Volume 3 Special Issue 1 2009
Ethnomedicinal Phytophores in Disease Management

Guest Editors

Debprasad Chattopadhyay

Debprasad Chattopadhyay, India (Indian Council of Medical Research)

http://icmr.nic.in/

CONTENTS AND ABSTRACTS

Debprasad Chattopadhyay, Hemanta Mukherjee, Paromita Bag, Soma Ghosh, Amalesh Samanta, Sekhar Chakrabarti (India) Ethnomedicines in Antiviral Drug Discovery (pp 1-25)

Full Text [PDF]

ABSTRACT

Invited Review: This review is an attempt to portray the discovery and development of ethnomedicine and its phytophores against some important viral diseases from galenical to genomical period. Natural resource, particularly the plants and animals have been the basis of traditional treatment since the dawn of human civilization and the modern medicine (Allopathy) has gradually developed, over the years, by scientific and observational efforts from traditional practice. However, with the advent of antibiotics the role of traditional medicaments in infectious diseases was sidelined. Interestingly after the 1980’s, society realized the problem of drug resistance, emerging and reemerging pathogens, adverse drug reactions of many antimicrobials, particularly the antivirals. Hence, the lag phase for plant medicine is changing as impressive successes have been achieved with many botanicals like artemisinin, baccosides, curcumine, phyllanthins, quinghaosu, rauwolfia alkaloids, psoralens, picrosides, withanolides, steroidal lactones etc against many chronic and difficult-to-treat diseases. A whole range of chronic and lifestyle related diseases including HIV/AIDS, SARS, and Herpesvirus infection require new effective drugs. Considerable research has been carried out on pharmacognosy, chemistry, pharmacology and clinical therapeutics on Indian Ayurveda, Chinese traditional medicine, and traditional medicines of Africa in the last few decades. Many of the major pharmaceutical companies have renewed their strategies for drug development where there are no effective drugs or vaccine. Hence, many new compounds have entered the international pharmacopoeia through ethno-pharmacology and traditional medicine. Traditional knowledge-driven drug development can reduce both time and cost following a reverse pharmacology path. The automated separation techniques, high-throughput screening and combinatorial chemistry can help ethnomedicines to serve as a powerful search engine to facilitate intentional, focused and safe natural products research and to rediscover the drug discovery process.

Candice Van Wyk, Francien Susanna Botha, Vanessa Steenkamp (South Africa) In Vitro Antimicrobial Activity of Medicinal Plants against Oral Candida albicans Isolates (pp 26-30)

Full Text [PDF]

ABSTRACT

Invited Mini-Review: In most countries of subtropical Africa, bacterial and fungal infections represent an increasing problem, particularly with patients suffering from severe immune deficiencies. Candida species are responsible for a wide range of systemic as well as superficial opportunistic infections. Candida albicans is a normal commensal, isolated intraorally in 17 to 75% of healthy individuals and all debilitated people. Eradication of candidiasis is complicated by the emergence of Candida strains that are resistant to the currently used antifungal agents. Furthermore, these antifungal agents are limited in number, are costly and in addition may be toxic. Plants as remedies are used by ~80% of the population in developing countries and their use is gaining popularity in developed countries. Although, many plants have already been investigated for their antifungal activity against C.albicans the search is still on to find a long-term prevention or cure for oral candidiasis. It is essential that such a product will prevent a recurrence of the condition, be inexpensive and prevent the development of antifungal resistance.

Kasi Pandima Devi, Perumal Vijayaraman Kiruthiga, Shunmugiahthevar Karutha Pandian (India) Emerging Role of Flavonoids in Inhibition of NF-kB-Mediated Signaling Pathway: A Review (pp 31-45)

Full Text [PDF]

ABSTRACT

Invited Review: Nuclear factor kappa B (NF-kB) proteins comprise of a family of structurally-related eukaryotic transcription factors. They were originally discovered in lymphocytes, but later found to be ubiquitously expressed in almost all animal cell types. In mammals the NF-kB family (also known as the Rel family) consists of five members: p50 (product of the NF-kB1 gene), p52 (product of the NF-kB2 gene), p65 (also known as RelA), c-Rel and RelB. NF-kB dimers exist in a latent form in the cytoplasm bound by IkB inhibitory proteins. NF-kB-inducing stimuli (stress, cytokine, free radicals, UV radiation, oxidised LDL, bacterial or viral antigens) activate IkB kinase complex that phosphorylates IkB, leading to its ubiquitination and subsequent degradation. IkB degradation expose the DNA-binding domain and nuclear localization sequence of NF-kB and permit its stable translocation to the nucleus and the regulation of target genes. The NF-κB signaling pathway plays a key role in inflammation, immune response, cell growth control and protection against apoptosis. Downregulation/inhibiton of NF-kB is regarded as a potential drug targets for therapeutic intervention in many diseases like cancer, inflammatory and autoimmune diseases. Many natural plant products have been found to downregulate NF-kB production, including curcumin, quercetin, green tea, and resveratrol. In this review we describe flavonoids as NF-kB inhibitors and their role in preventing NF-kB signaling pathway mediated disorders.

