Are there any natural methods to enhance breast growth in adult woman, with out surgery?

Brava. Only proven method is with the brava system wich provides augmentation with negative pressure. A newer method is to perform fat injections.
Fat grafting. There is a suction device which can enhance breast size but it is likely temporary and impractical. Fat injection is the new developing field and will likely be the best answer for moderate size increase. Unfortunately there is still some medical-legal debate and few doctors offer this except in reconstruction.
You cant. Unfortunately there is no food or medication, either prescribed or natural that can increase your breast size safely. They will likely increase with pregnancy and breastfeeding, but surgical breast augmentation is the only safe way to enhance your breast volume.