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Editorial - (2012) Volume 1, Issue 8
Artemisia is one the most widely studied genus for its chemical composition, morphology and chemical diversity. Artemisia, family Asteraceae, is widely distributed throughout the world, especially in North temperate regions, South Africa and America; most common on arid soils of W. United States and Russian Steppes, with approximately 400 species and 32 in India [1]. Recently, two new species viz., A. filiformilobulata Ling et Puri and A. austro-himalayana Ling et Puri from Western Himalaya (Uttarakhand) have been reported. There has been no work report on these two species because of ignorance of new name, or perhaps, the essential oil composition may have been published under different names/species [2,3]. This genus is industrially important due to its antimalarial, insecticidal, antimicrobial and other properties [4]. Among the species studied so far from Western Himalaya, Artemisia maritima L, A. gmelinii Web. ex Stechm., A. roxburghiana Wallich ex Bess, var. hypoleuca(Edgew.) Pamp, A. wallichiana Bess., A. myriantha Wallich ex. Bess. var. pleiocephala Pamp., A. elegantissima var. kumaonensis, A. indica var. indica, A. velutina Pamp., A. roxburghiana Wallich ex Bess. var. purpurascens (Jacq.) Hook.f., A. capillaris Thumb, A. parviflora Roxb. ex D. Don (A. japonica Thunb.), A. dracunculus L. and A. nilagirica (C. B. Clarke) Pamp., are worth to mentioned.
One of the authors ofthis editorial (SC. Singh) has noticed some morphological characters, as key feature to differentiate A. maritima and its varieties. A. maritima var. maritima (syn. A. brevifolia, Seriphidium brevifolium) is mainly distributed in Uttarakhand, and well differentiated with its open flower heads crowded on the branches, bright yellow heads and ovoid-oblong in shape, whereas A. maritima var. thomsoniana C.B. Clarke, (syn. Seriphidium thomsonianum) is a native of J&K with flower heads lax on the branches, and globose in shape.
Most of these species relate to isolation of essential oils, followed by constituent’s identification, using gas chromatography and gas chromatography/mass spectrometry techniques. Moreover, extensive study has also led to the characterization of many new constituents. First such publication on Artemisia appeared from Indian Himalaya in particular, entitled, “Essential Oil Composition of Some Himalayan Artemisia Species.”, has reported high thujone proportion, which was comprised of α-thujone (63.2%) and β-thujone (65.3%) in Artemisia maritima and A. roxburghiana var. hypoleuca, whereas artemisia ketone (28.2%) and 1,8-cineole (13.0%) were identified in A. gmelinii [5]. In addition, high thujone proportion has also been reported from Seriphidium brevifolium (Wall.) Y. Ling et Y.R. Ling (syn. A. brevifolia Wall. ex DC; A. maritima Hk. f. non L.) [6,7]. It is worth to mention here that A. maritima is one of the important components in most of the incense preparations of the inhabitants (Bhotias) of Western Himalaya. In recent years, variability in volatile pattern are reported in A. maritima due to the presence of chrysanthenone, 1,8-cineole, camphor and borneol, germacrene D and isoborneol [8,9]. Shah has studied essential oils, isolated from different Artemisia species viz., A. myriantha var. pleiocephala, A. wallichiana, A. roxburghiana var. hypoleuca, A. elegantissima var. kumaonensis, A. indica var. indica, A. maritima and A. gmelinii,collected from different places of Kumaun and Garhwal regions of Western Himalaya [10].
Till date, many low molecular weight terpenes and their oxygenated derivatives have been reported in moderate to high proportion from various Artemisia species from Western Himalaya. Sabinene, β-pinene, limonene, trans-sabinene hydrate and isoborneol were characterized in A. velutina [11], caryophyllene oxide, cis-β-elemenone and selin-11-en-4-α-ol in A. indica [12], borneol, β-cubebene, trans-guaiene, δ-cadinene and vulgarone B in A. indica var. indica [13], 1,8-cineole, chrysanthenone, β-eudesmol and β-pinene oxide in A. myriantha var. pleiocephala [14] and cis-cedryl methylketone, epi-cubebol and davanone identified in A. elegantissima var. kumaonensis [15]. In addition, β-caryophyllene and germacrene D were common constituents in all studied oils. A. capillaris [16] and A. dracunculus contained capillene as marker constituent [17], whereas A. parviflora contained camphor [18], and β-eudesmol and spathulenol [19], as marker constituents. Even though, most communications revealed consistent volatile compositions in Artemisia species. However, altitudinal effect resulted into varying compositions, has also been reported. This factor is supposed to play vital role in species such as A. nilagirica [20] and A. roxburghiana var. purpurascens [21]. Further, few reports showed increase in proportion of major constituents, after domesticated in Indian plain conditions, like A. myriantha var. pleiocephala [22].
Nevertheless, volatile composition of aromatic plants seems to be directly influenced by climatic condition, including temperature, soil texture, moisture and altitude. Consequently, commercial use may differ accordingly from one place to other. Artemisia species are well distributed in Himalayan habitat. Therefore, aerial parts may be potential source for perfumery, incense preparation, oil isolation, etc. Meanwhile, good agricultural practices shall be beneficial to enhance the production of plant herbage and essential oils. Keeping the reported volatile constituents in view, I do believe that Artemisia is a most suitable crop of commercial importance, and must be promoted by setting up small scale industries for livelihood upliftment of inhabitants of Western Himalaya.