Herbal Drugs: Ethnomedicine to Modern Medicine

Traditional Medicine for Memory Enhancement

2012-05-23T04:07:00.003-07:00

Abstract In traditional practices of medicine, numerous plants have been used to
alleviate memory impairment both in healthy individuals and those with disease
states which are now recognised as specific cognitive disorders such as Alzheimer’s
disease (AD).

An ethnopharmacological approach has provided leads to identify plants and their compounds that may have potential to modulate cognitive abilities by different modes of action. A variety of therapeutic targets have been identified as relevant in the treatment of cognitive disorders, including modulation of the cholinergic system, which may be achieved by the inhibition of acetylcholinesterase (AChE), and neuroprotection against glutamate-induced overstimulation
of N-methyl-D-aspartate (NMDA) receptors, by the use of NMDA receptor
modulators.

Other activities considered to be relevant in the alleviation of cognitive
impairment include anti-inflammatory, antioxidant and estrogenic activities. Two of
the currently licensed drugs used to treat cognitive symptoms in AD, galantamine
and rivastigmine, were derived from plant sources and have been characterised as
inhibitors of AChE.

However, some plant extracts which occur as a complex mixture of components, such as Ginkgo biloba L. extract, have demonstrated relevant biological activities in relation to cognitive function, but the compounds responsible for the observed effects or the mechanisms of action have not been well characterised.

Amongst the many plants reputed to enhance cognitive function in a variety
of traditional medicines including Ayurvedic, Chinese, European, African and
South American medicines, relatively few have been extensively studied to determine
any pharmacological basis for their historical uses. Some of those plants that
have generated particular interest in understanding and establishing their potential
for alleviating cognitive impairment are discussed.

Novel Leads from Herbal Drugs for Neurodegenerative Diseases

2012-05-23T04:04:00.005-07:00

Abstract This article summarizes the salient features of new therapeutic leads from
herbal sources for various types of neurodegenerative diseases.

Efforts made in using existing knowledge on several popular medicinal plants, particularly those utilized in the Indian traditional medicinal and Ayurvedic system discussed in light
of recent research.

A few promising plants such as Asparagus racemosus, Bacopa monnieri, Centella asiatica, and Mucuna pruriens are worth exploring for drug development for neuroprotection.

Safety and Efficacy of Phytomedicines in Cancer Prevention and Treatment

2012-05-23T04:00:00.003-07:00

Abstract In this review we discuss some aspects of herbal use either to prevent
cancer or to treat the disease or the side effects of chemotherapy. The most powerful
reasons, for cancer patients, to use phytomedicines are related to the wish to leave no
option untried and to the dissatisfaction with mainstream oncology treatments. In the
review, herbs commonly used in cancer and their mechanism of action are referred.
Moreover, clinical trials about the use of some herbs for treating the side effects of
chemotherapy and radiation are cited.

As regards the safety data of phytomedicines in cancer patients, considering the narrow therapeutic window of chemotherapic drugs, the risk of clinically relevant herb-drug interactions can increase: in the USA more than 100,000 deaths per year can be attributed to drug interactions, most of them connected to the use of herbs. Some experts believe that the potential risk of herb drug interactions is enough to recommend patients on chemotherapy not to
use herbal therapies.

At present, oncologists must be encouraged to discuss herbal use with their patients, and they should be aware of possible herb anticancer drug interactions. Furthermore, physicians should advise patients to refrain from using herbs, especially when their effects have not been well investigated.

Anticancer and Immunomodulatory Properties of Tinospora

2012-05-23T03:57:00.004-07:00

Abstract There has been an upsurge in the discovery of bioactive phytochemicals
having a chemopreventive ability against various diseases including immunological
disorders and cancer. Based on their uses in Ayurveda or herbal medicine, many
plants have been the subject of experimental evaluation to provide a scientific rationale
for their medicinal values.

In this regard, Tinospora has a long history of use against various ailments including spasms, inflammation, arthritis, allergy, diabetes, cardiotoxicity, and immunosuppression. However, scientific evidences for its biological activities are limited. Recently, many studies have been carried out to support the acclaimed as well as to discover the novel potential of Tinospora which
have also revealed its anticancer and radioprotective activities. Overall, the anticancer
and immunomodulatory activities of Tinospora and its bioactive components
could be further explored in relevant experimental model systems for its potential
clinical benefits.

Artemisinin: A VersatileWeapon from Traditional Chinese Medicine

2012-05-23T03:54:00.003-07:00

Abstract Traditional Chinese medicine (TCM) commands a unique position among
all traditional medicines because of its 5000 years of tradition. Our own interest
in natural products from TCM was triggered in the 1990s by sesquiterpene lactones
of the artemisinin type from Artemisia annua L.

