Introduction: Ocimum basilicum (OB), a herb known for its antihypertensive,
anticholinesterase and antioxidant properties was investigated for possible intraocular
pressure (IOP) lowering effects in rabbits with ocular hypertension (OHT). Methods: The
IOP lowering effect of a single drop of OB extract (OBE) was evaluated in oculonormotensive
rabbits using three concentrations (0.25, 0.5 and 1% w/v). The concentration showing
maximum IOP reduction was further evaluated in rabbits with water-loading and steroidinduced OHT. Results: IOP lowering effect of OBE 0.5% in oculonormotensive rabbit eyes
was significantly greater compared to OBE 0.25% (p0.05) to
OBE 1%. Therefore, 0.5% concentration was selected for further evaluation. Pretreatment
with OBE (0.5%) caused significantly lower increase in IOP after water loading amounting to
23.39% above baseline as compared to 54.00% in control eye, 15 minutes post water
loading. At 60 minutes, post water loading, mean IOP rise was 95.12% and 63.58% in
control and test eyes, respectively. Significant difference between the mean IOP of two eyes
persisted during the 2nd hr. In rabbits with steroid induced OHT, OBE 0.5% produced a
mean IOP reduction of 24.73% at the end of first hr and the mean peak IOP reduction of
31.63% was observed at the end of 2 hr. A significant difference between the IOP of test and
control eyes persisted from 1 to 6 hr. Conclusions: Ocimum basilicum seed extract showed
significant IOP lowering effect in rabbits with water loading and steroid induced OHT,
however, its utility as an effective antiglaucoma medication needs further investigations.