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Phytochemical investigation led to the isolation of three alkaloids [skimmianine (1), vulcanine (2) and evoxine (3)] from the aerial parts of Haplophyllum tuberculatum, and two diacetylenic spiroketal enol ethers [spiroketalenolether polyyne (4) and [7-hexa-2,4-diynylidene-1,6-dioxaspiro[4.4]nona-2,8-dien-4-yl] acetate (5)] and a sesquiterpene lactone [8α acetoxy-11β,13dihydrokauniolide (6)] from the aerial parts of Chrysanthemum coronarium. The chemical structures of the isolated compounds were determined by using spectral data of 1H NMR, 13C NMR, as well as by comparison with literature data. Compounds 4, 1 and 5 were the most potent inhibitors against plant pathogenic bacteria Rhizobium radiobacter, Ralstonia solanacerum and Pectobacterium carotovorum ss. carotovorum with minimum inhibitory concentration (MIC) values of 31.3, 62.5 and 31.3 µg/ml, respectively. In antifungal assay, compounds 1 (MIC 62.5 µg/ml), 2 (MIC 62.5 µg/ml) and 5 (MIC 125 µg/ml) caused the highest inhibitory effects against phytopathogenic fungi Verticillium dahliae, Fusarium oxysporum and Alternaria solani, respectively. Moreover, crude extract of H. tuberculatum and 4 were significantly the most potent inhibitors of seed germination, root and shoot growth of Echinochloa crus-galli.

Six monoterpenes, ((−)-citronellal, p-cymene, (−)-menthone, α-pinene, α-terpinene and (−)-terpinen-4-ol) and two phenylpropenes, (trans-cinnamaldehyde and eugenol) were tested for their insecticidal activity against the rice weevil, Sitophilus oryzae under laboratory conditions. The bioassays were carried out on wheat at the concentrations of 0.5, 1.0 and 5.0 g/kg. Adult mortality was assessed after 14 days of exposure. After this interval, the treated wheat was retained for an additional period of 90 days, in order to evaluate progeny production and wheat loss. At the concentrations of 0.5 and 1.0 g/kg, trans-cinnamaldehyde and eugenol achieved highest adult mortality. At 5.0 g/kg, all compounds except for p-cymene and α-pinene caused complete (100%) adult mortality. Generally, trans-cinnamaldehyde was the most potent compound causing complete inhibition of progeny at the three concentrations. Similarly, no progeny were observed in the wheat treated with (−)-citronellal, eugenol, p-cymene, (−)-menthone, and (−)-terpinen-4-ol at 5.0 g/kg after 45 and 90 days. Similar trends were noted for wheat weight loss and damage as the treatment with monoterpenes and phenylpropenes at the highest rate preserved the wheat intact and free from damage by S. oryzae for 90 days. Our findings suggest the tested compounds except p-cymene and α-pinene could be recommended for use as part of an integrated pest management program for S. oryzae control in stored wheat.

Six phragmalin limonoids, named tabulalin and tabulalides A-E, were isolated from the root bark of Chukrasia tabularis (Meliaceae). Their structures were determined by spectroscopic methods, and their antifeedant properties evaluated.

Three novel ring D opened limonoids corresponding to the phragmalin 8,9,14-orthoacetate with the addition of methyl 2,30-orthoacetate or a propionate, swietenialides A, B, and C and two ring-D opened phragmalin-type 1,8,9-orthoacetates, swietenialides D and E, were isolated together with one known mexicanolide, 2-hydroxyswietenin, from the ether extract of the stem bark of Swietenia mahogani JACQ. (Meliaceae). The structure of these unique compounds was elucidated by spectroscopic means.