Search

Biological soil disinfestations (BSDs) were developed separately in Japan and in The Netherlands as an alternative to chemical fumigations. In Japan, it was developed based on the knowledge of irrigated paddy rice and upland crop rotation system that was rather tolerant of soil-borne disease development. The methods consist of application of easily decomposable organic matter, irrigation, and covering the soil surface with plastic film, thereby inducing anaerobic (reductive) soil conditions and suppressing many soil-borne pests including fungi, bacteria, nematodes, and weeds. The methods are widely used by organic farmers in the area where residences and agricultural fields are intermingled. To note one advantage of these methods, maintenance of soil suppressiveness to Fusarium wilt of tomato was suggested, while soil treated with chloropicrin became conducive to the disease. Suppression of soil-borne fungal pathogens by BSDs might be attributed to anaerobicity and high temperature, organic acids generated, and metal ions released into soil water. Contributions of respective factors to suppression of respective pathogens might be diverse. Presumably, these factors might vary on the fungal community structure in BSD-treated soil. These factors also work in paddy fields. Therefore, the BSDs developed in Japan are probably a method to raise the efficacy of paddy-upland rotation through intensive organic matter application and through maintenance of a strongly anaerobic (reductive) soil condition.

A simple and precise method was established for the simultaneous determination of evodiamine and rutaecarpine in oriental pharmaceutical decoctions containing Evodia Fruit using high-performance liquid chromatography with sodium dodecyl sulfate (SDS) as an ion-pair reagent. Evodiamine and rutaecarpine were eluted within 60 min without interference from co-existing components using an ODS column and a mixture of water-methanol-acetonitrile-SDS-phosphoric acid (600:330:70:5:0.01, v/v/v/w/v, pH 5.0) as a mobile phase.

A simple and precise method was established for the simultaneous determination of daidzin and puerarin and the determination of daidzein in oriental pharmaceutical decoctions containing Puerariae Radix using high-performance liquid chromatography with tetra-n-heptylammonium bromide (THA) as an ion-pair reagent. Daidzin and puerarin were eluted within 45 min without interference with co-existing components using an ODS column and a mixture of 10 mM phosphate buffer (pH 6.5)-methanol (68:32) containing 5 mM THA as a mobile phase. Daidzein was eluted within 35 min without interference with co-existing components using an ODS column and a mixture of 10 mM phosphate buffer (pH 6.5)-acetonitrile (72:28 or 68:32) containing 5 mM THA as a mobile phase.

A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise determination of honokiol(3',5-di-2-propenyl-1,1'-biphenyl-2,4'-diol) and magnolol(5,5'-di-2-propenyl-1,1'-biphenyl-2,2'-diol) in eighteen species of oriental pharmaceutical decoctions containing Magnolia bark. An ODS column and a mixed solvent system of water involving 10 mM tetra-n-amyl-ammonium bromide (TAA) and acetonitrile (4:6) as a mobile phase were used for the separation. Honokiol and magnolol were eluted without interference of other coexisting components within 12 min.

A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise simultaneous determination of honokiol (3', 5-di-2-propenyl-1, 1'-biphenyl-2,4'-diol) and magnolol (5,5'-di-2-propenyl-1,1'-biphenyl-2,2'-diol) in oriental pharmaceutical decoctions containing Magnolia bark. An ODS column and a mixture of water involving 10 mM tetra-n-amylammonium bromide (TAA) and acetonitrile (4:6) as a mobile phase were used for the separation. Honokiol and magnolol were eluted without interference of other co-existing components within 12 min.

A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise determination of sennoside A in oriental pharmaceutical decoctions containing Rhei Rhizoma. This method was compared with other two methods, i.e. ion-suppression and phosphate buffer methods. Sennoside A was eluted without interference in this ion-pair method, while the determination of sennoside A was interfered by co-existing components in the other two methods.