Two new components from the roots of Angelicae koreana Kitagawa
Two new compounds, 2-hydroxyethylcarboxylic acid-5,9-eicodien-carboxylate and 1-(2′-propenoxy)undec-2-ene, and two known compounds, 2-hydroxy-4-methyl-acetophenone and β-sitosterol, were isolated from the roots of Angelicae koreana Kitagawa. The structures of the compounds were established on the basis of MS and NMR spectral data.
Acaricidal toxicity of 2'-hydroxy-4'-methylacetophenone isolated from Angelicae koreana roots and structure-activity relationships of its derivatives.
The acaricidal activities of 2'-hydroxy-4'-methylacetophenone derived from Angelica koreana roots and its derivatives against Dermatophagoides farinae, Dermatophagoides pteronyssinus, and Tyrophagus putrescentiae were examined by vapor phase and contact toxicity bioassays. In the vapor phase toxicity bioassay, 2'-methylacetophenone (1.25 μg/cm(2)) was 8.0 times more toxic against D. farinae than benzyl benzoate (10.00 μg/cm(2)), followed by 3'-methylacetophenone (1.26 μg/cm(2)), 4'-methylacetophenone (1.29 μg/cm(2)), 2'-hydroxy-4'-methylacetophenone (1.75 μg/cm(2)), and 2'-hydroxy-5'-methylacetophenone (1.96 μg/cm(2)). In the contact toxicity bioassay, 3'-methylacetophenone (0.58 μg/cm(2)) was 17.24 times more effective against D. farinae than benzyl benzoate (7.52 μg/cm(2)), followed by 2'-methylacetophenone (0.64 μg/cm(2)), 2'-hydroxy-4'-methylacetophenone (0.76 μg/cm(2)), 4'-methylacetophenone (0.77 μg/cm(2)), and 2'-hydroxy-5'-methylacetophenone (1.16 μg/cm(2)). The acaricidal activities of 2'-hydroxy-4'-methylacetophenone derivatives against D. pteronyssinus and T. putrescentiae were similar to those against D. farinae. In terms of structure-activity relationships, acaricidal activity against the three mite species changed with the introduction of hydroxyl and methyl functional groups onto the acetophenone skeleton. Furthermore, some of 2'-hydroxy-4'-methylacetophenone derivatives could be useful for natural acaricides against three mite species.
Interaction of Diclofop-Methyl and MCPA on Wild Oats (Avena fatua)
Diclofop-methyl {methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate} loses part of its activity on wild oats (Avena fatua L.) when it is applied in combination with ester or amine formulations of MCPA {[4-chloro-o-tolyl)oxy] acetic acid.} Uptake of diclofop-methyl is reduced in the presence of commercial formulations of MCPA, particularly amine formulations, which are only partly compatible with the diclofop-methyl formulation. With added MCPA, regardless of formulation, hydrolysis of diclofop-methyl to the acid diclofop is slowed down, both in intact wild oat plants and in a crude leaf extract. At the same time, conversion of any acid formed to inactive conjugates is accelerated in the presence of MCPA. It is concluded that the loss of activity of diclofop-methyl by MCPA can be accounted for by the effects of MCPA on uptake and metabolic conversion of diclofop-methyl.