Effect of Soil Moisture Content on Growth, Crude Drug "Cho-to-ko" Yield and Oxindole Alkaloid Content of Uncaria rhynchophylla (B. LIVING SCIENCE)

Uncaria rhynchophylla was cultivated by using soil with various moisture contents (20,40,60,80 or 100% of the maximum moisture content retained by soil). Both growth and crude drug "Cho-to-ko" (dried stem with hooks of U. rhynchophylla) yield of the plant were in the following order : 60%> 80%> 40%> 100%> 20%, while oxindole alkaloid content of the stem was in the following order : 20%> 60%> 100%> 40%> 80%. It is concluded that moderately wet soil is suitable for cultivation of U. rhynchophylla, in spite of the description in a Chinese literature that sandy soil is good for cultivation of the plants