Medicines
2015,
2(1),
28-46;
doi:10.3390/medicines2010028
Review
1
Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
2
V. I. Nikitin Institute of Chemistry, Tajik Academy of Sciences, Ainy St. 299/2, Dushanbe 734063, Tajikistan
3
Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA
*
Authors to whom correspondence should be addressed; Tel.: 
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Academic Editor:
Ronan Batista
Received: 18 December 2014 / Accepted: 9 February 2014 / Published: 17 February 2015
Abstract
: Tajikistan is a small country located in Central Asia. The mostly mountainous terrain with a continental, subtropical, and semiarid climate, is characterized by diverse flora. Many people in Tajikistan rely on medicinal plants as their traditional form of medicine to prevent and cure health disorders. Aromatic medicinal plants, in particular, have played an important role for the local people. In this review, we present a summary of the uses of 18 aromatic medicinal plants from Tajikistan and their compositions of secondary metabolites.
Keywords:
Tajikistan; aromatic plants; traditional herbal medicines; essential oil compositions; secondary metabolites1. Introduction
Plants have been and continue to be valuable natural treasures, providing an important source of nutrients and therapeutic agents. Plants must defend themselves against herbivory and microbial infections, and over the last 400 million years they have evolved a high diversity of secondary metabolites that are toxic to animals and microorganisms. Because of this evolutionary background, most secondary metabolites are biologically active. This did not escape our ancestors who started to use plants as a means to treat infections and health problems [1,2]. In this context, traditional medicine and our understanding of the pharmacological properties of plants were developed.The defense chemistry of plants includes a surprisingly wide diversity of biologically active compounds, such as alkaloids, glucosinolates, cyanogenic glycosides, flavonoids, tannins, coumarins, lignans, terpenoids, saponins, organic acids, and many others. A number of secondary metabolites, especially mono- and sesquiterpenes but also phenylpropanoids, are volatile. These compounds serve not only as deterrents against herbivory and often against microbial infection, but also as signal compounds to attract pollinators or predators. Aromatic plants have attracted human attention for a long time because of their mostly pleasant fragrances. As a consequence, many of them are used as raw materials for the production of perfumes and cosmetics; others have found application in aromatherapy and phytotherapy. Many aromatic plants serve as spices because they can reduce the load of microbial pathogens in food, improve the taste, and support digestion (e.g., as carminatives and choleretics).
Tajikistan is a mountainous country in the southeastern part of Central Asia (mostly between 36° and 41° N latitude, and 67° and 75° E longitude. Tajikistan shares borders to the north and northwest with Uzbekistan and Kyrgyzstan, to the south with Afghanistan, and with China to the east. The country covers 143,100 km2 (93% of this area is mountainous) and has a population of approximately eight million people. Tajikistan is divided into four provinces (viloyat). These are the provinces of Sughd and Khatlon, the autonomous province of Gorno Badakhshan, and the Districts of Republican Subordination (Figure 1). Tajikistan is diverse in terms of environmental conditions including climate, high altitudes, mountainous soil and minerals, relatively large number of sunny days per year, which can all affect plant growth, biosynthesis, and accumulation of biological active secondary metabolites. High mountains dominate the country with about 50% above 3000 m above sea level, and the relief differentiation has resulted in formation of numerous micro- and macrohabitats. The elevation starts at 300 m above sea level and ends with Ismoili Somoni Peak at 7495 m. There are over 900 rivers in Tajikistan longer than 10 km. The high-mountain ecosystems of Tajikistan have been regarded as biodiversity hotspots with around 4550 species of higher plants recorded in Tajikistan and about 30% endemism [3,4]. The high degree of biodiversity and endemism in Tajikistan is due to the presence of high mountain ranges that serve as barriers to migration of plants and animals. Additionally, Tajikistan is characterized by a low percentage of cloud cover, large temperature differences (absolute minimum of −63 °C in the Pamir and maximum of 48 °C in Panji Poyon), low humidity, and low precipitation. Several altitudinal plant zones have been described [3,5]: (1) sage desert dominated by Artemisia species; (2) juniper woodlands; (3) desert steppes; (4) high mountain deserts dominated by cushion plants; and (5) alpine.
Many Tajik plants have been used since ancient times in traditional medicine. The scientist Abu Ali ibn Sina (Avicenna) (born 980 in Afschana near Buchara in what is now Uzbekistan; died 1037 in Hamadan) described more than 750 pharmaceutical substances of vegetative, animal, and mineral origin, several of them from Central Asia, in his book Al-Qanoon fi al-Tibb (The Canon of Medicine). Many medicines (drugs) described by Avicenna have entered the pharmacopeia and are still in use [6]. His experience was influenced from his years in Central Asia, but he was also aware of the important Materia Medica of Dioscorides (who had lived 900 years earlier) [1,2]. The Materia Medica of Avicenna comprised more than 50 cardiac, 70 antiasthmatic, and 75 antidiabetic plants; 110 plants were described as useful for the treatment of kidney and gallstones, more than 40 plants for the treatment of vitiligo, dozens for wound healing, and others with antitoxic, antitumor, hemostatic and several other activities [7].
