Three novel compounds; two polymethoxylated flavonoids, 5,7,40 -trihydroxy-3,8,30 ,50 -tetramethoxyflavone (1), 5,7,30 -trihydroxy-3,8,40 ,50 -trimethoxyflavone (2), and a clerodane diterpenoid; 8-acetoxyisochiliolide lactone (3) were characterized from the leaf exudates of Microglossa pyrifolia. In addition, three known polymethoxylated flavonoids including; 5,7,40 -trihydroxy-3,8,30 -trimethoxyflavone (4), 5,30 40 -trihydroxy-3,7,8-trimethoxyflavone (5), 5,30 40 -trihydroxy-7-methoxyflavanone (6) and a clerodane diterpenoid; 7,8-epoxyisocholiolide lactone (7) were identified. Their structures were determined on the basis of spectroscopic evidence. All the compounds did not exhibit antiplasmodial and antimicrobial activities at 47.6 mg/mL and were not cytotoxic at 5 mg/mL. Compound 6 exhibited modest antileishmanial activity with IC50 value of 13.13 mg/mL with 5 and 7 showing activities with IC50 values of 31.13 and 38.00 mg/mL, respectively, therefore inactive. The flavonoids (quercetin derivatives, 4 and 5) showed similar antioxidant activities, using 2,2-diphenylpicrylhydrazyl (DPPH) assay, with IC50 values of 6.2 - 0.3 mg/mL for 4 (17.3 mM) and 5 (17.8 mM) respectively. These activities were comparable to that of the standard quercetin (IC50 value of 6.0 - 0.2 mg/mL (19.9 mM)), irrespective of methylation of the characteristic hydroxyl groups expected to be responsible for activity and additional substitution at C-8 in ring A of the flavonoid ring. These studies revealed that the presence of an hydroxyl group at C-40 positions and oxygenation at C-3 in flavone skeleton, appears to be necessary for good antioxidant activities as encountered in compounds 1, 4 and 5. Substantial reduction in antioxidant activity was shown by methoxylation of the 40 -OH as observed in compound 2 with an IC50 value of 8.79 - 0.3 mg/mL (24.4 mM).