R. K. Verma

Phytoremediation using aromatic plants: a sustainable approach for remediation of heavy metals polluted sites.

C of soil and water bodies with toxic heavy metals has often resulted from human activities. Conventional technologies for treatment of heavy metals polluted soil require a huge capital cost. Use of aromatic plants rather than non aromatic edible crops for the treatment of heavy metals polluted land is a sustainable, aesthetic and environmental friendly technique. Here we discuss the benefits of using aromatic plants and risks related to non aromatic edible crops as suitable phytoremediation candidate. Heavy metals pollution of soil and water due to human induced activities poses a major threat to environmental sustainability. A significant proportion of the total geographical area has been and being polluted by heavy metals throughout the world. Heavy metals are the natural component of earth crust that cannot be degraded and destroyed but accumulate through food chain and cause potential human health risk and ecological disturbances. Among all the available technologies for the removal of heavy metals from polluted sites, phytoremediation is considered as an effective, low cost, environmental friendly and preferred cleanup option for contaminated areas. Plants through several natural, biophysical and biochemical processes, such as adsorption, transport and translocation, hyperaccumulation or transformation and mineralization, can remediate pollutants. Many plant species are able to grow under heavy metals polluted environments. These plants must have specific adaptations to survive there; they must be metallophytes, pseudometallophytes, or hyperaccumulators. Despite the fact of human health risk, several researchers investigated and recommended many edible crops for phytoremediation purposes. Recently, a Scopus (www.scopus. com) based survey of the literature for the period 1995−2009 was carried out by Vamerali et al. (2010) in order to take a census of crop species involved in phytoremediation research of heavy metals throughout the world. Authors reported that B. juncea (L.) an edible oil producing crop was the most cited (148 citations) among other eight studied crops such as Helianthus annuus (57 citations), B. napus, and Zea mays (both 39 citations). It clearly shows that a little concern is given to aromatic plants for the phytoremediation. But the problem of heavy metal contamination remains the same if we use edible crops for phytoremediation. These crops are being consumed by human or animals in one or the other forms. Ecologically, use of edible crops for phytoremediation is not viable because the heavy metals enter into food chain either consumption by human or animals. This clearly indicates that scientific community lacking a safe technology, in which health risk is negligible for the phytoremediation of heavy metal polluted sites. Aromatic plants are grown for the production of essential oils and food processing. The essential oil of aromatic plants is being used in soaps, detergents, insect repellents, cosmetic, perfumes, and food processing industries. These plants are nonedible and are not being consumed directly by humans or animal like cereals, pulses, vegetables. The essential oil from aromatic plants is free from the risk of heavy metals accumulation from plant biomass. The heavy metals do not enter the food chain through phytoremediation by aromatic plants. The wild animals do not damage/eat the aromatic crops due to its essence. In fact, aromatic plant resources are very abundant, and they can be used on large scale. These plants offer a novel option for their use in phytoremedation of heavy metal contaminated sites. Aromatic plants like vetiver (Vetiveria zizanioides), palmarosa (Cymbopogon martinii), lemon grass (Cymbopogon f lexuosus), citronella (Cymbopogon winterianus), geranium mint (Mentha sp.), tulsi (Ocimum basilicum) are ecologically feasible and viable. Some aromatic grasses like, lemon grass, palmarosa, citronella, vetiver, etc. are stress tolerant and perennial in nature. The herb can be collected in subsequent years for hydro distillation of essential oil. These crops have high valued with low input. Therefore, we propose here a safe, economically feasible and eco-friendly approach for phytoremediation using nonedible

Chemical diversity in Indian oregano (Origanum vulgare L.).

The terpenoid composition of the essential oils of 17 different populations of Origanum vulgare L., collected from wild populations and subsequently grown under similar conditions in the sub‐temperate region of the Western Himalaya, was studied. Analysis by GC (RI) and GC/MS allowed the identification of 51 components, representing 90.15 to 99.94% of the total oil. The two classes of the phenolic compounds and the monoterpenoids were predominant in all the essential oils. On the basis of the major constituents, i.e., marker compounds, and by comparison of the results with previous reports, new chemotypes could be identified. Principal component analysis was performed to determine the chemical variability within the different populations of O. vulgare collected and grown under similar conditions. Based on the marker compounds, six chemotypes with significant variations in their terpenoid profile were noticed within the 17 populations.

Reverse‐phase high performance liquid chromatography of asiaticoside in Centella asiatica

A rapid and simple reverse-phase high performance liquid chromatographic method has been developed for the quantitative determination of asiaticoside, a pharmacologically active constituent from Centella asiatica. Using an octadecyl silane-packed column eluted with water (containing 1% trifluoroacetic acid):methanol (30:70, v/v), asiaticoside was well resolved from other constituents. These optimized analytical conditions allowed the determination of asiaticoside with a recovery of 97%. Copyright

RP-LC determination of oleane derivatives in Terminalia arjuna

A rapid sensitive and reproductive reversed phase high performance liquid chromatographic method with photo diode arrray detection is described for the simultaneous quantification of major oleane derivatives: arjunic acid (4), arjunolic acid (3), arjungenin (2) and arjunetin (1) in Terminalia arjuna extract. The method involves the use of a Waters Spherisorb S10 ODS2 column (250 x 4.6 mm, I.D., 10 microm) and binary gradient mobile phase profile. The various other aspects of analysis viz. Extraction efficiency, peak purity and similarity were validated using a photo diode array detector.

