The herb Artemisia annua has been used for many centuries in Chinese traditional medicine as a treatment for fever and malaria. In 1971, Chinese chemists isolated from the leafy portions of the plant the substance responsible for its reputed medicinal action. This compound, called qinghaosu (QHS, artemisinin), is a sesquiterpene lactone that bears a peroxide grouping and, unlike most other antimalarials, lacks a nitrogen-containing heterocyclic ring system. The compound has been used successfully in several thousand malaria patients in China, including those with both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. Derivatives of QHS, such as dihydroqinghaosu, artemether, and the water-soluble sodium artesunate, appear to be more potent than QHS itself. Sodium artesunate acts rapidly in restoring to consciousness comatose patients with cerebral malaria. Thus QHS and its derivatives offer promise as a totally new class of antimalarials.

Quinghaosu (artemisin): an antimalarial drug from china

Plant essential oils in general have been recognized as an important natural source of pesticides. They represent a market estimated at US $ 700.00 millions and a total world production of 45000 tons. The genera capable of elaborating the compounds that constitute essential oils are distributed in a limited number of families but the widespread range of activities of essential oils is being considered for both industrial and household uses. Essential oil compounds and their derivatives are considered to be an alternative means of controlling many harmful insects and their rapid degradation in the environment have increased specificity that favours beneficial insects. Essential oils based commercial products are being developed for a wide range of human and animal uses, including pest control. Unfortunately, most of the natural products used for pest control, are not always subject to rigorous testing. In view of the above points, the present paper focuses on the work done in the field of essential oils as biopesticides with special emphasis on essential oil chemistry, extraction, pesticidal properties, mode of action, synergism, phytotoxicity, commercialization prospects, safety aspects, socioeconomic impacts and sustainability.

	 

	Key words: Essential oil, insecticide, repellent, phytotoxicity, safety, economics.

A review on prospects of essential oils as biopesticide in insect-pest management

Phyllanthus amarus: Ethnomedicinal uses, phytochemistry and pharmacology: A review

An ecofriendly alternative to chemical pesticides is biopesticides, which encompasses a broad array of microbial pesticides, biochemicals derived from micro-organisms and other natural sources, and processes involving the genetic incorporation of DNA into agricultural commodities that confer protection against pest damage. Biopesticides fall into three major classes. The potential benefits to agriculture and public health programmes through the use of biopesticides are considerable. The interest in biopesticides is based on the disadvantages associated with chemical pesticides are discussed. The total world production of biopesticides is over 3,000 tons/yr, which is increasing at a rapid rate. India has a vast potential for biopesticides. However, its adoption by farmers in India needs education for maximizing gains. The market share of biopesticides is only 2.5% of the total pesticide market. The stress on organic farming and on residue free commodities would certainly warrant increased adoption of biopesticides by the farmers. Biopesticides being target pest specific are presumed to be relatively safe to non-target organism including humans. However, in India, the registration committee requires the data on chemistry, bioefficacy, toxicity and packaging and labeling, for registration. Pesticide Registration Committee has so far not approved any guidelines for the registration of GM biopesticides. In India, some of the biopesticides like Bt, NPV, neem based pesticides, etc. have already been registered and are being practiced.

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Biopesticides: an ecofriendly approach for pest control.

The major staple food crops production is not able to fulfill food requirement of the global population due to relatively higher population growth rate in developing countries. The research on these crops for exploring their ultimate yield potential is currently at a plateau level. To replace the existing pressure on these major crops there is an urgent need to explore other alternative crops having the potential to replace and fulfill the available food demand. FAO statistics reveal that there is a high frequency of low birth weight children in the developing countries, which is primarily due to deficiency of micronutrients in the mother's diet. Amaranth, an underutilized crop and a cheap source of proteins, minerals, vitamin A and C, seems to be a future crop which can substantiate this demand due to its tremendous yield potential and nutritional qualities, also recently gained worldwide attention. Recently, current interest in amaranth also resides in the fact that it has a great amount of genetic dive...

Amaranth: A New Millennium Crop of Nutraceutical Values

A collection of Phyllanthus amarus was made from various parts of India to determine the extent of genetic variability using analysis at DNA level. RAPD profiling of 33 collections from different locations, covering states of Tamil Nadu, Karnataka, Maharashtra, Gujarat, Assam, West Bengal, Tripura, Uttar Pradesh, Punjab and Haryana was generated. Analysis through UPGMA revealed up to 65% variation among these accessions. However, intra-population variation was found to be much larger in the accession from the southern part of the country. Nevertheless, inter-population variation also overlaps in the phylogenetic clustering, which is understandable from the natural dissemination of this plant species as a weed that has spread across the geographical boundaries. The study indicates the random hybridization across the populations falling within the range of possible cross-pollination in terms of physical distance. A study of these accessions at a single location, allowing free mating, would throw light on the extent of cross-pollination and genetic flow.

