission (IL), ejaculation (EL) and postejaculatory (PEL) latencies, intercopulatory interval (ICI) and copulatory efficacy (CE). An activity cage test was carried out to evaluate if Maca-induced locomotion changes could indirectly improve rat sexual performances. It was observed that both lower and higher Maca doses acutely decreased ML, IL and ICI in a significant way (P < 0.05), while only the 75 mg kg(-1) dose decreased the PEL (T = 29, P < 0.05). This effect seems to be the only one dose-dependent. After 15 days of treatment, both doses are able to significantly decrease ML, IL, EL and PEL, while the 75 mg kg(-1) dose decreased the ICI (T = 40, P < 0.05) too. IL, EL and PEL variations seem to be dose-related after chronic treatment. Moreover, chronic Maca treatment induced an apparently not dose-related increase in rat locomotion, during the second 10-min period of observation in the activity cage. The late in Maca-induced locomotion modification excludes that improvement of tested sexual performance parameters is related to an increase in rat aspecific activity. Thus, it was concluded that both acute and chronic Maca oral administration significantly improve sexual performance parameters in male rats.

Should we be concerned about herbal remedies

During the latter part of this century the practice of herbalism has become mainstream throughout the world. This is due in part to the recognition of the value of traditional medical systems, particularly of Asian origin, and the identification of medicinal plants from indigenous pharmacopeias that have been shown to have significant healing power, either in their natural state or as the source of new pharmaceuticals. Generally these formulations are considered moderate in efficacy and thus less toxic than most pharmaceutical agents. In the Western world, in particular, the developing concept that 'natural' is better than 'chemical' or 'synthetic' has led to the evolution of Neo-Western herbalism that is the basis of an ever expanding industry. In the US, often guised as food, or food supplements, known as nutriceuticals, these formulations are readily available for those that wish to self-medicate. Within this system, in particular, are plants that lack ethnomedical verification of efficacy or safety. Unfortunately there is no universal regulatory system in place that insures that any of these plant remedies are what they say they are, do what is claimed, or most importantly are safe. Data will be presented in this context, outlining how adulteration, inappropriate formulation, or lack of understanding of plant and drug interactions have led to adverse reactions that are sometimes life-threatening or lethal.

Pharmacognosy in the 21st century

The term pharmacognosy as a constituent scientific discipline of pharmacy has been in use for nearly 200 years, and it refers to studies on natural product drugs. During the last half of the 20th century, pharmacognosy evolved from being a descriptive botanical subject to one having a more chemical and biological focus. At the beginning of the 21st century, pharmacognosy teaching in academic pharmacy institutions has been given new relevance, as a result of the explosive growth in the use of herbal remedies (phytomedicines) in modern pharmacy practice, particularly in western Europe and North America. In turn, pharmacognosy research areas are continuing to expand, and now include aspects of cell and molecular biology in relation to natural products, ethnobotany and phytotherapy, in addition to the more traditional analytical method development and phytochemistry. Examples are provided in this review of promising bioactive compounds obtained in two multidisciplinary natural product drug discovery projects, aimed at the elucidation of new plant-derived cancer chemotherapeutic agents and novel cancer chemopreventives, respectively. The systematic study of herbal remedies offers pharmacognosy groups an attractive new area of research, ranging from investigating the biologically active principles of phytomedicines and their mode of action and potential drug interactions, to quality control, and involvement in clinical trials.

The potential of alkaloids in drug discovery

Alkaloids are an important group of diversely distributed, chemically, biologically and commercially significant natural products. This article suggests why now, with the presently available technology, and the remaining biome available and reasonably accessible, is an opportune moment to consciously focus on the discovery of further alkaloids with pharmacophoric utility.

Naturally occurring antinociceptive substances from plants

Despite the progress that has occurred in recent years in the development of therapy, there is still a need for effective and potent analgesics, especially for the treatment of chronic pain. One of the most important analgesic drugs employed in clinical practice today continues to be the alkaloid morphine. In this review, emphasis will be given to the important contribution and the history of Papaver somniferum, Salix species, Capsicum species and Cannabis sativa in the development of new analgesics and their importance in the understanding of the complex pathways related to electrophysiological and molecular mechanisms associated with pain transmission. Recently discovered antinociceptive substances include alkaloids, terpenoids and flavonoid. Plant-derived substances have, and will certainly continue to have, a relevant place in the process of drug discovery, particularly in the development of new analgesic drugs.

Complementary and alternative therapies to manage HIV-related symptoms

Persons with HIV infection report substantial use of complementary and alternative medical (CAM) therapies for symptom management. Anecdotal reports from patients indicate that CAM approaches are helpful; however, there is limited scientific information on the safety and efficacy of these therapies in the HIV population. The purpose of this review is to critically appraise the scientific evidence for selected CAM therapies that are used by HIV-infected persons to manage three common symptoms: nutritional alterations, pain, and depression.

