Current Pharmaceutical Design - Volume 14, Issue 29, 2008

One can assume that for every illness, which the nature has put infront of us, there is a possible remedy which is only waiting to be discovered. A great number of chemists, biologists, pharmacists, and other scientists believe in this prospect, and make great endeavor to determine the exact composition, and pinpoint the principals of biological activity of plant extracts, as well as to prepare derivatives of the existing isolated compounds of natural origin with the hope of arriving at a molecule with enhanced activity. This issue is dedicated to the composition of essential oils and other plant extracts, their biological activity, as well as isolation, characterization and synthetic modification of the constituents. The first paper [1] is an excellent review of liverworts constituents (the structures of more than 150 compounds are presented). The review of Professor Milosavljevic' research group [2] comprises 155 compounds, e.g. sesquiterpene lactones and flavonoids (Asteraceae), xanthones, secoiridoids and C-glucoflavonoids (Gentianaceae) and prenylated phloroglucinols (Guttiferae), as well as some other secondary metabolites, produced by the above families, which could be of pharmacological interest. Biological and pharmacological activities as well as possible in vivo mechanism of carvacrol are discussed by K. H. C. Baser [3]. Figueiredo and Coworkers [4] outline the taxonomy, ethnobotany, cell and molecular biology of Portuguese Thymbra and Thymus species and antibacterial, antifungal and antioxidant activities of their essential oils and other volatiles-containing extracts. Botany, chemistry and activity of Mentha species with special respect to their significance for the modern phytotherapy are described by Mimica-Djukic and Bozin [5]. Nemeth and Bernard [6] consider those scientific findings which confirm the broad spectrum of yarrow species activity. Structure, origin, biological activities of microbial polysaccharides and derivatives as well as their application as pharmaceuticals, are widely discussed by Smelcerovic and Coworkers [7]. The last paper is a mini review about antimicrobial and antioxidant activity of various extracts of Micromeria species [8]. It is my hope that some of the compounds presented in this issue will become real drugs in the future. At the end, I would like to thank all the authors for their contributions, reviewers for their valuable comments and particularly to the editor-in chief of Current Pharmaceutical Design, professor William Banks, for providing me the opportunity to be the editor in this eminent journal.

The bryophytes contain the Marchantiophyta (liverworts), Bryophyta (mosses) and Anthocerotophyta (hornworts) among which the Marchantiophyta contain cellular oil body and they produce a number of terpenoids, aromatic compounds and acetogenins, several of which show interesting biological activity such as allergenic contact dermatitis, insecticide, insect antifeedant, cytotoxic, piscicidal, muscle relaxing, plant growth regulatory, anti-HIV, DNA polymerase β inhibitory, anti-obesity, neurotrophic, NO production inhibitory, antimicrobial and antifungal activities. The isolation and chemical structures of biologically active compounds and their total synthesis are reviewed.

The results of phytochemical investigation, over the last decade, of some wild-growing plant species from Serbia and Montenegro belonging to the families Asteraceae, Guttiferae and Gentianaceae are reported. Most of the investigated species are endemites and the emphasis in this report is on those exhibiting biological activities that could be regarded as the potential sources of drugs. This review comprises 154 compounds, e.g. sesquiterpene lactones and flavonoids (Asteraceae), xanthones, secoiridoids and C-glucoflavonoids (Gentanaceae) and prenylated phloroglucinols (Guttiferae) as well as some other secondary metabolites, produced by the above families, which could be of pharmacological interest.

Oregano essential oils obtained from the genera Origanum, Thymus, Coridothymus, Thymbra, Satureja and Lippia are rich in carvacrol, a monoterpenic phenol isomeric with thymol. Turkey is the biggest exporter of oregano herb and oil to the world markets. Oregano is mainly used in food, spice and pharmaceutical industries. Carvacrol is responsible for the biological activities of oregano. Many diverse activities of carvacrol such as antimicrobial, antitumor, antimutagenic, antigenotoxic, analgesic, antispasmodic, antiinflammatory, angiogenic, antiparasitic, antiplatelet, AChe inhibitory, antielastase, insecticidal, antihepatotoxic and hepatoprotective activities and uses such as feed additive, in honeybee breeding and in gastrointestinal ailments have been shown. This paper highlights these activities and attempts to explain the possible in vivo mechanism of action of carvacrol.