The first description of the Chinese herb Artemisia annua L. (qinghao, Sweet wormwood) dates back to 168 B.C.E. Artemisinin (qinghaosu) was identified in 1972 as the active antimalarial
constituent of Artemisia annua L. Artemisinin and its derivatives are used for the
treatment of malaria. As shown in recent years, this class of compounds also shows
activity against cancer cells, schistosomiasis, and certain viruses, i.e., human cytomegalovirus,
hepatitis B anc C virus, and bovine viral diarrhea virus.

Interestingly, the bioactivity of artemisinin seems to be even broader and also includes the
inhibition of other protozaons such as Leishmania, Trypanosoma, and Toxoplasma
gondii, as well as some trematodes, fungi, yeast, and bacteria. The analysis of its
complete profile of pharmacological activities, as well as the elucidation of molecular
modes of action and the performance of clinical trials, will further elucidate the
full potential of this versatile weapon from nature against diseases.

Natural Products in Cancer Chemoprevention and Chemotherapy

2012-05-22T19:46:00.003-07:00

Abstract Medicinal plants are an important source of diverse chemical compounds
that have been used for the past several centuries in the treatment of cancer. About
25% of drugs in the modern pharmacopoeia are derived from plants, including several
anticancer drugs currently in clinical use such as vincristine, vinblastine, paclitaxel,
podophyllotoxin, camptothecin and combretastatin.

These natural products, their derivatives and analogues based on these drugs constitute an arsenal against various types of neoplasms. The traditional use of plants provides a lead for cancer chemopreventive molecules. The development of new derivatives from bioactive
compounds of food origin has been a viable way to reduce toxicity and increase
their effectiveness against cancer.

The combined efforts of botanists, pharmacologists, chemists and biologists are required to discover new effective drugs to fight cancer. An evaluation of the mode of action of these bioactive molecules will be helpful in designing novel drugs targeting mitosis. This article discusses natural products currently in clinical use, and under clinical trials, for cancer chemotherapy and chemoprevention.

The Effects of the Green Tea Polyphenol Epigallocatechin Gallate on the Central Nervous, Endocrine, and Innate Immune Systems

2012-05-22T19:41:00.003-07:00

Abstract The central nervous, endocrine, and immune systems interact at several
levels, including cell surface and intracellular molecules as well as compounds facilitating
intercellular communication. Molecules produced by components of the
immune system, such as reactive oxygen and nitrogen species and some cytokines
secreted by brain microglia, may induce disorders of the nervous and endocrine
systems if present in excess.

Pathologic conditions of these three systems, including neurodegenerative diseases, anxiety, memory loss, ischemia, multiple sclerosis, alterations in weight and metabolism, diseases of insulin dysregulation, and several autoimmune disorders, have several common themes such as changes in iron/Ca+2 levels, altered proteosomal activity, mitochondrial dysfunction, and activation of the caspase cascade, leading to apoptosis.

The green tea polyphenol epigallocatechin gallate (EGCG) has beneficial activity in a number of human diseases. It mitigates some of the above-listed damage in part by altering intracellular signal transduction pathways, by scavenging reactive oxygen and nitrogen species and iron, and by affecting cytokine production and expression of neurotransmitters or their receptors.
This chapter presents these activities of EGCG and how they affect diseases of these
related physiological systems.

Proprietary Herbal Medicines in Circulatory Disorders: Hawthorn, Ginkgo, Padma 28

2012-05-22T19:37:00.003-07:00

Abstract A look at the available clinical evidence of herbal preparations from
hawthorn (leaves, flowers, fruits), Padma 28 (Swiss-Tibetan herbal preparation with
20 herbal drugs) and ginkgo (leaves) in terms of circulatory disorders shows the
following: in chronic heart failure New York Heart Association (NYHA) II a metaanalysis
showed that hydroethanolic extracts from hawthorn leaves and flowers,
given at a daily dosage of 300 to 900 mg, can increase the maximum workload to
up to 7W when given concomitantly with standard therapy. The same was seen in
one RCT with an extract from hawthorn fruits and flowers. The herbal preparations
seem to be well tolerated and no interaction is known so far. The data on a possible
decrease on blood pressure are inconclusive.

