Author
Geetha Gopalakrishnan
Other affiliations: University of Madras
Bio: Geetha Gopalakrishnan is an academic researcher from Schering-Plough. The author has contributed to research in topics: Tetranortriterpenoid & Azadirachta. The author has an hindex of 18, co-authored 49 publications receiving 1575 citations. Previous affiliations of Geetha Gopalakrishnan include University of Madras.
Papers
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TL;DR: Bioassay guided fractionation of the acetone extract of Feronia limonia dried leaves afforded a potent mosquito larvicide, identified as n-hexadecanoic acid and found to be effective against fourth instar larvae of Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti.
262 citations
TL;DR: The antifungal activity of several xanthones isolated from the fruit hulls of Garcinia mangostana and some derivatives of mangostin against three phytopathogenic fungi has been evaluated.
Abstract: The antiungal activity of several xanthones isolated from the fruit hulls of Garcinia mangostana and some derivatives of mangostin against three phytopathogenic fungi, Fusarium oxysporum vasinfectum, Alternaria tenuis, and Dreschlera oryzae, has been evaluated. The natural xanthones showed good inhibitory activity against the three fungi. Substitution in the A and C rings has been shown to modify the bioactivities of the compounds.
218 citations
TL;DR: In the present study, bioassay-guided fractionation of petroleum ether extract led to the separation and identification of fatty acids; oleic acid and linoleic acid were isolated and identified as mosquito larvicidal compounds.
Abstract: In mosquito control programs, botanical origin may have the potential to be used successfully as larvicides. The larvicidal activity of crude acetone, hexane, ethyl acetate, methanol, and petroleum ether extracts of the leaf of Centella asiatica Linn., Datura metal Linn., Mukia scabrella Arn., Toddalia asiatica (Linn.) Lam, extracts of whole plant of Citrullus colocynthis (Linn.) Schrad, and Sphaeranthus indicus Linn. were assayed for their toxicity against the early fourth instar larvae of Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in whole plant petroleum ether extract of C. colocynthis. In the present study, bioassay-guided fractionation of petroleum ether extract led to the separation and identification of fatty acids; oleic acid and linoleic acid were isolated and identified as mosquito larvicidal compounds. Oleic and Linoleic acids were quite potent against fourth instar larvae of Aedes aegypti L. (LC50 8.80, 18.20 and LC90 35.39, 96.33 ppm), Anopheles stephensi Liston (LC50 9.79, 11.49 and LC90 37.42, 47.35 ppm), and Culex quinquefasciatus Say (LC50 7.66, 27.24 and LC90 30.71, 70.38 ppm). The structure was elucidated from infrared, ultraviolet, 1H-nuclear magnetic resonance, 13C-NMR, and mass spectral data. This is the first report on the mosquito larvicidal activity of the reported isolated compounds from C. colocynthis.
154 citations
TL;DR: Analgesic activity was significant with Toona ciliata (heart wood) ethanolic extract when compared with other extracts and its activity was confirmed by tail immersion method.
151 citations
TL;DR: Tests of the triterpenoidal mixture derived from the 90% methanol extract of neem oil against 13 phytopathogenic fungi revealed that various species were inhibited to different degrees, indicating possible additive/synergistic effects.
Abstract: Evaluation of the activity of the cold expeller neem oil(Azadirachta indica A. Juss.) and the fractions derived through solvent partitioning, againstDrechslera oryzae, Fusarium oxysporum andAlternaria tenuis showed that the active antifungal fraction is a mixture of tetranortriterpenoids. Further, testing the triterpenoidal mixture derived from the 90% methanol (MeOH) extract of neem oil against 13 phytopathogenic fungi revealed that various species were inhibited to different degrees. Direct preparative High Performance Liquid Chromatography (HPLC) of the active fractions and subsequent bioassay of the semi-pure fractions indicated that the active fractions contained major compounds such as 6-deacetylnimbin, azadiradione, nimbin, salannin and epoxyazadiradione. Pure azadiradione, nimbin, salannin and epoxy-azadiradione did not have appreciable activity. However, when these terpenoids were mixed and bioassayed, they showed antifungal activity, indicating possible additive/synergistic effects.
134 citations
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TL;DR: Findings of beneficial properties of GML's extracts and xanthones isolated from this plant so far are summarized.
654 citations
Journal Article•
TL;DR: The PEE of the seed of Pongomia pinnata was further tested for nootropic activity in an experimental model of Alzheimer’s disease and reversed both, the cognitive deficits and the reduction in cholinergic markers after 2 weeks of treatment.
Abstract: time, probably by stimulation of the hepatic microsomal enzyme system3. Similar properties were exhibited by its roots. However, the petroleum ether extract (PEE) of the roots enhanced pentobarbitone sleeping time, probably due to CNS depression4. The PEE of the seed of Pongomia pinnata was further tested for nootropic activity in an experimental model of Alzheimer’s disease (created by ibotenic acid induced lesioning of nuclear basalis magnocellularis). It reversed both, the cognitive deficits and the reduction in cholinergic markers after 2 weeks of treatment. Reversal of perturbed cholinergic function appears to be the possible mechanism5.
612 citations
TL;DR: The studies carried out on the use of plant products on fish aquaculture and their biological effects on fish such as growth promoter, immunostimulant, antibacterial and anti-parasitic are reviewed.
609 citations
TL;DR: The microbial safety of foods continues to be a major concern to consumers, regulatory agencies and food industries throughout the world, which necessitates the exploration of alternative sources of safe, effective and acceptable natural preservatives.
547 citations
TL;DR: Except for compound 2, which was isolated as a minor component, the antioxidant activities of all isolates were determined using authentic and morpholinosydnonimine-derived peroxynitrite methods, and compounds 1, 8, 10, 11, and 13 were the most active.
Abstract: As part of ongoing research on cancer chemopreventive agents from botanical dietary supplements, Garcinia mangostana L. (commonly known as mangosteen) was selected for detailed study. Repeated chromatography of a CH2Cl2-soluble extract of the pericarp led to the isolation of two new highly oxygenated prenylated xanthones, 8-hydroxycudraxanthone G (1) and mangostingone [7-methoxy-2-(3-methyl-2-butenyl)-8-(3-methyl-2-oxo-3-butenyl)-1,3,6-trihydroxyxanthone, 2], together with 12 known xanthones, cudraxanthone G (3), 8-deoxygartanin (4), garcimangosone B (5), garcinone D (6), garcinone E (7), gartanin (8), 1-isomangostin (9), α-mangostin (10), γ-mangostin (11), mangostinone (12), smeathxanthone A (13), and tovophyllin A (14). The structures of compounds 1 and 2 were elucidated by spectroscopic data analysis. Except for compound 2, which was isolated as a minor component, the antioxidant activities of all isolates were determined using authentic and morpholinosydnonimine-derived peroxynitrite methods, and comp...
522 citations