Essential Oil-Bearing Grasses: The Genus Cymbopogon

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Essential Oil-Bearing Grasses: The
Genus Cymbopogon by Anand Akhila
(ed). Boca Raton, FL: CRC Press; 2010.
Hardcover; 262 pages. ISBN 978-0-8493-7857-7.
$139.95.

Chances are that many of us can identify the aromatic lemony scents in Thai soup, natural mosquito-repellant, aromatherapy candles, or cosmetic lotion. If you wanted to know everything there is to know about the group of commercially significant and multidimensional plants that provide this aroma, then this comprehensive book is for you. A quick glance will certainly reveal its value to the phytochemist, industrial magnate, taxonomist, or ethnobotanist, although certain segments will also appeal to other natural product investigators, including forestry officials, agriculturalists, natural flavorists, and cosmetic formulators.

This book is authoritatively written solely on the group of grasses in the genus Cymbopogon, the essential oils of which have wide ranging appeal to a number of industries. The book will be most appreciated by the technically inclined--it is far from being any sort of aromatherapy book for the lay person. The editor, plus 10 contributors from various countries, demonstrate their expertise of the subject matter, having backgrounds in academia, scientific publications, regulatory affairs, and natural products chemistry. Through 9 chapters they delve into ethnobotany, pharmacology, phytochemistry, and more, focusing on the multiple uses of these plants.

A thorough examination of this genus begins by noting the approximately 180 species, subspecies, varieties, and subvarieties of these angiosperms, and continues with information on botanical identification, biochemistry, and molecular biology. Extensive chemistry profiles, diagrams, tables of analysis, and electron scanning micrograph photos will appeal to researchers and natural products chemists alike.

The economic importance of these essential oil-bearing plants is highlighted in the chapters on trade, harvest, and postharvest management, which may be of interest to growers, tea producers, and distillers of this extensive genus. Lemongrass (Cymbopogon citratus; C. flexuosus; C. pendulus), palmarosa (C. martinii) and citronella (C. nardus; C winterianus)--all in the family Gramineae--are among the most recognizable and significant oils discussed for fragrancing, food flavoring, therapeutic formulation, and insect repellant application. The history of these plants and their practical and health-enhancing uses are lightly touched upon, but these segments primarily focus on commerce, yield, harvest times, drying, storing, extraction methods, and oil content.

There are several chapters that may be of interest to the medical aromatherapist or clinical phytotherapist. One focuses on the antimicrobial and antioxidant activities of these plants. Addressing the main problem of solubilizing essential oils, the authors provide suggestions for overcoming this obstacle for in vitro testing.

The authors provide their test results on the effectiveness of Cymbopogon essential oils that specifically fight gram positive or gram negative bacteria, as well as the benefits of these oils in countering yeast and mold microbes. It is rare that the mechanism of this activity is well explained in an English language text. They also provide tables that outline which functional group of constituents is responsible for their effectiveness against such microbes, which is very useful In pinpointing biological activity, if only in vitro. Holistically minded practitioners will appreciate that activity of the whole oil is also reported.

Another chapter is on the thrombolysis-accelerating activity of these essential oils, certain to attract the attention of the beverage industry. This is welcome research, as information on oral application is also not often published in English. Within the chapter on chemistry, the authors cite research into the use of numerous essential oils with activity against worms, mosquitoes, and even cancers. They reference the investigation of biological activity of essential oils for pain relief, lowering blood sugar, and hair growth.

The book closes with information on toxicology, legislation, classification, and labeling, which may be of use to cosmetic chemists, safety officers, or company legal teams. Three pages of commonly used acronyms are clarified, and essential oil-bearing plants outside the easily red-flagged Cymbopogon genus are discussed briefly as alternate sources of sensitizing citral. Up-to-date regulatory information from the European Union should be valuable for creating compliant personal care products for global sales. Legally allowable concentrations of citral for cosmetic products are provided in a small but useful table.

This small book emerges as an updated and focused version of Ernest Guenther's encyclopedic treatise from the late 1940s and early 50s on essential oil-bearing plants. Extensive references at the end of every chapter demonstrate the meticulous research gathered for this book. CRC Press is known for its scientific and technical publications, and this is no exception. Aside from the questionable, if only occasional, errors in grammatical sentence structure, this is a great chemistry-bench reference book and a scrupulous analytical tool for the laboratory. It will be useful for those performing analyses of essential-oil bearing grasses. It may also be appreciated by the overall botanical book junkie and all technical beaker geeks investigating natural products.

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By Mindy Green, RA, RH (AHG), President, Green Scentsations Consulting Minneapolis, MN

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