Stability studies and degradation kinetics of some commercially available metronidazole suspensions in Nigeria

The present study was carried out to investigate the in vitro angiotensin converting enzyme (ACE) inhibitory and antioxidant activities of the methanolic seed extract of Apium graveolens Linn. belonging to the family Apiaceae. Traditionally, the seeds of A. graveolens L. were used as diuretic, anti-inflammatory and aphrodisiac. The ability to inhibit ACE was evaluated by quantifying the decrease in N-[3-(2-furyl)acryloyl]-L- phenylalanylglycylglycine (FAPGG) peak area at 345 nm using reverse phase high performance liquid chromatography (RP-HPLC). The antioxidant activities of the extract were determined by evaluating its superoxide anion radical, hydroxyl radical, nitric oxide radical scavenging abilities, ferrous chelating ability, reducing power ability and total phenolic and flavonoid contents. The ACE inhibitory potency of the seed extract (IC 50 = 666.26 ± 1.32 μg/ml) was found to be significant (P<0.01) when compared with the standard lisinopril (IC 50 = 0.19 ± 0.02 ng/ml). The extract showed a strong antioxidant activity when compared with the standard. The results of this study suggest that the methanolic seed extract of A. graveolens has significant ACE inhibitory and antioxidant activities.