Thymbra capitata and Thymus species are commonly known in Portugal as thyme and they are currently used as culinary herbs, as well as for ornamental, aromatizing and traditional medicinal purposes. The present work reports on the state of the art on the information available on the taxonomy, ethnobotany, cell and molecular biology of the Portuguese representatives of these genera and on the chemotaxonomy and antibacterial, antifungal and antioxidant activities of their essential oils and other volatile-containing extracts.

The use of mint species in traditional and conventional medicine is mostly due to the presence of two classes of secondary bimolecules: monoterpenoids in essential oils and different structural types of phenolic compounds. Essential oils are known to act as antimicrobial, antispasmodic, carminative, and antiviral agents. In addition, essential oils of several mint species have been recently qualified as natural antioxidants. However, since oil composition is highly variable, the pharmacological activity strongly depends on certain chemorace. On the contrary, composition of phenolic constituents is relatively stable within species. The most important phenolic compounds in Mentha species are flavonoids. Mints are characterized by the presence of specific lipophilic flavonoids. Phenolic compounds of mints are found to poses a wide range of pharmacological activity: antioxidant, antiulcer, cytoprotective, heptoprotective, cholagogue, chemopreventive, anti-inflammatory, antidiabetogenic etc. However, besides healing properties some mint species can exhibit an adverse effect on human health. Here we report on botany, chemistry and activity of Mentha species with special respect to their significance for the modern phytotherapy.

The genus Achillea consists of about 140 perennial herbs native to the Northern hemisphere. Traditional indications of their use include digestive problems, liver and gall-bladder conditions, menstrual irregularities, cramps, fever, wound healing. The Commission E approves its internal use for loss of appetite and dyspeptic ailments (gastric catarrh, spastic discomfort), externally it is used in form of sitz bath or as a compress against skin inflammation, slow healing wounds, bacterial or fungal infections. In the last decades, pharmacological studies became intensive, although human clinical investigations are still rare. Recent findings have confirmed several traditional uses. The largest number of data accumulated for antioxidant and antiinflammatory effects. There are positive results on the analgesic, anti-ulcer, choleretic, hepatoprotective and wound healing activities. First results on other interesting therapeutical areas - antihypertensive, antidiabetic, antitumor, antispermatogenic activities -need confirmation. Yarrow can be used also as an insect repellent. Contact dermatitis as adverse effect may be connected to sesquiterpenes. The diversity and complexity of the effective compounds of yarrow species explains the broad spectrum of their activity. According to the literature the pharmacological effects are mainly due to the essential oil, proazulenes and other sesquiterpene lactones, dicaffeoylquinic acids and flavonoids. Synergistic actions of these and other compounds are also supposed. Achillea species have different chemical and therapeutical values. Despite of numerous data, correct evaluation of the results is difficult because of missing generally accepted taxonomical nomenclature. The used chemical-analytical methods and bio-assays are utmost diverse, making the comparison complicated. Further research on the activity is needed using exactly defined plant material, standardized methods and chemical analysis.

The ability to produce polysaccharides is widely found among microbial species. The structural diversity of the microbial polysaccharides (MPS) leads to a wide diversity of their applications. This review focuses pharmacological properties of MPS and their derivatives. They have been reported to possess many biological activities, such as antiviral, antitumor, antimicrobial and anticoagulant activities. So, the MPS of the type β-1,3-D-glucans, including curdlan and scleroglucan, show antitumor and antiviral activity. A number of biological and synthetic sulfated polysaccharides, including sulfated polysaccharides from marine microalgae, inhibit viral infections. Many of MPS demonstrate a series of attractive properties as carrier materials in drug delivery systems and nonviral gene delivery. Furthermore, MPS have found an application as wound-healing agents, blood plasma expanders and vaccines. Some MPS, like chitin, chitosan and alginate have an unusual combination of biological activities and physicochemical properties leading to the development of novel or improved pharmaceuticals. They have become of a great interest not only as drug and cell carriers but also as new functional materials of high biological activity, and recent progress in MPS chemistry is quite noteworthy. This review also examines the advances in the application of MPS in the field of tissue engineering.

Published papers considering antimicrobial and antioxidant activity of Micromeria Bentham species were reviewed. Possible relationships between composition and bioactivity were discussed.