ABSTRACT
Three new labdane diterpenoids, leojaponicone A (1), isoleojaponicone A (2) and methylisoleojaponicone A (3), were isolated from the herb of Leonurus japonicus. The chemical structures of these secondary metabolites were elucidated on the basis of 1D and 2D NMR, including HMQC, and HMBC spectroscopic techniques. All the new compounds were tested in vitro for their acetylcholinesterase and α-glucosidase inhibitory activity. Compounds 1-3 exhibited low inhibitory effects on α-glucosidase with respect to acarbose and exhibited high inhibitory effects on acetylcholinesterase with respect to huperzine A.
Subject(s)
Acetylcholinesterase/metabolism , Cholinesterase Inhibitors/pharmacology , Diterpenes/pharmacology , Leonurus/chemistry , Plant Extracts/pharmacology , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/isolation & purification , Diterpenes/chemistry , Diterpenes/isolation & purification , Glycoside Hydrolase Inhibitors/chemistry , Glycoside Hydrolase Inhibitors/isolation & purification , Glycoside Hydrolase Inhibitors/pharmacology , Magnetic Resonance Spectroscopy , Molecular Structure , Plant Extracts/chemistryABSTRACT
The present study aimed at isolation and purification of the bioactive terpenoids from the herb of Leonurus japonicus by chromatographic separations such as silica gel, sephadex LH-20 and C18 reversed phase silica gel, as well as preparative HPLC. As a result, leojaponic acids A (1, C17H24O4) and B (2, C18H26O4), two homologous terpenoids, together with (-)-loliolide (3), 1-(3-ethylphenyl) ethane-1, 2-diol (4) and dibutyl phthalate (5), were isolated from the EtOH extract of L. japonicus. All the chemical structures of the isolates were elucidated on the basis of 1D and 2D NMR analyses. Compounds 1 and 2 were new terpenoids, and Compounds 3 and 4 were isolated and identified for the first time from this plant. In addition, the α-glucosidase and tyrosinase inhibitory activity of the new compounds were evaluated.
Subject(s)
Leonurus/chemistry , Plant Extracts/chemistry , Terpenes/chemistry , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/isolation & purification , Fruit/chemistry , Glucosidases/analysis , Glucosidases/antagonists & inhibitors , Magnetic Resonance Spectroscopy , Molecular Structure , Plant Extracts/isolation & purification , Terpenes/isolation & purificationABSTRACT
A new 12-membered ring lactone, (3S),(6R)-6-hydroxylasiodiplodin (1), with two known analogues, (3R)-lasiodiplodin (2), and (3R),(5S)-5-hydroxylasiodiplodin (3) were isolated from the EtOH extracts of normal Apriona germari (Hope)-associated fungus Sarocladium kiliense grown in rice medium. The structures of compounds 1-3 were elucidated by a combination of spectroscopic data interpretation, single-crystal X-ray diffraction analysis, and modified Mosher's method.