Margareth B. C. Gallo (Brazil/USA), Miranda J. Sarachine (USA) Biological Activities of Lupeol (pp 46-66)

Full Text [PDF]

ABSTRACT

Invited Review: This review covers mainly the past 25 years of research on the biological activities of lupeol, a significant lupane-type triterpene represented in the plant, fungi and animal kingdoms. Anticancer, antiprotozoal, chemopreventive and anti-inflammatory properties, plus the mechanisms of action of lupeol are emphasized. Some insights are provided regarding lupeol as a lead scaffold for synthetic chemical attempts to optimize pharmacological potency. Structure-activity relationship is also discussed.

Melanie-Jayne R. Howes, Peter J. Houghton (United Kingdom) Acetylcholinesterase Inhibitors of Natural Origin (pp 67-86)

Full Text [PDF]

ABSTRACT

Invited Review: The endogenous neurotransmitter acetylcholine (ACh), found in vertebrates, stimulates cholinergic (muscarinic and nicotinic) receptors to mediate cholinergic neuronal transmission. ACh has a short half-life, as it is rapidly hydrolysed in the neuronal synaptic cleft by the enzyme acetylcholinesterase (AChE). Modulation of cholinergic function has been recognised as a therapeutic target in some disease states and one approach to achieve this is to prolong the action of ACh through the use of AChE inhibitors. Consequently, AChE inhibitors have been investigated for a number of therapeutic applications including glaucoma, myasthenia gravis, anti-muscarinic poisoning and dementia. Many inhibitors of AChE have been derived from natural sources, with alkaloids generally being the most potent, although other compounds including some terpenoids have also been shown to inhibit AChE. It is particularly interesting that of the four drugs currently licensed in Europe to alleviate cognitive symptoms in Alzheimer’s disease, two (galantamine and rivastigmine) are derived from natural sources. Natural products continue to be investigated for anti-AChE activity to identify compounds that may have therapeutic potential, or that provide templates for the development of new drugs, with a particular focus on the alleviation of cognitive disorders. Many plants reputed to enhance cognitive function in a variety of traditional practices of medicine have been investigated to determine any pharmacological basis for their historical uses, and some of the extracts from these plants have shown promising AChE inhibitory effects, although for some plants the active compounds are yet to be elucidated. There are a number of other plants that are not associated with a traditional use related to cognitive disorders but their extracts have also been shown to inhibit AChE. Some of those plant extracts and compounds of natural origin that have shown inhibitory activity against AChE, and their therapeutic relevance, are discussed.

Natrajan Suganthy, Shunmugiahthevar Karutha Pandian, Kasi Pandima Devi (India) Cholinesterase Inhibitors from Plants: Possible Treatment Strategy for Neurological Disorders – A Review (pp 87-103)

Full Text [PDF]

ABSTRACT

Invited Review: Dementia is a chronic progressive mental disorder, which adversely affects memory, thinking, comprehension, calculation and language. Some of the most common dementias are Alzheimer’s disease, Parkinsonism, Dementia with Lewy Bodies and Myasthenia gravis. All of these disorders are related to abnormalities in the central cholinergic system, which shows a decline in acetylcholine (ACh) level due to substantial reduction in the activity of the enzyme choline acetyl transferase. A variety of strategies have been envisaged to implement the replacement of ACh, of which acetyl cholinesterase (AChE) inhibition has shown consistent positive results. Cholinesterase inhibitors act on the enzymes that hydrolyze ACh, following synaptic release. Currently several cholinesterase inhibitors such as tacrine, rivastigmine, donepezil and galanthamine have been used as first line pharmacotheraphy for Alzheimer’s disease. However these drugs have severe side effects like hepatotoxicity and gastrointestinal disorder, hence there is still a great interest in finding better cholinesterase inhibitors from natural sources. Natural products are significant sources of synthetic and traditional herbal medicines. A potential source of AChE inhibitors is certainly provided by the abundance of plants in nature. Huperzine, bacosides, hyperforin, desoxy-peganine and Ginko biloba (plant extract) are some of the natural drugs used in the treatment neurological disorders. This article aims to provide a comprehensive literature survey of plants that have been tested for AChE inhibitory activity. Numerous phytoconstituents and promising plant species as AChE inhibitors are being reported in this communication.

Manuela G. Neuman (Canada), Vanessa Steenkamp (South Africa) Toxicity Profile of Pyrrolizidine Alkaloid-Containing Medicinal Plants: Emphasis on Senecio Species (pp 104-108)

Full Text [PDF]

ABSTRACT

Invited Mini-Review: Pyrrolizidine alkaloids (PAs) are found in various plant genera worldwide. Poisoning by PA-containing plants is usually accidental, by the ingestion of grain inadvertently contaminated with seeds of pyrrolizidine-containing weeds, or the consumption of herbal or bush tea, or when taken as herbal infusions for medicinal purposes. In this paper the toxicity of PA-containing plants, with emphasis on Senecio spp. is reviewed. Although the toxicity of Senecio has been documented in numerous case reports, the mechanism of toxicity is not fully known. Elucidating the factors involved in herbal remedies-induced toxicity has medical significance. Currently, there is no antidote for natural-substances that induce liver damage. It is important to understand the need for monitoring the use of herbal medicine in order to optimize herbal/traditional medicine use and maximize the clinical and economical benefits. It is also necessary to enhance communication between scientists and physicians of all disciplines involved in complementary alternative medicine and clinical toxicology.