Isolation of secondary metabolites from Syzygium aromaticum (L.) Merr. & L.M.Perry. (cloves), and evaluation of their biological activities.

Phytochemical investigation of dried flower buds of Syzygium aromaticum (L.) Merr. & L.M.Perry. (clove) led to the isolation and identification of fourteen known compounds, oleanolic acid (1), betulinic acid (2), para methyl benzoic acid (3), sabrinic acid (4) eucalyptolic acid (5), nigricin (6), 3-O-trans-para-coumaroylmaslinic acid (7), methyl maslinate (8), maslinic acid (9), 3, 4, 5-trimethoxy-3',4'-O,O-methylideneflavellagic acid (10), lantanone (11) 3,4,3'-trimethoxyellagic acid (12), 11-oxo-oleanolic acid (13), and ß-sitosterol-3-O-ß-D-glucopyranoside (14). Their structures were identified by 1H NMR, 13C NMR, Mass spectroscopic techniques, and comparison with the literature data. Compounds 3, and 7-9 showed a strong mortality against root knot nematode, Meloidogyne incognita at 0.125% concentration after 72 hours (88-92% inhibition). Compound 4 showed a good anti-glycation activity with IC50 = 142.0 ± 1.8 µM when compared with standard, i.e. rutin (IC50 = 54.59 ± 2.20 µM). Compound 10 showed a comparable urease inhibitory activity (IC50 = 26.1 ± 0.19 µM) with the positive control thiourea (IC50 = 24.5 ± 0.34 µM).

Bioassay Directed Fractionation of Petroleum Ether Extract of Aerial Parts of Ceriops tagal: Isolation of Lupeol as the Nematicidal Agent against Cyst Nematode Heterodera zeae.

Plant parasitic cyst nematode Heterodera zeae is a pest, causing substantial economic losses in agriculture. Organic pesticides, based on plant products have emerged as eco-benign nematicidal agents. Ceriops tagal is a well-known marine medicinal plant which has not been evaluated against any nematode. Petroleum ether extract of the aerial parts of the plant (CTP), exhibited promising activity against infective stage larvae of H. zeae. On subjecting to classical solvent-solvent separation, it afforded petroleum ether soluble (CTP-S), methanol soluble (CTPMS-1, CTPMS-2) and insoluble (CTPM-IN-2) fractions, which exhibited activity against the cyst nematode within 24 h exposure. GC, GC/MS and HR-ESI-MS analyses of CTPMS-1 and CTPMS-2 fractions resulted in the identification of a number of compounds, including pentacyclic triterpenoids, lupeol (1), betunal (2), betulin (3), lupenone (4), betulonaldehyde (5), betulonic acid (7), methyl 3-acetoxy-27-O-(3,4-dihydroxy-E-cinnamoyl)-20(29)-lupen-28-oate (8) and ß-amyrin, along with phenylpropanoid esters, fatty acids and their derivatives, benzamide, and indole derivatives. CTPM-IN-2 which mainly contained lupeol (1) exhibited maximum nematicidal activity, with 91 % and 93 % mortality of the larvae of H. zeae, after exposure for 72 h at the concentration of 0.5 % and 1 %, respectively. Its fractionation and purification through column chromatography resulted in the isolation and identification of four lupane-type triterpenoids 1, 3, 4 and betulinic acid (6). One of its most abundant column fractions CC-9-18 (145 mg) which exhibited substantial activity, with 81 % mortality at the lowest concentration of 0.125 % after 48 h of incubation mainly contained lupeol. It seems lupeol, a wide spread bio-privileged triterpenoid is the nematicidal principle of the plant as its authentic sample showed LC50 value of 0.061 after 72 h exposure. It is for the first time that nematicidal activity is reported for any part of C. tagal and that of lupeol against H. zeae. Pentacyclic triterpenoids 1-8 are biosynthetically related. Of the twenty-four compounds isolated or identified in the present investigation only five constituents 1, 3, 6, 7 and palmitic acid have been isolated previously from C. tagal.

Isolation of Ceramides from Tagetes patula L. Yellow Flowers and Nematicidal Activity of the Fractions and Pure Compounds against Cyst Nematode, Heterodera zeae.

Investigation of yellow flower extract of Tagetes patula L. led to the identification of an aggregate of five phytoceramides. Among them, (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]icosanamide, (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]heneicosanamide, (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]docosanamide, and (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]tricosanamide were identified as new compounds and termed as tagetceramides, whereas (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]tetracosanamide was a known ceramide. A steroid (ß-sitosterol glucoside) was also isolated from the subsequent fraction. The structures of these compounds were determined on the basis of spectroscopic analyses, as well as chemical method. Several other compounds were also identified by GC/MS analysis. The fractions and some commercial products, a ceramide HFA, ß-sitosterol, and stigmasterol were evaluated against an economically important cyst nematode, Heterodera zeae. Ceramide HFA showed 100 % mortality, whereas, ß-sitosterol and stigmasterol were 40-50 % active, at 1 % concentration after 24 h of exposure time, while ß-sitosterol glucoside revealed no activity against the nematode.

Isolation of nematicidal compounds from Tagetes patula L. yellow flowers: structure-activity relationship studies against cyst nematode Heterodera zeae infective stage larvae.

Bioassay-guided isolation studies on the extracts of yellow flowers of Tagetes patula L. against the Heterodera zeae were carried out to identify phytochemicals lethal to this economically important cyst nematode. In vitro investigation of a polar extract and fractions showing activity led to the isolation of phenolic compounds (flavonoids and phenolic acids). In the nonpolar extract, a few fatty acids, their methyl esters, and thiophenes (including α-terthienyl) were detected. In studies of compounds obtained commercially, α-terthienyl and gallic and linoleic acids showed 100% mortality at concentrations of 0.125% after 24 h. Assessment of structure-activity relationships revealed that an increase in the number of hydroxyl groups in phenolic acids increased the activity; with fatty acids, activity depended on chain length and the number and position of double bonds. Crude extracts of the flowers of different colors also have promising activity.

Chemical constituents of Cordia latifolia and their nematicidal activity.

Following nematicidal activity-guided isolation studies on the fruits, bark, and leaves of Cordia latifolia, two new constituents, cordinoic acid (=11-oxours-12-ene-23,28-dioic acid; 1) and cordicilin (=2-{[(E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}-3-[4-hydroxy-3-(stearoyloxy)phenyl]propanoic acid; 2) were isolated from the stem and leaves, respectively, together with nine known compounds, namely cordioic and cordifolic acid from the stem bark, latifolicin A-D and rosmarinic acid from the fruits, and cordinol and cordicinol from the leaves. Their structures were determined by means of spectroscopic analyses including 1D- and 2D-NMR techniques. The nematicidal activities of these constituents were determined against the root-knot nematode Meloidogyne incognita. Hundred percent mortality was caused by all of these after 72 h at a 0.125% concentration. Compound 1 and cordioic acid were most active and caused 100% mortality after 24 h at a 0.50% concentration. Furthermore, compound 2, the ester of rosemarinic acid, was found to be more active than the free acid.