Chemical Diversity in the Essential Oil of Indian Valerian (Valeriana jatamansiJones)

To explore the diversity in the essential oil yield and composition of Valeriana jatamansi Jones (syn. V. wallichii DC) growing wild in Uttarakhand (Western Himalaya), 17 populations were collected from different locations and grown under similar conditions. Comparative results showed considerable variations in the essential oil yield and composition. The essential oil yield varied from 0.21 to 0.46% in the fresh roots and rhizomes of different populations of V. jatamansi. Analysis of the essential oils by GC (RI) and GC/MS and the subsequent classification by principal component analysis (PCA) resulted in six clusters with significant variations in their terpenoid composition. Major components in the essential oils of the different populations were patchouli alcohol (1; 13.4–66.7%), α‐bulnesene (3; <0.05–23.5%), α‐guaiene (4; 0.2–13.3%), guaiol (5; <0.05–12.2%), seychellene (6; 0.2–9.9%) viridiflorol (<0.05–7.3%), and β‐gurjunene (7; 0.0–7.1%). V. jatamansi populations with contents of 1 higher than 60% may be utilized commercially in perfumery.

SIMULTANEOUS DETERMINATION OF CATHARANTHUS ALKALOIDS USING REVERSED PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

A rapid and simple reverse phase liquid chromatographic method has been developed for the simultaneous quantitation of anticancerous drugs vincristine, vinblastine and their precursors catharanthine and vindoline. Peak purity evaluation of these compounds in plant extract has also been studied using photo–diode array–UV detector.

SIMULTANEOUS DETERMINATION OF IMPORTANT ALKALOIDS IN PAPAVER SOMNIFERUM USING REVERSED PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

A simple and rapid method for the quantitation of eight pharmacologically important drugs, morphine (1), codeine (2), oripavine (3), codeinone (4), reticuline (5), thebaine (6), papaverine (7), and narcotine (8), in Papaver somniferum samples by reversed phase liquid chromatography with photodiode array detection is described. The separation of these compounds was performed with acetonitrile-phosphate buffer (pH maintained to 3.8 using acetic acid) (20 : 80) using a Durasil C18 column with 10-μm particles (250 mm × 4.6 mm I.D.).

Complementarity among plant growth promoting traits in rhizospheric bacterial communities promotes plant growth.

An assessment of roles of rhizospheric microbial diversity in plant growth is helpful in understanding plant-microbe interactions. Using random combinations of rhizospheric bacterial species at different richness levels, we analysed the contribution of species richness, compositions, interactions and identity on soil microbial respiration and plant biomass. We showed that bacterial inoculation in plant rhizosphere enhanced microbial respiration and plant biomass with complementary relationships among bacterial species. Plant growth was found to increase linearly with inoculation of rhizospheric bacterial communities with increasing levels of species or plant growth promoting trait diversity. However, inoculation of diverse bacterial communities having single plant growth promoting trait, i.e., nitrogen fixation could not enhance plant growth over inoculation of single bacteria. Our results indicate that bacterial diversity in rhizosphere affect ecosystem functioning through complementary relationship among plant growth promoting traits and may play significant roles in delivering microbial services to plants.

Seasonal Variation in Essential Oil Content and Composition of Thyme, Thymus serpyllum L. Cultivated in Uttarakhand Hills

Thymus serpyllum L. grown in Kumaon region of Western Himalaya was investigated for essential oil content and composition in different seasons. The oils of fresh samples were obtained by hydrodistillation. The yield of essential oil (% v/w) during different seasons varied from 0.07 to 0.28% with the highest in summer season, at vegetative stage. The oils were analyzed by GC and GC-MS. Major components of all the samples were thymol (19.4-60.1%), γ-terpinene (0.3-13.8%) and p-cymene (3.5-10.4%). The results clearly indicated that season has significant effect on quality and quantity of thyme oil.

Essential oil composition of Pelargonium graveolens L’Her ex Ait. cultivars harvested in different seasons

To determine the seasonal influence on essential oil yield and composition of three rose-scented geranium cultivars, namely Bourbon type, CIM-Pawan and Kelkar, an experiment was carried out in western Himalayan region, India. The essential oil yield varied from 0.05% to 0.20%, from 0.10% to 0.25% and from 0.03% to 0.12% in fresh biomass of the cv. Bourbon type, CIM-Pawan and Kelkar, respectively. Gas chromatography/flame ionization detector (GC/FID) and /mass spectrometry (GC/MS) analyses revealed significant variations in the essential oil composition of rose-scented geranium due to cultivar and season of harvesting. The major components in the essential oil of cv. Bourbon type were geraniol (14.1–34.6%), citronellol (15.2–31.3%), linalool (2.9–9.2%), citronellyl formate (4.4–9.2%), isomenthone (4.5–6.6%), 10-epi-γ-eudesmol (4.7–6.7%) and geranyl formate (3.8–6.2%). The dominant constituents of the cv. CIM-Pawan essential oil were geraniol (11.9–31.9%), citronellol (16.1–30.2%), citronellyl formate (5.2–8.9%), linalool (3.7–6.4%), isomenthone (4.0–6.3%), 10-epi-γ-eudesmol (4.4–5.2%) and geranyl formate (4.3–5.0%). However, the chemical composition and odor of cv. Kelkar was quite different from the other two cultivars and the major components found in this oil were citronellol (51.0–63.4%) and isomenthone (9.8–17.8%).