While I don’t know about this one in particular, in family Apocynaceae, many plants are toxic. It might also be full of fluffy flying seeds and not juicy flesh.
Many species of plants from the family Apocynaceae have some toxicity, with some being extremely poisonous if parts are ingested, or if they are not handled properly. Genera containing cardiac glycosides— Cerbera , Nerium , Cascabela , Strophanthus,  Acokanthera , Apocynum,  Thevetia,  etc.—have therapeutic ranges, but are often associated with accidental poisonings, in many cases lethal (see below). Alkaloid-producing species like Rauvolfia serpentina, Catharanthus roseus, and Tabernanthe iboga are likewise the source of compounds with therapeutic ranges, but which have significant associated toxicities if not taken in appropriate doses and in controlled fashion.
There are limited dietary uses of plants from this family. The flower of Fernaldia pandurata (common name: loroco ) is edible. Carissa (Natal plum) produces an edible fruit, but all other parts of the plant are poisonous. The genus Apocynum was reportedly used as a source of fiber by Native Americans. The aromatic fruit juice from Saba comorensis (syn. Landolphia comorensis , the Bungo or Mbungo fruit) is used as a drink.