An operating mechanism by which the linear movement of a gearshift cable is converted into a rotational movement of an operating sleeve and transmitted to the interior of a bicycle multispeed gear hub. The second cover member is formed separately from the first cover member and is arranged side by side with the first cover member outside of the first sidewall. In addition, Gnetum extract is obtained by immersing sliced or ground Gnetum fruit or Gnetum seeds in water or water containing organic solvent and aging.