From a consideration of ethnobotanical and taxonomic information, seeds of 45 Scottish plant species encompassing 23 different families were obtained from authentic seed suppliers. The n-hexane, dichloromethane (DCM) and methanol (MeOH) extracts were assessed, both qualitatively and quantitatively, for free radical scavenging activity in the DPPH assay. The MeOH extracts of 37 species exhibited low to high levels of free radical scavenging activity (RC50 values ranging from 2.00 to 4.7 x 10(-4) mg/mL), and Alliaria petiolata, Prunus padus and Prunus spinosa were the most potent antioxidant extracts. The DCM extracts of 17 species showed similar levels of activity, and among those, Prunus padus and Prunus spinosa extracts were the most active with RC50 values of 2.5 x 10(-4) and 5.0 x 10(-4) mg/mL, respectively. The n-hexane extracts were much less active than the MeOH and DCM extracts, and 17 species, with the exception of Glechoma hederacea (RC50 = 1.94 x 10(-4)) displayed low to moderate levels of free radical scavenging property (RC50 values ranging from 2.00 to 8.7 x 10(-3) mg/mL).

Xylocarpus granatum J. König (Meliaceae), commonly known as 'dhundul', is a Bangladeshi mangrove tree, and well distributed in a number of other countries of south-east Asia, Australia and east Africa. Traditionally, X. granatum has been used as an astringent and febrifuge, and also for the treatment of fever, malaria, thrush, cholera, dysentery and diarrhoea in many countries including Bangladesh. Two limonoids, gedunin and 1alpha-hydroxy-1,2-dihydrogedunin, the latter being new, have been isolated from the bark of Xylocarpus granatum by reversed-phase preparative HPLC, and the structures were confirmed by spectroscopic means. The cytotoxic potential of gedunin has been evaluated by the Promega's CellTiter 96 non-radioactive cell proliferation assay using the CaCo-2 colon cancer cell line (IC(50) = 16.83 microM). A summary of the biological activities of gedunin reported to date is also presented.

Reversed-phase preparative HPLC of a methanol extract of the rhizomes of Eremostachys glabra yielded three new iridoid glycosides, namely, 6,9-epi-8-O-acetylshanziside methyl ester, 5,9-epi-penstemoside, and 5,9-epi-7,8-didehydropenstemoside. Their structures were elucidated on the basis of spectroscopic data interpretation. The free-radical scavenging activity of these compounds was assessed using the DPPH assay.

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Daucus carota L. (Family: Apiaceae alt. Umbelliferae), commonly known as 'wild carrot' or 'Queen Anne's-lace,' is an ecologically invasive erect biennial naturalized to Scotland. The ethnobotanical uses of this species include applications in the treatment of cough, diarrhea, dysentery, cancer, malaria and tumors, and as an antiseptic, abortifacient, aphrodisiac, carminative, stimulant, stomachic and tonic. The major constituents isolated from the methanol extract of D. carota seeds by reversed-phase preparative high performance chromatography were luteolin, luteolin 3'-O-beta-D-glucopyranoside and luteolin 4'-O-beta-D-glucopyranoside, three flavones. The constituents were assessed for their antibacterial and free radical scavenging activities, as well as toxicity towards brine shrimp. Among these three flavones, luteolin showed the highest degree of free radical scavenging activity (RC50 = 4.3 x 10(-4) mg/mL) in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Both luteolin and its 4'-O-glucoside demonstrated bactericidal activity against Staphylococcus aureus and Escherichia coli (Minimum Inhibitory Concentration [MIC] = 5.0 x 10(-2) - 1.0 x 10(-1) mg/mL). Luteolin also demonstrated antibactericidal activity against Bacillus cereus and Citrobacter freundii (MIC = 5.0 x 10(-2) mg/mL). Luteolin 3'-O-glucoside showed bactericidal activity against Bacillus cereus and Lactobacillus plantarum (MIC = 2.5 x 10(-1) mg/mL and 5 x 10(-1) mg/ mL, respectively). In the brine shrimp lethality assay, the LD50 value of luteolin was 5.3 x 10(-2) mg/mL, and that of its 3'-O-glucoside and 4'-O-glucoside were > 1.0 mg/mL.

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A new salicylic acid derivative, 2-carboxy-3-(2-hydroxypropanyl)phenol (1), and four new isoflavones, 5,7,4'-trihydroxy-8-(1,1-dimethylprop-2-enyl)isoflavone (2), 5,7,2',4'-tetrahydroxy-8-(1,1-dimethylprop-2-enyl)isoflavone (3), 5,2',4'-trihydroxy-4' ',4' ',5' '(xi)-trimethyl-4' ',5' '-dihydrofurano-(7,6,2' ',3' ')isoflavone (4), and 5,2',4'-trihydroxy-7-(3-methylbut-2-enyloxy)isoflavone (5), were isolated from the stem bark of Flemingia paniculata. The structures of these compounds were established unambiguously by spectroscopic data interpretation. The biogenetic pathways to 1 and 2-4 have been postulated.