From the linked article.
Police are warning local groceries in Phuket and Thailand that Kratom juice is listed as a controlled herbal product and any such controlled herbal product cannot be produced or sold without permission by the Thai Food and Drug Administration.
Kratom Juice is also not allowed to be added as an ingredient or mixed into other food or juice for selling. So even pure Kratom Juice in a bottle cannot be sold, especially on public streets.