Vyasji Tripathi

Fighting Against Leishmaniasis: Search of Alkaloids as Future True Potential Anti-Leishmanial Agents

Leishmaniasis, a group of tropical diseases caused by protozoan parasites of genus Leishmania, is a major health problem worldwide that affects millions of people especially in the developing nations. Generic pentavalent antimonials have been the mainstay for therapy in the endemic regions due to efficacy and cost effectiveness, but the growing incidence of their resistance has seriously hampered their use. In many cases the drugs employed for the treatment are toxic, marginally effective, given by injection and, compromised by the development of resistance. Therefore, the development of new mechanism based safe, effective and affordable chemotherapeutic agents to fight leishmaniasis would be an urgent priority research. The recent researches focused on natural products have shown a wise way to get a true and potentially rich source of drug candidates against leishmaniasis, where alkaloids have been found more effective. The present review briefly illustrates an account on current status of leishmaniasis, life cycle of parasites and biology, synergy of the disease with HIV, therapeutic options available to cure this disease and, highlights why natural products especially alkaloids as folk medicines are so important? Additionally, the outlines for the leishmanicidal activities of various alkaloids including indole, quinoline, isoquinoline, pyrimidine-beta-carboline, steroidal and diterpene alkaloids from various plants as well as alkaloids from marine sources have been provided with their mechanistic studies.

Alkaloids as potential anti-tubercular agents.

An increasing incidence of deaths due to tuberculosis and the known drawbacks of the current existing drugs including the emergence of multi drug-resistant strains have led to a renewed interest in the discovery of new anti-tubercular agents with novel modes of actions. The recent researches focused on natural products have shown a useful way to obtain a potentially rich source of drug candidates, where alkaloids have been found more effective. The present review focuses on current epidemiology of tuberculosis, synergy of the disease with HIV, current therapy, available molecular targets and, highlights why natural products especially alkaloids are so important. The review summarizes alkaloids found active against mycobacteria from the mid-1980s to late 2008 with special attention on the study of structure-activity relationship (SAR).

3β,24-Dihydroxyolean-12-en-28-oic acid, a pentacyclic triterpene acid from Lantana indica

Abstract A new oleanane derivative, 3β,24-dihydroxy olean-12-en-28-oic acid, in addition to oleanolic and ursolic acids, has been isolated from the roots of Lantana indica . The structure of the new triterpene acid has been established by chemical and spectroscopic methods.

An Antimicrobial Principle from Sphaeranthus indicus L. (Family Compositae)

AbstractA bicyclic sesquiterpene lactone has been isolated from the petroleum ether extract of the aerial part of the Indian Composite Sphaeranthus indicus. The compound deonstrated strong antimicrobial activity against Staphylococcus aureus, S. albus, Escherichia coli, Fusarium sp., Helminthosporium sp. and other microorganisms.

A new triterpenoid from Lantana camara.

A new ursane was isolated from the leaves of Lantana camara and its structure elucidated as 3,24-dioxo-urs-12-en-28-oic acid (1) by means of spectral analysis.

An antileishmanial prenyloxy-naphthoquinone from roots of Plumbago zeylanica

Leishmania donovani, an obligate intracellular parasite of genus Leishmania causes visceral leishmaniasis that affects millions of people worldwide, especially in the Indian subcontinent and East Africa. Generic pentavalent antimonials have been the mainstay for therapy in the endemic regions due to efficacy and cost effectiveness but the growing incidence of their resistance has seriously hampered their use. This study discloses strong in vitro antileishmanial activity of 2-methyl-5 -(3′-methyl-but-2′-enyloxy)-[1,4]naphthoquinone (1), a prenyloxy-naphthoquinone isolated and characterised from roots of the plant Plumbago zeylanica (family – Plumbaginaceae). The observed EC50 for the compound 1 against promastigote and amastigote forms of L. donovani was significantly (p < 0.001) lower than miltefosine, a reference drug. In context to limited treatment options and growing resistance for available drugs, compound 1 offers a greater prospect towards antileishmanial drug discovery and development.

An account of phytochemicals from Plumbago zeylanica (Family: Plumbaginaceae): A natural gift to human being #

The semi-climbing sub-shrub Plumbago zeylanica (family: Plumbaginaceae) is a widely accepted ethnomedicine around the world including India, Pakistan, Bangladesh, Sri Lanka, and Australia. The plant is credited with potential therapeutic properties including antiatherogenic, cardiotonic, hepatoprotective, and neuroprotective properties. The present review highlights the various medicinal and pharmacological aspects along with recent updates on phytochemical contents of the plant.

Natural products as leads to potential mosquitocides

Mosquitoes are the crucial vectors for a number of mosquito-borne infectious diseases i.e. dengue, yellow fever, chikungunya, malaria, Rift Valley fever, elephantiasis, Japanese Encephalitis, and Murray Valley encephalitis etc. Besides, they also transmit numerous arboviruses (arthropod-borne viruses) for example West Nile virus, Saint Louis encephalitis virus, Eastern equine encephalomyelitis virus, Everglades virus, Highlands J virus, and La Crosse Encephalitis virus. The emergence of widespread insecticide resistance and the potential environmental issues associated with some synthetic insecticides (such as DDT) has indicated that additional approaches to control the proliferation of mosquito population would be an urgent priority research. The present review highlights some natural product mosquitocides that are target-specific, biodegradable, environmentally safe, and botanicals in origin.

A novel flavonoid C-glycoside from Sphaeranthus indicus L. (family Compositae).

A novel flavonoid C-glycoside, 5-hydroxy-7-methoxy-6-C-glycosylflavone (1), was isolated from the aerial part of Sphaeranthus indicus. Its structure was elucidated by spectroscopic methods.

A novel naphthoquinone from Plumbago zeylanica roots

A novel naphthoquinone (1) was isolated from the methanol extract of P. zeylanica roots in addition to a known compound plumbagin (2). Their structures were determined by UV, IR, MS, 1H, and 13C NMR spectroscopic analysis, including 2D NMR.