[Study on suitable harvest time of Dendrobium officinale in Yunnan province].

In order to determine the suitable harvest time of Dendrobium officinale from different regions in Yunnan province, the drying rate, mannose and glucose peak area ratio, extract, contents of polysaccharide and mannose of D. officinale samples collected from six producing areas in Ynnnan province were determined. The results indicate that drying rate and the contents of polysaccharide and mannose arrived the peak from January to April, extract reached a higher content from September to December, and mannose and glucose peak area ratio from October to February of the coming met the requirment of the Chinese Pharmacopoeia. Hence, the suitable harvesting time of D. officinale in Yunnan province is from December to February of the coming year,according to the experimental results and the request of the Chinese Pharmacopoeia.