We don't have synonyms for lokao yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are loka, lakao and locao.
(n) :
A green vegetable dye from China, obtained from one or more species in the genus Rhamnus- probably Rhamnus globosa (syn. Rhamnus chlorophora), but Rhamnus utilis, as well as a mixture of Rhamnus davurica (or "Rhamnus dahurica") and Rhamnus globosa (as Rhamnus tinctoria) have also been given as the true source.
(n) :
A green vegetable dye from China, obtained from one or more species in the genus Rhamnus- probably Rhamnus globosa (syn. Rhamnus chlorophora), but Rhamnus utilis, as well as a mixture of Rhamnus davurica (or "Rhamnus dahurica") and Rhamnus globosa (as Rhamnus tinctoria) have also been given as the true source.