Introduction to the pharmacoeconomics of herbal medicines

This article explores the need to perform pharmacoeconomic evaluations of herbal medicines and assesses the extent to which this approach has been applied so far to these products. There seems to be no compelling need for pharmacoeconomic analyses of herbal over-the-counter medicines, but such analyses are certainly warranted for herbal prescription medicines that have a high level of reimbursement. Such preparations are used in Germany, in particular, where physicians prescribed ginkgo, hawthorn, St John's wort, horse-chestnut and saw palmetto to a value of more than DM50 million each in 1996. In our survey, only a single pharmacoeconomic study, of uncertain quality, was found on these 5 herbs, whereas several pharmacoeconomic reports on synthetic competitors were retrieved. The time has come to submit highly reimbursed herbal prescription medicines to the same rigorous pharmacoeconomic evaluations as their synthetic competitors. At present, such studies are particularly important for Germany, but in the future they may also become relevant for other countries, inside as well as outside Europe.

Current status of artemisinin and its derivatives as antimalarial drugs

Artemisinin is a promising and a potent antimalarial drug, which meets the dual challenge posed by drug-resistant parasites and rapid progression of malarial illness. This review article focuses on the progress achieved during the last years in the production of artemisinin from Artemisia annua. The structure, biosynthesis and analysis of artemisinin and its mode of action are described. The review also focuses on clinical studies, toxicity studies, pharmacokinetics and activity of artemisinin related compounds. The production strategies including organic synthesis, extraction from plants, in vitro cultures and alternative strategies for enhancing the yields are also discussed.

Efficacy, safety, quality control, marketing and regulatory guidelines for herbal medicines (phytotherapeutic agents)

This review highlights the current advances in knowledge about the safety, efficacy, quality control, marketing and regulatory aspects of botanical medicines. Phytotherapeutic agents are standardized herbal preparations consisting of complex mixtures of one or more plants which contain as active ingredients plant parts or plant material in the crude or processed state. A marked growth in the worldwide phytotherapeutic market has occurred over the last 15 years. For the European and USA markets alone, this will reach about $7 billion and $5 billion per annum, respectively, in 1999, and has thus attracted the interest of most large pharmaceutical companies. Insufficient data exist for most plants to guarantee their quality, efficacy and safety. The idea that herbal drugs are safe and free from side effects is false. Plants contain hundreds of constituents and some of them are very toxic, such as the most cytotoxic anti-cancer plant-derived drugs, digitalis and the pyrrolizidine alkaloids, etc. However, the adverse effects of phytotherapeutic agents are less frequent compared with synthetic drugs, but well-controlled clinical trials have now confirmed that such effects really exist. Several regulatory models for herbal medicines are currently available including prescription drugs, over-the-counter substances, traditional medicines and dietary supplements. Harmonization and improvement in the processes of regulation is needed, and the general tendency is to perpetuate the German Commission E experience, which combines scientific studies and traditional knowledge (monographs). Finally, the trend in the domestication, production and biotechnological studies and genetic improvement of medicinal plants, instead of the use of plants harvested in the wild, will offer great advantages, since it will be possible to obtain uniform and high quality raw materials which are fundamental to the efficacy and safety of herbal drugs.

Immunomodulatory effect of Nigella sativa proteins fractionated by ion exchange chromatography

Whole Nigella sativa (N. sativa) proteins were purified on a DEAE Sephadex A50 ion exchange column. Complete fractionation was achieved in four peaks. Analysis of the purified peaks was carried out by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Whole N. sativa showed a number of protein bands ranging from 94-10 kDa molecular mass. In mixed lymphocyte cultures (MLC), whole N. sativa and its purified proteins were found stimulatory as well as suppressive and this effect varied from one donor to another. Maximum stimulation (mean + S.E. of % relative index was 63.73 + 20.78) was observed with fractionated N. sativa proteins (P1) (10 microg/ml) in MLC. In MLC, also N. sativa peaks (P1 and P2) were stimulatory at all concentrations (10 microg/ml, 1 microg/ml or 0.1 microg/ml) used. However, a uniformly suppressive effect of N. sativa and its all four peaks at a concentration of 10 microg/ml was noticed when lymphocytes were activated with pokeweed mitogen (PWM). The effect of N. sativa proteins was further evaluated on the production of cytokines which were measured by using specific enzyme-linked immunosorbent assay. Large quantities of IL-1beta were secreted by whole N. sativa in culture medium with non-activated peripheral blood mononuclear cells (PBMC) (450 pg/ml) and with allogeneic cells (410 pg/ml). Fractionated N. sativa was less effective when compared with whole N. sativa proteins. No effect on IL-4 secretion was seen either by using non-activated, PWM-activated or allogeneic-cells. Whole N. sativa suppressed as well as stimulated the production of IL-8 in non-activated and PWM-activated PBMC respectively. All N. sativa peaks with protein concentration of 2 microg/ml were stimulatory for the induction of IL-8 by PWM-activated cells. However, no effect on IL-8 was seen either with whole N. sativa or its peaks when allogeneic PBMC were used. Stimulatory effect of whole N. sativa and fractionated proteins was also noticed on the production of TNF-alpha either using non-activated or mitogen activated cells.