A meta-analysis on Padma 28 showed that two tablets given twice or three times a
day over 16 weeks can increase the maximum walking distance by more than 100m
in patients with claudicatio intermittens. The preparation is well tolerated and safe.
Research evidence from a meta-analysis on an extract from ginkgo shows that its
use in the treatment of intermittent claudication can result in a significant but clinically
modest improvement in pain-free walking for distances up to 34m given at
a dosage of 160 mg per day. Despite the general evidence that ginkgo preparations
are relatively safe, physicians and therapists should be cautious when anticoagulants
(i.e. warfarin) are given as well.

The Role of Curcumin in Modern Medicine

2012-05-22T19:33:00.003-07:00

Abstract Curcumin (diferuloylmethane) is an orange-yellow component of turmeric
(Curcuma longa), a spice often found in curry powder. Since the time of Ayurveda
numerous therapeutic activities have been assigned to turmeric for a wide variety of
diseases and conditions, including those of the skin, pulmonary, and gastrointestinal
systems, aches, pains, wounds, sprains, and liver disorders.

Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and thus has a potential against various malignant cancers, diabetes, allergies, arthritis, Alzheimer’s disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Thus, curcumin, by virtue of its effect on multiple cell signaling pathways, could prove to be a panacea for modern human diseases.

Harpagophytum procumbens – Traditional Anti-inflammatory Herbal Drug with Broad Therapeutic Potential

2012-05-22T19:30:00.003-07:00

Abstract Harpagophytum procumbens (Devil’s Claw) is a traditional African herbal
drug used by the natives of the Kalahari and Savannah desert regions to treat a variety
of ailments.

In Europe, the anti-inflammatory properties of Harpagophytum
procumbens extracts (Hp) have been the basis for its popular use in the treatment of
inflammatory disorders of the musculoskeletal system and of low back pain. This is
the subject of a draft monograph recently issued by the European drug authorities
(EMEA).

There is good clinical evidence for Hp’s use in treating painful osteoarthritis,
but more evidence (such as from phase-III trials) is needed before Hp can be
considered a standard treatment of osteoarthritis and other chronic inflammatory
diseases. Here, the published evidence is reviewed that reveal the anti-inflammatory
effects of Hp including inhibition of key mediators and promoters of inflammation.
The relevance of these effects for the therapeutic use of Hp in osteoarthritis is discussed.

The main constituents of Hp, glycosides of harpagoside and of acteoside,
have been shown to act on molecular pathways that have become recognised as targets
in the development of new anti-inflammatory drugs. The pharmacological profile
of Hp is that of a modern anti-inflammatory agent. Today there is great interest
in new anti-inflammatory drugs as toxicological doubts have arisen concerning standard
drugs but also as it has become apparent that the therapeutic potential of novel
anti-inflammatory drugs goes well beyond the treatment of recognised chronic inflammatory
diseases.

Inflammation is now seen as a primary process in osteoarthritis
but also as a key pathophysiological factor in many common modern diseases (cardiovascular
disease, diabetes, osteoporosis, neurodegenerative diseases, dementia
and Alzheimer’s). The therapeutic potential of Hp, therefore, demands attention.

Herbal Treatments for Erectile Dysfunction

2011-10-27T01:32:00.001-07:00

Evidence for herbal treatments for ED is contradictory. This could be due
to differing definitions of ED, non-standardized outcomes and different procedures
used in the preparation of plant extracts.

Additionally, animal studies are not accurate because they do not allow cerebral aspects of sex to be evaluated and instead rely solely on basic mechanical or instinctive sexual function.

Preliminary research on a few drugs such as ginseng, PLC and DHEA is encouraging,
but well-designed randomized controlled clinical trials are lacking.

It is likely that the use of medicinal plants will increase in popularity as men seek subtle
methods of treating themselves.

However, whilst it is easy to purchase many ‘natural Viagra’-like substances over the Internet, the safety and reliability of many of these drugs is poor, and patients should be cautious when acquiring these products.

Information about how these herbal products interact with prescribed drugs is also
limited.

Ginseng and Male Sexual Behavior

2011-10-25T22:06:00.000-07:00

Ginseng is widely used in Asian countries as a tonic to promote and maintain good health and as a constituent in herbal medicines used to treat various diseases, including liver dysfunction, hypertension, cerebrovascular disease, atherosclerosis, cancer, postmenopausal symptoms, and impotence.

Very few controlled clinical studies have been performed to validate the medicinal use of ginseng
or its constituents in humans. However, laboratory studies, primarily using rodents, have elucidated potential medical uses for ginseng and ginsenosides in the treatment of a number of human disorders, including impotence and loss of libido.