Molecular diversity in Phyllanthus amarus assessed through RAPD analysis

Although a number of chemicals have been isolated from Terminalia arjuna, only a few have been evaluated for their biological significance. As a part of our drug discovery programme for cytotoxic agents from Indian medicinal plants, four novel cytotoxic agents arjunic acid (1), arjungenin (2), arjunetin (3) and arjunoglucoside I (4) were isolated from the bark of T. ARJUNA. Out of the four compounds, arjunic acid (1) was significantly active against the human oral (KB), ovarian (PA 1) and liver (HepG-2 & WRL-68) cancer cell lines. Further, the most active compound arjunic acid was converted into seven semi-synthetic ester derivatives 5 - 11. 2-O-Palmitoyl arjunic acid (6) showed two times more activity, while 2, 3-di-O-acetyl-, 2-O-p-anisoyl-, 2, 3-di-O-benzoyl- and 2, 3-di-O-p-nitrobenzoyl arjunic acid (7 - 10) showed 1.7 - 2.3 times less activity than the cytotoxic drug vinblastine against the liver cancer cell lines HepG-2 and WRL-68 respectively.

Cytotoxic agents from Terminalia arjuna.

The antimicrobial activity of Eucalyptus citriodora essential oil against pathogenic fungi, bacteria and drug-resistant mutants of Candida albicans , Escherichia coli and Mycobacterium smegmatis was evaluated following agar disc diffusion and broth dilution assay procedures both qualitatively and quantitatively. The essential oil of E. citriodora was found to be active against Trichophyton rubrum followed by Histoplasma capsulatum , Candida albicans (MTCC) and Cryptococcus neoformans . Similarly, it was found active toward Gram-positive bacteria compared to Gram-negative and showed activity towards drug-resistant mutants of C. albicans and E. coli . The findings of our pilot study suggest that characterization and isolation of the active phytoceutical(s) from the E. citriodora oil may provide a valuable antimicrobial agent for counteracting fungal and drug-resistant infections. Key words: Eucalyptus citriodora , antimicrobial, bacteria, fungi, drug resistant mutants EORC erc * Corresponding author.

Antimicrobial activity of Eucalyptus citriodora essential oil

The genus Swertia is well known for its medicinal properties, as described in the Indian pharmacopoeia. Different members of this genus, although somewhat similar in morphology, differ widely in their pharmacological and therapeutic properties. The most important species of this genus, with maximal therapeutic properties, is S. chirayita, which is often adulterated with other less- potent Swertia spp. There is an existing demand in the herbal drug industry for an authentication system for Swertia spp, in order to enable their commercial use as genuine phytoceuticals. To this end, we used amplified fragment length polymorphism (AFLP) to produce DNA fingerprints for six Swertia species. Nineteen accessions (2 of S.

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AFLP markers for identification of Swertia species (Gentianaceae).

Rauwolfia serpentina holds an important position in the pharmaceutical world because of its immense anti-hypertensive properties resulting from the presence of reserpine in the oleoresin fraction of the roots. Poor seed viability, low seed germination rate, and enormous genetic variability are the major constraints for the commercial cultivation of R. serpentina through conventional mode. The present optimized protocol offers an impeccable end to end method from the establishment of aseptic cultures to in-vitro plantlet production employing semisolid as well liquid nutrient culture medium and assessment of their genetic fidelity using polymerase chain reaction based rapid amplification of polymorphic DNA analysis. In vitro shoots multiplied on Murashige and Skoog basal liquid nutrients supplemented with benzo[a]pyrene (1.0 mg/L) and NAA (0.1 mg/L) and in-vitro rhizogenesis was observed in modified MS basal nutrient containing NAA (1.0 mg/L) and 2% sucrose. In-vitro raised plants exhibited 90-95% survival under glass house/field condition and 85% similarity in the plants regenerated through this protocol. Field established plants were harvested and extraction of indole alkaloid particularly reserpine, ajmaline and ajmalicine and their simultaneous quantitation was performed using monolithic reverse phase high-performance liquid chromatography (HPLC).

In vitro propagation of Rauwolfia serpentina using liquid medium, assessment of genetic fidelity of micropropagated plants, and simultaneous quantitation of reserpine, ajmaline, and ajmalicine.

S. P. S. Khanuja

Papers

Molecular diversity in Phyllanthus amarus assessed through RAPD analysis

Cytotoxic agents from Terminalia arjuna.

Antimicrobial activity of Eucalyptus citriodora essential oil

AFLP markers for identification of Swertia species (Gentianaceae).

In vitro propagation of Rauwolfia serpentina using liquid medium, assessment of genetic fidelity of micropropagated plants, and simultaneous quantitation of reserpine, ajmaline, and ajmalicine.