Diet, micronutrients, and the prostate gland

Diseases of the prostate gland, particularly adenocarcinoma and benign prostatic hyperplasia (BPH), are age-related. Prostate cancer is the most commonly occurring tumor in U.S. men. Differences in the incidence of this disease among ethnic populations are not due solely to genetic differences. Many efforts have been devoted to studying associations between nutrition and prostate cancer. The strongest association appears to be related to total fat intake and increased risk of this malignancy. Evidence also exists to suggest a role for certain micronutrients, such as zinc, selenium, vitamin E, lycopene, phytoestrogens, and phytosterols, although the role of nutrition and micronutrients in protection against prostate cancer is less convincing. Further research is necessary.

Supercritical fluid extraction and clean-up of organochlorine pesticides in Chinese herbal medicine

A method involving the simultaneous extraction and clean-up of 13 organochlorine pesticides (OCPs) from Chinese herbal medicines (CHMs) was developed using supercritical fluid extraction (SFE) followed by gas chromatography-electron capture detection and mass spectrometric confirmation. The pesticides in the study consisted of alpha-, beta-, gamma-, and delta-benzene hexachloride, heptachlor, aldrin, heptachlor epoxide, endosulfan I, 4,4'-DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethene), dieldrin, endrin, 4,4'-DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane), endosulfan II, 4,4'-DDT (2,2-bis(p-chlorophenyl)1,1,1-trichloroethane), endrin aldehyde, and endosulfan sulfate. A series of experiments was conducted to optimize the final extraction conditions [pure CO2, 250 atm extraction pressure (1 atm = 101,325 Pa), 50 degrees C extraction temperature, 5 min static extraction time, 20 min dynamic extraction time, 2.0-g Florisil sorbent on top of 0.1-g samples, 12-ml n-hexane eluting at 1 ml/min, and a 10-ml extraction vessel]. Florisil sorbent was placed with the sample in the SFE vessel to provide a facile and effective clean-up approach. Mean recoveries of 78-121% with reproducibilities of 5-31% were obtained for the pesticides except for endosulfan II, endosulfan sulfate and endrin aldehyde. The simple and rapid method may be used to determine OCPs in CHMs routinely, and in fact, was used to analyze CHMs sold in Taiwan.

Traditional pharmacology and medicine in Africa. Ethnopharmacological themes in sub-Saharan art objects and utensils

Drawing from the general description that ethnopharmacology studies the human use of crude drugs and poisons in a traditional context, ethnopharmacological themes in native art can be defined as themes visualizing different features of traditional medicines and poisons, such as natural sources, methods of preparation, containers, usage and implements, target diseases and effects. This review documents that native African art objects and utensils are a goldmine of such ethnopharmacological themes by focusing on the following subjects: (a) objects related to the use of medicines (sources as well as tools for their collection, preparation and keeping); (b) objects related to the use of poisons (e.g. for ordeals, hunting and fishing); (c) objects related to the use of psychotropic agents (e.g. alcoholic beverages, kola nuts, smoking and snuffing materials); (d) pathological representations (e.g. treponematoses, leprosy, smallpox, swollen abdomen, scrotal enlargement, goiter and distorted faces); and (e) portrayals of certain types of treatment (e.g. topical instillations, perinatal care, and surgery). To avoid the impression that ethnopharmacology has little else to offer than armchair amusement, an epilogue outlines the medical relevance of this interdisciplinary science for Western and African societies.

Natural products and diabetes treatment

Many natural products are promoted to improve the health status of patients with diabetes by people making a profit on these products. Few of these claims have any scientific basis. Certain natural products are potentially damaging to patients with chronic diseases, especially if the products are used instead of proven scientific treatment regimens. Many individuals believe that if a product is natural it must be effective and safe. What is ironic is that if the products were safe and effective, and if studies would have been done on humans to prove safety and effectiveness, the sales of the products would greatly increase (as opposed to present limited sales as herbs from health food stores). Some of the products do have a beneficial effect, especially as a placebo if the patient believes that the product is going to work. As can be seen from the summary of products that are listed here that claim to improve the treatment of patients with diabetes, very few are available in a standard form that would produce a known positive effect. The few products that do have a mild impact on lowering blood glucose levels are much less effective than standard treatments. In a recent review of the role of plant-derived drugs and herbal medicines in healthcare, no natural products were listed as having a beneficial effect on diabetes. Diabetes care providers need to confront the issue of the use of natural products with their patients. Patients should be taught the importance of using proven, effective treatment regimens. Any patient who decides to use a natural product should be followed closely to make sure that no toxic effects occur and that treatment objectives are achieved.