Panax ginseng and Panax quinquefolius have both been shown to enhance male copulatory behavior in laboratory studies. Human studies have suggested that ginseng ingestion may be a safe and effective alternative method for treatment of erectile dysfunction. Ginsenosides have been shown to interact with steroid receptors and, through nongenomic pathways, activate NO production.

How ginseng and its ginsenosides may act centrally to modulate sexual desire and copulatory performance is not known, but could potentially involve activation of NO pathways, perhaps in
brain areas involved in sexual behavior.

Indigenous People and Forests: Perspectives of an Ethnobotanical Study from Rajasthan (India)

2011-10-25T21:56:00.000-07:00

The state of Rajasthan has a sizable tribal population existing in the still surviving deciduous forests of the Aravalli and Vindhyan ranges. Though having undergone varying degrees of change, a substantial population even today can be seen thriving in primitive conditions with preserved traditions. Of such groups, the Bhils are the largest, followed by Garasias and Damors.

The Kathodias and Sahariyas are still sociologically not very well known. Living close to nature, the tribals have acquired unique knowledge about the properties and uses of wild plants, most of
which are not known to the outside world. Until a decade ago, nothing was known about the ethnobotany of the tribes of Rajasthan.

Exhaustive field work in tribal villages with a macro-level perspective brought forth interesting revelations from the panorama of their lives. The present work highlights useful ethnobotanical information about the uses of wild plants by the tribals of Rajasthan as food, medicine,
veterinary medicine, material culture, etc. This folk wisdom, if subjected to scientific
scrutiny, could benefit humankind in many ways.

The Chemical Diversity of Bioactive Molecules and Therapeutic Potential of Medicinal Plants

2011-10-25T21:51:00.000-07:00

The therapeutic use of herbs is as old as human civilization and has evolved along with it. The vast majority of people on this planet still rely on their indigenous system of medicine and use herbal drugs.

The Indian and Chinese systems of medicine are well established with written records going back around 3000 years. Medicinal plant drug discovery continues to provide new and important leads against various pharmacological targets including cancer, malaria, cardiovascular
diseases and neurological disorders.

Interest in herbal drugs and natural medicine is undergoing a renaissance at the present time. The medicinal properties of plants are due to the presence of active principles. These bioactive secondary metabolites are synthesized by two principal pathways: shikimic acid or aromatic amino acid, and mevalonic acid. Alkaloids, phenolics and terpenoids constitute many pharmacologically active compounds. Several natural-product drugs of plant origin have either
recently been approved by the US Food and Drug Administration (FDA), including
arteether, galanthamine and triotopium, or are in clinical trials.

Although drug discovery from medicinal plants continues to provide an important source of new drug leads, this work is constrained by the unavailability of sufficient plant material, selection
and implementation of appropriate high-throughput screening bioassay and the production of bioactive compounds in large quantities. This article reviews the use of herbs in traditional systems and bioactive therapeutic molecules responsible for this activity.

Medicinal Plants: A Renewable Resource for Novel Leads and Drugs

2011-10-25T21:43:00.000-07:00

Present-day drug development is strongly focused on finding active compounds on well-defined targets using high throughput screening approaches.

Unfortunately it seems that this approach is becoming less and less successful, as
in most cases already good compounds are on the market, and the rapidly rising
costs of drug development will make it increasingly difficult to make an economically
competitive novel drug for any major disease.

In other words, the reductionist approach presently used is becoming less successful. The time has come to rethink drug development. Many Western medicines are based on traditional knowledge from Europe and the Mediteranean region. This is why interest is rapidly increasing
in Indian and Chinese medicine, both of which represent a very long tradition
of apparently safe use.

However, these healthcare systems are different from Western medicine, so novel methods are required to verify the efficacy and safety of the therapies. As it often concerns personalized medication with complex mixtures, a reductionist approach of screening for a single active compound on a known target will in many cases not be successful, as more than one target may be involved; in addition, and complicating the situation even more, synergism and prodrugs may be involved. Systems biology as a novel holistic way of dealing with biological problems
seems here an interesting option.

Systems biology means proceeding without a hypothesis, just observing, measuring as many parameters as possible in a biological system and afterwards using chemometrics to reveal any meaning in the data. This approach has already proven successful in studying medicinal plants and, in combination with the classical natural-product-based drug lead finding, is expected
to be a major issue in the coming years.

As present-day patent laws require innovative and unexpected findings, the development of old knowledge does not fit this requirement. Therefore, to support the development of evidence-based traditional medicines, it would be of great interest if some sort of protection could be obtained for companies developing such medicines so that they could earn back their huge R&D investments.