Catalyzes the iterative condensations of 6, 7 or 8 molecules of malonyl-CoA to produce various aromatic polyketides. Produces the heptaketide aloesone, the aglycone of aloesin, from 7 molecules of malonyl-CoA as a major product. Also able to produce a hexaketide pyrone, a heptaketide 6-(2-acetyl-3,5-dihydroxybenzyl)-4-hydroxy-2-pyrone, a novel heptaketide 6-(2-(2,4-dihydroxy-6-methylphenyl)-2-oxoethyl)-4-hydroxy-2-pyrone and octaketides SEK4/SEK4b. kcat is 0.0075 min(-1). Optimum pH is 6.0. Secondary metabolite biosynthesis; flavonoid biosynthesis. Homodimer. A.arborescens is a medicinal plant rich in aromatic polyketides, such as pharmaceutically important aloenin (hexaketide), aloesin (heptaketide) and barbaloin (octaketide). Belongs to the thiolase-like superfamily. Chalcone/stilbene synthases family.